And the Earth will be swallowed by the Sun and vaporized at that point, won’t it?
Let me ask the question this way: if you had a pencil, dime, extracted tooth, whatever, doesn’t matter, and it was sitting within a foot of a big ass 'nuke (big ass - technical term for ‘way big’) and the 'nuke went off, what would be left of the pencil and how small would the particles – if any – be?
The most broken down your test pencil would get is a plasma (a soup of electrons and nuclei). The nuclei would not break down into constituent nucleons, although a portion of them would undergo induced fission or become slightly heavier due to neutron bombardment. Upon cooling, the electrons and nuclei from everything that got “plasmized” would form new atoms and molecules.
I believe that only gamma ray bursts and quasars feature the “beams” of energy, but I could be wrong on that. GRBs are featured in the biggest supernovae (a recent Discovery channel show called them hypernovae, but I’m getting really tired of super-hyper-mega- getting added to everything). GRBs can also result from magnetars.
Depends. My semi-competence at Google-fu wasn’t able to nail down ranges for 1-solar-mass red giants, though I’m sure the figure is out there somewhere I didn’t look. My impression, though, is that it takes a supergiant to get out to 1 A.U. or greater in radius. The Sun’s diameter would increase dramatically, from 0.8 million miles to something on the order of 3-10 million, on a WAG pending somebody nailing down a decent number.
Certainly the Sun going red giant will not be good for Earth – vastly increased insolation from a larger disk, albeit at lower frequencies than today, will heat the planet up immensely. But I don’t believe it would engulf, or even come close enough to vaporize, Earth. Think Mercury-surface temperatures, is what I’ve been given to understand. Life? Maybe a few extremophile bacteria may eke out a niche for survival, but that would be about it.
Even though most stars’ destiny is to go red giant, what garners writeups is the more spectacular supergiants and hypergiants. “764 Hamburgerensis is so distended that if its center was where the Sun is now, its visible surface would be at the orbit of Saturn.” Well, cool, but most stars don’t get that distended.
Where are Podkayne[sup]1[/sup] and Angua[sup]2[/sup] when we really need them?
- I note that Dex went on leave of absence shortly after Poddy disappeared. Probably that suave Admin. whisked her off to a life of decadence in Venusberg, or some such Gotterdammerung place.
2, Same thing with Angua. Hmm – haven’t seen much of Captain Carrot lately either. Somebody check with 'punha and find out if his brother has a thing for beautiful astrophysicists who really turn into a beast when they PMS.
[sub]Doesn’t everyone have a thing for beautiful astrophysicists?[/sub]
We’re not really sure just how symmetric most supernovae should be. We can model them on supercomputers, but most of the models assume spherical symmetry for simplicity, and the more complicated models that don’t often don’t work at all. We can make observations of the ones we see, of course, but those are plagued by selection effects: If they are beamed, then we’ll mostly just see the ones that are aimed straight at us.
And to nitpick, it isn’t the destiny of most stars to go red giant. Most stars are red dwarfs, which will just sort of quietly whimper in place, without hardly expanding at all. Only a few percent of stars are Sun-sized or larger.
Polycarp, Angua has posted just today. She hasn’t gone anywhere. And if anyone has swept her off to a life of decadence, it would be her boyfriend bonzer (who also posted today). At least I think those two are still together. I haven’t talked with either of them in almost five years.
Thanks for that, Wendell; hopefully she will find and address this thread.
The bit with Captain Carrot stems from the fact that both she and he selected characters from Terry Pratchett’s books for their Doper-names, and the two characters (not the two Dopers) are a couple. Having just played the same game with Podkayne (whose Heinlein-character namesake was being courted by Dexter (Cunha, not C.K Haven, though), I decided to extend it to Angua as well.
Saw the thread and decided to pop in. Sorry to say, Polycarp, reports of my demise are greatly exaggerated. 
I’ve been pretty much in hiding for a while as I had US immigration, a move, a new job and all of that to cope with and am just finally settling down here in the good ol’ USofA. Its not exactly a life of decadence, but its pretty decent and is without bonzer, we split up two years ago now when I was in the running for USA-based jobs. OK, now that the “I’m baaack” moment’s been clarified, down to the physics!
From what we know about the death of stars like our Sun, our eventual fate is not going to be vaporization into constituent atoms, but its going to be pretty nasty nevertheless.
As the Sun expands into its first red giant phase, Mercury will be enveloped by its atmosphere and essentially jut get vaporized into its constituent atoms. The radius of something like our Sun when it goes into its first red giant mode will be about 0.75 AU, but the heat generated from earlier stages will have killed off our atmosphere, boiled the oceans, and generally made the place inhospitable.
After its first brief red giant phase, the sun will go into a He burning mode and will be hotter and brighter than now (as you need higher energies to fuse He compared to H). And then once the He runs out, it’ll eventually go into a second red giant phase, growing out to about 0.85 AU. The lower mass of the Sun will cause both Venus and Earth to move away from the Sun, moving us out to about 1.7 AU. The Sun will then undergo a phase of rapid mass loss, culminating in unstable pulsations that cause the Sun to expand out to about 1 AU. Eventually those pulsations will blow off the remaining outer bits of atmosphere, and we end up with a hot Carbon-Oxygen white dwarf about the size of the Earth. The Earth, or what’s left of it at least, will settle into a new orbit at around 1.85 AU. Or at least this is what some models suggest. Other models suggest slightly different fates, none of them are pleasant, but at least no vaporization, right?
Our Sun cannot go supernova, unless, as has been mentioned earlier, it hooks up with another star once its in its white dwarf stage. But given that the Sun will have had to go through the red giant stage before getting to a white dwarf stage, we’re not going to know about it if it does – we’ll have been vaporized already.
As for supernovae and symmetry, there’s a lot of new evidence and observations that suggest that even standard supernovae are asymmetric explosions – you have the spin of the progenitor star, and local conditions to take into account, together with the fact that a star isn’t a solid ball of explosive etc, that all contribute to the asymmetry. Things like hypernovae are likely to be very massive stars exploding with fast rotation rates, that we observe along the line of explosion (i.e. the spin axis is aligned with our line of sight).
Thanks, Angua! So I was in error on the size of red giants.
To get those AU/million miles numbers into a uniform format, let’s take millions of KM:
Present diameter of Sun: 1.4
Present distance of Earth orbit: 150
First-phase red giant diameter: 112.5
Interim new Earth orbit: 255
Second-phase red giant diameter: 127.5
Final new Earth orbit: 277.5
Pulsating giant Sun, average diameter: 150 (pulsations would mean significant differences from this, both higher and lower, through that phase)
White dwarf, 0.6 solar masses*: 0.011
Thanks for the useful, informative analysis. I gather from that that the Sun’s shell formation will stop with “helium burning” to produce carbon, with some oxygen and perhaps neon element synthesis going on towards the end of the red-giant phases?
- Approximate mass of the Sun after the pulsation phase is complete and it contracts to white-dwarf size.
Wow, I LOVE this place!
Small point about the nature of the Earth in relation to a hypothetical solar kablooie. Whilst we like to think of the third rock from the sun, in reality we are much less a rock and far more a droplet. The earth is for all intents a molten drop of material with a tiny thin solid layer on top. This layer is so thin that you could ignore it in the face of a supernova. The earth will behave like a drop of liquid. It won’t fracture, break, or ablate. It will splatter.
Think of the difference between hitting a rock with a golf club and hitting a raw egg.
Thanks, Angua. As you can see, I’m pretty out of it about other posters’ personal lives. This will teach me not to talk about people who I haven’t seen in almost five years.
So no kaboom? There was supposed to be an earth-shattering kaboom! 
“This is the way the world ends.
This is the way the world ends.
This is the way the world ends.
Not with a bang but a whimper.”
– T.S. Eliot
Indeed. As the available He runs out, mainly due to the triple-alpha process (I think), where two He nucleii form Beryllium-8 which then combines with another He nucleus to form C. Also, once you have some C, you can use the He and C to produce oxygen, neon and magnesium, depending on the pressure at a given point – hence part of the onion-layer effect.
Wendell Wagner – no worries – I certainly don’t expect anyone to keep up with my (sadly now non-existent) personal life!
I think it would be more akin to being sandblasted than being hit with a golf club.
How much of the energy released would be as neutrinos? Most of those would pass through Earth, but those that reacted would dump their energy essentially evenly throughout the bulk of the planet - like a microwave oven set on superhigh.
About 99% of a supernova’s energy is carried away by neutrinos, but that’s taken into account in the above figures. (That is, the actual energy release is about 100 times larger than the numbers given above.) The neutrinos would have negligible impact compared to the rest.
So, Angua, if I am understanding you correctly…
So I can come along and sweep you up into a lifetime of decadence?
To follow up: I calculate that the neutrinos would deposit a grand total of…
20 kJ
into the Earth. (It’s not called the weak interaction for nothin’.) So, you could maybe boil some water or something, if you could capture all that energy.