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[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.

ShadoCat
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  • Related: How close must a supernova be to severely harm the Earth? – Alexander Oct 08 '18 at 18:45
  • @Alexander, yes. That's why I'm asking about being in the Sun's shadow and only considering the burst. – ShadoCat Oct 08 '18 at 18:48
  • Related: Is it possible for coronal mass ejections or perhaps a gamma ray burst... – Frostfyre Oct 08 '18 at 18:51
  • 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. – Alexander Oct 08 '18 at 18:52
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    @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). – ShadoCat Oct 08 '18 at 19:01
  • GRBs would in no way destroy the (big rock named) Earth. Are you asking whether it would destroy life on the Earth, and the ozone layer? – RonJohn Oct 08 '18 at 19:03
  • @Frostfyre, yes. I've seen your answer to that question. That's why I was wondering about the Sun's shadow. – ShadoCat Oct 08 '18 at 19:04
  • @ShadoCat but this question assumes that Earth, however unlikely, is hit by the GRB, right? My point is that its destructive capabilities are not very significant. Life on Earth will be hurt by it, but we are not talking about an extinction event. – Alexander Oct 08 '18 at 19:08
  • @RonJohn, clarified, thank you. I hadn't considered the "vape the planet" aspect of my question. – ShadoCat Oct 08 '18 at 19:34
  • @Alexander, I've been led to believe from other sources that a GRB is an extinction level event. If it isn't, well, there goes that setting.... – ShadoCat Oct 08 '18 at 19:36
  • I figured you meant "life on" Earth, but it never hurts to clarify. After all, you might be the one who thinks it would actually incinerate the whole planet. – RonJohn Oct 08 '18 at 19:44
  • One link from Frostfyre: Are Gamma Ray Bursts Dangerous? states that GRBs can be extremely dangerous, but unfortunately does not offer any calculations for how close a supernova needs to be to cause an extinction event. The answer that I mentioned suggests that it indeed needs to be very close. – Alexander Oct 08 '18 at 19:48
  • Records of the incident may be irrelevant. The actual thing that creates the GRB can't be seen or detected until the blast arrives. – David Thornley Oct 08 '18 at 21:21
  • If Sirius.. or Arcturus went supernova.. and collapsed into a quasar of some sort.. and it's poles were aligned towards us... It may cause us problems.. but the chances of us being in the polar beam of a sufficiently close (light years) object are vanishingly small. – Richard Oct 09 '18 at 00:21
  • at 1000 LY, neither the Earth not the Sun are in direct danger. Nor is the radiation strong enough to directly endanger life on Earth. The planet's magnetosphere, and upper atmosphere will take a quite interesting punishment. As will the Sun, but not to the point of destabilizing it.... Now it the distance was 20 LY, that's a completely different story! – PcMan May 14 '21 at 12:59

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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.

Ummdustry
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If behind the Sun, yes. I can't imagine there would be any effects on Earth. GRBs are very short timescale phenomena, and Sun is vastly more massive than what is needed to block that.

GRBs are just about certainly caused by supernovae, so there would be a remnant to see after 1000 years, if there is someone to look with a telescope. Also, the supernova itself would be very much visible for a naked eye for some months if it happened in our galaxy.

Elmore
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