# What should humans do in a supernova?

In my story where thousands of humans are transported to the planet with dinosaurs that is 400 light years away, there are bound to be lots of warnings on the generation ship. Friendly aliens are transporting them. Nuclear fusion is what powers the ship. However the heat is confined to that relatively small area in the back of the ship. The speed of the ship is .5C(half light speed).

Most of the warnings, I know what the aliens would do. Change speed for asteroid belts, change path for stars and planets etc. But a supernova I have no clue. The aliens would need to know ahead of time if it is a type 1 or type 2 supernova. If it is a type 1 supernova, the other star or stars could be right in their path. But would any remnant of it have more gravity than the star thus diverting them from the star's path? For a type 2 supernova, they would need to know if a neutron star or black hole will form and act accordingly(because if a black hole forms, they might be right in the event horizon).

But the humans would need to do something different. Would they need to crouch down under something sturdy and be as close together as possible or what?

Edit:

The humans are not driving the ship, just being transported. The aliens are relevant in that they are the ones that would change course during supernovas.

As to what I am really asking. I am asking what the humans should do if possible during a supernova to survive it(since supernovas are super hot and super bright, even with cosmic ray protection the humans could still go blind or get extreme heatstroke and heat burns both of which are not wanted).

• This is a confusing question, can you define what you are actually asking for more? are the humans driving the ship? are 'the aliens' even relevant in any form? are you looking for a science based answer? I guess I'm not grasping the scenario at all. – Marky May 28 '16 at 23:25
• What changes from being transported with 0.5c and flying generation ship with speed 0.5c. Supernovas can be predicted, probably for years ahead. Candidates for supernova maybe for millions years. if you concerned about radiation gamma burst whatever, any star core will shield you from effects of explosion - just park on opposite side, and wait. – MolbOrg May 28 '16 at 23:43
• What should humans do in a supernova? Die. – Lyndon White May 29 '16 at 0:49
• Related: Inconstant Moon, by Larry Niven. – Peregrine Rook May 29 '16 at 1:46
• @MolbOrg this should be added as an answer – yobddigi May 29 '16 at 11:24

In case of supernova, don't be anywhere near it.

The way to survive a supernova explosion is to be a long, long way away from it when it happens. Comparing various online answers, the minimum safe distance for Earth for a supernova is 50-200 light years. Maybe your transport is more survivable that what some experts consider safe for Earth, but radiation would proportional to $\frac{1}{r^2}$, so at 10 light years, you would encounter 25 times the radiation as you would at 50 light years.

You can safely ignore any "black hole" related problems if you survive the explosion, the gravity will be very small at any safe distance. In fact, just because a star goes nova, it does not have any more gravity than before just because a portion of it turns into a black hole -- The total mass energy (and thus the gravity field) of star is the same as before. Eventually, as the remnants disperse the amount of concentrated mass will of course decrease.

The visible light could blind you at some distance from the supernova, but the huge amount of gamma radiation would be able to kill you at a much greater distance.

In theory, you could construct enough shielding to protect you against the gamma, but it would require quite a bit, and since gamma is naturally light speed, you would not have any immediate warning when the explosion happens, so the entire ship would have to be shielded to protect all of the passengers.

Go a few kilometers underground and wait!

You can hunker down inside a large planetoid. Dig down 50 kilometers and build cities inside a rock the size of Vesta or Ceres. Wait it out. The rock will protect you from gamma rays and cosmic particles.

When your neutrino detectors go bonkers, it means you have a few hours until the main blast. When that happens, tell everyone to get off the surface of your planetoid and get underground pronto. Every spaceship that can't land or shuttle its crew to safety should hide behind a planet for a few days.

• This strategy may be less effective than you think. Consider hunkering down in a planet 1 AU from the supernova, and lets grant that you are shielded from the cosmic rays and particles. You still get a lethal radiation dose from neutrinos.. Supernovas are really big -- normal common sense answers can be very wrong. – Gary Walker May 29 '16 at 14:06
• @GaryWalker why not 0.1 a.e. from supernova? This is't question (and answer as I assume) about surviving supernova blast in system where this blast happening. So your assumption is a bit odd, however * lethal radiation dose from neutrinos* that is nice, interesting idea. – MolbOrg May 29 '16 at 16:31
• @GaryWalker Thanks for the XKCD link. That's one of my favorite webcomics! Your comment makes sense if the rock is 1 AU from the supernova. If you were a few light years away, then you could survive the neutrinos. Based on the original question, I assumed the vehicle was a few light years away. (Why would any spacecraft captain in her right mind go within a few light years of a supermassive star about to go kablooie?) Maybe the spaceship should be a hollowed-out asteroid for a generations long voyage just to protect the crew from a supernova or hypernova. – RichS May 29 '16 at 16:41
• Even a few light years from a supernova is considered likely to cause cancer from neutrino radiation. XKCD is fun, but others have made a more serious calculation for lethal dose for at a distance at about 100 AU. Neutrino radiation is far more effective than Munroe computed at biological disruption because in penetrates the body completely and interacts in a more destructive way with the heavier atoms, esp. oxygen. – Gary Walker May 29 '16 at 20:15
• But I thought neutrinos were these particles that almost never interact with atoms because they mostly end up in the quantum field that takes up most of the atom and even with the trillions of trillions of atoms that make us, there would still be an incredibly low chance that neutrinos would interact with any of our atoms and so any damage would be extremely minute and the cells could degrade these damaged molecules and replace them with the right molecules and the body could excrete those damaged molecules. – Caters Aug 9 '16 at 12:16