# Is a matter anti-matter collision comparable to Gamma Ray Burst (GRB) energy output?

Is a matter anti-matter collision (please assume two cosmological objects, neutron star sized say), the largest energy release method known?

Would it be comparable in order of magnitude to gamma ray bursts?

Finally, is it possible to plot frequency versus intensity for such a collision? i.e, will we know it when we see it, however unlikely the chance of it happening.

If the answer is, read this paper, that will be fine and appreciated. Also there may be well be a duplicate and if so I will delete this. It's the comparison to GRB energy that is of interest.

• Do you mean that you have one very large clump of matter colliding with another very large clump of anti-matter? I don't know of any macroscopic bodies that are entirely anti-matter, especially given the asymmetry we see between the two. – drglove May 25 '15 at 20:09
• No, I don't think there is any evidence for any significant antimatter in the observable universe. It's just a thought experiment to try to compare the purely hypothetical output of matter anti-matter to the real observed energy output of Gamma Ray Burst Sources. – user81619 May 25 '15 at 20:14
• en.wikipedia.org/wiki/Antimatter_comet#Gamma-ray_bursts – DilithiumMatrix May 25 '15 at 22:10
• @zhermes thanks, didn't see that before – user81619 May 25 '15 at 22:13

This depends entirely on the kinematics. Imagine I'm throwing an electron at a positron. If the two interact, then the resulting photons (two or more, although the more you add, the less likely the process is of occurring) will have energies entirely dependent on how fast you threw them together. If you throw them together hard enough, you can create heavier particles, like the D mesons or $W^{+/-}$ and you'll get neutrinos out.

Now if you assume they are simply moving slow enough, such that almost all the energy is stored in the mass and not the momentum, then you'd have that the energy released is $2M_{NS} c^2$. For a neutron star about twice the mass of the sun, this is about $4\times10^{57} \textrm{GeV}$, a huge quantity, many orders of magnitude above the Planck mass. We have never even probed close to these energies, and there could be swaths of new particles undiscovered in this regime. The energy produced by this does not need to be carried by photons, as you could have many complicated processes turn, say, $e^+ e^-$ into these heavier dudes we haven't seen which could decay very elaborately.

Long answer short, our physics as we know it from particle physics would break down at this scale, and we'd have no idea what could happen here. You could take the standard model and apply it, and you could in theory, see what the spectrum would look like.

As far as gamma ray bursts go, a GRB typically might output $1/2000$ solar masses worth of energy $(\sim5\times10^{53}\textrm{GeV})$, so we're a few orders of magnitude above what we saw before. If you tweak the masses, they could have comparable energies overall, but the underlying processes are quite unknown.

• thanks very much for taking the time to answer, the question was motivated by the GRB energy scales. Back to basic general relativity studies, that's more than enough to contend with, for me:). Thank you – user81619 May 25 '15 at 20:49
• Your math is wrong, 1 solar mass is $10^{54}\,\rm GeV$ so 1/2000 of it is $\sim10^{51}\,\rm GeV$ (not that GeV is the generally-used unit here, erg is). Note also that there are several ultra-bright ones with 5 solar masses of energy (a few $10^{56}\,\rm GeV$), which is quite comparable. – Kyle Kanos Jun 18 '15 at 19:31
• And the usually-quoted total energy of a GRB is around $10^{51}\,\rm erg=10^{53}\,\rm GeV$ (which appears to be larger than the 1/2000 solar mass quoted, which is weird because the article totally says my written value & not 1/2000, more investigation needed). – Kyle Kanos Jun 18 '15 at 19:37
• $1\textrm{GeV} \sim 2\times10^{-27}\textrm{kg}$ and the solar mass is $M\sim 2\times10^{30}\textrm{kg}$. I get that a solar mass is about $10^{57}\textrm{GeV}$. – drglove Jun 18 '15 at 20:06
• I also find the 1/2000 solar mass figure just from wikipedia: en.wikipedia.org/wiki/Gamma-ray_burst#Energetics_and_beaming Also, note my last sentence which states that it is possible to have comparable energies. – drglove Jun 18 '15 at 20:19