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Two potentially life-friendly planets found orbiting a nearby star

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Re: Two potentially life-friendly planets found orbiting a nearby star

#71
post #17

Earlier quoted context omitted.

"However, more recent research is somewhat more optimistic." I am deeply skeptical of that "recent research", which AFAIK is "computer models, where we have zero capability to verify the computer models against even a single data point". The incentives to keep kicking the computer model until it provides something publishable, with no countervailing force provided by real data to be explained by the model, are just t…

Physics models are often checked against other models (which might have had some confirmation) in simple cases, and there are a lot of other sanity checks you can make on them to ensure they are providing reasonable results. Obviously, one shouldn't blindly accept them without experimental confirmation, but one shouldn't also be wildly pessimistic in believing calculations grounded in three centuries worth of validat…

Yes, I'm sure the simulations don't have results like making these atmospheres suddenly collapse into black holes due to errors in the simulation or something. They'd notice.

But these atmospheres have to stable across cosmological scales in a highly iterative, chaotic environment. There is a mathematical lower bound on the rate such simulations must leak bits as a result of those things. I don't think we have enough bits of real information to make up for that, as it would take rather a lot.

Against the mathematical argument, I set the human argument that, like I said, there's all sorts of incentives to report the one simulation that produced the result that there may be an atmosphere and maybe it could even sustain life! That's a lot of high-profile articles and probably a promotion for getting my department some public attention. Even if hundreds of other simulations all result in "Yeah, the atmosphere freezes out".

Between the math saying we can't really expect this sort of simulation to contain meaningful information and the human factors involved, I can't put a lot of confidence in a model which can't be validated against real data.

I do find it amazing how people who probably think they're really in favor of science and support it will jump up to defend a methodology that literally runs off of zero data. Can someone explain the scientific process to me clearly that involves having no data at any point?

Re: Two potentially life-friendly planets found orbiting a nearby star

#72

Earlier quoted context omitted.

I always visualized that the tidal locking to be sort of like meshed gears, such that the one revolution around itself is same as a rotation around the star/planet if its a satellite. But that shouldn't affect the day/night in this case right? Since we are talking about planets not satellites of planets and they are light sources not just reflecting light from the star. Can you please correct where I am wrong?

Tidal locking means that the denser side of the lighter body always faces the heavier body, and the less-dense side of the lighter body already faces away from the heavier one. The moon is tidally locked to the Earth, which is why it has a dark side.

There is no dark side in the moon.

There is a far side.

Re: Two potentially life-friendly planets found orbiting a nearby star

#73
post #27

Stop teasing me, Universe - and show me the aliens already!

Check out the Dyson Dilemma for a well-reasoned theory as to why it is a high probability that there is no space-faring intelligent life anywhere in our galaxy or even perhaps our super-cluster. https://www.youtube.com/watch?v=QfuK8la0y6s

There are holes wide enough to fit a solar system through that argument. Reductio ad absurdum.

Here, I'll construct an argument in a similar form. People don't like mosquitos, for various reasons including that they transfer deadly diseases. Therefore the presence of mosquitos says there's a high probability that the planet isn't actually inhabited by us, because we would have killed them by now. After all, we have the technology.

Maybe, by the time we get around to wanting to construct a Dyson Sphere, we will have found a better alternative. Maybe they aren't a good idea for any number of reasons (if you need one, read the Cixin Liu "Dark Forest" series).

Any argument of the form "X is inevitable but hasn't occurred, therefore Y" first needs very strong proof of the inevitability of X.

Re: Two potentially life-friendly planets found orbiting a nearby star

#74
post #55

Earlier quoted context omitted.

Tidal locking means that the denser side of the lighter body always faces the heavier body, and the less-dense side of the lighter body already faces away from the heavier one. The moon is tidally locked to the Earth, which is why it has a dark side.

So the Apollo "earthrise" photos are just "earth"?

No; they weren't taken from the moon; they were taken from the Apollo 8 spacecraft, which was orbiting, so the Earth did in fact 'rise'.

Re: Two potentially life-friendly planets found orbiting a nearby star

#75
post #27

Stop teasing me, Universe - and show me the aliens already!

Let's just say a part of Mass Effect is real and there are actually many civilizations right now. What are the chances that we could even know they exist with the current technology?

Re: Two potentially life-friendly planets found orbiting a nearby star

#76
post #51

Earlier quoted context omitted.

Are you talking about the propulsion system where a series of nuclear explosions push the vessel along? https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

yes, we should explore (and eventually exploit) all forms of propulsion and decide between them based on physics, not politics

That Orion project was a failure though. No tangible results to exploit.

Re: Two potentially life-friendly planets found orbiting a nearby star

#77
post #32

"just 12 light-years away" I love the "just". I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-)

Look into Project Orion. With thermonuclear bombs you could hit 8% c, which would get you there in "only" 150-200 years including acceleration and deceleration time. That is still beyond humans with present day life spans, but extend life span to ~1000 years or go full AI and you can totally ride the "devil's pogo stick" to stars Fusion rockets would probably be better. I mention Orion because we sort of know how to…

>Orion is a fabulous and quite valid counter to the folks that seem to like to repeat the canard that interstellar flight is impossible.

I’d never say it’s impossible, if we maintain a civilisation for long enough it might even be inevitable at least at a minimal level.

However, Daedalus/Orion is far from as straightforward as has been suggested by you and others. It’s based on projections of technology made in the 70s, not 70s technology. There are also formidable obstacles, such as obtaining enough Helium3. The authors suggested extracting it from the atmosphere of Jupiter or Uranus. That by itself would be as hard as building the vehicle itself, if not harder. I’d like to see a design for a Jupiter atmospheric scoop and return vehicle.

Also Daedalus couldn’t take people. Staggeringly huge as it was, it was a flyby mission with a 450 ton payload. If it was going to decelerate instead it’s payload was about the size of a washing machine.

Re: Two potentially life-friendly planets found orbiting a nearby star

#78
post #77
post #32

Earlier quoted context omitted.

Look into Project Orion. With thermonuclear bombs you could hit 8% c, which would get you there in "only" 150-200 years including acceleration and deceleration time. That is still beyond humans with present day life spans, but extend life span to ~1000 years or go full AI and you can totally ride the "devil's pogo stick" to stars Fusion rockets would probably be better. I mention Orion because we sort of know how to…

>Orion is a fabulous and quite valid counter to the folks that seem to like to repeat the canard that interstellar flight is impossible. I’d never say it’s impossible, if we maintain a civilisation for long enough it might even be inevitable at least at a minimal level. However, Daedalus/Orion is far from as straightforward as has been suggested by you and others. It’s based on projections of technology made in the 7…

Not Daedalus, Orion. It was a 1960s research project involving Freeman Dyson and others. Google it. There is a fantastic documentary that I think is on YouTube.

Orion is kind of shockingly practical. It was forgotten for some time as it was a military research project not NASA or academic.

Re: Two potentially life-friendly planets found orbiting a nearby star

#80
post #45

Earlier quoted context omitted.

You're not alone. I grew up reading and watching a lot of sci-fi. Today I recognize that most of it was garbage in terms of physics, but I'm still saddened that the universe isn't that easy - we can't just hop on a space cruise ship and do a tour of a nearby nebula...

Going to Mars may be routine some day, though!

Just going to Mars will significantly increase your risk of cancer, unless we find smart ways to repair our genetic material as we go.
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