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Water found on a potentially life-friendly alien planet

nationalgeographic.com

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Re: Water found on a potentially life-friendly alien planet

#371

Post by not_a_cop75 »

cthalupa wrote: post #164
grumpy8 wrote: post #156

Earlier quoted context omitted.

Or sending a HUGE human civilization spaceship somewhere.. maybe it will outlast the earth?

In a lot of ways, living on spaceships/space stations/other artificial constructions is likely a better path forward than looking to colonize new planets in general. O'Neill cylinders are quite practical, and with advances in technology that seem likely to occur, even larger projects like Bishop rings should be doable. They can be linked together to form constellations, and have enough free floating resources within…

O'Neill cylinders are so practical that most of this stuff we have no idea how to practically accomplish.

Edit: The sizes involved for launch would present no less than a hundred trillion budget at the moment.

Re: Water found on a potentially life-friendly alien planet

#373

Post by typeformer »

anyfoo wrote: post #183
typeformer wrote: post #25

I say let's go. Now, whether you believe it or not, it is a fact that the US government has acquired alien technology and yet continues to keep it hidden by being stuck in a cold war mindset of, "well, we can't let the Chinese or Russians get their hands on this". That is the ultimate expression of narrow thinking, especially when there is a whole universe out there! Bring on the downvotes but history will vindicate…

You think any sizable group of people would be able to keep any secret, not even talking about such a juicy one, for any significant amount of time?

NSA Domestic spying kept secret 30 years Area 51 kept secret 39 years National Reconnaissance Office kept secret 51 years Operation Paperclip kept secret 53 years US service members who died during d-day rehearsal kept secret 34 years Amnesty to Japanese war criminals in Unit 731 kept secret 51 years

The truth is UFO’s and the alien pretense are too big to keep secret that his why there are already so many leaks from within the military, but until things are officially acknowledge the public is still just guessing.

Re: Water found on a potentially life-friendly alien planet

#374

Post by najarvg »

Sorry if it's been mentioned in the threads before - Here is Phil Plait's (@badastronomer on twitter) practical explanation of this finding - https://www.syfy.com/syfywire/water-vapor-detected-in-the-at... TLDR - "NO, THIS DOES NOT MEAN THE PLANET IS EITHER EARTH-LIKE OR HABITABLE."

Re: Water found on a potentially life-friendly alien planet

#375

Post by klyrs »

bestest wrote: post #368
healsjnr1 wrote: post #321

Earlier quoted context omitted.

1G would be great as it would remove any unexpected physiological impacts of living in zero or low gravity. Having said that, the distance and duration means that only a small portion of this journey would be under acceleration, the rest would be in zero g. Spending a century in zero g would probably have a bunch of strange side effects and almost certainly mean that the people alive when they arrived wouldn't be abl…

Not quite true. You'd spend half of the travel time under 1g accelerating, then the ship does a 180 degree flip in 0g, and then you spend another half of the travel time under 1g decelerating. Edit: Of course, at constant 1g acceleration, at day number 354 we reach 1c. Don't know if we should start coasting before we reach 1c or just the hell with it and see what happens if we keep accelerating.

So many people in this thread are acting like constant acceleration is possible. Unfortunately the faster you get, the more energy it takes to maintain constant acceleration.

> Don't know if we should start coasting before we reach 1c...

Don't worry about it. Your rocket would need to expend an infinite amount of energy to accelerate to c. The energy stored in your finite-sized rocket is finite. At a certain point it becomes futile to keep trying to accelerate -- though I suspect that the impacts of space dust will eventually cause a significant amount of drag

http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/r...

Re: Water found on a potentially life-friendly alien planet

#376

Post by cthalupa »

not_a_cop75 wrote: post #371
cthalupa wrote: post #164

Earlier quoted context omitted.

In a lot of ways, living on spaceships/space stations/other artificial constructions is likely a better path forward than looking to colonize new planets in general. O'Neill cylinders are quite practical, and with advances in technology that seem likely to occur, even larger projects like Bishop rings should be doable. They can be linked together to form constellations, and have enough free floating resources within…

O'Neill cylinders are so practical that most of this stuff we have no idea how to practically accomplish. Edit: The sizes involved for launch would present no less than a hundred trillion budget at the moment.

I mean practical in that there's no exotic science required. Everything required we have ideas on how to accomplish now, and the big issues are making it cost effective.

And as for the 100 trillion budget, if you're launching from the earth, sure. Geologists are pretty sure the moon has plenty of materials useful for building stuff. We've already built mass drivers, and the physics for building one that could launch raw materials from the moon are perfectly sound.

Yes, we need to figure out mining materials and building stuff in space. But we're going to have to figure that out anyway if we want to survive as a species in the long term, and there's plenty of advantages in starting to figure that out now, especially since we're staring down the barrel of a gun vis-a-vis climate change.

Re: Water found on a potentially life-friendly alien planet

#377

Post by methodover »

gradschool wrote: post #306
methodover wrote: post #170

Earlier quoted context omitted.

Err, that isn't a correct understanding of physics, I believe. The ship wouldn't need to reduce its output as it gets faster relative to some other object in the universe. It can happily keep accelerating at 9.8 m/s for as long as it likes (or has fuel). No passengers would get squashed.

If the ship's means of propulsion is set to impart a constant force, then I understand that the passengers could experience a constant acceleration indefinitely, but that constant acceleration would be with respect to the ship's reference frame, not ours. A constant acceleration of 1g in our reference frame would mean by definition that the speed reaches 2c in two years, which can't be right. Subject again to the dis…

Oh I see! 1G from our reference frame! Fascinating! That’s a perspective I haven’t seen before, I didn’t realize that that’s what you meant. Indeed, it isn’t possible. We’d see the ship slowly approach but never reach the speed of light, no matter how hard or long they step on the accelerator.

Re: Water found on a potentially life-friendly alien planet

#379

Post by tunesmith »

healsjnr1 wrote: post #321
tunesmith wrote: post #264

Earlier quoted context omitted.

No, it assumes you start and end at whatever that maximum velocity is that we've been able to achieve. That'd be fun to add, though. I'm not really sure what human-safe acceleration is - people here assume it's in the 1g-3g range. (That seems like a lot to me though, particularly for a long period of time - I think anything more than a fraction of g would be wildly uncomfortable.)

1G would be great as it would remove any unexpected physiological impacts of living in zero or low gravity. Having said that, the distance and duration means that only a small portion of this journey would be under acceleration, the rest would be in zero g. Spending a century in zero g would probably have a bunch of strange side effects and almost certainly mean that the people alive when they arrived wouldn't be abl…

Can you alternate accelerating and decelerating? I mean that's a heck of a lot more energy, but at least you're not risking reaching light speeds.

Re: Water found on a potentially life-friendly alien planet

#380

Post by wahern »

wahern wrote: post #285
dragonwriter wrote: post #142

Earlier quoted context omitted.

> If you put some money in an interest-bearing account you could at least buy a new home when you got back. If you do it in a country that doesn't allow you to be declared legally dead when you are out of contact for a couple centuries, and if the institutions involved don't collapse, and if the interest on the account outpaces inflation, sure. What percentage of the banks that were around 222 years ago have not fail…

That's not the right question, though, because the expected rate of failure isn't constant throughout the lifetime of a bank. See, e.g., https://en.wikipedia.org/wiki/Lindy_effect Seems like your best bet would be to park your money with several very old banks: https://en.wikipedia.org/wiki/List_of_oldest_banks_in_contin... Also might want to think about purchasing bonds: https://en.wikipedia.org/wiki/List_of_oldest_…

2nd link was supposed to be https://en.wikipedia.org/wiki/Perpetual_bond with information about a bond from 1648 with the issuer still paying annual interest.
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