Is it possible for a reasonably Earthlike planet to exist in orbit of a star that could go supernova? If so, is it possible for earthlike conditions to persist right up to the event, or are the changes involved in the lead-up to the event so significant that they would change the environment of the planet to non-Earthlike.
Or to put it another way, is it possible for a planet to experience a long period in which there is an Earth-like environment - long enough for life to arise, perhaps long enough for huge diversity, complexity and perhaps intelligent life and civilisation (so lets say 3 or 4 billion years) - terminated abruptly by its sun blowing up?
Correct me if I’m wrong, but the bigger the star, the shorter the lifespan. And since only the largest stars go supernova, I doubt their solar systems would exist long enough to produce life.
Now, as for regular - non-“super” - novae, I’m not sure. I know you need a double-star system for those, but I don’t know how big the stars need to be, and I don’t know if a double system can support life.
The lifespan of a star large enough to go supernova is long enough…but
the processes preceding the supernova itself would destroy a planet dependent upon being at exactly the right distance from the star that supported its evolution.
There are other events which could take out a nice planet with no warning, though. Nature doesn’t really care how cool something is; physics is physics.
If we make it another 5B years or so we’ll fry too (ending the debate about global warming). Not in a supernova, though…not enough mass in the sun.
Alessan, I think I was hasty saying there is enough time; would .5-2B years for a low-mass supernova be enough? Sorta speculative, I guess. Here is a cute little program to get star lifespan against mass.
One of the greats (A C Clarke probably or Asimov maybe) wrote a short story around this - an exploration team finds a blasted planet orbiting a white dwarf with clear signs of advanced technology, no life of course.
The star was about 2000 lightyears from earth…
in the skies over Bethleham
Of course, that was written a long time ago, and it was a story.
The problem is that the lead-up to a star going supernova would involve such fluctuations of stellar output that any “earth-like” planets would not remain in the habitable zone, and the actual supernova event would probably blow the planet away - physical impacts from the exploding stellar surface, radiation pressure, and the change in gravitational forces would be tremendous, too (due to loss of stellar mass).
Also, the changes would be telegraphed a long time ahead, allowing any civilization the chance to escape in some fashion.
OK, how about an Earthlike planet existing in a stable state near to another system containing a supernova-capable star - sufficiently near that the supernova, when it happens (or actually x years after it happens) would instantaneously destroy all life on the planet, but sufficiently far that the pre-supernova fluctuations wouldn’t upset the stability?
Sure, but the question is - is it possible for them to be instantaneously buggered by the supernova, without having been messed up by the pre-supernova events?
Is such a Goldilocks zone possible?
Any star that goes supernova within about 30 light years of a planet would send out enough x-rays to sterilize that planet when it blew.
The question is whether stable stars could exist within 30 light years. My guess is no, since the unstable stars are so new that they either are in a cloud of young stars or else have perturbed the local environment for a hundred million years.
So, in the end, the question is whether a civilization could be completely surprised by a supernova and be destroyed while they shop and water their gardens, right?
Half-true, I think. The worst of the radiation would be over in a matter of seconds, too quick for the planet to rotate under it. So only half the planet would be immediately effected. And unless the supernova were right over the equator, there’d be a portion of the planet which wouldn’t get any radiation at all (aside from the harmless neutrinos and gravitational waves, of course). It’d still be bad for those parts, since the radiation would be enough to burn nitrogen and temporarily opacify the atmosphere, but there are surely some critters which would survive.
And I think you could even put the supernova in the same stellar system, with the planet surviving to the end (but probably not after). Put two old, cold neutron stars in a close orbit around each other, with a nice yellow main sequence star like the Sun further out, and put your planet in a comfortable orbit around the yellow star. The neutron stars will slowly and uneventfully spiral together, until eventually, they merge in an Earth-shattering kaboom.
I was citing an astronomer (whose name I am blanking on: he’s from Philadelphia) who said this about the supernova. He could easily have been simplifying for the audience. However, I think an event sterilizing one-half the planet, along with any accompanying effects, would be the end of human civilization at least which is enough for this thread.
Mostly, I was thinking of bacteria which could just go dormant in spores and wait a few years for the air to clear up. The ocean-floor vent ecosystems would probably also be only minimally affected.
