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Old 05-07-2012, 02:17 PM
 
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Quote:
Originally Posted by Glitch View Post
I agree that migration to another solar system would be our best, and possibly our only, alternative. Furthermore, we do not have billions of years before we have to act. We have only a few hundred million years before the luminosity of the sun increases.

In another billion years the sun will be 10% brighter than it is today. The moon will have moved another 25,000 miles further from Earth during that billion years and the rotation of Earth would increase, shortening the current 24 hour day, while having smaller tides.

Earth can see what its inevitable future will be like by looking at Venus. In about a billion years or so the heat from the sun will boil off the oceans, increasing atmospheric pressure. Life will die out in the reverse order it was created. Plants will be the last complex life forms on the planet, and after they go, all the oxygen will be gone a few million years later. Cyanobateria and other thermophiles will persist for a few more million years, but complex life on Earth will be finished.

There is not enough mass in our solar system to give the sun more than a few more million years of life, assuming we could somehow throw entire planets at the sun. Our only alternative, assuming our species survives the next 500 to 800 million years, is to leave the solar system.

Getting to another solar system would not be that difficult. The travel time to another solar system could happen within just a decade or two without using faster-than-light travel. An engine capable of producing a constant one gravity of thrust could get a space craft to Alpha Proxima (4.2 light years away) in 3.6 years. A round-trip would take the spacecraft 7.2 years due to relativistic effects. To observers on Earth the round-trip will have taken 8.4 years.

Providing there was enough fuel, and the engines were 100% efficient, it would take as little as 6.6 years at a constant one gravity thrust to reach the star Vega, 27 light years away. Or 20 years to reach the center of the Milky Way galaxy, 30,000 light years away.
The 5 billion year time frame is roughly looking at the point at which the Sun will have become a white dwarf. It's expected to be a very long, slow process. By that time, the planet itself may be nothing more than a cinder.

The contention of the study in the OP is that as the Sun depletes its fuel, layer by layer, the exhausted material of gas and particles will be pushed out from the Sun, in effect causing the Sun to swell up to a red giant. Once the Sun's fuel is finished, the gasses and other debris form a cloud that may ultimately be material to form a new star. However, the authors contend that as the Sun swells, it could cause a lot of chaos for the planets in the solar system with objects crashing into each other, potentially turning the system into a field of gas and rubble.

I think in the time frame of a few hundred million years, any descendants of humans still on the planet could well go underground for protection, at least for a while. If the fossil record of evolution serves as a guide, homo sapiens could have branched off into several different species, some of which would likely be destined to extinction, by a few hundred million years from now.

A lot of things can happen between now and then. It's possible the Earth could be hit by a large asteroid or comet. If a comet the size of the Shoemaker-Levy 9 fragments were to hit the Earth, the entire planet would be toast. If a strong enough magnetic flare from the Sun were to hit the Earth, the entire power grids around the planet could be destroyed. That would mean no power, no communication, no food, those in urban areas would have no running water (although water could be obtained from rivers, streams, lakes). If the population continues growing, diseases could wipe out large numbers, not to mention starvation from not enough food to go around. It might not wipe out the entire population, but it could certainly result in a massive setback to technological progress. The Yellowstone super-volcano could blow. There are any number of other things that could potentially happen that could seriously hamper humanity or cause an extinction in the near future, as easily as it could the far future. As Stephen Hawking suggests, we need to find a way off this rock and spread out to increase our chances to preserve life long into the future.

Unless something unforeseen gets in the way, we could have the means to begin spreading out in the galaxy. Although other stars similar to ours have been discovered to have planets in the "habitable zone", we have no idea if any of those planets are suitable for human life. Regardless of whether or not we can ever reach speeds fast enough to make it to nearby star systems within a decade or so, for a mass migration scenario, it would either require a LOT of spacecrafts heading out or some extremely large crafts to accommodate large numbers of people. I suspect there would be some who would choose to stay behind. In any case, it would require a profound amount of material to create such interstellar spacecrafts. The Asteroid Belt would supply only so much, maybe not enough though. We'd have to mine and process objects for material out in the Kuiper Belt. In my opinion, we'd probably need a highly developed network of robotics in large numbers to do the grunt work. Such a project is an incredibly tall order at a magnitude that staggers the imagination.

There's also a major problem with high speed spacecrafts. Traveling at such speeds to be able to reach nearby star systems is likely to have to contend with objects along the way. A collision at such high speeds, even with an object the size of a pebble or a grain of sand, could release such enormous energy that it could cause a catastrophic explosion. There'd have to be a way to shield and harmlessly deflect objects that are drifting around in the galaxy. It's possible we my have ways to handle such problems in the future, but it's really hard to imagine it here in the present. Slower multi-generational crafts would be safer, although it would also have to be viewed as a long term objective, very long term. Who knows? Within the next several hundred or thousand years, we might well have resolved issues that we now see as obstacles and problems. My guess is that humans won't be traveling to other star systems any time soon, if ever. It would be more practical and less costly to send robots out to blaze the trail and do the initial exploration of exoplanets, just like we're beginning to do now in our own solar system.
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Old 05-07-2012, 04:49 PM
 
Location: Pueblo - Colorado's Second City
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All my point is with how much we have advanced in 100 years if we are around the kind of technology we will have in 1 billion years or more is most likely nothing we can comprehend now and I hope we would be a type 3 civilization. Then finding a perfect sun with no planets or making a brand new sun and beaming it at the suns current location or even adding hydrogen to save this sun or something else will be so technically easy for them they wont think anything of it and want to save the solar system they came from much like we save historic buildings.
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Old 05-08-2012, 07:11 PM
 
Location: Texas
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I remember watching a long show about how best to build a generation ships, but I've not been able to find it in a short period of time.
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Old 05-08-2012, 08:37 PM
 
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Quote:
Originally Posted by Josseppie View Post
For us today that would be impossible. For us a few billion years now maybe not so much. Or they can do what was done in Star Trek. Find a sun that is the exact same mass that has no planets around it and instantaneously beam that sun where our sun is and our sun where that one is. That way our old sun can go out to pasture and become a white dwarf while the new sun takes over keeping our solar system alive and well for a few billion more years.
I dunno about you but if I were still here in a billion years I'd be pretty bored of this solar system and Earth...

How about this? (Larry Niven's Ringworld)



The heck with mud ball Earth....
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Old 05-08-2012, 09:29 PM
 
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Quote:
Originally Posted by Brian.Pearson View Post
I remember watching a long show about how best to build a generation ships, but I've not been able to find it in a short period of time.
There was something similar with a multigenerational craft concept in the far future that was featured in part of one of The Universe series (I think that was the series). The animation showed a so-called 'Mother Ship' a monster as part of an entire fleet of these giants. They looked like gigantic cylinders made up of hundreds or thousands of smaller cylinder-shaped ships which could detach and travel to or near a prospective planet, perhaps to settle or to extract resources. Interesting design and scenario. The idea was that Earth and the solar system had been abandoned, with ships scattering out here and there to different parts of the galaxy.
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Old 05-08-2012, 10:13 PM
 
Location: Texas
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Yep, that sounds like it. seems like they started out with Voyager's slingshot around the sun.
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Old 05-08-2012, 11:04 PM
 
5,203 posts, read 8,205,785 times
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Quote:
Originally Posted by Brian.Pearson View Post
Yep, that sounds like it. seems like they started out with Voyager's slingshot around the sun.
I would think with a craft that size, able to support millions of people, there wouldn't be any real need to live on planets, when you'd have what would amount to a mobile 'planet' that can go anywhere. No doubt stops would be necessary now and then for resources or just to see the sights.

The population for a multigenerational spacecraft would most likely have to be in the millions to ensure that each future generation can produce enough people who can operate the craft if necessary, although computers should be advanced enough to handle the entire operation.
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Old 05-08-2012, 11:14 PM
 
Location: Florida
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Final fate of earth according to scripture is its is destroyed by fire and is replaced by a new earth. Actually the old heaven (perhaps stars/planets?) and the old earth (this earth) shall pass away and a new heaven and a new earth will replace it. That God is soo cool!
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Old 05-09-2012, 12:00 AM
 
15,924 posts, read 17,648,084 times
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Originally Posted by DASULAR17 View Post
Final fate of earth according to scripture is its is destroyed by fire and is replaced by a new earth. Actually the old heaven (perhaps stars/planets?) and the old earth (this earth) shall pass away and a new heaven and a new earth will replace it. That God is soo cool!
Yes, many of the ancient fairy tales bring smiles and laughter to the people who read them....
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Old 05-09-2012, 08:14 AM
 
Location: Texas
5,070 posts, read 9,076,032 times
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Quote:
Originally Posted by NightBazaar View Post
I would think with a craft that size, able to support millions of people, there wouldn't be any real need to live on planets, when you'd have what would amount to a mobile 'planet' that can go anywhere. No doubt stops would be necessary now and then for resources or just to see the sights.

The population for a multigenerational spacecraft would most likely have to be in the millions to ensure that each future generation can produce enough people who can operate the craft if necessary, although computers should be advanced enough to handle the entire operation.
I just had a thought. There was the stairs problem in another string and I got to thinking whether or not tidal effects might screw up things. Then when I got here, the tidal effects from the sun could screw things up with such a big ship as it slingshots around the sun.
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