This is one thing I have always been wondering about. Suppose that the human race raised above all the challenges that seek to destroy civilization as we know it. We manage to survive for millions of years, until the sun is about to go super-nova.
If we launch “generation ships” then, would they be able to find any life sustaining planets?
Here’s the thinking process
Alpha Centurai is about the same age as Earth. If Earth’s sun is going super-nova, there’s probably not much time left there
For further and younger planets, we are looking at time backward in time. So an Earth-like planet, say, 10 million light years away, will actually be quite nearing its expiry date when we reach there via. generation ships (assuming we can travel at the speed of light)
But it’ll still at best slag the planet when it expands into a red giant, so for this discussion it doesn’t matter; Earth’s still dead.
To answer the OP; the universe is still young enough that new stars are being born; by the time ours dies, there still should be ones around about our Sun’s present age, with lots of time on their clocks. Whether any will happen to have life is another matter; but realistically, we’ll be able to terraform them or just live permanently in space colonies long before then. Assuming organic life even still exists.
Others have pointed out that our Sun will never become a supernova. However, the Sun expanding to a red giant as it leaves the main sequence is the least of our problems. This event is not expected to happen for ~5 billion years, and while it will likely result in the vaporization of the Earth, life on Earth will almost certainly have died off billions of years before this ever happens.
The reason is that the Sun is getting hotter. Since its birth, the Sun has increased its output of energy by approximately 40%. Various natural cycles, including the carbon cycle, have managed to maintain habitable conditions on Earth for the last 1-3 billion years. However, these processes will eventually be overwhelmed as the Sun’s output continues to increase, and the Earth will become uninhabitable by life as we know it.
Right now, it’s anyone’s guess as to what will happen first: the loss of the Earth’s oceans, runaway greenhouse effect, or insufficient carbon dioxide to sustain plant life.
I read an interesting book on this topic a few years back:
If only there was a forum where factual replies could be given and corrections provided. Or snarky ones could at least be done with a hint of “the funny”.
Perhaps someday.
Back to the OP.
You’re talking about billions of year until the Sun expands and swallows the Earth. Funny thing is, as the Sun ages it burns hotter (hence why it expands). Since it’ll burn hotter the Earth will heat up and become effectively uninhabitable long before it’s consumed (debate exists as to whether or not 'we" get eaten by the sun).
So lets say 200 million years. 200 million is a tiny slice of time in the life of a star and there are vast reaches of space filled with stellar nurseries. We’d have plenty of time.
Note - post assumes we can travel interstellar distances without being cooked/frozen/broiled/irradiated/bored by the environment through which we would traverse.
If it were up to me, and we were able to build generation ships, I’d just find a suitable sun and setup housekeeping in orbit about it. After several generations living aboard our trusty ship, why disembark on some dusty, smelly rock with no guaranteed climate control?
Sun will not go supernova, but instead turn into a red giant within the next 5 Billion years or so.
Long before then however, the increased EM radiation will have boiled the seas and melted the surface of our planet, rendering life as we know it impossible.
The ultimate fate of the planet is still unclear. There is a chance that our orbit will increase and the planet will avoid being swallowed (this won’t really affect our previous fate mentioned above), and there is a chance that it will fall into the behemoth that will be our star.
There is a problem with this bit too though. First, how will we even detect an earth-like planet at that distance? That’s not interstellar space, that’s inter galactic space. Our own galaxy is only 100,000 light years across. And as far as we can tell right now, we cannot, nor will we ever be able to travel at light speed. Local solar systems would be our best bet, I would imagine.
And here comes my question: Will other planets in our solar system possibly become habitable by virtue of the Sun turning into a red giant? I know Mars would be too close, but maybe a large moon from one of the outer planets? What would be humanity’s (assuming we stick around that long) best bet within our own solar system?
You’re talking about many millions of years in the future. Do you really think we will still be “human,” and still stuck on this one planet in all that time?
Allow me to rephrase, ignoring our descendants, will the increased energy output of our dying star cause any of the outer planets/moons to become hospitable to life? Will Miranda, for example become a sea world?
We simply move the Earth away from the expanding sun. Impossible, No. Believe it or not recent studies show it can be done my deflecting asteroids into an orbit that gives the Earth a little push in the right direction. The Bad Astronomer talks about this in his new book.
To actually answer the OP’s question: “Yes.” Stars are generational; the big ones that do produce supernovas reseed the space around them with the stuff of new stars. Nebulae are full of new stars, some are even called stellar nurseries.
Many of the stars shining today are second or third generation; since this process is ongoing, there will still be new stars available for colonization using the awe-inspiring terraforming/transportation technologies of the next 4 billion years.
There is a limit, of course. If the expand/collapse model of the universe is true, we’ve only got until the collapse. If the constant expansion model is true, there’s still proton decay and heat death. But those things are on vastly greater timescales than the brief flicker of our sun.
The first step would be creating a simple life form here on Earth. We know how to create amino acids but we have a long way to go.
I’ve just finished reading about this, and basically life in the form of anerobic life, got started very quickly. Around 350,000 years after Earth was formed, we find old fossils of it. These are the kinds of life that we find today that live in heat vents under extreme conditions and consume sulfur.
But then life stalls on Earth. It doesn’t disappear but stays the same for about 4 billion years. Then all of a sudden life begins to take off very quickly (by comparison, in reality it’s hundreds of millions of years). But we get oxygen, and bacteria and boom, life starts evolving rather quick in comparison to the last 4 billion years.
As the Sun expands Earth will likely wind up similar to Venus. As the Sun expands it is thought it will consume Mecury and Venus but it will also push the Earth’s orbit back. Though some think it may consume the Earth, others think it’ll stop expanding before it reaches the Earth. This is due to the Earth’s orbit being pushed back (as well as the other planets. Earth would wind up as a runaway greenhouse like Venus is.
But what could happen is Mars or the moons of other planets that are now inhospitable to life may move into a zone similar to the zone Earth is in now. If we could plant life on these planets (or moons) to get it started we could possibly move there.
Eventually even if that worked, the sun will die out and life has to move to other stars.
That was the intended jist of my post. Given enough time, our own evolution (both biological and technological) will trump any evolution of the sun. It may become a simple matter of controlling the sun, or replacing it.
Experts, correct me if I’m wrong, but I believe the cause would be tidal acceleration (assuming you are talking about the increase in the Earth’s orbital angular momentum).