## Saturday, August 10, 2013

### Detonation of the Sun

A frequent source of links has sent me the coordinates of a page
Explosion of Sun
introducing a paper by Alexander Bolonkin and Joseph Friedlander urging all the physicists to think about the possibility that a malicious regime will send a thermonuclear weapon into the Sun and speed up the reactions inside the Sun – effectively converting all of our beloved star to a giant H-bomb long before our main source of useful energy is expected to go red giant around the year 7.5 billion AD.

This picture contains just a real-world eruption! Via IO9.

In the authors' opinion, physicists and others have a moral duty to either exclude the possibility, or look for security measures that would protect us against such a rogue regime, or prove that such a protection is impossible.

First of all, is such an explosion possible?

I don't think so. Note that the concern isn't much different from the old concern that some fathers of the H-bomb had to think about – namely whether the H-bomb would start to devour the whole atmosphere and the rest of the Earth as it realized that it's a thermonuclear fuel that may be burned.

Why is it similar?

It's similar because the present authors are afraid of the increase of the Sun's temperature from the current 9-17 million Celsius degrees in the Sun core to temperatures that are at least an order of magnitude higher and allow the reactions to be exponentially sped up. Consequently, the present temperature is negligible relatively to the desired one. In that respect, the comparison of real and "desired" temperatures is analogous to the situation on Earth where the atmosphere is also much cooler than the temperature needed to change the atmosphere to thermonuclear fuel. In both cases, the initial temperature may be neglected and approximated by zero.

Moreover, the Sun density is about 1.4 times the maximum density of water so it is surprisingly comparable to the densities encountered on our blue, not green planet, too.

The arguments showing that such a risk isn't there are somewhat subtle – the "proof" that we're safe is in no way trivial from a beginner's viewpoint. But I am confident it may be formulated. It seems to me that the "detonating Sun alarmists", much like the "detonating Earth's atmosphere alarmists", are neglecting various other quantities describing the environment that go beyond the temperature and density.

It's plausible that you may create much higher temperatures in a cubic meter of the Sun – probably only on the surface because it's implausible that any material will be able to penetrate through the solar matter whose temperature starts at 6000 Celsius degrees or so (all conventional materials melt and/or evaporate around that point). But if you create such huge temperatures in a small region, it doesn't imply that they will spread.

It seems clear to me that the rate of cooling of the "detonatingly hot" region will be too high when the size of the region grows. More importantly, you just never obtain a high density in this way. The density of the Sun is what it is, dictated by the overall solar mass and the solar volume, and an extra bomb doesn't change this counting much. Because the density of the bulk of the Sun will remain fixed, the ultimate near-equilibrium temperature of fusion is pretty much dictated by this density, and this temperature is what we observed in the Sun today.

See also my answer Why Jupiter isn't a star, whether Jupiter may be blown up and what it would mean, how to stop or blow apart a star, why asteroids around us don't have relativistic velocities, or many other questions and answers about related dramatically catastrophic cosmic (im)possibilities. ;-)

For these reasons and others, I am not really afraid of a Khamenei who would like to turn the ancient Egyptian God, the Sun, into an unhinged Allah. ;-)

#### 14 comments:

1. Wouldn't that device melt long before it got to the sun anyhow? Would it be possible to get a device close enough to the sun that it could detonate?

2. The newspapers or maybe the warmers themselves often describe the ocean uptake of sunshine in thermonuclear equivalents.
So we are supposed to believe the sun that pounds our planet with X gigatons of solar energy every minute is supposed to notice Kim Jong Ill's atom bomb?

Switch to spf 120 you should be fine.

3. or like an alcubiere drive that would locally change the space-time but would have little to no influence on the rest of it around... :)

4. I think that some ideas can not be said, that there are moral limits to knowledge (manipulation of viruses, ultimate weapons), because this knowledge is useless (the same results can be obtained as basic research).
As physicists we can imagine, or build weapons of mass destruction, but I think we have to limit our research fields.

5. I don't think I have read anything by Bolonkin, but he has the amusing habit of attaching his initials to many of his "ideas". Thus on vixra he talks about "AB-needles" of "femtotechnology" and about hypersonic "AB-engines", and here there is an "AB-criterion" of whether the sun can be exploded. Sorry, Alexander Alexandrovich, but you are supposed to wait for other people to use your name in referring to your ideas...

6. I assume the hypothesis that " If it's theoretically possible, nature would have already run the experiment."

Is it possible to create artificial flying machines? - Yes, nature ran the experiment and created bugs, birds, bats, and pterodactyls.

Is a sustained fission reaction possible ? It was done by those in the Manhattan Project, but nature beat them to it 2 billion years ago.

http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor

Is it possible to blow up a sun sized star?
Well, nature has run the experiment. Novas require double stars, where a white dwarf siphons material off a nearby star- the sun is not a double star so that type of explosion cannot happen to the sun- and the mass is less than 1.4 suns, so a supernova cannot happen.

7. A hydrogen bomb needs a significant amount of tritium in order to ignite, otherwise it would fizzle out., but the Sun does not contain enough tritium imho for an explosion.

In other words, the classical "super problem" of Teller (before the discovery of the Teller-Ulam configuration) is applicable here and suggests that one cannot ignite the Sun.

8. Any package sent to the sun would fall into a deep gravitational potential well. As it began to enter the sun’s atmosphere the solar gases would have a very high effective temperature, almost one million degrees, just due to the package’s incoming velocity (even if the sun were cool). Using retro-rockets to slow it down would require about 3000 times more thrust than slowing a package approaching earth and even this is impractical. A multi-stage rocket (with a tiny payload) would be required even here if the earth’s atmosphere could not be used to absorb most of the kinetic energy.
Sending anything to the sun is an absurdity. It would not get close to the sun’s photosphere before vaporizing.

9. Why blow up Sun? It's pretty much easier blow up Earth! Just detonate antimatter bomb on/under ground. Chain reaction causes GRB observable by other civilisations in universe. But why would you do that???

10. I have advocated, at least half seriously, that we send nuclear waste into the sun.
When I present this idea to friends who are very scared of nuclear waste, they say it is too dangerous, because we might blow up the sun. I point out that there might be danger at the launch, but that once it got close to the sun it would vaporize. They still insist that if we launch anything, nuclear or otherwise, into the sun we risk blowing up the sun. I am a layman and can't do a lot of the math, but sometimes I am amazed at the conceptual scientific ignorance of some of my fellow layman. Some of them appear to have no concept of the massive size of the sun.

11. If we must spend time and money worrying about things that might destroy the Earth, global warming, being hit by an asteroid, or blowing up the sun. I would rather spend time and money looking for an asteroid, but even that I wouldn't spend too much time and money on, because there isn't that much we can do about it anyway.

12. You are right, of course. Anyone who thinks we puny earthlings can have any effect on the sun whatsoever has absolutely zero sense of scale.
Dumping nuclear waste into the sun would be safe and has been proposed many times but it is far cheaper and safer to store it right here on earth (because of possible launch failures).

13. Poor sun, it doesn't have free-will. It doesn't stand a chance against us, eventually.

14. lol

for your listening pleasure on a related matter

http://www.myoldradio.com/old-radio-episodes/the-goon-show-the-fireball-of-milton-street/7