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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

#161
post #77

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.

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

While not an interest bearing account, investing in an index fund of global stocks should outpace housing. Investing in a REIT should roughly keep pace with housing costs.

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

#162
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.?

[deleted]

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

#163

Earlier quoted context omitted.

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

accelerating at 1G to the mid point, then decelerating at 1g, will mean you’ll get there in about 15.8 ship years, or 115 earth years. Spend twice as long on boats though (32 years) and you can do about 10,000 light years.

A constant acceleration of 1g would cause the ship to hit c in about one ship year.

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

#164

Earlier quoted context omitted.

It seems like it would be much easier to terraform the real estate around us than try to opt for something 100 light years away. Mars has a leaky atmosphere - sure it's a real fixer upper. But we have a better chance of fixing it, or even correcting the orbit of our planet so that in 500 million years it's still livable.

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 the solar system to be able to build enough of them to support populations in the trillions.

It probably sounds less than ideal to you and me, vs. living on a planet, but it probably wouldn't be so bad to someone born in that sort of environment and is used to it.

With that in mind, I don't know if it makes sense to try and find human habitable planets, vs. just places with lots of raw material we can use. Unless there's alien life we want to go meet up with, at any rate.

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

#165
post #82

> potentially life-friendly Spoiler: it's not

Life friendly != human friendly.

I understand that. This planet is far more likely to not be habitable, period. We might as well consider Neptune to be "potentially life-friendly".

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

#166

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

> traveling at the speed of light it would take 4 billion earth years to get there

Genuinely wondering how you got that number. I'm reading 111 light years in the article, wouldn't that simply be 111 years of travel time, at the speed of light? Am I missing something?

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

#167

Earlier quoted context omitted.

Just under a year at 1g (according to google. I'm on mobile and would have to derive from F = ma on paper to solve). Energy is variable. I'd assume energy isn't relevant, as it's currently impossible, so we're taking that for granted. Not really that long.

Not a physicist, but I think it might not be that simple. From our point of view, a ship with constant 1g acceleration increases its speed by 9.8 m/s every second, but people on a ship moving at a significant fraction of c take more than one of our seconds to experience one of their seconds. During the time they experience one of their seconds, the speed increases more than 9.8 m/s, so they must experience greater th…

Isn't a second now officially defined as a single period of atomic decay of a certain atom (I think Cessium?)? So this theoretical near-lightspeed craft could adjust it's accelerators based on an onboard atomic clock that would not be based on seconds as we tend to perceive them, but on SI seconds. I assume these would be getting longer as velocity approached 1c. Unless radioactive decay is also affected by relativity (obviously I am not a scientist), in which case of course that wouldn't work.

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

#168

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 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…

Bitcoin! :)

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

#169
post #56
post #52

Earlier quoted context omitted.

Light does not experience time at light speed - it is stuck in a static moment. So from our stationary perspective, light takes 111 years to come from a 111 light year distance, but from light's perspective it takes an instant.

Every time I think I’m closer to understanding matters of time and space...

So, actually, like, it's actually really intuitive I feel like:

From the perspective of an object accelerating, newtonian physics works totally intuitively. If you had a rocket that could accelerate at 1g indefinitely, you just go faster and faster and faster and you get to any destination you want (even far away!) pretty quickly. And it would be a rather comfortable trip! You'd have Earth-like gravity the whole way.

It's really only the observer's perspective that things get confusing. When an observer watches something accelerate, they see it never going faster than the speed of light, no matter how fast it "actually" goes.

The trick is time. Time for slow things passes faster than time for fast things. A clock on a very fast rocket ticks much more slowly than clocks on (relatively) stationary things. That's how the paradox is solved.

Let's say you wanted to visit the Andromeda galaxy, which is around 2,500,000 light years away. If you had a rocket that could travel at 1g indefinitely, you'd get there in a comfortable 29 years! However, observers on Earth would see the trip taking around 2,500,000 years.

If you'd like to play with these numbers yourself, feel free to check out this neat calculator (not made by me)

http://nathangeffen.webfactional.com/spacetravel/spacetravel...

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

#170

Earlier quoted context omitted.

Just under a year at 1g (according to google. I'm on mobile and would have to derive from F = ma on paper to solve). Energy is variable. I'd assume energy isn't relevant, as it's currently impossible, so we're taking that for granted. Not really that long.

Not a physicist, but I think it might not be that simple. From our point of view, a ship with constant 1g acceleration increases its speed by 9.8 m/s every second, but people on a ship moving at a significant fraction of c take more than one of our seconds to experience one of their seconds. During the time they experience one of their seconds, the speed increases more than 9.8 m/s, so they must experience greater th…

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.
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