[EDIT: this question is about life on Earth surviving, not the physical destruction of the planet]

Could the Earth survive a gamma ray burst if that burst occurred in our galaxy and the Earth is in the Sun's shadow?

The main factors of that question are: if the Sun is massive enough to block it and if the burst is of short enough duration that the Earth will be in the Sun's shadow long enough.

The gamma ray burst took place at least 1000 years ago so there will be no records of the incident. The source does not need to conform to any known massive stars.

Also, Venus will be in conjunction with the Earth so I don't have to explain why it kept its atmosphere.

The only restriction on the source of the gamma ray burst is that it needs to be from within our galaxy and, likely, on this side of the galactic bulge (since I can't see much of the burst's energy getting though that thick star soup).

This is the first in a series of questions to see if the setting I'm creating gets past the sniff test. I have a number of questions along these lines but if the answer here in no, then it's back to the drawing board.

  • $\begingroup$ Related: How close must a supernova be to severely harm the Earth? $\endgroup$ – Alexander Oct 8 '18 at 18:45
  • $\begingroup$ @Alexander, yes. That's why I'm asking about being in the Sun's shadow and only considering the burst. $\endgroup$ – ShadoCat Oct 8 '18 at 18:48
  • $\begingroup$ Related: Is it possible for coronal mass ejections or perhaps a gamma ray burst... $\endgroup$ – Frostfyre Oct 8 '18 at 18:51
  • $\begingroup$ According to that question, a supernova needs to be close than 10 parsecs to Earth to substantially harm it. If Earth is perfectly shaded from the burst by the Sun, I presume the distance can be as close as 1 parsec. $\endgroup$ – Alexander Oct 8 '18 at 18:52
  • 1
    $\begingroup$ @Alexander, unlike the general radiation and other matter thrown off by a super-nova, a gamma ray burst is a focused burst of energy coming from each pole of a spinning star as it collapses into a black hole. That makes the burst a much more dangerous long distance threat (though much more unlikely since a super-nova's pole has to be aimed at us for it to matter). $\endgroup$ – ShadoCat Oct 8 '18 at 19:01

Yes, the earth would definately survive an in-galaxy GRB if it was behind the sun, though that is unlikely (since the sun takes up such a small section of the sky, it is unlikely to block any given GRB).

Gamma rays can be stopped by the few inches of lead shielding nuclear reactors, the Trillions of yotta grams that make up the sun will be absolutely fine for the job.

You also don't need to worry about venus losing it's atmosphere, the worry with a GRB is that it destroys the ozone layer not that it flat out strips away our atmosphere.

The shortest GRB's can be two seconds long so earth could definitely be behind the sun for the entire duration of one.

there is also a mass extinction event that could have been caused by a G.R.B. if you don't want to bother with putting earth behind the sun https://en.wikipedia.org/wiki/Ordovician%E2%80%93Silurian_extinction_events#Gamma-ray_burst_hypothesis and if it fits your timescale.


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