Expert: James Gort - 1/2/2010

Question
QUESTION: What would be the effect on the sun (if any) if a powerful gamma-ray burst were to hit it directly, during the most active period of the sun's 11-year 'sun-spot' cycle when it is churning up more solar flares than normal. Could it cause more powerful solar flares to erupt or would the effects of the GRB on the sun be negligible?

Thanks for your time!

ANSWER: Hi Josh,

Interesting question!  And this is one that we don't have a lot of observational evidence to support, so I'll just give you my best guess.  Others may disagree, but science is often like that!

I think that a powerful GRB will affect the sun.  And it could be a large affect. The sun's atmosphere (where solar flares arise) is involved in hydrostatic equilibrium - keeping the sun stable by transporting energy from the core to the surface.  A GRB will cause additional Compton scattering in the atmosphere, which affects one of the transport mechanisms to get energy out of the interior.  The hydrostatic equilibrium could be put temporarily out of balance, resulting in a greater release of energy from the core (through massive solar flares).  If the additional Compton scattering caused more opaqueness in the atmosphere, it could even result in a layer of the outer atmosphere being blown off.

All conjecture, of course, and it depends on the strength of the GRB.  But that's my best guess.

Cheers,

Prof. James Gort

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for your response. I have one more question, though. I know that as stable as our sun is, and as strong as our atmosphere is, that it is very unlikely a solar flare created during the sun's normal cycle would be powerful enough to fully penetrate the ionosphere and magnetosphere as well as the other layers, where it could actually do some major damage to the earth's surface. However, is it possible one of these super-massive solar flares (created by the scenario from my first question) could be powerful enough to disrupt and/or penetrate the atmospheric layers of earth, causing massive destruction or even possibly mass extinction?

Thanks again for your time!

-Josh

Answer
Hi Josh,

I might stick my head out a little, but I'd say that the sun could, given your GRB scenario, produce a massive solar flare that could cause great destruction or even mass extinction.  Improbable, but theoretically possible.  

Cheers,

Prof. James Gort