How do you jumpstart a dead star?

Mar 14, 2014 by Fraser Cain, Universe Today
Artist’s impression of a red giant star.

It's a staple of science fiction, restarting our dying star with some kind of atomic superbomb. Why is our sun running out of fuel, and what can we actually do to get it restarted?

Stars die. Occasionally threatening the Earth and its civilization in a variety plot devices in . Fortunately there's often a Bruce Willis coming in to save the day, delivering a contraption, possibly riding a giant bomb shaped like a spaceship, to the outer proximity of our dying Sun that magically fixes the broken star and all humanity is saved.

Is there any truth in this idea? If our sun dies, can we just crack out a giant solar defibrillator and shock it back into life? Not exactly.

First, let's review at how die. Our sun is halfway through its life. It's been going for about 4.5 billion years, and in 5 billion years it'll use up all the hydrogen in its core, bloat up as a red giant, puff off its outer layers and collapse down into a white dwarf.

Is there a point in there, anywhere, that we could get it back to acting like a sun? Technically? Yes. Did you know it will only use up a fraction of its fuel during its lifetime? Only in the core of the sun are the temperatures and pressures high enough for fusion reactions to take place. This region extends out to roughly 25% of the radius, which only makes up about 2% of the volume.

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Outside the core is the radiative zone, where fusion doesn't take place. Here, the only way gamma radiation can escape is to be absorbed and radiated countless times, until it reaches the next layer of the Sun: the convective zone. Here temperatures have dropped to the point that the whole region acts like a giant lava lamp. Huge blobs of superheated stellar plasma rise up within the star and release their energy into space. This radiative zone acts like a wall, keeping the potential fuel in the convective zone away from the fusion furnace.

So, if you could connect the convective zone to the solar core, you'd be able to keep mixing up the material in the sun. The core of the sun would be able to efficiently fuse all the hydrogen in the star.

Sound crazy? Interestingly, this already happens in our Universe. For red dwarf stars with less than 35% the mass of the sun, their convective zones connect directly to the core of the star. This is why these stars can last for hundreds of billions and even trillions of years. They will efficiently use up all the hydrogen in the entire star thanks to the mixing of the convective zone. If we could create a method to break through the radiative zone and get that fresh hydrogen into the core of the , we could keep basking in its golden tanning rays for well past its current expiration date.

Cutaway to the Interior of the Sun. Credit: NASA

I never said it would be easy. It would take stellar engineering at a colossal scale to overcome the equilibrium of the star. A future civilization with an incomprehensible amount of energy and stellar engineering ability might be able to convert our one star into a collection of fully convective red dwarf stars. And these could sip away their hydrogen for trillions of years.

Explore further: Will the sun explode?

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antialias_physorg
5 / 5 (9) Mar 14, 2014
A future civilization with an incomprehensible amount of energy and stellar engineering ability might be able to convert our one star into a collection of fully convective red dwarf stars.

My question would be: Why bother?
I cannot see a civilization that lasts billions of years (or even just a few more thousands of years) staying on planets.
Once you're free to choose your own biological (or whatever) makeup - there's really no point in sticking to gravitational wells anymore.
nkalanaga
5 / 5 (5) Mar 14, 2014
I agree that a truly advanced civilization wouldn't be tied to planets, but that's the kind I feel is most likely to try stellar engineering, for several reasons.

They'd have the technical ability. We have a hard time delivering a payload to Mercury, much less doing anything more sophisticated. And the Sun is even harder to reach.

They wouldn't be worried about failure. If we failed, we'd die, either through blowing the Sun to bits or through its natural death. Better to use our limited resources to move somewhere else. They'd already BE somewhere else, so could afford to experiment.

And, if they were still "human", they'd be curious as to whether it could be done, so would try it just for the challenge.
Whydening Gyre
not rated yet Mar 14, 2014
I agree that a truly advanced civilization wouldn't be tied to planets, but that's the kind I feel is most likely to try stellar engineering, for several reasons.

They'd have the technical ability. We have a hard time delivering a payload to Mercury, much less doing anything more sophisticated. And the Sun is even harder to reach.

They wouldn't be worried about failure. If we failed, we'd die, either through blowing the Sun to bits or through its natural death. Better to use our limited resources to move somewhere else. They'd already BE somewhere else, so could afford to experiment.

And, if they were still "human", they'd be curious as to whether it could be done, so would try it just for the challenge.

This is starting to sound similar to "2010"....
marko
1 / 5 (2) Mar 14, 2014
Perhaps a very large asteroid or planet Mercury could be equipped with a super H bomb and driven into the sun with a rocket.

There is no theoretical limit to a H bomb.

Getting the planet to enter the sun for a significant distance would be a trickier design aspect.
Shelgeyr
1 / 5 (6) Mar 14, 2014
It's a staple of science fiction

No, not really. Not a "staple" at all. Perhaps a dank, dark, extremely sparsely populated, lonely-beyond-comprehension corner of the science fiction universe, but a staple? No. If this was really a staple, science fiction would be starving amidst a famine of historical proportions.

Occasionally threatening the Earth and its civilization in a variety plot devices in science fiction.

I hate to be a grammar nazi, but Fraser Cain really needs to check his.

First, let's review at how stars die.

I've got to stop here. Mercifully, I know.

This is the latest lame - very lame - attempt to prop up the "standard model" doctrine with yet more chanting of the same tired old verses. It is all unsupported supposition, and before you scream your head off about "learning some science" or whatnot, I suggest you (and the author) step back and actually check your base assumptions. If you can.

Boo. 45.25 thumbs down.
Mimath224
5 / 5 (2) Mar 15, 2014
It seems to me to be an unwise move to start thinking about this problem. Yes, the Sun will eventually become a problem for 'us'(?) but the way things are going 'down here' I would say that the Sun isn't our immediate problem. Another point is that I do appreciate that there are different 'schools of thought' about the Std. Mod. but what that implies is, we don't know for sure what is really going on. So we need scientists to continue study and then come to a general agreement about what can and can't be done. I don't think we are in a position to try such things...a back up plan?
nkalanaga
5 / 5 (3) Mar 15, 2014
Mimath224: It's never too early to think about something, but I'll admit that it's far too early to try to make plans. The Earth won't be uninhabitable due to the aging Sun for at least half a billion years, so we can certainly wait a million or so before we have to start making serious plans. By that time we'll likely be 1) extinct, 2) spread so far the loss of Earth won't matter, 3) evolved, naturally or artificially, into something else that doesn't need to worry about it, or 4) technologically advanced enough to handle the job.
Whydening Gyre
4.7 / 5 (3) Mar 15, 2014
Did see a movie about this a few years ago. Can't remember all the actors... maybe James Spader...
Must not have been very good.

Anyway, this sort of musing is not very scientific. At this point, it IS science fiction.
Frazier must be coming out with a book or something...
jsdarkdestruction
5 / 5 (4) Mar 15, 2014
Interesting but the earth will be rendered uninhabitable long before the sun dies so I think its kind of a moot point.
alfie_null
5 / 5 (3) Mar 15, 2014
In that distant future, assuming whatever's still here has us in its ancestral tree, those descendants may have evolved past caring whether or not they survive. Whether or not the Sun dies. If we evolve into something electronic, subjectively we will have lived far longer that that few billion years - we'll be quite old, unimaginably unrecognizable to current-day us. With desires and motivations that will be a complete cipher.

Another thought: if we advance to the point where stellar engineering is possible, perhaps we would rather moderate the Sun's nuclear engine rather than figuring out how to feed it all the fuel it wants. Move whatever needs the radiation closer to the Sun, or focus the radiation, etc. If red dwarfs might last for a trillion years, how long might our sun last, sipping its greater supply of hydrogen?
Captain Stumpy
5 / 5 (2) Mar 15, 2014
Another thought: if we advance to the point where stellar engineering is possible, perhaps we would rather moderate the Sun's nuclear engine rather than figuring out how to feed it all the fuel it wants

@Alfie
IMHO it is more likely that the technology will be present to be able to do the job, but it would be unnecessary given our advancement
IF we learned enough to manipulate a whole star, we would also know enough to create smaller versions in order to generate the power requirements to feed our needs without having to tote around/utilise the bulk
which makes me think that your thoughts about "sipping its greater supply of hydrogen" are spot on, but maybe from a slightly different perspective? and we WOULD have to start larger and then scale down...
I dont know, really... but it is interesting to speculate about... AND if we are then mobile spacers, then the ability to utilise ANY star would come in handy... so you have great points IMO
marklade
Mar 15, 2014
This comment has been removed by a moderator.
Diogenes Tha Dogg
5 / 5 (2) Mar 15, 2014
We've all read The Last Question, and even after (a lot more than) trillions of years, the stars run down eventually. Sad, isn't it.
Whydening Gyre
5 / 5 (3) Mar 15, 2014
IF we learned enough to manipulate a whole star, we would also know enough to create smaller versions in order to generate the power requirements to feed our needs without having to tote around/utilise the bulk
which makes me think that your thoughts about "sipping its greater supply of hydrogen" are spot on, but maybe from a slightly different perspective? and we WOULD have to start larger and then scale down...
I dont know, really... but it is interesting to speculate about... AND if we are then mobile spacers, then the ability to utilise ANY star would come in handy... so you have great points IMO

Cap'n. Technically speaking, we ARE on a spaceship, exploring. Or maybe we are all just tourists...:-)
Whydening Gyre
5 / 5 (1) Mar 15, 2014
We've all read The Last Question, and even after (a lot more than) trillions of years, the stars run down eventually. Sad, isn't it.

LOVE that story...
Burnerjack
1 / 5 (2) Mar 17, 2014
It is conceivable that in such a time frame as 1 billion years, such an enduring civilization would have solved the problems posed by interstellar travel. In such a scenario, colonization of the closest star groups would be likely rendering "fixing" the Sun a non-priority.
Of course, learning to get along with each other has to occur first, otherwise, such an enduring civilization is quite improbable.

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