I'm planning on setting a story on Earth where the Sun is slowly becoming a red giant. I guess with so much solar activity and probably less atmosphere and magnetic field, the surface of our Earth will be hit by lots of ionizing radiation.

Given that ionization favours mutation: is it scientifically possible that some animals (or even humans) has developed resistance to radiation and maybe some very visible mutation in their body after a rather small period of time (a couple of hundred years)?

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    $\begingroup$ An additional note. If you read my answer and go..."oh...nevermind" that doesn't mean you can't ask another question about an earth-like planet that is in a similar situation but doesn't get destroyed. $\endgroup$ – James Mar 31 '16 at 16:05
  • $\begingroup$ Thanks for your answer. I admit I badly explained myself (not so good for a wannabe writer) as I thought of a sort of intermediate phase between now and the very-big-red-giant-that-swallows-Earth when life is hard but not impossible. I'll change the question but I think I've got the answer I needed. $\endgroup$ – karmalu Mar 31 '16 at 17:00

As the case with a lot of questions here, you are not focussing on world building here but rather trying to figure out what would happen to Earthly creatures when the sun gets in red giant phase.

There are times when evolution drives extremely fast. One of those times was the early part of Cambrian Period. This fast phase of evolution is known as Cambrian Explosion. Even then it took several millions of years for creatures to be distinctly different from their predecessors.

So strictly genetically speaking, a couple of hundred years is far far too less for any large scale evolutionary change to occur. You would at least require some tens of millions of years. And then too, I personally don't think any creature would be hardy enough to stay alive, considering that there would be no oceans on Earth at all, and no atmosphere either. Even extremophiles would go extinct because they would be simply boiled to death. Notice that while some hardy microbes can stay alive at very high temperatures, they do so only in aquatic environment. No bacteria can stay alive at 300 °C in dry conditions. That is the temperature of coal fire.

That's what Earth would be, then.

  • $\begingroup$ Silicon-based life might find it rather cold at 300 degrees. So the "second biosphere" that lived deep underground and went unnoticed by surface dwellers spreads out and becomes the dominant form under the new conditions. $\endgroup$ – JDługosz Mar 31 '16 at 17:02
  • $\begingroup$ ... silicon might find it rather cold at 300 degrees, but it would definitely have to be a completely dry-based life. as water wouldn't be in or on the creatures anymore. such life is pretty alien already. @JDługosz $\endgroup$ – Youstay Igo Mar 31 '16 at 17:36

Welcome to the site Karmalu, the question of mutation is likely irrelevant as the sun will likely consume the earth during the red giant phase...that's bad for mutation...

If you would like some more reading check out this scientific american article for some hypothesizing on how it'll work.


  • $\begingroup$ This is true, and it's worth noting that things will get pretty crappy in the millennia leading up to this, but the Sun will take a long time to expand to its full red giant size, or even close to it. During a good part of the Sun's life as a red giant, Earth will still be fine. Pretty toasty, but still habitable. $\endgroup$ – HDE 226868 Mar 31 '16 at 17:00

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