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Four Earth-sized planets detected orbiting the nearest sun-like star

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Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#41

Post by ceejayoz »

baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

Humans manage to live in the Sahara, the Himalayas, tolerate being a hundred pounds overweight fairly well, Alaskans deal with weird day/night cycles, etc. I don't think we're quite as sensitive as you make us out to be.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#42

Post by opdahl »

baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

At this point, we might have to see that it is necessary to genetically modify humans so that they can survive in these alien environments. Maybe we cannot be comfortable with 10% higher gravity, but we can _make_ ourselves be comfortable.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#43

Post by Pigo »

baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

I'm left wondering these same kind of issues every time there's a Mars habitation post. Having a third the gravity, microscopic dust, and a complete lack of nature (or Internet) seems to be trivial to some people.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#44

Post by throwanem »

Pigo wrote: post #43
baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

I'm left wondering these same kind of issues every time there's a Mars habitation post. Having a third the gravity, microscopic dust, and a complete lack of nature (or Internet) seems to be trivial to some people.

Also: no magnetosphere, so none of the same barrier to most cosmic radiation behind which we've evolved.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#45

Post by sqeaky »

dmix wrote: post #36
gnarbarian wrote: post #29

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... Project Orion is awesome and I am a big supporter. Unfortunately people won't stand for the thousand some odd nuclear bombs it would take to get the interplanetary version out of the atmosphere. Because it is so massive, building it in space also poses a problem unless we capture a iron meteorite and bring it back or mine/build it on the moon. Both of wh…

Is there a significant difference between a nuclear explosion in space compared to on earth? Would it be less powerful or offer greater thrust?

A nuclear explosion in space wouldn't push against the air and would expand spherically unless somehow contained.

Because it doesn't use conventional chemistry the presence or absence of chemicals, like ambient oxygen wouldn't change the output (like it might for a fuel air bomb) but their their properties might change it. Air will provide some resistance and fluoresce at high enough temperatures. I am curious how big this effect would be though. Debris leaving a nuclear explosion in space would only stop when it hit something and that I think is the biggest flaw with the Orion motor.

If the motor and fuel can be designed so only particles are emitted and somehow ensure that no bullet size fragments are ejected then it seems likely it could be made safe in a practical sense.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#46

Post by jlebrech »

1812Overture wrote: post #30
lmm wrote: post #18

Earlier quoted context omitted.

If we wanted it badly enough, we could get to tau Ceti with current technology. The Orion designs are sound, and could carry a population capable of sustaining itself for the 100-odd years it would take to get there.

Orion designs really only work if you're evacuating the planet. Massive fallout and radiation would be caused by each launch.

the could launch it using a nuclear powered cannon

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#47

Post by dmix »

svachalek wrote: post #33
h4l0 wrote: post #2

Hearing distances like 12 light years makes you think if it is ever possible to travel there. However, when you start to think about it, nihilist thoughts start to kick in.

12 light years is actually very close as interstellar distances go. Such a mission could probably be launched in our lifetimes if the whole world got together behind it (which they won't but still...)

Which has fascinating implications when considering extraterrestrial life. But at the same time it's entirely possible that the closest other life is extremely far away which would make any theoretical travel time be too long to meaningfully discover earth.

Does anyone recommend any books that have explored these ideas?

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#48

Post by dmix »

sqeaky wrote: post #45
dmix wrote: post #36

Earlier quoted context omitted.

Is there a significant difference between a nuclear explosion in space compared to on earth? Would it be less powerful or offer greater thrust?

A nuclear explosion in space wouldn't push against the air and would expand spherically unless somehow contained. Because it doesn't use conventional chemistry the presence or absence of chemicals, like ambient oxygen wouldn't change the output (like it might for a fuel air bomb) but their their properties might change it. Air will provide some resistance and fluoresce at high enough temperatures. I am curious how bi…

So the two biggest issues seem to be a) stopping after accelerating and b) not getting hit by space debris while travelling at those speeds.

That said they at least all seem like solvable problems given enough time and resources.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#49

Post by jcadam »

kowdermeister wrote: post #10
chrismealy wrote: post #7

The fastest spacecraft ever built would take 4000 years to travel one light year.

In 4000 years we can build way way more faster ships and catch up to those poor guys launched a centuries earlier just because they thought they are fast enough :) On the serious side, we only need antimatter and the drive problem is kind of solved (yes, I might be the one in the good enough ship :)).

Good, the folks on the faster ship can arrive ahead of us 'poor guys' on the first ship and get stuck with all of the hard work of establishing the colony and performing any necessary terraforming before we arrive.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#50

Post by scotty79 »

baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

Why would gravity be the problem? There are people that weigh twice the weight of other people same height. I guess very low gravity could affect calcium in the bones and there could be other various effects. But people are life and life is adaptable. Day/night cycle? It varies greatly on earth too. Also one person's nightmare is just life for some other.
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