NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth | Hacker News Reader

NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

nasa.gov

851 pointsrandomname2294 comments

Open articleView on HN

To help out anyone trying to search for stuff,

* This exoplanet is now "Kepler-452b" (kepler_name),

* In the "Kepler Object of Interest" catalog, it's KOI "K07016.01" (kepoi_name),

* Its star is both K07016 and Kepler ID 8311864 (kepid),

* In the broader 2MASS sky survey, the star has the id "J19440088+4416392"

Sources (catalog search engines),

http://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph...

https://archive.stsci.edu/kepler/kic10/search.php

(edit): Here's a mirror of the Kepler catalog entries -- KIC for the star, KOI for the planet:

https://gist.githubusercontent.com/anonymous/deef2bd542224f3...

I really like comments that are made to provide some provenance to a news piece. These facts/references should arguably should have been in the text of the article. Double kudos for providing provenance for your provenance.

Thanks, awesome comment!

Awesome comment, saved me a lot of time. Thanks!

The significance is this: it's very likely that there are a lot more such planets a lot nearer to us. This is because Kepler can only detect planets which lie in the same plane as earth and the star so the planet occults the star. Assuming random distribution, there's probably thousand fold amount of off plane planets.

There are 259 stars within about 30 light years. Communication could be conceivable with such distances...

http://joy.chara.gsu.edu/RECONS/TOP100.posted.htm

I believe you meant occludes rather than occults

Most of this discussion is beyond me, so I won't speculate on his intent, but occultation is a real thing too.

https://en.wikipedia.org/wiki/Occultation

https://en.wiktionary.org/wiki/occult#English

The verb form is used thus: "The earth occults the moon during a lunar eclipse."

> This is because Kepler can only detect planets which lie in the same plane as earth and the star so the planet occults the star.

What would be necessary for a more comprehensive survey?

If the planet is not transiting there are two other ways to detect it: radial velocity measurements, and direct imaging. In the radial velocity technique you measure the wobble of the star due to the gravitational pull of the planet. This also requires that the planet be somewhat edge-on, but the requirement isn't nearly as strict as with the transit method. The difficulty is that Earth size planets have very little mass, and so impart a very small wobble to the star, on the order of only ~10 cm / s.

In the second method, you just try to block as much light from the star as you can and go look for the reflected light of the planet. This is much, much more difficult and so far has only been done for very large, distant planets.

What kind of resolution is possible with direct imaging at 1400 ly away? I would imagine that it's probably milliseconds of arc within the field of vision of any telescope, so how close could we actually look at the planet?

With adaptive optics it's possible to achieve resolutions down to ~30 milliarcseconds. At 1400 ly that would subtend a distance of 13 AU, so you wouldn't be able to find Earth-like planets. But even if it's theoretically possible to resolve 13 AU separations at 1400 ly, in practice the light from the star is so much brighter than the planet that it bleeds all over the image and completely washes out the reflected light of the star.

To do direct imaging you really need to look at systems near the Earth, maybe a few tens of ly away. Then you can separate the planet from the star by enough that you can hope to mask the light from the star and still be able to detect the planet.

To get some idea of the techniques required to do this, take a look here: http://astrobites.org/2013/06/09/lowest-mass-exoplanet-disco...

Likely something facilitating direct imaging, which would require canceling out almost all of the light from the parent star (diminishing it by a factor of at least 10^6:1).

While there are some techniques that could facilitate that (such as enormous star shades coupled with space telescopes) they wouldn't enable the sort of shotgun survey approach that Kepler has been able to do, but it would enable us to survey and extensively study stars one at a time for planets.

So what's the current fraction of stars that have habitable zone planets? (i.e. how many stars were surveyed?) That would get us an estimate of how many of those 259 might contain Earth-like planets: we use the fraction of orbital those planets that Kepler detects to estimate the total fraction of planets per star, and multiply that by 259.

From a paper on the Kepler project[1]:

"Kepler has observed over 156,000 stars simultaneously and near continuously to search for planets that periodically pass in front of their host star (transit)"

From the article:

"The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030." — and I have verified that this refers specifically to planets confirmed by Kepler, not just planets in total.

From Wikipedia[2]:

"four, including Kepler-296f, were less than 2 1/2 the size of Earth and were in habitable zones where surface temperatures are suitable for liquid water."

These figures give us an approximate sense of the number of planets that occult their host star, as a proportion of the number of stars surveyed.

TRIGGER WARNING: SKETCHY BACK-OF-THE-ENVELOPE MATH

259 stars within 30 light years

1030 / 156000 = 0.00660256410256 (fraction of Kepler-surveyed stars possessing Kepler-confirmed planets that transit)

4 / 1030 = 0.00388349514563 (fraction of significantly Earth-like Kepler-surveyed planets)

259 * 0.00660256410256 * 0.00388349514563 = 0.00664102564102 or 0.66% (chance of a transiting Earth-like within 30 light years)

And that's not even factoring in planets that do not transit their host star.

[1] http://ntrs.nasa.gov/search.jsp?R=20100030619 [2] https://en.wikipedia.org/wiki/List_of_exoplanets_discovered_...

Yup, but as others said it might be better since Kepler doesn't detect all orbital planes. So it would be 0.0066 * 1/(fraction of orbital planes) -- but this boost is probably less than an order of magnitude? So still probably no luck for planets reachable within a lifetime eh :P

Are you sure it will be probably less than 1 order of magnitude? Unless there is some restriction that limit the plane of the orbit around a star with relation to the galaxy, which is unlikely...

Assume the plane needs to be within 1 degree from the line joining the star and kepler. I would guess it probably less. It would be a function of size of the planet, size of the star, radius of the orbit and distance of star from kepler.

That would give about 179 planes that we cannot see, which is two orders of magnitude, but the probability calculation won't be that simple.

Oh yea I just realized it obviously has to be quite low, shouldn't be too hard to estimate for earth (the problem is, it varies with planet size). I would guess two orders of magnitude or more actually, which would indeed put the expected number close to 1.

A naive calculation for Earth would be Theta ~= 2 * (Earth diameter) / (Mean distance to Sun), which is ~2*10^-4. Since most planets found by kepler were much larger than earth, it seems 10^-2 is a reasonable guesstimate.

> Assume the plane needs to be within 1 degree from the line joining the star and kepler... That would give about 179 planes that we cannot see...

Assuming you mean 1 degree in either direction, or 2/360 = 1/180, this is off by about a factor of pi/2 ~= 1.57. The correct answer is sin(pi/360) ~= pi/360 ~= 1/115. Still two orders of magnitude, but slightly better. The reason is that the degrees are not equally likely (small degrees, that you want, are more likely, and large degrees less likely).

Here's the calculation: Consider the unit vector normal to the equator of the orbit, using say the right-hand rule. This vector is uniformly distributed over the unit sphere (surface area 4pi). You want the vector to lie within +-1 degree of the rim of the sphere. Call the region of such vectors R; the probability of a good planet is P = area(R)/(4pi).

R is an annulus going around the equator and up/down by 1 degree. In area, this is close to a rectangle with width 2pi (circumference of sphere) and height 2pi/360 (i.e., 2 degrees), so P ~= (pi^2/90) / (4pi) = pi/360.

The area of R (an equatorial annulus) can be computed exactly using calculus---or looked up on Wikipedia [1]: area(R) = 4pi - 2(2pi(1-sin(pi/360))) = 4pi sin(pi/360). Thus, P = sin(pi/360).

[1] https://en.wikipedia.org/wiki/Spherical_cap#Volume_and_surfa...

Ah that's some good analysis. I would love seeing this calculation done precisely, for that 30 light year figure (and other distances). There's other factors to put in too whose significance idk like the size of the sun -- if it's much larger this increases significantly the range of angles in which occlusion occurs.

Indeed taking into account that the sun is much larger than earth I got the value of P=0.00465 by taking P=sin(arctg(solar radius/1 au)). So the planet size actually shouldn't matter significantly on this particular probability, since the planetary radius is like 1% of the solar radius.

> Assuming random distribution, there's probably thousand fold amount of off plane planets.

For a star like ours with a single Earth-size planet at 1AU, the odds of observing a transit are 0.47%. There is a page devoted to this question which gives some idea of the variables involved: http://certificate.ulo.ucl.ac.uk/modules/year_one/NASA_Keple...

Thanks, that's an excellent response!

Assuming a constant density of earth like stars, a density of 200 earth likes in a 1500 light year sphere would mean one earth like in 250 light year sphere.

Assuming a disk instead, it would be about 100 light years.

Don't know how it relates to the local star neighbourhood... https://en.wikipedia.org/wiki/Orion_Arm

Of course, sampling from this small amount of data is pretty prone to problems...

>> Assuming random distribution (of plane of planets),

Has there been any research on this? I have no actual insight, but I'd guess the plane of the galaxy would affect plane of stellar rotation and perhaps also planetary disk alignment.

I've asked that before too and been told that they are randomly distributed. Here's a link!

http://curious.astro.cornell.edu/236-are-the-planes-of-solar...

Thank you. I've been wondering about that for years but never got around to looking it up.

The milky way galaxy is about 200,000 light years in diameter, but only about 200 light years thick.

Given this thickness, I imagine you'd need to look beyond the 200-light-year range to notice a significant influence of the plane of the galaxy on the distribution of stars (and planets).

This solar system orbits the galactic center every 250 million years or so; making us a young adult of around 18 Galactic years old, living in a suburb of quite a busy galaxy.

Every eighteen year-old suburbanite[1] has already been pretty well socialised by local interactions in the context of a global system of local interactions, performed massively in parallel.

[1] metaphors mixed and units of measure utterly messed-around with

I love this galactic orbit measure of things. Dinosaurs like the Iguanadon were alive ~125mya, which means that the impressive thing when looking at a fossil is not that it's old, it's that it came from the other side of the galaxy. You can go and pick up a trilobite that's coming up to its third orbit.

Yes, I know, it's still from Earth, but I do think it's a weird way of looking at dinosaur fossils.

More other-side-of-the-galaxy dinosaurs:

http://www.enchantedlearning.com/subjects/dinosaurs/mesozoic...

Grabs the Iguanodon skull

- What did you see out there? What horrors and wonders hide on the other side of space? Tell me, what did you see?

Awesome observation, thanks for it.

>There are 259 stars within about 30 light years. Communication could be conceivable with such distances...

Wouldn't that mean a minimum of 60 years to get a reply to any message?

Terrible latency but still possible to conceive communicating. Also 60 years would be the upper bound for those stars, unless you are suggesting crafting a reply takes a significant amount of time. Which it may. No need to rush a reply with that time lag.

so we would only be able to detect those [non cross planar with earth ] planets if their orbit occluded another background star [ not their own sun ] .. wonder how rare that is.

At 2 billion years older than Earth, I can't begin to imagine what kinds of things could possibly be living on this planet. Given, of course, that it's got the right ingredients for life to arise. What if it's suffered huge extinctions recently? What if there's a domineering species out to conquer the planet just like humans? What if there's a society there more sophisticated than us? It's a very exciting discovery.

I propose it's unlikely that any technological civilizations more advanced than our own have existed on this planet in the past few billion years, otherwise some subgroup of their species would likely have seeded the local universe with life (it's only ~1400 lightyears away) and they would be here instead of us. Unless of course the panspermia hypothesis is correct and that is indeed where life on Earth came from.

It could also be that there was a technologically advanced civilization which destroyed itself.

Maybe we are them. We used to live there, and conditions reached a point when we had to leave, and we came to present Earth. Haha.

Good sci-fi material here.

Plausible, but what would be explanations for sending ourselves back to the stone age instead of carry advanced knowledge along?

Maybe they tried and failed? Maybe they arrived on a sterile Earth 3.6 billion years ago with supplies and huge tomes of knowledge, promptly died off within a couple hundred years of arrival, tectonic movement subsumed their landing ship and all other physical records of their existence here and we're all just descendants of their gut flora?

All of this has happened before, and will happen again.

Can you explain that?

I wouldn't have expected every possible situation to have occurred given the finite history of the universe.

But I really have no idea what I'm talking about, so my request is serious.

It's a reference to the plot of the recent Battlestar Galactica remake.

It could also just be their resources were insufficient and they plateaued or fizzled out before escaping their own planet was possible.

Or that the distances and difficulty of transporting anything very large or complex between star systems turns out to be just too great of an engineering problem for any life form. The energy required to move a life-sustaining amount of mass between stars is mind-boggling huge and beyond our own technological capabilities for the foreseeable future ( we only anticipate interstellar life is a possibility by assuming our technological growth curve will continue unimpeded and then guessing there's life out there further along tha us, which may not be accurate or possible).

Or that they are indeed spreading but doing it in a way undetectable to our technologies we're looking with and we just didn't come up lucky enough to be directly contacted by them in their spread (yet?).

Or maybe they developed a Matrix-like utopia, a self-maintaining and long lasting support system and stopped outward appearing progress?

Or going in another direction, perhaps we really are inside a simulation and $life_bearing_planet is set to 1.

The hypotheticals are nearly endless and not necessarily due to overtly negative outcomes.

Apparently it has a diameter 60% larger than that of the Earth, and so if we assume it has the same density as the Earth it would have about 16m/s^2 gravity on the surface, and an orbital velocity of around 12km/s @ ~1000km (in comparison to the Earth, where a 1000km circular orbit is closer to 7km/s).

This means that merely achieving orbit would be approximately as difficult as launching a probe on a Hohmann transfer orbit to Mars is. (Except that such a launch vehicle would need nearly twice the thrust/weight, cutting down the mass ratio even further.) It is not unreasonable to think that a species on such a planet would have never seriously developed space travel.

To colonize or seed life you don't need to launch huge space vehicles with enough life support to maintain a breeding population, though. You can just launch some kind of self-replicating microbes capable of directing themselves into the forms of life you want to encourage over time. The precise ability to do this would depend on your current state of technology, but we're pretty close to developing full blown synthetic biology and genetic engineering ourselves, so it's hard to imagine they'd need to be more than a few hundred years more advanced than us at most. Microbes can be engineered to be immune to most dangers from space travel as well, similar to tardigrades.

To head off the common rebuttal of "maybe they wouldn't have any interest in it," with more advanced technology smaller and smaller groups of individuals would be capable of instituting such a project, to the point where any high school kid with a synthetic biology kit and some toy rocketry kits could colonize the entire universe (owing to relativistic effects). You'd have to assume their society underwent some kind of massive convergence of social norms away from any individuality such that no few members of their species ever had both the capability and desire.

The entire plan is mostly laid out by: http://www.tedxvienna.at/watch/why-aim-for-the-stars-when-th...

This might work on a baron world, but any place with a developed ecosystem would likely see these things out competed very quickly do to the massive overhead of needing to survive in space for a long time.

Or they would be engineered with huge advantages against an ecosystem which had never adapted defenses to them (typical of successful invasive species on Earth), and work on timescales much faster than typical evolutionary ones. These would basically be microscopic von Neumann probes, presumably with some kind of self-organizing emergent AI to direct their progress, not just spraying random bacteria everywhere and hoping for the best.

Only a tiny fraction of species end up as invasive, because the local ecosystem tends to be better adapted. As to ‘grey goo’ there is fairly good evidence that’s far less possible than you might think.

If you don’t stick with Hydrogen Carbon Nitrogen Oxygen you’re going to have a much harder time finding what you need to grow on earth. For extra solar stuff even those might be hard to find.

If you do stick with HCNO it's hard to get a leg up on nature without simply making a few minor improvements which has limited value outside specific situations. There are also a lot of tradeoffs with binding energy etc.

By the same logic, any depressed high school kid could also engineer a pathogen to wipe out their entire civilization before that happened. (I think this is a plausible great filter candidate)

You seem to be assuming a notion of continual human progress. In a few hundred years, we'll probably be in another Dark Age, judging by current trends. We're like the Roman Empire in 200 AD.

Progress is the exception, not the rule, so far in human history.

> Progress is the exception, not the rule, so far in human history.

You're either cherry-picking your intervals or have a very weird definition of "progress".

With human-style chemical rockets, sure. But what about nuclear pulse propulsion? Or some sort of exotic equatorial railgun?

But they'd have seriously huge muscles. And I think it's safe to say that their Mr. Universe would easily kick our Mr. Universe's ass.

As a counter point, it's always possible that a civilization that developed past where we are now would have been masterful at space travel, but not advanced enough to completely figure out a 1400 light year long journey. We're still having hard times figuring how to get squishy meat sacks to Mars without being irradiated to death or creating a launch vehicle made of lead. Besides the engineering problems there's the social cost of a venture like that. Unless their societies would be structured in a wholly different way (which is likely) then there is significant political and social momentum that would need to go behind a project like a mission where the minimum acknowledgement time of success is 2800 years away. There's plenty of time to go extinct or make yourself die off.

You don't have to figure out a 1400-ly trip to be here. You just ("just") need to be able to move from one star system to the next.

If they took 100 years to get to the next star system 5-ly away and then 500 years to populate that system enough to start a new colonization, that's just ("just") 168,000 years to be here. Given a 2 billion year head start, that's easy.

Even if it only took them 100 years to get to a star system 5 ly away, I would be amazed and impressed by a society that would be okay with investing in and working on at minimum a 105 year mission. Perhaps they live much much longer than we do :)

If they lived much longer, comparisons on earth would lead one to expect they'd be much slower to get anything done. Small burrowing rodents that live a couple of years hit the ground running, build extensive dens, and reproduce before they're a year old. OTOH giant tortoises never actually do anything except walk around slowly.

>working on at minimum a 105 year mission

Cathedral building in the middle-ages was a multi-generational 80+ year affair and some of the Pyramids took even longer IIRC. So societies were/are definitely capable of working on ~100 year missions :)

Or the Sagrada Familia in Barcelona for a contemporary and in-progress example.

Maybe a generation ship needs to have some sort of 'cathedral-in-the-sky' religion connotation in order for us to commit to building it. Sounds like an interesting idea for a sci-fi plot!

> We're still having hard times figuring how to get squishy meat sacks to Mars without being irradiated to death or creating a launch vehicle made of lead.

But we've only been working on that for a few decades. 2 billion years is a lot longer. If there is a civilization there at all, it's extremely improbable that it hasn't figured out how to do exploration on a scale of thousands of light-years.

There's an implicit assumption running through most of this thread that if there's a civilization there, it's enjoyed 2 billion years of continuity.

I suspect that's unlikely, even if there were advanced life there for 2 billion years.

> I suspect that's unlikely, even if there were advanced life there for 2 billion years.

Why do you think so? "Continuity" doesn't have to be having the same government or the same political structure, or even the same physical form (the article itself talks about uploads and nanomachines). It just means continuity of technological development. It doesn't have to mean steady progress either; our civilization hasn't had that, yet in ten millennia or so we have progressed from basic agriculture to space travel. For this planet, we're talking about two million millennia, or 200,000 times the time we've had. All the variables we've observed in our civilization's history become rounding error on that timescale.

Yes, I mean continuity of technological development. I suspect that the prior millennium’s dark ages are but a pale inkling of how far a civilization can collapse, especially given geological time scales. I also suspect that technological development can plateau for sociological reasons.

Even during the dark ages here on Earth, there was technological advancement. Also, the dark ages weren't worldwide. I would be skeptical of a plateau in technological development for any significant length of time for the same reason: even if one part of the planet was in one, the rest of it wouldn't be.

On those timescales mass extinction events (asteroid, supervolcano etc.) become rather probable, which I guess could be what GP was trying to say.

A mass extinction event would mean there wouldn't be a civilization on the planet at all. That's certainly possible, but for this particular subthread I am taking as a premise that there is a civilization there.

Perhaps they were wiped out by a virulent disease contracted from an unexpectedly dirty telephone?

It's fun to think about all of the things that could prevent a far more advanced civilization relatively nearby in the cosmos from making contact; it gives us a better perspective on how lucky or fragile our own development is and where we might be focusing on the wrong things.

Perhaps no civilization of any sort has ever developed there. Maybe conditions on the planet are inhospitable, perhaps evolution simply never went that way. I think people tend to assume that evolution naturally leads towards more intelligent creatures, but that's not true. Humans are a very very recent development on our planet, in geologic time scales, and our early existence was pretty improbable.

Perhaps civilizations have existed there, but never achieved technological advancement. There are still tribal civilizations on Earth that are using 50kya technology; there's no guarantee that a civilization must develop science and technology.

Perhaps it has had civilizations with similar technological advancements to our own, but they have been destroyed or set back by any of a number of things: extinction-level impact events (could easily happen to us), disease, warfare, or resource shortages. Maybe, for some reason, they never developed easy access to a high density fuel; imagine if humanity had tried to go directly from steam engines to nuclear or solar power because oil didn't exist or wasn't easy enough to find or its significance was never understood.

Perhaps they reached a level of technological advancement far, far superior to our own, but they never made an effort to explore the cosmos. The vast majority of people on Earth right now don't see any point to even exploring other worlds in our own solar system; that mindset could easily dominate for the rest of mankind's existence. Maybe we assume that there is some kind of shortcut around the speed of light and there isn't and, no matter advanced a civilization gets, there simply aren't enough volunteers for a 10,000-year journey to another tiny little planet that may or may not harbor life.

Perhaps all of these are wrong, but they simply visited Earth a million years ago and found it to be entirely uninteresting and haven't been back since. Maybe their civilization has even ceased to exist, and our civilizations will never ever cross paths because we missed eachother by a few minutes in geologic time.

I'm generally optimistic about the chances of advanced civilizations elsewhere in our galaxy, even relatively close by, and entirely pessimistic about our odds of ever being able to interact with those civilizations in any meaningful way.

Here's another scenario: they could have colonized other worlds, but had no interest in setting foot on every last planet. Perhaps their culture is insular, and they are either apathetic to (or forbidden from) contacting us. It's not hard to imagine that we would be unable to detect them, either.

Maybe they are here and it IS us?

https://www.youtube.com/watch?v=N8hEwMMDtFY

https://news.ycombinator.com/item?id=4843540

But they did seed the planet, but the stargate got buried and we forgot all about them, until just a few years ago when ... Oh wait, sorry !

cue aliens impersonating Egyptian gods and enslaving the human race until being killed off by Kurt Russell and James Spader

Nah, it was Amanda Tapping and MacGyver that did all the hard work.

Or the "zoo hypothesis"[1] is true and we're quarantined off on our little planet out here. I figure we're like the people on North Sentinel Island[2]. We haven't even invented fire, and we kill anyone who tries to shows up on our island. We're so remote that the local authority in the area has declared our Island a protected zone, just as India has with North Sentinel Island. We occasionally see helicopter and try and shoot arrows at them.

1.https://en.wikipedia.org/wiki/Zoo_hypothesis

2.http://www.odditycentral.com/travel/north-sentinel-island-th...

The engineer in me says that it's overwhelmingly likely that there's nothing alive there.

The little boy in me so wants me to be wrong.

I don't understand your reasoning!

There is good evidence that life apeared on earth more or less as soon as it cooled down, so there is just as much reason to think that this new place may have life as not.

However, by the same reasoning it seems to me that the life may be bacteria like!

> The engineer in me says that it's overwhelmingly likely that there's nothing alive there.

Our planet has life in all kinds of niches. Why would an Earth-like planet not be overwhelmingly likely to have life on it? (I am an engineer also...)

True but all of our planet has an atmosphere conducive to supporting life.

Don't get me wrong, I'm not saying that Earth-like planets generally won't support life. I have no idea how many will. It just seems unlikely that the first one found happens to tick all the relevant boxes.

Having said that, the fact that they've found one so quickly, relatively speaking, seems like a good indicator that there are an awful lot of good candidates for life-supporting planets. The more there are, one would assume, the more chance that some will have everything in place.

But then again, we could just get lucky and hit it first time. Which would be stellar (sorry).

> True but all of our planet has an atmosphere conducive to supporting life.

The composition of Earth's atmosphere was pretty similar to Venus and Mars, before photosynthesis changed it to the current composition.

It's jarring to think that if intelligent life were on Kepler 452-b and observing Earth, we're so far away that they would be seeing our "civilizations" in 615 AD: shrinking global population as the old Roman and Byzantine empires are overrun by barbarian hordes and Arab conquest, with some pockets of human progress in China. They would have no way of knowing that the descendants of those squabbling warlords just cooperated to fling a space probe at 36000 MPH past a tiny ball of rock at the edge of our solar system.

I hope they were recording the whole time and upload the videos to YouTube. I can't wait to watch Hannibal on the Pyrenees From Space.mp4

My favorite thought is that they've sent probes millions of years ago and we could send a request to watch some HD surveillance of dinosaurs roaming the Earth. It'll just take ~3k years to receive the requested footage.

Not if you board a spaceship and travel to them at close to light speed! Then you, personally, would just wait a few hours.

Once again, it will be easier to bring people to the data, than data to people.

You're right about the idea, but a few hours is way too short, because of how the Human body tolerance to strong accelerations.

Assuming an acceleration of 10 m/s^2 (similar to Earth's gravity), it will takes roughly one year to accelerate to a speed close to the speed of light were relativistic effects occurs, and you will need one more year to decelerate.

You'll have to wait 6000 years to see it on YouTube: 1500 for them to hear about YouTube and 4500 for them to upload (assuming TCP)

Sheesh. I can't believe after 6000 years TCP is still in use.

At least 25% of it will be over IPv6!

> At least 25% of it will be over IPv6!

We probably will need IPv10 to connect all the dots in the sky!

Actually no! Estimates I found are of around 10^23 stars in the universe. There are over 10^38 IPv6 addresses, so even if there were tens of inhabitable worlds per star and billions or even trillions of addresses per world, we'd have enough! (Although it is possible that stars number is a significant underestimate.)

IPv6 only has space for 10^19 networks, so you would need to heavily chop up /64s if you wanted to number the universe.

But IP is not designed for high-latency networks, so this only really matters if FTL communication is invented.

Internet of Stars™

Maybe even as much as 26%, who knows...

That might be the funniest thing I've ever read on HN.

For a second I thought I was on reddit.

I was beginning to think we collectively lost our sense of humor.

There is hope. Now quick, someone post a cat pic and a relevant gif.

Edit: Not complaining about the downvotes, but guys, this is the internet, not work. Loosen up. Smile for once. It's good for you, and confuses people.

It seems like UDP is probably a better protocol for this use case.

Until a gamma beam disrupts the connection and you miss the best part, that is!

I've got a really good joke about UDP, but you might not get it.

That's fine. I've got a great joke about TCP, and I'll just keep telling it to you until you get it. I'll just speak slower each time...

ROFLMAO I got it, I got it... so I think I'm TCP? :P

no redirect to https?

It would go faster if they loaded a bunch of usb sticks in a station wagon and shot the wagon across space.

Only if they can average 0.25c, which seems unlikely :)

do they have a pirate bay?

Hannibal lived 247 – 183/182/181 BC. That's a few hundred years earlier than 615 AD.

One can perhaps take comfort in the fact that a civilization advanced enough to be aware of us would likely be aware of the fact that we were more advanced than what they could see at any given moment (or they had found a way to narrow the perception lag).

They would likely have extrapolated the savagery they saw and realized that we may pose some problems for the galactic community. RKKVs are probably on their way towards Earth as we speak.

> It's jarring to think that if intelligent life were on Kepler 452-b and observing Earth, we're so far away that they would be seeing our "civilizations" in 615 AD: shrinking global population as the old Roman and Byzantine empires are overrun by barbarian hordes and Arab conquest, with some pockets of human progress in China.

Is there something uncivilized about the Arab conquest of Byzantine lands? Had the Kepler 452-b-ians been observing Earthians but a few hundred years prior, they'd have seen the Romans doing much the same to expand their own empire. And the Arabs did quite a good job to not only preserve the Roman intellectual and scientific state of the art, but to contribute their own advancements of those fields.

Not a dig at anyone, especially not the Arabs who basically preserved philosophy and mathematics while Europe entered the Dark Ages. My point was simply that Kepler 452b-ians observing Earth would be seeing lots of war and destruction even though we're currently peacefully collaborating among mankind to discover and explore planets.

> observing Earth would be seeing lots of war and destruction even though we're currently peacefully collaborating among mankind to discover and explore planets.

If they were observing us today, they'd still see plenty of war and destruction.

It just so happens that a fraction of the worlds population lives under "peaceful" conditions. That's not universally true.

Most of the worlds population lives under peaceful conditions these days.

> My point was simply that Kepler 452b-ians observing Earth would be seeing lots of war and destruction even though we're currently peacefully collaborating among mankind to discover and explore planets.

There's a quite a bit more human energy going into war and destruction right now than into "peacefully collaborating among mankind to discover and explore planets."

It is more proper to refer to them as Muslims, not Arabs. The whole point of Islam was to unite everyone under the same ideology. That's why it's called the Islamic civilization.

Source: I'm both an Arab and a Muslim.

Was anybody but Arabs involved in the conquest of the early 7th century? Ie I'm sure other people took on Islam afterwards but he was talking about a specific point in history.

We don't call the Spanish conquest of the Americas a Christian one even though they were Christians who ultimately converted everybody to Christianity.

Quite a few of the Prophet's companions were not Arabs, but yes the majority were. Nonetheless, it is more correct to identify as a Muslim before an Arab.

What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs", when most of them were not Arabs at all. It's such a simpleminded and sweeping generalisation that clearly shows the thoroughness of the so-called orientalists.

That seems like a silly thing to get greatly irritated about.

Imagine if all the great Scottish scientists were referred to as 'the English'. That might piss some people off.

I'm sure some people track these sort of tribal affiliations between inhabitants of the British isles over the course of a millenium, too, but again I'd consider it a silly thing to get riled up about.

I think people tend to care about these things when one nation is subjugated by another, more powerful one, which tends to exert its dominance.

Hence the 'weaker' nation feels deprived of its history when its proudest moments are appropriated away.

I think it may be the preferred nomenclature in the Muslim world since all the people who were conquered are now Muslim - so they should have an easier time accepting the fact of being Islamicized as that's their culture now (whereas bringing up the fact that they were conquered by a foreign people might stir up tensions).

I agree with you about the second point. I guess it's due to the fact that they wrote in Arabic and many of the people they actually belonged to no longer exist (for example al-Khwārizm was from a Persian family but born in what is today Uzbekistan - I actually visited his hometown :)

>What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs"

To me it's strange to ascribe such areas of study to the religion. What does Islam really have to do with optics besides Ibn Al-Haytham being a Muslim? No one ever ascribes enlightenment science as 'Christian science'.

If they have the ability to telescope us before we do. They can probably guess that technology accelerates. In fact I feel more pessimistic of the human's future as we found more and more such older planets -- If their million or billion years older civilization cannot reach us, then we might not reach out that far as well in the next billion year, or ever.

That thought makes me sad.

>we're so far away that they would be seeing our "civilizations" in 615 AD: shrinking global population as the old Roman and Byzantine empires are overrun by barbarian hordes and Arab conquest, with some pockets of human progress in China.

Err, the Byzantine empire was still going strong for 6 centuries after that (and still existed, but not in a good shape, for 8).

It never got overrun by "barbarian hordes", but it did have a run in with thieving "supposedely christian horders" on their way to the Crusades in the 12th century, and was finally overrun by the muslim Ottoman empire in the 14th century.

I would want to wait for the day when NASA announces to watch earth from light years or light months away and show us earth back in time.

You'd have to travel faster then light to outrun the light emmited from years ago.

If there was an intelligent life form, like humans, it would have expanded into the cosmos and colonized the entire galaxy within only a million years of developing technology. Since we don't see traces of them everywhere, we must presume they don't exist.

Perhaps government funding for their space exploration programs dried up, industry regulations interfered with commercial space exploration programs, and they all just gave up and shifted technology resources to making games for their mobile phones.

If there is a intelligent live form millions years ahead of us it's most likely AI that doesn't want to make the contact.

And also doesn't want to use any resources, or perform any heat-generating computation?

Your big unstated assumption is that any intelligence will always consume the maximum resources it can and cause the maximally possible transformation of any habitat. Normally, when physicists look for these kinds of large-structure signs, the implicit assumption is that it's sufficient for one civilization to behave this way, but you seem to assert they all must be like that.

Any of the hypotheses we discuss in this thread (whether they are over-confidently stated as facts or marked as speculative) are inevitably deficient due to data derived from a sample size of one.

That's an unfounded presumption.

It's like, nobody has considered that advanced life might not even feel a need to live on planets at all. It's expensive to get resources from, and there's a near limitless supply of easy to get smaller debris.

Additionally, the difference a 2 billion year head start could make is hard to imagine. One thing that's not hard to imagine is that they don't live in meat bodies for most of that time. They could easily be machines or virtual, and then would look and act nothing like anything we're looking for.

We have sensitive telescopes. If there was life out there, we would have noticed. You would have astronomy conferences filled with people trying to figure out what all these weird spectra objects are, or trying to decipher all these structured radio observations.

We just found the first planet that is somewhat similar 1400 light years away... and you think our 'sensitive telescopes' would have definitely discovered all possible life in the universe if it existed???

What? No, absolutely no we would not just see them with sensitive telescopes. Perhaps, if you're thinking of some sort of interstellar space travel, maybe we'd see the engines? But no, even that seems unlikely.

Any space habitat of any plausible size will be completely undetectable, or at least indistinguishable from a planet. And I would think they'd be much smaller than that.

And structured radio? Lots of possible reasons not to see it. One, possibly not using radio. Two, encryption. Communication will likely look like noise. But even so, the distances involved means long range transmissions will need to be very directed and narrow beam. And even then, it's only a few light years before the signal is undetectable. I would suspect any really long distance communication would be bounced through relays. Also, why? You have to wait years for messages to go around. All of this means no, we're not likely to easily find stray radio signals.

I think you are completely misunderstanding the point. He have to vent heat somehow in the most efficient ways of doing so are not natural in their spectra. An encrypted radio transmission is still perfectly detectable -- you may not know what it says but you know that it is there. Artificial signals are blindingly obvious.

And this is without getting into Dyson spheres and other efficient but detectable technology.

Encrypted signals are not blindingly obvious. An encrypted radio transmission will appear as pure random noise and no different from all the rest of the noise that we pick up.

If an astronomer picks up a radio signal it is extremely obvious whether it is an artificial source or not. Natural sources have very inefficient spectra of very specific types. Artificial sources have very clear frequency cutoffs, having come from an antenna. Even frequency-hopping sources may jump around in a way that makes eavesdropping difficult, but if you stick around long enough on a single channel (as radio astronomers do) you'll get little blips now and then as the signal hops through your channel and is gone again.

How do we know this? Because astronomers see these every single night and have developed sophisticated filters to remove them. But by checking how the source is moving it is quite easy to tell if source is local or not, and sure enough all these artificial sources come from satellites, the troposphere, or an unshielded microwave.

It is actually remarkably difficult and a challenging problem in itself to create a communication mechanism which looks like a natural source. It defies imagination to think that every single intelligent species out there has purposefully masked their existence in such a way, including giving up useful technology like ground control radar or mobile communications.

The reason they have to filter out artificial sources, and the only reason they're a problem, is we are literally right on top of the source. These aren't even as far away as, say, Mars. New Horizons, for example, can't communicate with Earth unless it points its transmitter / receiver directly at us. And that's in our own solar system! Only a few light hours away.

Just think about it. The signals are going to be so weak by the time the photons get here they will be indistinguishable from the CMB.

"We have to vent heat somehow..."

Yes, of course. And the heat of a star will make that heat completely invisible in comparison.

The "spectra" that heat would be vented at is infrared, which is infrared no matter the source.

Say you had some gargantuan fusion power harnessing space station in deep space. lots of assumptions here about alien cultures, but this is likely the easiest to detect. They will do whatever they do with their energy, and then vent the waste heat. That heat will be infrared. What does a dim infrared source look like (if even visible at all)? It looks like a brown dwarf. But this is assuming a lot. It assumes some alien would even build brown dwarf sized space stations. We don't know if or even why they would do that.

> We have sensitive telescopes. If there was life out there, we would have noticed.

I'm sorry, but that's way off.

Our current telescopes can't even see the majority of the exoplanets in our galaxy; we are made aware of their existence by observing the behavior of their host star (wobbling/dimming). Unless something is extremely close, unfathomably enormous, or emitting/reflecting large amounts of electromagnetic radiation (light, radio, etc.) that isn't bent/filtered/reduced to noise, then we are completely unaware of it.

They can see stars. There wouldn't be stars in a type 2 civilization. There would be amorphous blackbody spectra which we do not see.

That assumes that civilizations derive power by encasing their host star in a Dyson sphere, which is not a foregone conclusion; that prediction was based on our current understanding if technology. Think of Huygens who imagined that Venusians sailed the seas on ships held together with hempen rope.

An "amorphous blackbody" source, from anything reasonably distant, just looks like a smaller star. There are a bunch of if's and unknowns involved, but it could be maybe possible to detect a Dyson sphere. This[1] article talks about it. The upshot is that it is nowhere near blindingly obvious, and we don't currently have the ability to differentiate between a natural or artificial infrared source.

https://en.wikipedia.org/wiki/Dyson_sphere#Search_for_extra-...

"SETI estimates, for instance, that with a radio telescope as sensitive as the Arecibo Observatory, Earth's television and radio broadcasts would only be detectable at distances up to 0.3 light years, less than 1/10 the distance to the nearest star."

https://en.wikipedia.org/wiki/Fermi_paradox

I sometimes wonder if "like humans" is the key. What if past some level of technical advancement, organisms cease inhabiting the same scale as us. Physically and temporaly; they become microscopic and perceive+act on a time scale faster than us by orders of magnitude. Why inhabit the days/hours/seconds timescale when you can have the same experiences in micro/nanoseconds? So we would be mostly not interesting to them and expensive to interact with at our timescale. Not sure if we would notice them right under our noses.

Or maybe the next step in the evolution of a civilization is the realization that 'colonizing' is much more fun if the colonists are just dropped off without any technology and let to develop into a civilization and discover who they are and do the same thing over again. You know, just to keep the game going. All that's needed for that is already encoded in their DNA.

Maybe there are other channels of exploring spacetime than just the physical reality. Maybe that's where all the advanced civilizations reside.. Like the place we are in before we are born or after we die...

1 million years of mind evolution should not only bring advanced tech, but also advanced wisdom and understanding of who we are and what we are doing here. I doubt that expansion to all possible planets is the ultimate goal, the mystery must go much deeper than that ;).

Based on what evidence? I would posit that it there was an intelligent life-form, it would have descended into war and eventually extinction. Self-interest isn't exclusive to Earth.

Edit: I've said that self-interest isn't exclusive to Earth, without providing evidence and I don't have any; I should have said that self-interest isn't exclusive to humans, the simplest forms of life (bacteria, as an example) make war also.

It's like an anthill in the middle of the Amazon saying "If there were life on Earth that is more intelligent than us, why can't we see their enormous anthills? Why haven't they tried to contact us yet?"

According to transhumanists, all we find there are running server farms.

There was an kind of on-topic post on imgur about that today:

[The Fermi paradox: We're pretty much screwed...](http://imgur.com/gallery/Wtog9)

I find myself thinking that the existance of Dark Energy/Dark Matter is the solution to the fermi paradox. there is some kind of energy creating system which creates dark matter. This matter is no good for normal matter so it is transported far away from stars/galaxies and dumped. This would probably be true if we could create a physics model that can explain like 1% of Dark Matter occurring naturaly. Then we just assume that other species have discovered how to create a ton of energy with Dark Matter as the by-product. We haven't been able to observe them for the same reasons our telescopes can't see the New Horizons spacecraft out by Pluto, just too small. And as far as observing communications. It's likely that all true interstellar communication on frequencies we could understand are sent with a targeted focus, like a laser, rather than a blast. Think of all our deep space equipment which has their uplink bits pointed toward earth.

Or maybe there is no Dark Matter and we can't see a huge portion of stars because all of the light is being captured like a Dyson sphere. Unfortunately both of those hypotheses are rather improbable, we can observe very very distant galaxies and they all seem consistent with respect to Dark Matter AFAIK.

I am surprised more people don't believe all this is just a trick because we base everything on our knowledge what if something out there is tricking us? We see the universe through a telescope and other sensors. But if something puts something in front of it, you will see different reality. It is like if you use binoculars and I put a fake image in front of you, you could start believing there is something else. It is also like magician.

So we could be in ZOO experiment. Other civilizations want to see if we are capable of evolving and joining them so they make sure we are not disturbed by other life out there because if we discover intelligent life, we will freak out. We might start fighting for our survival and it could affect our evolution to higher species.

We could also be a part of some computer simulation (with enough power you can create rules with particles and simulate the universe). Maybe somebody is trying to answer this question: If you create a big enough simulation, will be the simulation able to figure out it, it is being simulated?

Or maybe everything that we see is true but it is just impossible to overcome some physical limitations. We assume there are no limits and everything is possible and one day we will master it. But what if communicating and traveling through universe is nearly impossible? Maybe there are limits that we don't know about yet.

Maybe every civilization reaches point where they know the answer to everything and they don't see a reason to live anymore or they leave the universe and move somewhere else.

My point is that we assume something that will eventually turn out false and everyone will be surprised by the truth.

Totally agree with you. There are so many possibilities of evolution besides building high tech spaceships and conquering planets and stuff.

Imagine how much more wisdom (besides technological advancement) the average humans will posses in just 200 years (provided things evolve like they have been evolving during the last century minus the wars ).

What wisdom and knowledge will we have in 1000, 2000, 50000 years (again, provided we are still alive) ?

Maybe there is no need to physically travel through light years of space, maybe the 'truth' is much closer - right inside our own minds.

In just a couple of decades we'll be able to build simulations which simulate all our senses and are just as real as our 'current' Universe - enter there and take a pill which makes you 'forget' about this reality and you can basically live another life without knowing about your current one.

What if our current life is the result of such a 'game' which we entered and forgot about the 'outer' life. What if we're level 64 deep in such a simulation within simulation ? :)

So many possibilities, but hopefully we'll somehow figure them out ..

You just described the movie Vanilla Sky

Why was this comment down voted? It's another point of view in the conversation, which I find valuable.

If you have facts to prove him wrong, feel free to reply and publish them.

If I were writing a science fiction story there would be primitive villages on higher inland areas, and partially submerged technologically advanced cities on the coastlines :-)

But what I find most amusing is that when I was a kid "science" was saying "but we don't know if any other star even has a planet!" and to me as a kid it seemed preposterous that other stars wouldn't have planets. And now of course we know that pretty much ever star has at least some planets. The unusual case is no planets.

Similarly with life, it seems ridiculous to think that somehow this planet at this time was the only place anywhere that sentience emerged. So it really makes me wonder, why the heck aren't we already talking with them?

What is it that keeps intelligent life that originated on other planets from communicating with the intelligent life living on this planet? Why won't they talk to us?

With a larger planet, they may have been inescapably bound to the surface for their world for millions of years by the tyranny of the rocket equation.

Interesting thought, but then again, maybe they would just use external acceleration on such planets (ie catapult launch assist).

I want answers to three questions before I get excited:

1. Does it have active plate tectonics?

2. Does it have a working deep carbon cycle?

3. Has its atmosphere hung on to its hydrogen (that is, has it managed not to lose it all to high-altitude UV splitting and solar wind)?

If the answer to all three of those is "yes" then this suddenly gets a lot more interesting, whether or not we can see any free oxygen in the atmosphere. And while we won't be able to get answers to them using current technology, next-generation direct-observation planet seeking telescopes might be able to deliver within the 15-30 year time scale (if the astrophysicists I know are correct).

We may never know the answers to these questions. Though it is currently possible to say something about the atmospheric composition of some close exoplanets, and that ability will be improved with better telescopes, the planets that Kepler observed during its mission are too far away to learn much about for the foreseeable future.

I'm curious why active plate tectonics makes the planet more interesting. Do those contribute to the "liveability" of a planet in some way?

Google on "great oxygen catastrophe" and prepare for an eye-opening experience.

(Note that neither Mars nor Venus have active plate tectonics. The surface of Venus melts every couple of hundred million years due to trapped heat, while Mars has no magnetosphere to speak of ...)

You omit a key point. The oxygen event (initial uplift from near zero at 2.3Ga) is not directly related to plate tectonics. Instead, plate tectonics appears to have helped the oxygen boost at 1Ga: increased volcanic activity released large stores of phosphorus, which is required for photosynthesis, which produces oxygen.

You're attributing a statement of causality to me that I never made; I merely said that plate tectonics would make an earth-like exoplanet more interesting -- for exactly the reason you note: it appears to be a prerequisite for an oxygenation event.

Yeah, good questions. The thing that indicates to me is that, if we can find this one (and we exist)...there are probably lots of planets like this. Probably billions.

And if there are billions of them, then what are the odds that some of them would have plate tectonics, a deep carbon cycle and hydrogen?

Seem pretty high to me.

It's amazing that Kepler continues to discover new planets and (I hope) it will get to the point where we just expect it to be the norm. Oh, another planet in the Goldilocks zone? It's just a shame it'll be a long time before we can actually step foot on any of those planets.

How would the physics of those three observations work, and what angular resolution would be required? I can see spectroscopy working for #3 and #2, #1 stumps me.

In theory #1 could be answered by looking for an atmosphere temperature that are similar to Earth’s despite being in an orbit that should make the planet cooler. If there is no plate tectonics then all the CO2 gets locked up in carbonates and the temperature falls (e.g. Mars) or you get a run away greenhouse like Venus. It is plate tectonics that have kept earth in the habitable zone. In theory we should be able to detect such a temp delta.

Personally I find this discovery rather sobering.

It's becoming increasingly clear that solar systems are quite common. As our planet detection abilities increase to smaller and smaller planets I believe we'll find more and more of those too. Some of these (like this one) will be in the habitable zone of a star. Some of those assumedly will develop life. Some of those will develop sentient life.

I just picture a timeline like Earth's projected on this planet, which of course has no basis in fact. But imagine a civilization that's had 2 billion years of life longer than ours?

That's a really long time obviously. It's hard to imagine that such a civilization couldn't develop automated methods to populate the local space around them. This is one of the counterarguments to life being common in the universe of course. At 1% of the speed of light you could populate the galaxy with autonomous robots in a "mere" 10 million years.

So our inability to detect anything like this gives weight to the argument that no such starfaring civilization exists or that they're less than ~10 milllion years old.

Was there civilization on this planet and it died out for some reason? We'll probably never know.

As these planets mount up (as I believe they will), it'll further strengthen the idea that we're basically doomed (ie the Great Filter) and further suggest we are a mere cosmic blink.

Live audio here http://www.nasa.gov/news/media/newsaudio/index.html?2015-07-...

And slides here (currently on Figure 10) http://www.nasa.gov/keplerbriefing0723

EDIT booooo - audio stream has gone down

EDIT yay!

Back up!

The slides (specially #5/9/11) gives a very good info for people to understand the significance.

  The size and extent of the habitable zone of Kepler-452 
  is nearly the same as that of the sun, but is slightly bigger because 
  Kepler-452 is somewhat older, bigger and brighter. The size of the orbit of 
  Kepler-452b is nearly the same as that of the Earth at 1.05 AU. Kepler-452b 
  orbits its star once every 385 days.

Close to 300K people tuning in!

My viewer says 4.3K

To rephrase another comment in the other submission - how do we know/can we infer so much about a planet so far away when we are just now getting reasonable pictures of Pluto?

Looking at the images (aside from the artist interpretation), it looks like they're just guessing based on size and location?

I believe they're basing it on size, temperature, and the assumption that the planet is rocky.

Sounds like age, size, density/mass, orbit/location

We had a good idea of what pluto looked like for decades. But no photo to confirm; the fact it was red, rocky, pocked, etc. We know characteristics about distance, composure, mass, energy, etc. using spectroscopic techniques. Those spectroscopic techniques are applicable to those planets way out there as well.

One thing to keep in mind is that there is one thing that happens with exoplanets that can never happen with Pluto: the planet can pass between its star and us (i.e. eclipse the star). This gives a lot of information about the planet's composition, because light from the star will scatter/change color according to the planet's composition. See this image: http://seagerexoplanets.mit.edu/images/transitschematic.gif.

Now maybe you can do that with Pluto using some far-off star for reference, not sure. Also, I'm not sure if in this specific example the exoplanet made a transit of its star, or if it was detected by other means (usually by measuring its gravitational affect on the star, i.e. its star "wobbles").

> Now maybe you can do that with Pluto using some far-off star for reference, not sure.

It has been done for Pluto, first in 1988, with an occultation of a background star[0].

[0] http://www.space.com/29885-pluto-atmosphere-to-be-revealed-b...

And most recently with SOFIA at the end of June:

https://sofia.usra.edu/News/news_2015/06_29_15/index.html

This will help tie in past and future occultation observations to the New Horizons data.

As I understand, star transits by Pluto helped to better estimate its size before NH. But as you said, it's complicated to get a full spectrographic analisys of its atmosphere this way.

Kepler is a mission that mostly works with photometric measurements of planet transits in front of their stars.

And indeed the fact that the observed transits were "fuzzy" told us that Pluto has a (very tenuous) atmosphere. Indeed, Pluto's diameter had considerable uncertainty before New Horizons arrived due to this (unlike Charon's whose transits were always tack sharp.)

Indeed this is exactly what New Horizons did very recently. After shooting past Pluto, the probe spun around to view it with the sun behind it. http://pluto.jhuapl.edu/Multimedia/Science-Photos/image.php?...

"385-day orbit" ... Can't wait to have to take into consideration different "year" zone in my code.

> Can't wait to have to take into consideration different "year" zone in my code.

I guess with Kepler you're safe for the next couple of thousand years, unless we find something much closer.

In theory there should be thousands of such planets within 30 light years so who knows, maybe we will have to start thinking about that soon :)

seconds since January 1, 1970 on earth is still a valid strategy : )

Almost, but not quite.

While seconds since Jan 1, 1970 is a perfectly fine system, sadly unixtime has deviated from that simple definition, due to the introduction of leap-seconds.

It feels extremely frustrating to know -- not just wonder but to know exactly where -- that there are planets similar to our own, which have a very high probability of harboring life, yet to be condemned to never be able to take a really close look at it.

No FTL travel, no working cryonics, no mind-upload tech. Just harsh reality.

Not having those technologies but being captivated by the possibilities enabled by their existence is essentially what motivates many scientists. Instead of looking at it like a harsh reality, look at it like a grand challenge for yourself to be amongst those who contribute to their development (or provide the building blocks for later generations who do).

Frustrating or motivating? As far as I am concerned, if I live long enough to get even a blurry image of an exoplanet, I will die happy. And the best part: I have a good chance of this happening: http://exep.jpl.nasa.gov/presentations/AIAA_Space_2014Blackw...

Not saying that getting an image of an exoplanet at all wouldn't be exciting, but I'd die happier if we could land a rover there.

Maybe the happiness is in the hope. Is there anything you would find there that would actually fulfill you? Maybe it's like when people become rich and they realize that didn't fill them up.

Donate to the relevant parties. Unless you're already very old or very sick, it's hard to say you're condemned. A lot can happen in the next 40 years.

Indeed. FTL travel not so much, but working cryonics (with revival) isn't _that_ far-fetched in a reasonable timeframe.

Cryonics with revival is far, far closer in technological achievement (and actually has working science associated with it) than is any realistic FTL travel. Worm holes, Einstein...and those who have further derived his special and general theories of relativity, namely Alcubierre, Natario and White, all towards a "warp" type drive, are at best "speculative". One step above educated fantasy at this point. No working science. Just incomplete math and ideas. FTL.. warp and worm holes are thousands, if not tens of thousands of years beyond us. A suspended animation scenario... about 100 to 150 years....if that far.

Now, if only NASA would announce that Kepler-452b is full of oil, we would have warp engines in under a decade.

Why go that far? Titan, Saturn's moon, is loaded with far more hydrocarbons than are available on Earth.

Don't tell that to the politicians! We'll never get to leave the solar-system if they believe they can have all the oil they'll ever need right here in the neighbourhood!

That's probably the next logical step, though, honestly. Not necessarily oil specifically, but resources in general and even colonization of any nearby planets/etc. that will allow it.

How did we discover (and begin actually using) the Americas? Christopher Columbus was sent on a trip to retrieve resources from India. It was a financial trip, supposed to enrich the government, not an exploratory one.

That's kind of how it's always been. Societies have discovered new people, lands, and resources by accident while trying to expand their empires (generally).

Furthermore, as we continue to consume resources and grow our population, we should probably strive to expand our society to other locations before we overconsume and overpopulate to the point that it starts to cause problems.

So wouldn't a good next step be to point a bunch of radio telescopes at this system and start listening?

IIRC, the amount of radio waves leaking from Earth into space has decreased substantially over the last few decades. I wouldn't be surprised if energy efficiency gets to the point where, if a foreign alien civilization notices radio waves from Earth, by the time they transmit a round-trip back at Earth we'll have long since stopped leaking terrestrial radio waves by accident into space.

True, but our radio telescopes have also been improving. The Square Kilometre Array, under construction in Australia, would supposedly be able to detect "an airport radar system on a planet 50 light years away". I suspect that an advanced civilization 500 ly away would still likely leak enough radio for us to detect it with current or near-future technology.

Unless their technology developed along a completely different path, and the concept of radio waves is too foreign to them because they use an altogether different method of communication that we can't even begin to imagine.

How big is it? They have 2 numbers:

>> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet.

And then:

>> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.

I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

The second reference talks about the star, which is named Kepler-452.

I think "Kepler-452" is the star, and "b" is the 2nd planet in the system. I'm not certain of their naming convention. Edit: Another poster says "b" is the 1st planet found in the system, regardless of position in the system.

Earth is 12,742 km in diameter, so "b" must be 20,387 km in diameter.

Our Sun is 1,391,684 km in diameter, so Kepler-452 must be 1,530,852 km in diameter.

Since the star is 10% larger and 20% brighter, but the same temperature, does that mean it is burning fuel 20% faster, and will enter its later stages earlier?

>I think "Kepler-452" is the star, and "b" is the 2nd planet in the system. I'm not certain of their naming convention.

Yep, you understand it correctly.

I'm not sure this is correct. According to one source[1],

"The name of a newly discovered exoplanet is dependant on the name of the star which it orbits and also if any other exoplanets orbiting the same host star have been discovered. The first exoplanet discovered around a star is given its host star name with ‘b’ appended. The next exoplanet discovered in the same system gets the letter ‘c’ appended and so on. Planets in multiple planet systems are always labelled b, c, d… in the order of discovery."

It's not clear to me why they would begin with 'b' instead of 'a', but basing the order of names on the order of discovery makes intuitive sense. The largest planets would presumably be discovered first, even though they may be in the middle zone of their systems (such as in the Solar System).

EDIT: Kepler-26[2] is an example of the named order not matching the distance from the star. The planets in that system, in order of distance from their star, are: d, b, c, e

[1] https://www.paulanthonywilson.com/blog/how-are-exoplanets-na...

[2] https://en.wikipedia.org/wiki/Kepler-26

Kepler names are numbers for stars and numbers followed by a letter for planets. 452 -> star, 452b -> that star's second planet.

Kepler-452 is the parent star around which Kepler-452b is orbiting.

Kepler-452b is the planet, without 'b' is the star.

Kepler-452 is a star. Kepler-452b is a planet.

Kepler-452b is the planet; Kepler-452 is the star around which it is orbiting.

Kepler has to be one of the most interesting NASA missions in the last few decades. We always suspected there were thousands of planets, but knowing it is exciting.

Does anybody know what the path is to performing some kind of spectroscopy on this planet? Detecting molecules that might indicate life - water, ozone?

When the planet passes in front of its host star, you can measure the change in the stars spectrum, the new chemicals that aren't normally present in a star are assumed to be the planet's.

Telescopes that can do this are still a tiny bit away reality I think.

This can be done now with bright enough stars. The trouble is that the stars in the Kepler field are typically very far away, and thus not really bright enough to do these sorts of studies. Spectroscopic observations of exoplanets have occurred with nearer and brighter targets.

Due to the diameter being 60% larger than Earth's diameter, Kepler-452b's ESI score[0] cannot be any higher than 0.85.

It might not be the most earth like exo-planet as Kepler-438b[1] has an ESI score of 0.88.

[0]https://en.wikipedia.org/wiki/Earth_Similarity_Index

[1]https://en.wikipedia.org/wiki/Kepler-438b

Wow, closer than 452b to us and similar size, have we done any focused listening in its direction yet?

In the article they mention that Kepler-438b is likely subject to extreme solar radiation during flares because it's so close to its star. That would make it poor candidate despite scoring high on the ESI scale.

What's next??? How do we find out if there is life?

More money spent on science and technology.

This, I think the spending on education, science and technology should be the by far the most spending, like 10x imo.

What benefit could that possibly have for humanity? /s

We'll learn how big the invasion force is, and when they're likely to arrive.

I wonder how much of the $100M[1] is going to get aimed at this planet.

1. http://www.scientificamerican.com/article/stephen-hawking-an...

I think the basic procedure is to see what chemical signatures can be observed when the planet passes in front of its star (I believe all Kepler-discovered planets do, it's how it finds them) and then try to infer if those could have occurred through purely physical/chemical reactions or if some form of "life" had to be involved.

But, consider that there are a few places in our own solar system that "could" support life, probably with more confidence than we have in this planet so far, and yet the question is still wide open. I wouldn't expect a firm answer for many decades to come.

A much better telescope

if there is intelligent life there and they point a telescope at us right now, they would be seeing earth ~ 500 years ago.

"check out this planet, looks like a promising place once we run out of materials here."

The planet is 1,400 light-years away. They'd be seeing earth at around 600AD.

by the time our today's signal reaches that planet, we ourselves will already be there to listen to it :)

FTL Travel?

of course. We know that it is possible - the light speed is the limit of speed only in fixed metric space-time, and the Universe itself shows that non-fixed metric space-time(expansion/contraction) can produce FTL speed - just look at all those far galaxies running FTL away from us. It is just a "simple" matter of engineering of local space-time metric geometry changes :)

Things like this boosts my thoughts of life out there living alone, discovering/inventing everything from scratch over and over. While we pride ourselves on passing the knowledge generation by generation to be where we are now, imagine if we could learn/share it beyond our planet, solar system, galaxies.... Long way to go!!

I wonder if we'll abide the prime directive when the day comes ;)

The prime directive is fiction, so probably not.

Well, we would need something like that pro re nata! :) But the very possibility is exciting!

We might... what if we are on the other side... less developed..?! ;)

> 1,400 light-years away

Very cool that we can find it, but I don't think we'll be visiting this one any time soon...

http://www.universetoday.com/15403/how-long-would-it-take-to...

So best case about 28,000 years.

Which is a bugger as I'm out that week.

I think there is a theory that we can travel nearly the speed of light , but yeah even then we are a millennia away :(

If you could accelerate at 1g, you could reach it in 7 years, in your reference frame.

Wait for the observer... isnt it.... 1800 / 17.... 100 years.

So that means, a baby could reach the exoplanet, before it dies of old age, on a spaceship travelling 99% the speed of light, which can theoretically built right now.

How did you arrive at your calculation of 7 years?

Thanks!

I eyeballed it from here[1], which I should have just linked with my post.

[1] http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.h...

I'm actually more excited about Mars-like terrestrial planets. Mars is large enough to have geologic activity and ores, yet it's small enough to be quite easy to get off of and into orbit.

I had a bigger, older cousin when I was a kid. He was awesome. He showed me his Playboys and taught me how to shoot.

On a serious note, I'm looking forward to the discovery of a smaller cousin. That seems to me to be more promising for life: Stuff in water oceans won't sink as readily, so will be able to absorb more sunlight. Avian species will find life easier going (predicated on a suitably dense atmosphere). Any advanced civilizations will have an easier time getting out of its gravity well, and so on.

Buoyancy is actually increased under high G, as the recent SpaceX failure illustrated.

for proportion, studying that planet and its sun is like trying to observe a flea orbiting a ping pong ball floating in space as far away as the moon...

It IS great news... But it's terrible to see the media here in Brazil going like "We're finally close to discover life in another planet" and things like that... And even worse, people sharing like crazy around the internet, without even reading it or trying to understand what really was discovered.

EDIT: typing error

Life could mean anything though. It could be bacterial life or advanced life. This discovery doesn't show otherwise, but it does indicate that there are other places which could harbor earth like life.

I thought that was why we come on website like HN, to get above the average kind of discussions. I don't think complaining about normal channels of discussion is really relevant.

The 385 day year is mentioned. What about hours in a day? Do we know that?

Wouldn't be able to tell from the data. The yearly cycle produces a partial eclipse of the parent star. A day comes from the planet spinning on its axis and there isn't an actual image of the planet that we could analyse for varying brightness.

What is the statistical probability that a star will have a planetary disk that Kepler can view edge on and has planets that will occult the star?

Less than 1%. For every star Kepler has detected a planet around, there's a hundred more stars in its field of view with planets it can't see.

I think the most important issue is:

Are they like us? a civilization that loves going to war and colonize others? that is the most important thing we need to know.

Are they enough like us be incapable of sustaining a space program?

Can anyone show me where Kepler-452b is on a star chart?

Constellation Lyra

Right ascension (α) 18h 46m 35.000s

Declination (δ) +41° 57′ 3.93″

Apparent magnitude (mV) 14.467

"Where is everybody?" --Enrico Fermi

What are the odds that this is just a sunspot?

Only news such as this has the potential to unite humankind.

M class planets.

is there one of me?

There was an older article in the #1 slot with well over 200 upvotes and a ton of comments, but I don't know what happened to it? Perhaps the mods removed it for some reason?

It plummeted down off the front page, and is now a bunch of pages deep: https://news.ycombinator.com/item?id=9935198

I guess it hit some metric in the ranking algo!

It was probably just user-flagged since it was kind of a lightweight submission.

Today NASA, apparently experiencing hard times with budget [1], announces "let's say" just found exoplanet. With pictures. Awesome high res pictures, reposted by every media in the world, of an object 1400ly away from Earth. Oh, uhm... of an object as it was back in 1875.

Photoshop? Sure. For popularization? I wouldn't say. Begging for money? Yeah, more buzz, more money. From whom?

2 days ago Yuri Milner, Russian oligarch and media magnat, announced 100M$ financement of mission to discover new life. Literally 1 person got all this money - Stephen Hawking.

Another 100M$, Yura? Davai, at least now you know where to fly!

[1]: http://www.slate.com/blogs/bad_astronomy/2014/03/05/nasa_bud...

Meh, given the hype for this press-release, I was hoping for something more extraordinary frankly. Not that finding other exoplanets isn't amazing, just that we're all waiting to find out whether we are alone or not in the universe.

Finding out that other advanced civilizations exist out there would bring such an amazing new meaning to life. If I could ask for one wish, it would be to find out if we're alone or not. Somehow knowing we're alone would be a large one to swallow, but the universe works in ways that it doesn't care about our feelings.

Read: "Where are all the aliens?" http://qz.com/452452/where-are-all-the-aliens/

"We’re rare, we’re first, or we’re fucked."

Can't interstellar travel just be impossible?

Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.

Interstellar travel is perfectly possible if you're not in a hurry.

Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.)

If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic.

It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like planets to colonise - they'd be looking for much colder and more stable locations.

And we wouldn't be looking for the right spectroscopic signals to give them away, because we don't know what they are.

The problem isn't just sending something (or someone) to another star (though it would take far longer than 1400 years with any currently plausible technology and energy expenditure). It's sending something accurately to another star (can't use too much energy adjusting course, since fractional additions to weight require tremendously more power) with a payload that's still operational by the time it gets there. Think about the myriad problems NASA probes have after just a relative handful of years or so in space.

Also worth noting is that all deep space missions thus far have had to rely on nuclear power, usually using 238-Pu with a half life of less than 90 years. With such technology, a well-shielded, self-correcting computer system traveling at reasonable speeds and energies could not survive too long because it would simply run out of power. AFAIK, workarounds for this rely on exotic power sources and unproven physics--it's entirely possible that these don't pan out, and this provides our "Great Filter."

There's been some nifty work done on the practicality of electrodynamic tethers and using them to turn a starship against the galactic magnetic field. You won't get sci-fi ship maneuverability out of this, but it's useful for course corrections without having to carry or expend reaction mass.

As far as onboard power sources go, fission seems perfectly cromulent. You just have to protect those radiators.

I can only find one source on using tethers in interstellar travel: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005021.... To quote the article, for energy production:

> Since the tether current is 1,333 amps, ne = 3 X 10‘‘ m-3 and the ship’s velocity is 900 km/sec, the effective electron-collector radius is approximately 3 13 km.

This appears to have a toroidal-field ramscoop as a prerequisite.

For thrustless turning, a 0.06 degree turn requires a tether 10^3 km long:

> To obtain a six-degree trajectory modification during a 1,400-year journey with the tether current assumed, the tether length must be increased by a factor of lOOX to equal l0^5 km. This would increase tether mass to 2.7 X lo5 kg.

And this is using a reference ship many scientists are skeptical about:

> ...it is assumed here that the primary propulsion for these ships is the ultra-thin, space manufactured solar sail unfurled as close to the Sun as possible at the perihelion of a parabolic or hyperbolic solar orbit. After acceleration to interstellar cruise velocity, it is also assumed that sail and cables are wound around the habitat section to provide extra cosmic ray shielding. The sail is unfurled again for deceleration at the destination star.... since the baseline sailcraft for this analysis is somewhat faster, either more advanced sail/cable materials are required or the pre-perihelion orbit is hyperbolic.

I'd definitely categorize that under "experimental power sources and unproven physics." Perhaps you are thinking of a different article?

I got that from a Robert Forward nonfiction book. The craft he described didn't have ramscoops, but were lightsail craft.

1,400 light years/~45,000mph (the speed of New Horizons) = 23,844,146.8 years of travel time. I guess that wouldn't be impossible, but if you've got a ship that can last that long in interstellar space, then what do you need a planet for? Or for that matter, a star?

You wouldn't try to make a 1400-ly trip, and you would try for a much faster departure than NH did.

There are about 10 stars we know about within 11-ly of earth. A serious attempt to reach one would involve doing slingshots around many bodies in the solar system, probably culminating with a dive to the Sun in order where the major rockets would be fired. (The Oberth effect says you get the most ∆v boost at the point closest to the orbiting body. You cannot logically use the Sun as a passive slingshot because you are trying to leave the solar system.) Getting the speed to 1% of c this way looks entirely reasonable, which gives about a century of travel time.

It would be very expensive, but in a few more centuries society will be a lot richer. This is also something that would only occur after significant colonization within the solar system, and mapping of distant star systems to find good candidate systems.

That would be a case of the "great filter" being in the future, no?

I've always read the "great filter" as some kind of mass extinction. I just think that the Fermi paradox gained popularity when everyone thought that both our travel speeds and our population would continue to grow exponentially, making space colonization both inevitable and necessary.

What if we (and every other intelligent life) just level off when we start reaching the limits of physics and the available resources within our own solar system?

I see it as a galactic cold war. On a galactic time scale, any civilization will reach a technology level of "maximum allowed by physics" relatively quickly, unless physics is indeed an infinite maze of rabbit holes.

Therefore inter-species conflicts are resolved by mass/energy available. Any civilization that doesn't expand to interstellar levels of power is subject to the whims of those that do. If you can expand, you must.

Or, "We're deaf, blind, and isolated."

That was an incredible read. Thanks for sharing!

By some accounts we should probably be desperately hoping we are alone in the universe (at least with regards to technological civilizations), since it would mean the Great Filter is behind us rather than ahead. The alternative being we're very likely to go extinct before we get a chance to colonize the galaxy, and since that could probably be done using synthetic biology developed within the relatively near future, that would give our civilization an expected lifetime of less than a few hundred years at most. The more life that exists close to or surpassing our own level of development, the more bleak the future looks for our civilization.

I can understand the disappointment. It's helpful to always keep in mind that when it comes to discoveries, it's easy to hype ourselves up excessively. Recognize that the PR arms of scientific organizations and universities are also somewhat responsible.

I find it helpful to remember that any Big Announcement like definite signs of life or advanced alien civilizations or asteroids hurtling toward Earth wouldn't be in such a small-scale announcement. You'd have the President appearing on TV or something.

Reply on news.ycombinator.com