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Old 05-05-2012, 05:12 PM
 
Location: Pueblo - Colorado's Second City
12,203 posts, read 21,312,970 times
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Quote:
Originally Posted by Trackwatch View Post
When our sun does its final dance, humans would have been gone from Earth for millions maybe bilions of years. Whether we had gone extinct or relocated for possibly environmental reasons is yet to be played out.
Quote:
Originally Posted by orogenicman View Post
If the fossil record is any indication, Homo Sapiens will have been long extinct by the time the sun goes poof.
That is why I posted "if we are still here".
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Old 05-05-2012, 08:08 PM
 
5,206 posts, read 8,210,851 times
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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.
Why bother when it would be simpler just to relocate elsewhere, assuming anyone is still around, and assuming there's a habitable "elsewhere" to relocate to. The problem with your scenario is that it's beginning to appear more likely that stars like our sun already have planets. If there are any inhabitants on any of those habitable earth-like planets, swiping their parent star would be a pretty raw deal for them, especially if their star is about the same age as the Sun is now. Can you imagine what it would be like if our Sun instantly vanished and replaced with a white dwarf star? If a civilization were advanced enough to instantly teleport stars, it's probably a good guess they could instantly teleport themselves a lot more easily. What reason would there be to even bother remaining in this same spot in the galaxy?

Once the Sun has depleted all its fuel and becomes a white dwarf, by that time, the solar system as we know it would already have become a forgotten memory. The outer planets would probably have left the system to become orphans wandering the galaxy since the gravitational attraction of the white dwarf star would be too weak for them to remain in their orbits.
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Old 05-05-2012, 11:58 PM
 
3,426 posts, read 2,791,710 times
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The problem is not just in finding a habitable planet. Far and above, the hardest problem to tackle is getting there. And I suspect that isn't going to happen for a very long time, if at all. I believe that the most sensible thing to do is to learn to take care of the planet we already have. That IS something that is definitely doable. We only need the will to take the necessary actions to make it happen.
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Old 05-06-2012, 12:24 PM
 
5,206 posts, read 8,210,851 times
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Quote:
Originally Posted by orogenicman View Post
The problem is not just in finding a habitable planet. Far and above, the hardest problem to tackle is getting there. And I suspect that isn't going to happen for a very long time, if at all. I believe that the most sensible thing to do is to learn to take care of the planet we already have. That IS something that is definitely doable. We only need the will to take the necessary actions to make it happen.
I agree, that's something we certainly need to learn how to better manage now. Josseppie was speculating that a few billion years from now, we might have the technology to teleport a star to our solar system to replace the dying Sun. I contend that if we were that technologically advanced, it would make more sense just to migrate to a different solar system with a habitable planet.

While I agree that the idea of a mass migration to another star system is pretty much out of the cards at the present time, it might be feasible at some point in the distant future. Within the next few hundreds of years from now, we may well have identified hundreds, maybe thousands of potentially habitable Earth-sized planets located in other star systems.

Traveling there could be a big problem if the only objective is to reach such planets within a relatively short period of time. On the other hand, such a migration is conceivable using truly gigantic multigenerational spacecrafts, large enough to sustain a good-sized population, a small artificial planet that can move through the interstellar space of the galaxy. Of course it raises the question, if we had such spacecrafts, why bother to colonize another planet? We probably wouldn't need to, other than to exploit various resources. Keep in mind that it's just speculation of what might be possible within the next few billion years.

What seems fairly certain is that the Sun will eventually run out of fuel and come to an end in about 5 billion years from now. If humanity or descendants that have evolved from humanity are still on the planet billions of years from now, the Earth would still be destined to cease being a habitable planet. If future intelligent life on Earth has any hope to continue thriving and surviving, then moving off the planet and out of the solar system would be the only option. If that would never be an option, then all life on Earth will eventually perish, if not from collisions, then from the swelling Sun.

The scenario in the link of the opening post is that as the Sun swell, the solar system would be thrown into a chaotic mess, disturbing the orbits of planets, moons, asteroids and comets. Massive planet-shattering collisions could be expected, ultimately reducing the inner rocky planets to an accretion disk of gas, dust and rubble orbiting a small white dwarf star that was once our Sun. Even the outer planets could be disturbed, my guess being they'd probably drift out of the solar system into interstellar space. There might not be enough gravitational attraction from the white dwarf star to hold them in orbit.

Having said that, the fate of the Sun is a long time off in the future. In the meantime, we need to be concerned about taking care of the planet, if for no other reason than that it's the only planet we live on. Part of that includes keeping watch for asteroids and comets that could potentially be life-threatening to the Earth, and devise workable solutions to avert such collisions. At the present time, there's a lot of discussion about ways to avoid smaller asteroids, but we have no means right now to prevent such a catastrophe should something really destructive be zeroing on on the planet. The best we could manage, and I don't think we're equipped to do it, is to send thermonuclear devices out to intercept such an object and hopefully nudge it off course to avoid such a collision. We'd need a lot of advance warning for such a potential threat from asteroids. Comets on the other hand, are hard to spot until they get close enough to the Sun to begin forming a tail, and by the time we actually spot them, it could be too late to do anything about it.

A hundred or so years ago who would've thought people would in fact be sent to the Moon and survive the trip? I think we will eventually have to find a way off this planet, and find ways to safely survive new environments within the galaxy. We have two tasks to accomplish. One is to better manage the planet. The other is to learn how to better survive and thrive elsewhere off the planet. We're already taking baby steps in that direction. To be fair though, we have no idea if there will be any intelligent life, or any other life, on the planet 4 or 5 billion years from now.

However, I do agree with you that we're not likely to be soaring off to the stars any time in the near future. In the next few hundred or few thousand years, who knows? There is the proposed DARPA 100-Year Starship Study with the objective to determine how we could send a crew to a nearby star system, probably a one-way trip. The idea of the study is to spark public interest. Among other things, including a lot of money, a lot of it would depend on developing a propulsion system that's able to achieve interstellar flight. This is all happening now. Just where it will end up is anyone's guess.

The 100-Year Starship: US Agencies Ponder Interstellar Travel | Technologies for Building a Spaceship to Visit Another Star | Warp Drive & Futuristic Tech | Space.com

100 Year Starship Project Has a New Leader

DARPA Wants Your Ideas for a 100-Year Starship
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Old 05-07-2012, 12:09 AM
 
Location: Florida
595 posts, read 750,761 times
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According to 2 Peter 3:10-12 the earth will be destroyed by fire chronologically beyond the 1000 year reign of Christ on earth and following the very finalbattle of Gog and Magog (between satan and God).

Das
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Old 05-07-2012, 12:45 AM
 
16,308 posts, read 25,270,527 times
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Not to worry, the smartest [sic] animal on this little rock will bring it all to an most unpleasant end, and much much sooner than the sun loosing it's cool.
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Old 05-07-2012, 01:40 AM
 
Location: PRC
3,250 posts, read 3,365,783 times
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I love all this speculation about what we humans might be able to do in a couple of hundred/thousand years from now, but we are poisoning our planet so badly with nuclear waste that it is really, really unlikely that we will survive.

The other point about this speculation is that if we can do it in this time fram, what do we suppose that other non-humans have already done as they have been around probably for a lot longer than we have.

And we continue to think we are the only ones in this portion of space. These two speculative viewpoints dont sit well together.
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Old 05-07-2012, 03:26 AM
 
Location: Viña del Mar, Chile
16,410 posts, read 26,680,073 times
Reputation: 16511
Quote:
Originally Posted by NightBazaar View Post
An article in Universe Today provides an interesting look at what might happen to the Earth and the solar system, when the Sun becomes a white dwarf star some 4 to 5 billion years from now. The thinking is based on looking at 4 white dwarfs located within 100 light years from the Sun.

Will This Be The Fate Of The Earth?

This can all be prevented as long as we go green.
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Old 05-07-2012, 09:53 AM
 
Location: Wasilla, Alaska
17,825 posts, read 20,504,794 times
Reputation: 6500
Quote:
Originally Posted by NightBazaar View Post
I agree, that's something we certainly need to learn how to better manage now. Josseppie was speculating that a few billion years from now, we might have the technology to teleport a star to our solar system to replace the dying Sun. I contend that if we were that technologically advanced, it would make more sense just to migrate to a different solar system with a habitable planet.

While I agree that the idea of a mass migration to another star system is pretty much out of the cards at the present time, it might be feasible at some point in the distant future. Within the next few hundreds of years from now, we may well have identified hundreds, maybe thousands of potentially habitable Earth-sized planets located in other star systems.

Traveling there could be a big problem if the only objective is to reach such planets within a relatively short period of time. On the other hand, such a migration is conceivable using truly gigantic multigenerational spacecrafts, large enough to sustain a good-sized population, a small artificial planet that can move through the interstellar space of the galaxy. Of course it raises the question, if we had such spacecrafts, why bother to colonize another planet? We probably wouldn't need to, other than to exploit various resources. Keep in mind that it's just speculation of what might be possible within the next few billion years.

What seems fairly certain is that the Sun will eventually run out of fuel and come to an end in about 5 billion years from now. If humanity or descendants that have evolved from humanity are still on the planet billions of years from now, the Earth would still be destined to cease being a habitable planet. If future intelligent life on Earth has any hope to continue thriving and surviving, then moving off the planet and out of the solar system would be the only option. If that would never be an option, then all life on Earth will eventually perish, if not from collisions, then from the swelling Sun.

The scenario in the link of the opening post is that as the Sun swell, the solar system would be thrown into a chaotic mess, disturbing the orbits of planets, moons, asteroids and comets. Massive planet-shattering collisions could be expected, ultimately reducing the inner rocky planets to an accretion disk of gas, dust and rubble orbiting a small white dwarf star that was once our Sun. Even the outer planets could be disturbed, my guess being they'd probably drift out of the solar system into interstellar space. There might not be enough gravitational attraction from the white dwarf star to hold them in orbit.

Having said that, the fate of the Sun is a long time off in the future. In the meantime, we need to be concerned about taking care of the planet, if for no other reason than that it's the only planet we live on. Part of that includes keeping watch for asteroids and comets that could potentially be life-threatening to the Earth, and devise workable solutions to avert such collisions. At the present time, there's a lot of discussion about ways to avoid smaller asteroids, but we have no means right now to prevent such a catastrophe should something really destructive be zeroing on on the planet. The best we could manage, and I don't think we're equipped to do it, is to send thermonuclear devices out to intercept such an object and hopefully nudge it off course to avoid such a collision. We'd need a lot of advance warning for such a potential threat from asteroids. Comets on the other hand, are hard to spot until they get close enough to the Sun to begin forming a tail, and by the time we actually spot them, it could be too late to do anything about it.

A hundred or so years ago who would've thought people would in fact be sent to the Moon and survive the trip? I think we will eventually have to find a way off this planet, and find ways to safely survive new environments within the galaxy. We have two tasks to accomplish. One is to better manage the planet. The other is to learn how to better survive and thrive elsewhere off the planet. We're already taking baby steps in that direction. To be fair though, we have no idea if there will be any intelligent life, or any other life, on the planet 4 or 5 billion years from now.

However, I do agree with you that we're not likely to be soaring off to the stars any time in the near future. In the next few hundred or few thousand years, who knows? There is the proposed DARPA 100-Year Starship Study with the objective to determine how we could send a crew to a nearby star system, probably a one-way trip. The idea of the study is to spark public interest. Among other things, including a lot of money, a lot of it would depend on developing a propulsion system that's able to achieve interstellar flight. This is all happening now. Just where it will end up is anyone's guess.

The 100-Year Starship: US Agencies Ponder Interstellar Travel | Technologies for Building a Spaceship to Visit Another Star | Warp Drive & Futuristic Tech | Space.com

100 Year Starship Project Has a New Leader

DARPA Wants Your Ideas for a 100-Year Starship
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.
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Old 05-07-2012, 10:29 AM
 
Location: Wasilla, Alaska
17,825 posts, read 20,504,794 times
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Quote:
Originally Posted by ocpaul20 View Post
I love all this speculation about what we humans might be able to do in a couple of hundred/thousand years from now, but we are poisoning our planet so badly with nuclear waste that it is really, really unlikely that we will survive.

The other point about this speculation is that if we can do it in this time fram, what do we suppose that other non-humans have already done as they have been around probably for a lot longer than we have.

And we continue to think we are the only ones in this portion of space. These two speculative viewpoints dont sit well together.
99.999% of all the species that have ever existed on this planet are now extinct, at no fault of their own. Why should humans be an exception?

The longer we stay on one planet, the greater the likelihood that our entire species will become extinct. Whether we cause our own extinction or it occurs naturally, it really will not matter - we will be extinct. Therefore, it behooves us to seek a means in which to preserve our species.

The time frame is speculative in itself. Most just consider the life span of the sun as the ultimate time frame. However, conditions on the planet will change much more rapidly than the sun. As a species homo-sapiens have only been around 180,000 to 200,000 years. We came into being as a result of a dramatic climate change, and I expect that is most likely how we will go out. Like most of the other species that have already gone extinct.

We came into being, as a species, during an ice-age. Even though we are currently experiencing an inter-glacial warming period during the current ice-age, our species has never had to endure the CO2 levels and temperatures our planet has averaged over the course of its existence. When this current ice-age ends a few million years from now, we are going to see another mass extinction like we have in the past, and we could very well be part of that.

So as far as the time-line is concerned, I do not think we have as much time as others might speculate.

As far as being the only ones in this portion of space, it really depends on what you mean by "this portion of space." We know of every star within a 1,000 light years of Sol. We have been listening for radio signals (which travel at the speed of light) since the 1950s. Which means that if a planet within 60 light years of Sol was producing radio signals, odds are we would have heard it by now. We have been producing radio signals for just over 150 years. Which means that only those beings within 150 light years of Sol could have heard it by now.

While we have found hundreds of extra-solar planets, very few have been within the habitable zone of its star, and fewer still have been the size or density of Earth. Furthermore, as you suggest, other alien species could have evolved, thrived, and died out long before our solar system even came into existence. The universe is so unbelievably vast that I find it highly unlikely that more than a small handful of advanced intelligent critters could exist at the same time in the same galaxy.
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