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Water found on a potentially life-friendly alien planet

nationalgeographic.com

71–80 of 410 posts

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

#71
post #4

Earlier quoted context omitted.

It's 111 light years away. For all intents and purposes, that's a one way trip right there; irregardless of the rocket equation. Even at relativistic speeds, you can't come home anymore.

Theoretically, you can. At 0.99c 111 light years take about 15 years of ship time to travel.

Which would put you in your 50s to 60s if all you did was go there and back.

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

#72
I am thinking to get a not very expensive refraktor (120 mm) with Azimutal mounting, for deep space and terrestrial observations. Just interested in Astronomy, but have no idea what level of details can be seen with that kind. I am fascinated by Orion Nebula and Andromeda which I can see with simple 8x42 ED binoculars. Now thinking about telescope. Dobsonians look pretty heavy, I want something portable and inexpensive. Do you have any suggestion? Are refractors good for that?

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

#73

Earlier quoted context omitted.

Theoretically, you can. At 0.99c 111 light years take about 15 years of ship time to travel.

You can make the trip arbitrarily small from your perspective (in theory at least :) ). The issue is that by the time you've made it back home, it's 222 years later. Hence "you can't go home anymore". :)

If you put some money in an interest-bearing account you could at least buy a new home when you got back.

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

#74

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…

Evidence?

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

#75

Earlier quoted context omitted.

Exactly From the reference article: > Travelling from the surface of Earth to Earth orbit is one of the most energy intensive steps of going anywhere else. This first step, about 400 kilometers away from Earth, requires half of the total energy needed to go to the surface of Mars. Which means that if we use something like a balloon/blimp in the first stage, it would be a lot more energy efficient. Anyone knows why it…

most of the energy spent getting to that 400km low earth orbit is spent accelerating to very very fast lateral speeds. If you use a balloon to get your rocket up as high as you can before launching it you limit the weight of the rocket you can lift up there, and most of the weight of rockets is used to gain that lateral speed. The plane + rocket idea has been shelved for now, as reusable rockets have decreased the pr…

Isn’t that orthogonal to interplanetary travel though?

If you go straight up far enough you’ll be out of Earth’s gravity well.

You’ll still need acceleration to escape the solar gravity well, but you’ll never need horizontal acceleration necessary for Earth orbit.

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

#76

Earlier quoted context omitted.

Surface gravity will be around 2g, so even if it has a rocky surface it's not going to be a very comfortable home from home.

So a 150lb person will weigh 300lb. Sure that's gonna suck on day one but there's plenty of people who weigh that much who get by. Without all the health complications from high body fat it wouldn't be that bad. You'd probably die young but I don't think that would bother people.

Not sure the two are comparable. 300lb obese person's bone structure weighs the same, their heart and lungs weigh the same. I suspect 2x the weight on every organ is going to be seriously detrimental for sustained periods.

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

#77

Earlier quoted context omitted.

You can make the trip arbitrarily small from your perspective (in theory at least :) ). The issue is that by the time you've made it back home, it's 222 years later. Hence "you can't go home anymore". :)

If you put some money in an interest-bearing account you could at least buy a new home when you got back.

You know where I can find one of these interest-bearing accounts that can outpace housing cost inflation?

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

#78
post #65

Earlier quoted context omitted.

Theoretically, you can. At 0.99c 111 light years take about 15 years of ship time to travel.

And how much time will it take a person to reach that speed at human-safe acceleration? And how much energy would it take?

I calculate it to take about a year, with 1 g acceleration, but don't take my word for it, am curious to compare with a more authoritative answer.

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

#79

Earlier quoted context omitted.

You can make the trip arbitrarily small from your perspective (in theory at least :) ). The issue is that by the time you've made it back home, it's 222 years later. Hence "you can't go home anymore". :)

If you put some money in an interest-bearing account you could at least buy a new home when you got back.

Better do it in different countries and in different currencies and hope none of them get confiscated or have hyperinflation.

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

#80
post #8

With a planet this large, visiting it would be a one way trip due to the "The Tyranny of the Rocket Equation" [0]. I'm looking forward to the day we start finding exo-planets that are closer to Earth in size and which could potentially have space-faring races (and which we could leave if we were ever to visit them). [0] - https://www.nasa.gov/mission_pages/station/expeditions/exped...

So that's purely for a chemical rocket, right? Is there any combination of tricks that can realistically push the envelope there? For example can we use a space elevator to start higher/faster (or, I don't know, balloons? a catapult or railgun or something?), laser power delivery from the ground, so we don't have to carry all the fuel, and an orbiting way-station for refueling, etc.?

Nuclear bomb rockets would probably do https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
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