What? The sun could be infinite?

[Blacklight]

The name of this post should be "What? The sun could last forever?" instead of what I typed.

I was randomly looking around on the web and I came upon a question on "wiki.answers.com" that asked "How long does the sun have left?"

The responses is: "Nobody really knows, since we haven't been around long enough to observe the entire life cycle of a star. By putting together clues from the stars that we can observe, I've seen estimates that range from 6 billion to 10 billion more years, based on an age of 4.5 billion years so far. Stars are apparently fairly short lived, compared to the galaxies in which they are formed and live out their lives. If the sun was a very large star, it could have been gone long ago, as the bigger the star, the faster it burns up its initial fuel, so that some stars are done in only 10 million years! Ours is probably going to be around for a very long time to come.

Edit: Through the use of modern un-melting magnets, estimates have shown that the suns life span can be infinite."

The top part, I knew, but that bottom part intrigued me. I've never heard of this experiment. How can the life of the sun be infinite? I'd imagine that it wouldn't be looking anything like it currently does in a few billion years. Anyone here know of this theory and care to elaborate? My instinct says that it's nonsense, but then again, I'm not a physics expert so I decided to ask here about it.

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[Quick_Nick]

I don't know about it but it sounds like nonsense indeed. A candle doesn't burn forever. You'd have to dump more fuel into the sun...and remove the heavy 'waste'.

 

[MattBaker]

I could only imagine splitting heavy elements in the sun into lighter elements, that could fuse again, but:
1. That would consume a lot (really A LOT) of energy
2. I don't know what happens if there is nuclear fission in a star, or if it's even possible...

 

[Quick_Nick]

I could only imagine splitting heavy elements in the sun into lighter elements, that could fuse again, but:
1. That would consume a lot (really A LOT) of energy
2. I don't know what happens if there is nuclear fission in a star, or if it's even possible...

I would be more receptive of a perpetual motion device.
Very interesting idea though.

 

[Blacklight]

I would imagine that the energy required to turn the sun's heavy elements to lighter ones would completely obliterate the star.

What experiment using un-melting magnets is this guy talking about? I've never heard of a magnet that can't melt.

 

[Keatah]

The sun's been a little more active lately, but yet at the same time, a little different.

 

[Artlav]

I don't know about "un-melting magnets", but one force of nature that is overlooked in estimating Sun's life span is us humans.
We have billions of years free for exponential growth of our world-tweaking potential (if we survive over the nuke-ourselves threshold), who knows what would we do to the Sun long before then.

 

[Linguofreak]

The top part, I knew, but that bottom part intrigued me. I've never heard of this experiment. How can the life of the sun be infinite? I'd imagine that it wouldn't be looking anything like it currently does in a few billion years. Anyone here know of this theory and care to elaborate? My instinct says that it's nonsense, but then again, I'm not a physics expert so I decided to ask here about it.

It wouldn't quite be *infinite* (eventually it would cool off to the temperature of the rest of the universe), but it could be very long (depending on what kind of output you wanted the sun to sustain, and I'm not sure I'd call the kind of setup that would be needed "modern", it's at least centuries, more likely millennia beyond our current capabilities). Basically, you use part of the sun's output to drive a ring of giant electromagnets placed around the solar equator, and the magnetic field from those intensifies the solar wind from the poles by a large amount, causing the sun to lose mass at a much faster rate. Smaller stars live longer than more massive stars, (because of a lower burn rate, as well as more thorough mixing in the interior, allowing helium to be brought out of the core and fresh hydrogen to be mixed in), so by doing this you can extend its lifetime.

See: [ame="http://en.wikipedia.org/wiki/Star_lifting"]Star lifting - Wikipedia, the free encyclopedia[/ame]

 

[Vast fury]

The sun may stay lit for a quite a long while, but I dont think that it will stay lit forever. Well it may be possible, for the fact that it has unique energy-recycling abilities, but as we all know and as what we have observed with our current level of understanding...... All things have time limits of their existence.

 

[mojoey]

It wouldn't quite be *infinite* (eventually it would cool off to the temperature of the rest of the universe), but it could be very long (depending on what kind of output you wanted the sun to sustain, and I'm not sure I'd call the kind of setup that would be needed "modern", it's at least centuries, more likely millennia beyond our current capabilities). Basically, you use part of the sun's output to drive a ring of giant electromagnets placed around the solar equator, and the magnetic field from those intensifies the solar wind from the poles by a large amount, causing the sun to lose mass at a much faster rate. Smaller stars live longer than more massive stars, (because of a lower burn rate, as well as more thorough mixing in the interior, allowing helium to be brought out of the core and fresh hydrogen to be mixed in), so by doing this you can extend its lifetime.

See: Star lifting - Wikipedia, the free encyclopedia

But, wouldnt the lessened output from the sun affect life on Earth, or did I completely misunderstand you?

 

[Artlav]

But, wouldnt the lessened output from the sun affect life on Earth, or did I completely misunderstand you?

If you can make a power regulator for a star, moving a planet closer to it would be trivial, no?

 

[mojoey]

You have a point. Though the implications of these actions may be worse than the reward. Maybe it would be for the best if we packed up and moved across the galaxy.

 

[Ghostrider]

Maybe it would be for the best if we packed up and moved across the galaxy.

Yeah. We manage to get our luggage lost for 500 km of air travel, imagine the grief while crossing the Milky Way. And not a Duty Free Shop in sight.

 

[werdna]

Yeah. We manage to get our luggage lost for 500 km of air travel, imagine the grief while crossing the Milky Way. And not a Duty Free Shop in sight.

I think we will eliminate luggage problems long before we achieve intragalactic travel.

As for exponential growth/technological singularities... I'm all for that, but I don't see it as something possible looking at today's world. Ask me in 20 years and my answer might be much different...

But if we do achieve mastery of megascale engineering one day, manipulating a star should be possible. That said, it will take lots of mass to construct such devices.

There's only so much mass in the solar system. Would we have enough for a dyson swarm or something similar? Maybe... And if we do run out of usable materials, I won't discount the possibility of a civilization midway between type II and III (perhaps II.5? ) developing ships to haul trillions of tons of mass across interstellar distances- such a civilization would have plenty of energy to spare for those ships.

Just forget about it happening within your great-great-great-great grandchild's lifetime...

 

[T.Neo]

Simple solution: 'stir' the sun to maintain conditions within the core conducive to the fusion of hydrogen, thus greatly increasing its lifespan.

It's simple, really. You just need a spoon that's large enough for the job...

 

[Jarod]

A fantasist strategy :

Heavy metals due to fusion migrate to the core, they're removed and maybe replaced by hydrogen.

 

[Quick_Nick]

I don't know about "un-melting magnets", but one force of nature that is overlooked in estimating Sun's life span is us humans.
We have billions of years free for exponential growth of our world-tweaking potential (if we survive over the nuke-ourselves threshold), who knows what would we do to the Sun long before then.

It's only a relative handful of years til we can't be called homo sapiens sapiens anymore. In a billion years, as long as we don't find ourselves perfect, every known species will have evolved a thousand times or more likely died out long before.

 

[T.Neo]

It's only a relative handful of years til we can't be called homo sapiens sapiens anymore.

Depends on the rate of evolutionary change. Many species present on Earth have existed for several millions of years; some members of specific genera or cladistically higher groups are physically strikingly similar to relatives that lived tens or hundreds of millions of years ago.

Rate of evolutionary change depends on selective pressure, and in the case of developed human societies, that pressure is very small. Even hunter-gatherer societies should probably not be expected to undergo Dixon-esque radiations over millions of years, as humans are not specialised organisms (unless 'generalist tool user reliant on intelligence' is regarded a biological specialisation).

 

[Quick_Nick]

Depends on the rate of evolutionary change. Many species present on Earth have existed for several millions of years; some members of specific genera or cladistically higher groups are physically strikingly similar to relatives that lived tens or hundreds of millions of years ago.

Rate of evolutionary change depends on selective pressure, and in the case of developed human societies, that pressure is very small. Even hunter-gatherer societies should probably not be expected to undergo Dixon-esque radiations over millions of years, as humans are not specialised organisms (unless 'generalist tool user reliant on intelligence' is regarded a biological specialisation).

Talking billions of years though.
And we're getting significant ability to alter our genome already.
But this is all extremely off-topic.

 

[T.Neo]

Off-topic of course, but the issue is not the time scale involved but rather the selective pressures that drive evolution. Adaptations are caused when mutations produce advantageous heritable traits that are passed on to many offspring. As society develops (food, shelter, medicine become increasingly available), the number of mutations that are advantageous enough to become dominant traits is reduced, because selective pressures become greatly reduced or nonexistant. Zoological and paleontological evidence demonstrates that organisms can see little evolutionary change over hundreds of millions of years, so an organism remaining recognisable over a significant timescale does seem possible provided the right conditions.

Genetic engineering faces similar issues, despite not being bound by evolutionary law. The more unusual modifications that may be possible either confer little or no important advantage to the subject, or are likely better achieved through other technological means.