NASA finds a large amount of water in an exoplanet's atmosphere
nasa.gov
nasa.gov
https://en.wikipedia.org/wiki/James_Webb_Space_Telescope [0]
Evidence of photosynthesis as well!
You do not need animals to have plants. Plants came before animals here on earth. But I’m not sure of a way for animals to exist without plants. So yeah a stronger indicator of photosynthesis than cellular respiration.
Conscious Venus Flytraps that seek after other plants to enhance their vitamins.
But secondly, even if you do, it's a positive feeling, as long as it doesn't replace thinking and acting. Which this comment clearly doesn't.
The Earth is pretty small and far from the sun compared to the kinds of exoplanets we've been able to detect, so the wobble (which might be detectable via doppler shift of light from certain elements in the sun) would be slight and probably hard to detect without some pretty sophisticated instruments.
It might be possible to detect something the size of the Earth from several light years away with a good enough telescope, but I'm not sure what the limit of that is.
Such orbits are extremely rare. Any such orbit would be highly unstable, as any perturbation would cause the planet to deviate from its location. (Strictly speaking, there are five points where objects can have an orbit that matches that of another planet. They're called the Lagrangian points, and the only ones that are stable are L4 and L5, 60˚ ahead and behind the planet in its orbit.)
Knowing what a planet is made of would require some other technique. I think the best you could do from looking at the wobble would be to say things like "planets that orbit stars like this and having a mass of such and such with an orbital period of so many days are likely to be made of the same things that other planets with those characteristics are made of".
On the other hand, we can know pretty easily quite a lot about what it's host star is made of by examining the light it emits.
Edit: Well, as per the simulated stable thread, apparently you can have Trojan etc pairs of planets in the same orbit. Interesting.
With a 6.5 meter space telescope and a star shade, we pretty much have the capability within just a few years to blot out the direct light from the host star and perform spectral characterization of exo-Earths using the light from their host star that is bouncing off of them. In particular, this is a direct exoplanet observation, not indirect like the host-star radial velocity method. An example being studied right now is HabEx (https://en.m.wikipedia.org/wiki/Habitable_Exoplanet_Imaging_...).
From such spectra, we can use chemical and general circulation models to constrain the atmospheric composition, height, and temperature. We can investigate whether the atmosphere is in chemical equilibrium, or if there is some non-chemical process active. The paper referenced in the article actually does some of this (although this is a larger planet).
See for example the Viking experiments: they detected signs of life on Mars, only to be disproved later by better understanding of soil chemistry.
https://en.wikipedia.org/wiki/Viking_lander_biological_exper...
https://www.forbes.com/sites/startswithabang/2017/02/16/supe...
https://www.astrobio.net/alien-life/seeing-earth-exoplanet-s...
And if you're wondering about the techniques and possibility of detecting life, IIRC the eponymous book has a whole chapter about exactly that.
Is that a lot?
Odd choice, indeed.
Must be a lot!
https://saturn.jpl.nasa.gov/resources/7549/?category=amateur...
I guess what's messing with me is that it just looks so smooth, which life-long exposure to CGI has taught me to mean that it's fake.
This reminds me of what Elon Musk said about his Tesla in space: you can tell it's real because it looks so fake.
I'm trying to imagine how the result of a close encounter between Saturn and a Saturn-sized bathtub full of water could be anything other than a single merged sphere with a lot of water content.
An Olympic swimming pool scaled for a Saturn-sized swimmer on the other hand... Ignition!
High resolution transmission spectrum of the Earth's atmosphere -- Seeing Earth as an exoplanet using a lunar eclipse
Its an answer to the age old existential dilemma: are we alone in the cosmos. And would indeed provide a modicum of hope for the future of humanity ;)
Exoplanet hunters rethink search for alien life
https://www.nature.com/news/exoplanet-hunters-rethink-search...
700 LY is practically our backyard and makes it much easier to observe.
Even if we never visit that particular planet, we may learn something useful that tells us something about planets nearby, or even about our own solar system.
At this point, we're just collecting data about extra-solar planets, which we weren't sure even existed until recently. With so many unknowns, it's exciting whenever we can fill in our knowledge gaps just a little bit.
But of course the 'catch' is that time dilation (and length contraction) kick in. And so while from the frame of reference of the ship and all its travelers only 12 years will have passed, from the frame of reference of everybody back on Earth - 700 years would have passed. What we would observe is that as the ship approached the speed of light, its apparent mass would approach infinity, reaching a velocity asymptote at the speed of light.
And these values are also not linear. It's possible to travel a practically unlimited distance in the span of a single human lifetime - from the perspective of that human. 100 trillion light years would take about 62 years at 1g from the perspective of those on board our ship. There's also really really fun paradoxes available here. Imagine somebody leaves Earth towards this planet and at some point decades, or perhaps even centuries later, we develop technology that enables substantially faster travel. Our planetary settlers on their 12 year journey could arrive 12 years later to find that not only is the planet indeed colonized, but it's colonized by the descendents of Earthlings that left decades, or even centuries, after they did.
The really exciting thing here is that NASA seems to have gone silent on the EM drive after having it pass every single test they threw at it. In my opinion, this is evidence of classification which is something that would make sense. If the EM drive somehow actually works - and everything we know says it most certainly should not - that would change absolutely everything. The ability to actually start realistically considering these sort of missions would be mundane compared to other possibilities, which I'm not even going to get into as they sound, and should be, absurd. As an aside, this part on the EM drive is 100% speculation - not to be confused with everything stated above, which are direct and heavily tested (even if absurd sounding) consequences of relativity.
It is absolutely a limit on effective travel (if we ignore things like wormholes for a second). Conventional motion through space is bounded by c for several reasons, not the least of which being that the closer you get to c, the more energy it takes to make smaller and smaller changes in velocity (the object acts as though it's gaining mass the faster it goes). In fact, it's asymptotic. Accelerating a particle to c would require an infinite amount of energy.
You are currently moving at near the speed of light relative to many things at this very moment, yet your mass is certainly not approaching infinity, America notwithstanding! And if you accelerated enough in the opposite direction of your relative partner to exceed the speed of light it's not like you'd suddenly start finding it impossible. No, it's a matter of observation. From the other particle's perspective it would see your mass approaching infinity and your speed would slow, but the distances you covered would remain the same due to length contraction.
A similar effect explains why, for instance, particles in CERN's reactors travel distances that should be impossible for them to travel before decaying. E.g. if the speed of light was 10m/s and a particle decays after 3 seconds then it should be impossible to see that particle travel more than 30 meters. Yet we see it travel hundreds of meters. Isn't relativity fun?
In short, you can't go faster than light in any reference frame, relative to any other observer.
Here's another source: https://physics.stackexchange.com/questions/75501/lorentz-an...
As you accelerate more and more you will never observe yourself or anything else exceeding the speed of light. Instead what will happen is that time will begin to slow down and distances will begin to contract. If in our frame of reference a distance is 100 meters, it would begin to seem to be, for instance, 10 meters.
And the people observing you will also never see you exceed the speed of light. Instead they will see you approach it, and then start to level off asymptotically. Both views are correct. Time itself is what changes. From the perspective of the observer, time will be moving more slowly for the observed. e.g. this is why particles at CERN travel vastly greater distances than they 'should' be able to before decaying. Imagine what it would be like to experience that travel from the particle's perspective.
This is why we see our particle last much longer than it should. And if humans could live for 1500 years, this is why we would see things like our ship make it's 700 light year journey, and then beam back a message that would only hit us 1400 years later - telling us that they're safe and sound and got there in 12 years. Quite fun stuff!
Put another way, this would be the timeline of our ship in years from its perspective and from earth's perspective:
0 earth relative = ship leaves
0 ship relative = ship leaves
700 earth relative = ship arrives at planet
12 ship relative = ship arrives at planet
1400 earth relative = message from ship on planet arrives at earth
712 ship relative = message from ship on planet arrives at earth
This is the most counter intuitive thing about relativity, and time dilation. It's not some 'trick' or matter of perspective. Time itself does literally move at different rates for different people in different scenarios, even when we're all in the same universe. Our ship pilot could make the 12 year journey back and indeed 1400 Earth years would have passed in the interim, and if was somehow able to measure the age of the other planet - 1400 years would have also passed there as well. Even though he himself had only aged 24 years.
Should we achieve the ability to reach relativistic rates of travel - some people may get their wish. Expect huge chunks of the rich to up and leave 'to the future' (from our perspective we'd just see them constantly zipping around near the speed of light... for centuries) in hopes of discovering if humanity has overcome mortality by then! Reality is much stranger than fiction.
> The speed of light is not a speed limit on effective travel, but on observation.
Which is absolutely factually false.
There tend to be three groups of people:
- Those that accept things at face value, which is quite silly. What I'm saying should challenge all intuitive notions of reality making open acceptance simply bizarre.
- Those that reject things at face value. No better than the first and generally driven by an extremely superficial understanding of physics. As Feynman phrased it, people sipping martinis at a cocktail party and discussing relativity, "Ah yes.. how insightful. Though I think some things may indeed be inherently correct. Mmm..."
- And those with a strong physics background already, to whom you provide no additional value to anyhow.
You’re missing a couple of zeroes there ;)
Since we're speaking of planets light years away. The only way for humans to get out there, is to stay in some kind of spaceship with gravity.
Floating around on the International Space Station is nice for an hour. But after that, I bet it gets boring real quick. Especially, if you need to go use the restroom, and handle liquids and solids.
So, having artificial gravity is nice. It will keep liquids down. You can drink out of a cup. Food doesn't float away. You can surgically operate safely. You can use the restroom normally.
But, you would need a very large structure, to spin around, in order to not get the effects of Coriolis Force. And since it is currently difficult to build such a large structure in space, then I wondered if we could cheat.
The method is to apply a constant force, but at an angle. This angle will allow the space craft to simulate a rotation, like it is being spun around with an invisible tether. This angular force will push all the occupants inside, to feel 1 G of gravity. And after one full rotation, then the space craft will return to the origin point.
So, the idea is to apply an angular force, to cause a space craft to rotate in place, to simulate artificial gravity.
This is similar to the idea of constantly accelerating a spacecraft, so that the occupants feel 1 G of gravity. But that acceleration would shoot the occupants straight into deep space, which is not what we want.
Instead, this method would be like simulating a Ring World, but instead of rotating the space station, it would use constant angular force to cause the rotation, in order to simulate the artificial gravity.
I was thinking something like an electric-ion engine could be used to provide the constant thrust. It would need to be computer controlled, to automatically administer the right force, at the correct angle, at the correct time, in order to rotate and simulate the artificial gravity. And it can be powered by nuclear, or possible solar. And of course, the thrust can never be turned off, otherwise, the space craft would shoot off into deep space.
One idea I thought was to have this be in a large orbit around the earth. The other location would be at the Earth-Moon Lagrangian Point.
Any space infrastructure architects want to take a stab at this idea? Possible or not?
Their ships accelerate at a comfortable level to generate gravity for half of the destination, and then "flip-and-burn" by accelerating in the opposite direction at the same comfortable level to generate gravity.
Not sure we can do that for an extended amount of time (read: a few hours) without bringing along lots of fuel
That or we invent that special drive of that dead Martian.
On the plus side you quickly approach c. At constant 1g acceleration / deceleration, Andromeda is about 28 years away.
Because you can't cover 2.578 million light years in only 28 years moving at c from the reference frame of Earth.
If you can generate 1 G of force (which is far beyond the capabilities of an ion engine), you’d be better off accelerating directly toward your destination and doing the “flip and burn” half way.
Do you have a citation (or better yet, a calculation) for this? I’ve been searching for about 10 minutes and and it doesn’t quite make sense.
The full moon typically casts about 0.05 - 0.1 lx.[1] With perseverence and some eye strain, I think I could read by that on a particularly clear night. This isn’t a perfect heuristic, but it seems reasonable to start with as a baseline.
Per this calculation[2], 1 lx is approximatly equal to 5 x 10^15 photons per second per square meter. The best moonlight you can typically expect from a full moon is approximately a tenth of this luminosity.
Then per the notes here[3], there are only something like 450 photons per cubic cm in space on average, which seems reasonable for a first approximation of diffused light in interstellar space. That’s vastly lower than 0.1 lx, and that’s before considering that the majority of those photons aren’t actually visible light.
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1. https://academic.oup.com/astrogeo/article-abstract/58/1/1.31...
2. https://electronics.stackexchange.com/questions/174314/calcu...
3. https://physics.stackexchange.com/questions/196366/does-the-...
http://www.badastronomy.com/bad/misc/badstarlight.html
It doesn't seem so unreasonable. I have also read the human eye can detect a single photon and 450 photons per cm³ is about 3e10 photons per second.
What is max velocity we can, with current tech, achieve for shooting a probe to a target;
Possible to build a giant rail gun in space where a falcon heavy is the payload (plus a nuke battery) and we shoot the falcon heavy out the rail gun, then at some point it’s various components engage to keep it heading to target.
Also if you shoot a rocket out a rail gun, and it’s clipping along, will the rocket thrust add any velocity, or should you save all that fuel to land the heavy on the remote planet?
Do rail guns behave differently in space?
In practical terms we'll need a warp drive. And the whole new type of mathematics and physics to support it.
With extreme longevity you can even get over the time aspects (If a human can live for multiple centuries, a few decades spent on travel isn't that much time).
※ No need to terraform - instead of adapting the planet to humans, adapt humans to the planet. Scarce atmosphere? Add the Nepalese genes to survive at high altitude[1]. Heavy gravity? Increase bone and muscle mass. Water world? Gills it is!
[1] https://www.sciencemag.org/news/2014/07/tibetans-inherited-h...
Edit: I got my numbers from http://convertalot.com/relativistic_star_ship_calculator.htm...
If you really want to get things over with quick, 10gs will get you there in well under 2 years. I wonder if that's survivable, if you were under water the whole time with a scuba tank or something?
The ship's mass will also increase relativistic-ally, as it will reach a maximum speed of ~0.9999961c, so more mass will require more force for the same acceleration.
NASA > Phys.org
The paper link is worth following if you're interested.
It describes using an exoplanet general circulation model (atmosphere model) to recover the temperature-vs-pressure profile within the exoplanet atmosphere - pressure being a proxy for height (Fig. 11a). They also retrieve temperature-vs-longitude.
But the NASA.gov page is just a blank, black screen until you turn on javascript and it renders the text in.
> In 2014, the Israeli facilities of Hadera, Palmahim, Ashkelon, and Sorek were desalinizing water for less than US$0.40 per cubic meter. As of 2006, Singapore was desalinating water for US$0.49 per cubic meter.
Try drinking a thousand liters of water, and get back to me with how much you think it would be possible to spend this way before killing yourself through excessive water consumption.
In any case, it sounds like a few dollars a month for normal usage.