Terra forming and the death of the earth.
Discussion
After reading this and this article linked to in the comments, my interest in terra-forming was re-awakened.
However a thought occurred about the death of the solar system - assuming the sun becomes a red giant and humans still exist on earth what sort of time scales are we talking about between us noticing all is not well with Sol and the earth becoming uninhabitable?
Would we have enough time to get to Mars, terra-form it and make that home for while while we plan our next jump, or does this sort of thing happen too quickly (ie the sun becoming a red giant)?
(I appreciate Humans may not exist, or by then we could have already gone but the question is more about the time scales than the validity of the scenario)
However a thought occurred about the death of the solar system - assuming the sun becomes a red giant and humans still exist on earth what sort of time scales are we talking about between us noticing all is not well with Sol and the earth becoming uninhabitable?
Would we have enough time to get to Mars, terra-form it and make that home for while while we plan our next jump, or does this sort of thing happen too quickly (ie the sun becoming a red giant)?
(I appreciate Humans may not exist, or by then we could have already gone but the question is more about the time scales than the validity of the scenario)
Current estimates give around 5 billion years until the sun enters it's red giant phase. Current research suggests the earth will be consumed, but ther is also a view that as the Sun expands it will lose mass and the earth go move out and away from it's current orbit. But angular momentum will also decreaase so the sun's equator will "bulge" and the earth will be consumed.
I think the time frame is apporx 5 millions years for the red giant phase.
So yes I would think many generations ahead will have found a way to leave earth and terra form Mars, but even this may not be enough. Who knows wew are more likely to be finsihed off by a comet or asteroid long before the earth dies anyway.
Sadly none of us will ever know.
I think the time frame is apporx 5 millions years for the red giant phase.
So yes I would think many generations ahead will have found a way to leave earth and terra form Mars, but even this may not be enough. Who knows wew are more likely to be finsihed off by a comet or asteroid long before the earth dies anyway.
Sadly none of us will ever know.
Sheets Tabuer said:
Once the earth stop dragging it the moons orbit will slow, when it slows enough the gravity of the earth will rip it apart.
Anyhow its all academic as we'll not be here to witness it.
I wouldn't have thought so. The moon is drifting further away from the earth each year. The further away it moves, the less tidal forces caused by the earth are exerted on the moon. My understanding is that the moon will drift away from the earth until the earth's axial rotation slows to the point where they both end up permananely facing each other in a tidal lock. However, this process is happening so slowly that the sun will reach red giant stage before that point has arrived.Anyhow its all academic as we'll not be here to witness it.
Gokartmozart said:
Current estimates give around 5 billion years until the sun enters it's red giant phase. Current research suggests the earth will be consumed...
...So yes I would think many generations ahead will have found a way to leave earth and terra form Mars,
I think you'd agree there'd be zero point in moving to Mars under the circmstances. The entire Solar System would be uninhabitable by the time the sun reached the Red Giant stage, so what would be the point in expending all that effort to move to the next rock along?...So yes I would think many generations ahead will have found a way to leave earth and terra form Mars,
Edited by dr_gn on Sunday 24th October 11:17
Eric Mc said:
Sheets Tabuer said:
Once the earth stop dragging it the moons orbit will slow, when it slows enough the gravity of the earth will rip it apart.
Anyhow its all academic as we'll not be here to witness it.
I wouldn't have thought so. The moon is drifting further away from the earth each year. The further away it moves, the less tidal forces caused by the earth are exerted on the moon. My understanding is that the moon will drift away from the earth until the earth's axial rotation slows to the point where they both end up permananely facing each other in a tidal lock. However, this process is happening so slowly that the sun will reach red giant stage before that point has arrived.Anyhow its all academic as we'll not be here to witness it.
The only thing keeping it up there is the speed it is going as I'm sure you are aware.
But it is also moving away. The further away it is, the slower it needs to orbit to stay in orbit. At what point would tidal effects of the earth's gravity start breaking up an entire body. Those tidal effects weaken with distance. The moon would break up if it started getting CLOSER to the earth, not if it drifted further away.
Gravity alone does not break things up. It is the tidal forces created by gravity that do the damage.
Gravity alone does not break things up. It is the tidal forces created by gravity that do the damage.
Maybe I'm not explaining the theory properly.
It is moving away because it is being dragged faster, once it gets sufficiently far away it will stop being dragged faster and its orbit will slow, when it slows it will start to fall back to the earth.
It is in a perpetual state of falling but its velocity keeps it up there.
It is moving away because it is being dragged faster, once it gets sufficiently far away it will stop being dragged faster and its orbit will slow, when it slows it will start to fall back to the earth.
It is in a perpetual state of falling but its velocity keeps it up there.
The faster something moves relative to the object it is orbiting, the orbit will increase in diameter and the object wiioll then slow down. It's a kind of balancing act.
There is also the situation regarding conservation of momnetum of a two body system, which is tied into orbiting speeds, orbital distance and axial rotation of each body relative to each other. It all gets very complicated but the end result is always that the total amount of momentum is the system is maintained. As the moon recedes, the earth's rotation on its own axis slows down. The system stabilises when both bodies are locked with one hemipshere of one body permanently facing one hemisphere of the other body.
The earth's rotation has been slowing down ever since the earth/moon system formed, and the moon has been receding in direct proportion to the slowing of the earth's day.
There is also the situation regarding conservation of momnetum of a two body system, which is tied into orbiting speeds, orbital distance and axial rotation of each body relative to each other. It all gets very complicated but the end result is always that the total amount of momentum is the system is maintained. As the moon recedes, the earth's rotation on its own axis slows down. The system stabilises when both bodies are locked with one hemipshere of one body permanently facing one hemisphere of the other body.
The earth's rotation has been slowing down ever since the earth/moon system formed, and the moon has been receding in direct proportion to the slowing of the earth's day.
dr_gn said:
Gokartmozart said:
Current estimates give around 5 billion years until the sun enters it's red giant phase. Current research suggests the earth will be consumed...
...So yes I would think many generations ahead will have found a way to leave earth and terra form Mars,
I think you'd agree there'd be zero point in moving to Mars under the circmstances. The entire Solar System would be uninhabitable by the time the sun reached the Red Giant stage, so what would be the point in expending all that effort to move to the next rock along?...So yes I would think many generations ahead will have found a way to leave earth and terra form Mars,
Edited by dr_gn on Sunday 24th October 11:17
dr_gn said:
I think you'd agree there'd be zero point in moving to Mars under the circmstances. The entire Solar System would be uninhabitable by the time the sun reached the Red Giant stage, so what would be the point in expending all that effort to move to the next rock along?
Quite happy for the other debate to carry on but this is where my question really lies, once the end of Sol starts (yes I know you could argue that it has started already, but once things start going a bit pants) how much time would we have between Earth becoming uninhabitable and Mars becoming habitable then uninhabitable, IYSWIM?I don't think anyone really knows. It's very hard to extrapolate from observations of the behaviour of other similar stars to our own. We've only held these theories on star death for less than 100 years so we have had very little time to make decent studies of what is actually happening out there.
The time period could range from hundreds of thousands of years to millions of years.
The time period could range from hundreds of thousands of years to millions of years.
Surely the debate on terraforming planets in this system is irrelevant if you are discussing the terminal stage of this star, once that goes none of the planets are going to be fantastic places to live (not that most of them are already). Billions of years in the future I'd expect it to be irrelevant as we'd either no longer exist or have moved on both physically or mentally.
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