Earth-like planet spotted orbiting Sun’s closest star
nature.com
nature.com
From the paper (Introduction and Conclusions, respectively) [1]:
The habitability conditions of Proxima b, which orbits within the HZ of the star, have been extensively studied (e.g. Barnes et al. 2017; Ribas et al. 2016; Turbet et al. 2016; Meadows & Barnes 2018). On the other hand, the candidate Proxima d orbits much closer to the star and outside the HZ range.
In particular, the discovery of an Earth-mass planet orbiting Proxima Centauri (Anglada-Escudé et al. 2016), our closest stellar neighbour, was one of the most significant results in the field, in part because the planet orbits inside the habitable zone (HZ) of the star (e.g. Kopparapu et al. 2013).
So, Proxima d is too close to the star to be inside the HZ; it's within the HZ in the sense that the HZ is further out from the star.
The author of the Nature commentary, which claims that "it could have oceans of liquid water that can potentially harbour life", apparently didn't read the paper.
[1] https://www.eso.org/public/archives/releases/sciencepapers/e...
"With the small stellar radius, Proxima d ... equilibrium temperature may reach 360K,"
NB: Earth's is 255K. Venus 260K, Mars 215K. So this doesn't tell the whole story, but is probably quite hot.
So it has a hot side, a cold side, and an intermediate ring at the terminator.
Probably not very comfortable.
And Mercury is almost tidally locked. Venus will be, before long.
Why couldn't something orbit the star fast without being tidally locked?
Planets with fast orbits are closer to the star and get more drag- hence more likely to be locked.
I dislike the term "Earth-like" in these publications because it conjures images of a strange alien world able to support (human) life. Even assuming there were life capable of withstanding the constant flares from the host star, I suspect it would have to look very different in color and likely composition to the plant life here due to needing to capture a different part of the spectrum.
Visible light being right in the middle is the trick which gives us photosynthesis, and sight, because in both cases a photon can be captured by a photosensitive bond. It's harder to come up with plausible photosensitive bonds for IR light, and most anything is photosensitive once you get far enough into UV.
Is this unique to IR?
Waves which are relaxed enough to pass through ordinary matter, but interact in interesting ways with metals and other electron clouds, we call radio. Microwaves start out doing this: usefully, they spin water molecules around, hence microwave ovens. What we call microwaves 'bottom out' on not doing so, it's a useful but somewhat artificial category which I would split between radio and IR if you gave me the gavel.
Unlike visible, which is 'visible' because it has distinct properties.
A world evolved under lower energies and temperatures would select chemicals with weaker bonds. Other worlds evolved under higher energies and temperatures would select chemicals with stronger bonds.
Visible light is visible to us because it is important for molecules we use.
This is not to say that all points on the energy continuum are equally favorable to potential metabolic processes, but life adapts to conditions, even where they are not optimal. I don't know of any reason to assume the regime where Earth life has landed is optimal, but it has proven more than adequate.
Fun fact: Go outside on a clear night, and you can see 5-10,000 stars. There are 8 times that many red dwarfs in your field of view, and none of them are visible to the naked eye. But in 2016 Proxima was for a few minutes.
In March 2016 we saw a superflare: Proxima briefly became nearly a factor of 100 brighter, reaching a brightness just visible to the naked eye from dark sites.
https://www.star-facts.com/proxima-centauri/
Also fascinating, a relative distance vs time graph of close stars. It turns out we'll have closer distances for 6 in the next 10,000 - 50,000 years.
https://www.star-facts.com/wp-content/uploads/2020/08/Neares...
Somehow I feel like Elon Musk has a print out of that graph on his office wall.
There are 6 if you count Proxima Centauri and Alpha Centauri separately; 7 if you count both stars in the Alpha Centauri pair separately, and 5 if you count Alpha and Proxima Centauri separately.
Alpha Centauri is the binary system of Alpha Centauri A and Alpha Centauri B, which are separated by about 10-30 AU. It's very, very close in terms of interstellar distances to Proxima Centauri, which is a red dwarf that orbits Alpha Centauri A and B at a distance of 13000 AU, or 0.2 LY - a remote enough orbit that it makes sense to keep track of whether it's on the near side or far side of the triple-star system.
Belta-lowda! Belta-lowda! Belta-lowda!
They laughed at me when I bought investment property on Proxima Centauri b, but who'll be the one laughing in 10.000000001 billion years?
So we just need to tackle climate change and learn to live sustainably on Earth, then we’ll have a few billion years to figure out how to get to Proxima Centauri.
Loving the Foundation series sofar as well on AppleTV, but the books are great ofcourse.
The current fastest man-man object is the Helios 2 space-probe, reaching something like 25 000 kilometres per hour. Proxima Centauri is 1.3020 parsecs away from Earth.
So, just diving one by the other, we'd looking at something like 18 000 years as a rough order of magnitude for sending something from Earth to Proxima Centauri.
You'd be much better off waiting, well, even a thousand years for technology to improve rather than sending something now.
Note: this is a very dodgy line of reasoning. The Helios probe got a massive speed boost from a close encounter with the sun. But even if the speed is wrong by a factor of ten, we're still looking at somewhere between a thousand and a hundred-thousand years.
If we ever figure out light-weight fusion drives, we could build light hugger space ships that accelerate to a decent fraction of the speed of light. At 1g acceleration it takes about one year to get to 0.9c, which would make the Proxima system accessible with a travel time of about 6 years. Or 8 years at 0.5g. Or 9 years if we 'only' get to 0.5c.
The same goes for laser-driven light sails if we just wanted to send a probe, although deceleration would be an issue. (There is currently an aspirational research project for this called Breakthrough Starshot)
The exciting thing about these technologies is that they don't require new physics in principle, just a lot of engineering. Of course, uploaded minds would probably always be better suited for space travel, but it's neat to know that even biological people could in theory make these trips.
Propulsion maybe the easier part of engineering. Afaik we are nowhere near to life support and environment control that could be considered stable for a time period of maybe 10 years or more.
The biggest biological advantage, adaptation is meaningless for large organism on such a timescale and maybe dangerous on a microbial level.
Maybe someone has a link to more information, that’s just what I remember from years ago.
You need to use the same amount of energy and time to decelerate, as you did to accelerate.
So you'd only be able to sustain constant acceleration for half the distance. Then deceleration for the second half of the journey.
That would make the travel time much, much longer than your calculations, since you'd be traveling at relatively slow speed for both the first & last 20-25% of the distance.
For the cynical or pessimists: I'm not optimistic about humanity reaching year-4,000, I'm just possibilistic about it (as in the philosophical meaning [1]).
[1] https://en.wikipedia.org/wiki/Actualism#:~:text=possibilism,...
No, we couldn't. The energy density of fusion isn't anywhere near close enough to make a lighthugger, you'd need insane mass ratios[1] and ramjets are probably unfeasible (as in, even-if-your-a-Kardeshev-II-civilization-unfeasible[2]).
[1]: http://www.projectrho.com/public_html/rocket/slowerlight3.ph...
[2]: https://www.sciencedirect.com/science/article/pii/S009457652...
I don't agree with everything there either, but usually it's only very minor gripes. In this case though, it's hard to argue with the reality of the rocket equation.
[1]: https://twitter.com/nyrath/status/1436010987086286853?s=20
What are the other few sites you do know of?
And you are absolutely right about the rocket equation. You can't really get around it.
[1]: https://gregegan.net
[2]: http://xenology.info
In my mind, using the admittedly poor analogy of space-time as a membrane that is distorted by gravity, my thinking is we'll find some way to effectively bring two points in space-time adjacent to each other and 'step' between them. Wormholes, Warp, or whatever you want to call it.
Think of a flexible membrane 10 meters long and we are going to travel from one end to the other. We can either travel in a linear fashion over its surface for 10 meters or we can wrap the membrane so both ends are next to each other and travel 0.01m across the gap between them.
Yes, I know there are all sorts of obstacles and arguments against this simplistic visualisation but this is how I've always imagined the physics of any science fiction faster-than-light travel - worm-holes, warp drives, etc.
If you want an actual, real, possible-right-now analogy, think of our current situation where the fastest way to travel from London, UK to Sydney, Australia (1/2 way around the world) is through the atmosphere in an aeroplane travelling ~17000 kilometers and taking at best 19.5 hours.
SpaceX (Musk) Virgin Galactic (Branson), other companies [0], and space agencies [1] have talked about, and are actively working toward, stepping outside the atmosphere into space to reduce the time element to around an hour.
So just like with supposedly faster-than-light travel, by 'stepping outside' the linear/conventional thinking/physics we reduce the time of travel element dramatically. The start and end points don't move but the distance travelled by the transport vehicle itself changes in order to enable the reduction in time.
[0] https://www.telegraph.co.uk/travel/news/new-flights-space-lo...
[1] https://edition.cnn.com/travel/article/hypersonic-flight-air...
On top of it, let's handwave all of this away, poof. Any aliens anywhere in the Universe would also be using it once their technology got to that level. Just from the lack of visitors, we have three possibilities that are immediately evident:
1) Humans are among the first intelligent species to get to this technology in the entire Universe.
2) Other species have it, but all of them, every last far-flung one of them, even the renegade civilizations or the mad scientists at the individual level, abide by not using it around humans. Despite all of their numerous reasoning capacities and utterly inhuman motivations, every last sophont with access to the tech has agreed upon this, and has for thousands of years.
3) That tech can't exist.
The first and second are unlikely, statistically.
I mean we, as humanity, have to have an eccentric billionaire start a Martian fire (SpaceX Starship) under our lazy asses to even start to think about getting to Mars in a reasonable timeframe and in reasonable numbers (to start a colony). We are not funding making our species multiplanetary for the last few decades because we were too lazy, how can anyone expect us sending anything to the closest star (other than the sun)... You can't.
Basically, the tech you need to make a Mars colony truly self sufficient is something like a compact fusion powerplant.
Before we have that, no point in worrying about using Mars as a "backup plan", because if Earth was screwed, Mars would have a couple of years to live at most.
And obviously it would be vastly better for humanity if Musk spent money on zero-emission large scale energy production, than on rockets.
- They don't need fusion. A StarShip can deposit hundreds of solar panels and put them on the ground. No, dust isn't an issue because they'll bring a roomba. No, this isn't a joke, NASA martian probes' solar panels were cleaned by a light Martian breeze.
- They will be able to become self-sufficient rapidly. They're not going to send 1M tons of cargo to Mars without a deployment plan. SpaceX and Tesla have already demonstrated effective vertically integrated supply chains and manufacturing. They have the institutional knowledge to mine raw materials and build factories that build complex parts.
- There are plenty of other Earth-bound governments and billionaires that could devote funds to zero-emission large scale energy production projects. Musk, his companies and assets amount to a very small fraction of the global economy. Your ire is misdirected: your anger about the situation is properly directed at the rule of corrupt imbeciles and their questionable resource allocation decisions (Netflix, coal, etc.) here on Earth rather than one team of folks who seem extraordinarily mission driven and effective.
A large asteroid has only one of these problems, by virtue of not coming with any atmosphere, ionic or otherwise.
I kinda hope Elon is bluffing and actually plans to head to the Belt. I've penciled it out and and he'd have to be insane not to. Surely he has pencils as well.
Q: What does zero-g do to the human body?
A: It's really really unhealthy.
So while it is a “storm” it isn’t like a tropical force hurricane or anything. More like a very minor annoyance that deposits a bit more Martian dust on your stuff over time.
Can this happen? I imagine before we can settle on Mars we first should be comfortable flying there, and the latter should be sufficient for asteroid mining. But, right, our technology is just not at a comfortable level yet.
Mars might not be sustainable in our lifetime but in a century or two? I think it's within the realm of possibility.
As for the urgency, the last two years has demonstrated the exact opposite to me. Modern civilization is a hop, skip, and a jump away from instability and disaster. When you say that we should instead spend resources on large zero-emissions energy production, well, we've had Nuclear Fission for half a century. The reason we didn't use it to prevent Climate Change is 90% political, not technical, another problem that having a self-sustaining colony, outside the sphere of Earth's influence, would solve.
Eh. The physics and proliferation risk are pretty intertwined.
Who's to say we would have been better off with greater historical nuclear weapon proliferation risk but lower climate risk?
We know the path we chose, limited global use of fission power, mostly avoided nuclear weapons proliferation, and did avoid nuclear exchanges. So it's provably a successful (or probably successful) path. Whether an alternative would have gotten the same outcome?
Only if you value the lack of nuclear exchanges over the impacts of climate change. Which one of the two is more likely to cause a mass extinction type issue on the planet, one puts the control in the hands of people and the other the forces of nature.
Unfortunately, our civilization is also mostly centralized. Cities, ports, highly productive land : total land area.
If you're talking persistent radioactive effects for a decade+, it doesn't take many to severely cripple the world.
As an example, a 100kt weapon (or smaller dirty) could knock a port out of action. Now look at a list of ports [0] and imagine what would happen if one or more of them dropped off the global trade grid for multiple years.
[0] https://en.m.wikipedia.org/wiki/List_of_busiest_container_po...
Consequently, for widespread nuclear reactors (read: in many countries), you also had widespread proliferation of lightly enriched uranium (in the fuel) and proliferation of plutonium (produced in the fuel as the reactor runs).
Both of these remove the most time and energy consuming step (low level enrichment) as an obstacle to state nuclear weapons development.
And they're fundamental to the way light water reactor technology works, especially with the limitations of the period. So the only way you could have had proliferation-resistance would have been to have some sort of global fuel-control and -custody agreement (presumably run by the United States, USSR, and maybe France, depending on the time period). Which sovereign countries would have likely felt some kind of way about.
It's not obvious to me that having more nuclear reactors in the US, Britain or Germany would had made it significantly easier for rogue states like Iraq, Iran or North Korea to developed nuclear weapons.
That seems... ethically dubious.
And I'm confused. Your reasoning around why more reactors wouldn't have increased nuclear weapon proliferation was contingent on only the US, USSR, Britain, and Germany (and presumably countries like them, to an approximation) having more reactors.
Either you get to say that (a) all countries, or (b) only "responsible" (for lack of a better word) countries should have used more nuclear power.
If (a), then you have increased proliferation risk. If (b), then you're establishing (and presumably militarily enforcing) a two-tier ability to access cheap energy, that favors developed nations.
But lets I assume you're right and 'a' is somehow correct (I don't agree with the premise that increase in global nuclear power generation capacity would somehow automatically result in a higher risk of nuclear weapons actually being used) that would still mean that the western world, Russia, China, India, Pakistan and all other countries in their sphere of influence or aligned to them would have access to cheaper power (which is at least 80-90% of the global population). And I don't consider 'because Iran does not have access to nuclear power then it would be unfair for anyone else to have' to be very good argument.
In fact even if only developed countries had access to nuclear power (which is obviously not fair and not realistic anyway, good luck preventing Russia and China export their reactor to whoever they want) I still think that would be preferably to nobody having it.
I mean, you would somehow have to make Earth less hospitable than Mars to make the effort worth it.
Classic zero sum thinking. Spacex doesn't cost money, it makes it. How much money do you think Musk put into it? The answer is ~100 million seed. It is now worth 35,000 million.
How far do you think that 100m would go to develop fusion. The ITER project alone costs 65,000 million.
ITER is a dead end, no matter what, so not a useful data point.
There is a difference between buying something and putting in money. If I buy a cheeseburger, I can't say I "put in" $5 to McDonalds and should have some ownership. If I pay my contract plumber to fix my toilet, I don't own their business either.
I think you will be hard-pressed to find any substantial examples where the US gov wasn't buying something from SpaceX.
Just build bunkers here and staff them in shifts. Much cheaper.
Your remaining threats for which Mars would be better than "ruined" Earth are something like a grey goo event, or an asteroid so large that it liquefies much of the crust (killing everyone in all your bunkers). So, a fair bit bigger than the one that killed the Dinosaurs.
I am very interested in watching people try to colonize Mars, but find the "backup for Earth" argument ridiculous, especially if presented as something urgent.
Perhaps in the near future life extension technology will become common place, people may continue to have kids, but natural deaths may be rare; the human population will increase exponentially and need somewhere to live and something to do -- terraforming Mars in exchange for property may be reasonable.
From a standpoint of reducing emissions on Earth, it would be cool to see Elon Musk's best take on how to build a practical fusion generator though. I've heard of a few potential paths that could lead to net power much faster and cheaper than ITER. Supposedly superconducting magnets have gotten considerably better since ITER was proposed, and since power output in a tokamak reactor is something like the third or fourth power of the magnet strength IIRC, there's potential for a newer and smaller reactor design to outdo it in both timeline and cost.
I'm pretty sure not even that.
My favorite moonshot project would be to create robotics that can clean up the environment and handle recycling. Having the technology to pick up dog poop and plastic bags in an efficient and affordable manner or separating recycling items would be a huge technological challenge that would create a ton of spin-off opportunities including a base on Mars. Or clean up the pacific garbage patch with robots.
However, it's likely that one task (going to Mars, even sending a couple rich bozos there) is small enough that you can probably do that and work on fixing things "at home".
In fact, one could argue that one set of big companies that exist this decade that didn't exist last decade is just a shopping list of "Crap I'll need for my martian condo"
... has been said for the entirety of human history. And in all that time, they've only ever been right about Australia. (J/k Aussies!)
Only one technology matters: that which enables transportation.
Animal husbandry. Sailing. Railroads.
In the end, humans are plentiful. As long as it's done in full disclosure and as an uncoerced individual choice, who the hell are we to stand in the way of adventurers taking a chance on a better life?
You can argue from either the perspective of futility of attempt (no chance of success) or futility of outcome (success wouldn't be worth it), but I'm pretty convinced both would be weak arguments, both logically and historically.
And if it hasn't been required, then how are we to look at existing practice and say we're bad at or incapable of it?
You might as well argue that you can build a self-sustaining base on Antarctica.
Of course you can't, because Antarctica can't support life. No amount of shouting into a bullhorn about adventure will change that.
It might be possible with an absolutely epic effort to airlift soil, nuclear reactors, nuclear and other fuels, machinery for every eventually (including chip fabs), raw materials that aren't locally available (which means almost all of them), and habitable structures.
At the end of that epic effort you'll have something that will barely have a toe-hold on long-term survivability. Possibly. If you're lucky.
Not only is Mars far colder, it also doesn't have air. Or surface water. So all the challenges are at least an order of magnitude harder.
And it's much much further away.
Rhetoric and wishful thinking are not going to give you a better life if you can't deal with the reality of the challenges.
There may also be more carbon below the surface, see https://phys.org/news/2020-05-carbon-emissions-moon-theory-b...
The only thing Mars has going for it is hype.
If you want to go somewhere beyond Mars, stopping there and then starting again just sets you back. (Same goes for the moon, or lunar orbit.) "Stepping stones" have strongly negative value in space transport.
If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.
If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not Mars.
Is this really so difficult? Stop, breathe, and think.
This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.
If your true goal is to have crap on and in orbit around Mars, do that without pretending it has any other value. You don't fool anybody, but you make people wonder about you.
Versus, cannibalising several extremely expensive ships in order to get one ship to a destination it's never coming back from.
And this is just one example. The lower delta-v from Mars would allow extra payload to the belt, so if anyone ever intend to exploit those resources, starting from Mars will allow them to get heavy equipment there in less time and fewer trips (provided, of course, that they can manufacture that equipment on Mars).
Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing around in puddles everywhere. There is an interior liquid water ocean, and ice lava flows.
Seriously, if you need more delta-V for a Jupiter or Saturn trip than spaceship design A gives you, you are much better off making a spaceship design B with enough tankage to make the trip. (Maybe B is just A with an extra tank strapped on; or, a tug boosts A to escape velocity and then loops around Luna and back, aerobraking to LEO.) Park fuel depots at both low and high Earth orbits; you waste nothing by using those, unlike anything parked foolishly at Luna or Mars.
Luna, anyway, has stuff that is worth visiting, like craters in permanent shade at the south pole, and lava tubes where vapors have maybe drifted in and froze for hundreds of millions of years. Mars is the armpit of the Solar System.
> You start by shipping a million tons of freight to Mars
The equipment for generating the electricity to perform ISRU on Mars is supposedly within the payload capabilities of a single Starship, 100-150 tons, not a million, and this should be enough for a ton per day, enough to resupply in the 26 month launch window. The equipment for collecting water and CO2 is another matter, and I don't see estimates on that, but with the above and some engineering margin, it seems plausible that this operation can get off the ground in under ten ship-trips to Mars.
Any trip to the outer Solar System that stops at Mars is, energetically, much more costly that one which does not stop at Mars.
In addition, getting stuff to Mars is itself a huge expense that completely swamps any imagined benefit of extracting fuel and launching it to stop by for.
If you want to go to Mars, go without promoting obvious falsehoods about any value it has as a transport hub. It has none. Period.
If, to make sense, your Mars story needs for Mars to be a useful transport hub, then it fails, and you need a different story.
> If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.
This is as asinine as saying, if you can't get somewhere without a stop at the gas station, then you really, really can't get there with a stop at the gas station. Stopping at the gas station costs extra.
After all, it costs fuel to take an exit on the freeway and go to the gas station. It costs fuel to leave and go back on the freeway. It costs extra! Energetically, any trip where you have to make a detour to a gas station, costs more than a trip where you don't make a stop there.
Source?
- 38% of Earth's gravity
- 24.5 hour days
- lots of resources such as iron, carbon, oxygen, water (ice)
- aerobraking in the atmosphere saves fuel
- it's big (same land mass as Earth's). There's enough room for growth.
- temperatures are better than elsewhere in space (-63°C to +20°C at the equator)
- Lava tubes that could offer protection against radiation and meteorites for habitats
- good potential of life / former life
Nobody has colonized Antarctica not because it's impossible, but because it's difficult enough and useless enough that we all agreed on a treaty prohibiting it.
In contrast, we constructed the 63 radars (some with bases) of the DEW line in the late 1950s in under 3 years, with part of the Air Force's budget. Because it was useful.
Establishing a Mars colony is not impossible, it's just extremely hard. Which means expensive. Which means it needs a justification. Which is what I think the knee-jerk is really about.
And is a fair opinion. You may think interplanetary colonization should not be a priority. I think it should.
Our basic priorities are not in order and that is true for a lot of the world.
Tons of people need solutions now to problems we can solve, and we do not solve them because those priorities are not in order.
And with that, there goes that justification.
Higher priority items include:
Not shitting where we eat,
A much reduced focus on killing one another.
There are many others.
I agree with the other commenter.
It may be very frustrating and disappointing to get married to those ideas. No one reading here is going to see them.
Both aquaponics and aeroponics provide ways to grow plants without soil. Breeding insects or algae may provide nutrition with very small amounts of mass needing to be transported.
> nuclear reactors
Yes, these are a necessity but we've sent one to Antarctica before and we could send a more modern one to Mars.
> nuclear and other fuels
The good thing about nuclear fuel is that you need a very small amount of it to produce a lot of energy for a long time.
> machinery for every eventuality (including chip fabs)
Colonists by necessity must make do with less and that does mean a lower standard of living and higher mortality but you know what they do it anyways because some things are worth trading comfort and a decade or two of life for. English colonists didn't bring the entire industrial infrastructure with them to the New World. They brought what would fit on the boats and had to make do with what they could create from local resources or do without. They had the benefit of subsequent voyages but I don't think anyone here is imagining colonizing Mars or Antarctica with a single expedition.
> raw materials
Mars (and Antarctica for the most part) do lack anything biological in origin, no oil or wood or crops as feedstock for chemical reactions but there are always alternatives. We usually don't use those alternate sources here because they are too labour or energetically or materially expensive but when they are your only option price and effort become less of a concern.
> all the challenges are at least an order of magnitude harder
No one who is attempting to work towards this is doing it because it is easy. I remember there being a speech about that which ended up with some pretty spectacular results.
I am all for exploration and science for the sake of science, but any talk of colonies is just wasted breath at this stage. We need to first explore how to live within our means on earth.
I'm not saying we should ignore all the other things in favour of escaping to space. The Earth is the largest volume of habitable space that we have right now but it is also the only one and that's the problem. We should be building other habitats in parallel with solving our current problems. We need a literal backup plan in case things go seriously wrong.
Imagine a StarCraft/Factorio player who hides out in his starting base, building it up more and more and more forever, while talking about "living within his means".
There are effectively unlimited resources right there for the taking! Let's go take them!
Also - "right there for the taking" gets to the heart of my objection as it is nowhere near true. Space is vast and delta-v is expensive - even if we get past the problem of deadly radiation outside the ionosphere, we are incredibly far from being able to make space travel anything other than an enormous sink for money and resources.
I think this argument extends to colonization efforts as well. What is the economic and cultural benefit of founding a new nation? It's not something that we are familiar with at this point in history so we are relatively blind to it. We just take it for granted that the nations in which we live have always been there since they have always been there for us. I have no doubt that once we begin colonizing Mars or the Moon or even just Earth orbit it will have as great of an impact as the colonization of the New World.
Ignoring energy sources (solvable using by a fission reactor), the entire Earth has a similar feedstock problem as Antarctica. There's plenty of hydrogen and oxygen there. CO2 can be mined from the atmosphere by plants. Nitrogen is the remaining building block of life. At this point, most of the nitrogen in human tissue was extracted from the atmosphere using the Haber-Bosch method (which, roughly speaking, converts atmospheric Nitrogen and energy to fertilizer).
I agree that Antarctica would be an easier (and safer) place to build the first self-sustained "moon base"
Is this tongue-in-cheek? I genuinely hope so.
The fact that random groups people from the Old World decided to start colonies without any prior experience or preparation precisely shows that they didn't consider America to be "super-hostile".
Just don't stand in the way of those who chose to go.
Your "golly I'm on Mars!" euphoria would thin out very, very fast. "This place f'n sucks!" malaise would grow steadily and without bound.
Maybe that's a confusing distinction for some.
We can build much better outside of gravity wells. Whatever you would land on Mars is more useful in solar orbit, parked next to any convenient asteroid.
And there's still the problem of ISRU.
"A stop" is not just useless, but is actively harmful in space transportation. You go, for free, until you get there, and then use up fuel stopping. Starting and stopping are exactly what costs. Stopping halfway makes the whole trip cost literally twice as much.
Until you understand this, everything you say about space travel will make zero sense, and furthermore will deeply embarrass you for long after you finally catch on. You make a fool of yourself by continuing in this vein.
https://blog.theclymb.com/out-there/because-its-there-the-qu...
The 1950s-2000s NASA model for space exploration was unusual in its centralized approach.
In today's world, mega corporations have no defense if a government actor decides to use force against them.
This utter defenselessness against violence is the main difference between a modern corporation and a feudal actor.
They get the freedom to focus on their business, within the bounds of the law, by ceding violence authority to the government. And in return, the government establishes and enforces those laws.
"A probe based on nuclear pulse propulsion could do it in around 50 years, with today's technology."
I was always under the impression that these vast distances were basically entire unreachable in several human lifetimes.
Let's see... Neptune's orbital diameter 8.3 light hours.
At 10% c (speed of light) you would need 83 hours. Yes, insane speed, yet hopefully enough time to take quite a few pictures.
Also the plan is not to send a single "disc", but many (thousands?). Together they could potentially provide a treasure trove of data from within the alien solar system.
So we have the ability today to move 50K tons of parts into orbit, and come up with vast quantities of helium-3?
this is why we don't see any signs of life out there. there really isn't any point in trying to venture beyond your home. universe is just too big even at the speed of light when you start venturing beyond your local group.
If you get really close to the speed of light (which is not really practical from a materials engineering standpoint) your time of transit is significantly shorter.
Once these (extremely hard) engineering problems are solved, a trip to the next star can be a week-long affair from your point of view, but your friends back on Earth won't see you for about a decade.
That just isn't practically doable with any technology within humanity's reach, probably for centuries. If it ever will be at all.
The amount of energy needed to propel anything at that speed is enormous.
In order to spend a leisurely "cruise-ship" week to Proxima you'd need to go very close to c. At that speed, even friction with a non-ideal vacuum is a problem :-D.
You’d need to travel at around 233x the speed of light to make getting to the nearest star be a week trip, no?
[0] about 0.99999c if what someone else in this thread said is correct
None. Photons don't experience time, they are time.
But, for all intents and purposes, this is impossibly fast ;-)
Unless you are on the Bistromath, that is.
We have barely scratched the surface of what is truly going on out there. It would be incredibly “human centric” to think our current understanding of the universe is “it”, in my opinion.
I guess that's why arthur c clarke said sufficiently advanced technology is indistinguishable from magic. I just think that kind of magic would be visible to us. Or maybe it is, but we just can't tell.
We should and do send probes anywhere that's practical. The question is more like when it will be practical to build star probes.
The current fastest man-man object is the...
The current fastest man-made object wasn't intended to reach the stars.
On the other hand, there are many challenges that make more sense to undertake as previous steps to develop the needed technology.
The fastest crewed spaceship was Apollo 10 at 39,705km/h before reentry. After orbiting the moon they had lots of fuel left over so they just floored the engine on the way home. Not just falling back towards the planet but actively flying towards the ground for longer than any other Apollo mission.
This record can be broken with current technology, we just have to go back to the moon.
quoting from reddit:
> You may be thinking of the Sun as a big gravity well and how you can just drop things in a well. But orbits don't work anything like that at all. Sure if you are stationary relative to the Sun then you'll fall right into it. But anything that leaves Earth is very far from stationary. You're going at 30 km/s 90 degrees off your target. Possibly the first idea many people think of if they want to hit the Sun is to cancel that 30 km/s of speed, and sure it'll work. But you need 30 km/s of delta-v. On the other hand, to escape the solar system from Earth you only need a velocity of 42 km/s relative to the Sun, of which you already have 30 km/s. So you only need to increase your speed by about 12 km/s. (And for both cases add one or two km/s to counter Earth's gravity.)
https://www.reddit.com/r/askscience/comments/wjv87/comment/c...
https://www.forbes.com/sites/startswithabang/2019/09/20/this...
252 792 km/h
And even if we could get the adversial networks to model all this garbage, etc it needs to line up with the plan of the rest of the Universe from the franchise and the managers can't even decide whether the photon is going to be a wave or a particle. Jeez. Vaporware like HL2.
https://news.ycombinator.com/item?id=29638529
Of course that doesn't necessarily preclude a nearby higher level Kardashev Civilization becoming interested in all the noise we're making and heading over.
As we put up systems beyond Webb, it may be possible to observe a hypothetical inbound craft / fleet some years off, which would have interesting effects on our current human society, once it became generally known..
My suspicion is that the social media generation would react a lot worse than the radio generation did to the 1938 broadcast of H. G. Wells' War of the Worlds:
https://www.space.com/40435-finding-aliens-humanity-reaction...
Indeed. If that's the case, the universe is an infinitely big and infinitely boring place.
OTOH, our future uploaded selves may be able to slow down their clock rates and make the trip so much shorter.
And you don't need to leave your dear ones on Earth - just bring forks of them along you (chances are a fork of you will remain on Earth anyway).
Looking at current aging research, there's a good possibility we'll see rejuvenation in the next decade or two and it'll profoundly change our society. In 20 years, everyone will be looking 25 years old and pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers.
Once that's out of the way, we'll eventually get comfortable with building arbitrarily large objects on orbit, and we could as well build a huge spaceship with an onboard self-sustaining ecosystem and fly that to other stars, the boring way. Yes, it will be a very long journey, but it's possible without the reliance on yet to be discovered new physics.
It's not rock-solid that this is going to happen for the whole body soon, but some truly breakthrough things are happening right now in this field, nothing like the previous decades.
Even a very big ship can be boring after a sufficiently long time.
Except those people are more likely to be too poor to afford it instead of unwilling to take it.
Then you have the "surfeit of princes" problem.
This isn't just grand political power: imagine being unable to progress in your career because geriatrics above you aren't retiring.
That's just one possible secondary effect. We could enumerate many others.
Just to be clear: I'm not from the US, we do have not a very good but nevertheless somewhat working public health system over here.
In the US, we just will do neither for the majority of Americans. If you're too poor to afford rejuvenation, you'll be too poor to afford other treatments. And you'll just die.
Sure the cost of each treatment might be pennies (although it probably will cost a lot and not have those economies of scale) but total profit is not maximized by a smaller markup. Better to get Gates/Bezos/Musk/other billionaires to give you 90% of their fortunes.
Unless, of course, living a thousand years brings some wisdom with it.
I’m totally ok with a post-scarcity socialist society.
We ARE good at extreme, surgical and or heavy medicating intervention. Doesn't go hand-in-hand with life extension at all.
Also please do look through the playlist in a sibling comment. Michael Levin's research is truly badass. He has grown tadpoles with an extra working eye on the back, and recently he has regrown an amputated leg on a frog.
There's an astonishing amount of untapped possibilities in biology that are opening up only now as we finally have the right tools.
I bookmarked this thread specifically to watch your links later. I appreciate them and will watch, as I am really interested in the topic.
My hope is that biotech is the next step, but as I mentioned, for now I am highly pessimistic. We can't seem to treat virtually anything in any real sense, despite the experiments you mention. If anything, the progress in prosthetics (including the spinal bypass) has been great, but nothing to do with life extension or genuine recovery of lost functionality without surgical intervention.
Personally, it seems to be me that the closest thing we can do so far as individuals is reduce risk factors and try to stay high on Death Clocks: https://www.lifespan.io/news/grimage-is-the-best-clock-for-p...
Completely unrelated, but this reminded me that we can't seem to regrow cartilage either. This is a huge issue after cancers and cardiac deaths. Any falls, excessive wear and tear, etc all destroy quality of life with the joints. Latest efforts here: https://www.studyfinds.org/arthritis-pain-regrowing-cartilag...
Thing is, medicine/biology is a unique field because it relies quite a lot on advancements in other fields for its tools. You couldn't research cells before microscope was invented. You can't begin figuring out what each part of a genome does before you've sequenced it. You can't begin to research functions of specific proteins before you've solved their structures and got the ability to manipulate their production and/or attach markers to them. And so on, and so forth. Not so long ago the main approach in medical research was basically "try stuff randomly on lab animals and see what has a beneficial effect". Now that we can peek into the internal workings of biological systems we can use a more direct, more engineering-like approach.
If we can, from time to time, merge our memories and refork, this wouldn't be a big issue, as both forks would experience both lives.
I think that, at this point, we wouldn't be that much human anymore.
We'll still need some form of magical propulsion or, worse, some magical power source. There aren't many things that can keep providing energy for thousands of years. I'm pretty sure fission is a non-starter here and even nuclear fusion designs would need a source of tritium because, after a couple thousand years, there won't be much left of the initial fuel.
It orbits the star every 5 days; it's a quarter of the earth's mass. It's also a tenth the distance from its star that Mercury is from the Sun. It's earth-like only in that its temperature is consistent with there being liquid water.
The abstract refers to it as "sub-Earth", and a "Earth-mass".
So even if the thing's tidelocked, and has no atmosphere because stellar flare-ups, it still counts as earth-like. TIL.
And suddenly i am imagining lots of very smart people drinking lots of caffeine.
"To find the wobble.."
this is not helping :)
"ESPRESSO is kept in a special room at the observatory, inside a tank "
oh come on ..
It has a significant life span of about 4 trillion years and could easily outlive the present universe several times.
On a more serious note is this a good candidate for JWST, would it be able to infer chemical composition from the planet's spectrum or something?
Awesome though we went from (in my lifetime) learning at school that other planets have never been observed, to finding them sprinkled around basically every star just like our own. I feel like it won't be long before we detect the first potential chemical markers of alien life, if it's out there. Keep doing your thing space science folk!
The odds that there is life on our generational ship when we arrive are not that great either.
Oh... and did I mention that Proxima is a known flare star?
Wake me up when they find a terrestrial world in the habitable zone of Alpha Centauri instead.
Anyway if Stellaris has taught me anything it's that the flares will add additional energy credits to the system... what's not to like?
It’ll be Spacey McSpaceface if we put it to a vote.
Titanic. Moribund. Lethe. Purgatory I-X. etc.
- - - -
Tangent: Have you read Gene Wolfe's Book of the New Sun? It's less famous than the books above, but (IMO) it's in the same rarefied company as Dune and J.R.R. Tolkien's work.
I haven't even heard of Wolfe's book. Will check it out, thanks.
After a week of reflection, I think it was a slight overreaction -- the book is still very very good but i dont think #1 for me.
But something about the way the story took shape and culminated in the final third of the book was so engaging, and so satisfying. I think I stayed up until 4 or 5AM the night I finished the last 200 pages.
Full name is A Remembrance of Earth's Past.
Quite a nice concept - accelerate the probe with lasers- no plans for deceleration though
What's becoming clear though is the only thing stopping us from lots of Earth-mass planets is the abilities of our detectors to detect ever-smaller gravitational wobbles and ever-smaller transits. Bear in mind we only tend to find planets around stars where we're on their ecliptic planes.
So planets seem to be really common. If they weren't the odds of finding planetary systems on our nearest stellar neighbour would be quite low.
But the distances are still so vast that the energy expenditure and timelines are completely impractical (if you assume the speed of light of a hard cosmic limit, which I do).
So if planets are common and interstellar travel is impractical, the only way to expand really is around your own star. This is the Dyson Swarm. This would actually solve the energy issue of interstellar travel (ie"stellar highways") so it's almost a prerequisite. Thing is, Dyson Swarms are likely detectable from vast distances due to their IR emissions (ie the only way to get rid of heat is to radiate it into space and that has a specific frequency depending on the temperature of the radiating object).
But if planets are really common and we don't see any Dyson Swarms it seems that spacefaring life is extremely rare and the most likely number of such civilizations in the Milky Way is 1 including us.
Do we really know enough to be able to say if a planet is habitable? Or could there be other forms of life that we don't know of yet... We have only recently put a man on the moon, and now we're saying we would be able to detect dyson spheres...?
I mean, I know the proof of life is us, but the human-centered view of the universe does reek of prior historical "knowledge" that the earth was the center of the universe. I understand searching for life like us, as that is what we can extrapolate from current data. But to use that to infer that we're it, it's just too much for me.
The key question is that if planets are so common and space is so big, why does it seem to be so empty of life? You bring up an argument that maybe life is so different as to be undetectable. It's a fair question to ask but the beauty of the Fermi Paradox is that you don't need to argue about what's most likely. You simply have to be concerned with what's possible.
Let me put it this way. let's say that there is 1 other spacefaring civilization in the Milky Way and they've evolved like you said in a way completely alien to us and as such don't follow a path we can easily detect or at least we don't think to look for it. I can buy that as entirely possible.
But now let's assume there are 1,000 spacefaring civilizations in the Milky Way. What are the odds that every one them falls in this category? What are the odds that none of them follow a similar evolutionary path to us and what we consider highly likely? It becomes increasingly incredulous as you scale up the number of civilizations.
So what's more likely? 1,000 civilizations followed a path alien to us independently? Or that there are few to no other civilizations out there to detect?
To say we're the only 1 of 1,000 to follow this path is really a different kind of human-centric hubris.
Extracting energy from a star is so low-tech it defies logic to think we're the only ones who will (likely) do it.
A moth doesn't even have electricity, but it can detect a lampshade. A Dyson sphere is basically a stellar lampshade; we can detect it if the laws of thermodynamics hold, and we're pretty sure they do. (A Dyson swarm is similar, though a bit harder to detect.)
1. The speed of light is a hard limit; and
2. Thermodynamics (particularly the Second Law) applies. Specifically, you can't get energy from nothing.
From this you can draw a few conclusions:
1. The likely sources of future energy are solar (most likely IMHO) and nuclear fusion. I hope fusion is viable. I'm not yet convinced it is. More exotic far-future options include antimatter and black holes. Antimatter is something you'd make. Think of it like a battery. So you still need the energy to make it. Black holes as propulsion are the same way. Generating power around a large black hole is theoretically possible but has a bunch of issues;
2. Reaction mass is a huge problem for traveling large distances, so much so that using photos to impart momentum seems the most practical. Fusion could be viable here. Antimatter and black hole propulsion are theoretically possible;
3. Because of energy demands, capturing the Sun's energy makes the most sense and doesn't require any "magical" or exotic science or technology;
4. Because of thermodynamics, eventually heat will radiate into space. It's really the only way of dissipating heat, ultimately.
5. Like I said, the IR signature is purely a function of temperature; and
6. A star with a Dyson Swarm will have a very strange (to us) spectrum. Very little visible light. High amounts of IR. There is really no hiding such a megastructure.
So this is essentially a natural conclusion based on physical laws we have no evidence for that they're false or meaningfully incomplete. Thing is, if the speed of light isn't a hard limit that actually makes it more likely we'd find spacefaring life not less because the reach of such a civilization would be so much farther.
Space travel is only considered to be impractical for humans, or similarly large organic entities within their limited lifespan.
The time constraint and the mass constraint may not be particularly relevant to intelligence that no longer has organic form.
An artificial lifeform may not have a defined life span and thus taking 100,000 years to travel the stars may be acceptable.
Additionally, they may only need to make the trip once to establish the receiving antenna, in order to transmit their "progeny" around the galaxy.
Tldr; We are like ants thinking that we need to figure out how to make really long tunnels to cross the Atlantic, instead of focusing on the limitations of our physical bodies.
Rocks though space, but that doesn't help learn much. Rocks bring up the other issue is we don't know how many high velocity things might be between starts, numbers below the noise limits of our current sensors is enough to destroy anything we could send out.
If you haven't already, give Rendezvous with Rama a read.
2) speed of light is a hard limit, you cannot keep accelerating and you need more energy the closer you get to that limit
No that would be a waste of effort. A flyby mission definitely makes the most sense. The 3.5 years are with deceleration though.
> Humanity’s first chance to explore this nearby world may come from the recently announced Breakthrough Starshot initiative, which plans to build fleets of tiny laser-propelled interstellar probes in the coming decades. Travelling at 20% of the speed of light, they would take about 20 years to cover the 1.3 parsecs from Earth to Proxima Centauri.
4 trillion years. Wow. If there was life on one of the planets, it would have a long time to evolve.
"Earth-like planet spotted orbiting Sun's closest star" is a lot sexier than "We detect a signal at 5.12 ± 0.04 days with a semi-amplitude of 39 ± 7 cm s−1. The analysis of subsets of the ESPRESSO data, the activity indicators, and chromatic RVs suggest that this signal is not caused by stellar variability but instead by a planetary companion with a minimum mass of 0.26 ± 0.05 M⊕ (about twice the mass of Mars) orbiting at 0.029 au from the star. The orbital eccentricity is well constrained and compatible with a circular orbit."