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Imagine a space cataclysm, where the Earth is hit by a deadly wave sterilizing all life of the bright side, but the dark side is more or less intact (at least the atmosphere and life are still in place).

The catch: it is not a momentary strike like a GRB, but a prolonged (and rather wide) beam of death. While the Earth rotates, all life is slowly cooked, except maybe for those in underground shelters (though I'd prefer them to die too) and submarines. The beam is wide enough, so the Earth, while moving through space, has enough time to rotate a couple of times before leaving the beam (or before the intensity drops down).

The survival: flying an aircraft from East to West, staying in the shadow long enough for the Earth to leave the deadzone (of for the beam to lose intensity).

The questions: what kind of source can emit such a beam? And what kind of aircraft can carry enough fuel to circumvent the Earth a couple of times, and provide the necessary velocity? Let's assume that we only have a few hours to prepare our craft (the other side is already toasted), so we can't reingeneer a passenger plane, for example, to carry fuel tanks in the passenger space; attaching standard outboard tanks is ok. Number of seats is unimportant for now.

The candidate: the Sun going supernova ("Inconstant Moon" by Larry Niven), but I'd prefer a more plausible scenario.

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  • $\begingroup$ Beams generally disperse through space and don't really remain as high intensity directed beams...curious what answers others have here. Longest range on an aircraft is in the 14'000 km range, or about 1/3 around the equator. However you might get away with flying around at a higher latitude instead of the equator which makes that distance smaller $\endgroup$
    – Twelfth
    Apr 11, 2015 at 0:16
  • $\begingroup$ Just to verify...are you looking for a natural event, or could this originate as an 'alien attack' on earth instead? $\endgroup$
    – Twelfth
    Apr 11, 2015 at 0:24
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    $\begingroup$ Does it need to be specifically on Earth? Because otherwise, you could consider setting the planet around a flare star (but life cannot evolve naturally around such star). Or find a reason why the star would suddenly become less stable. $\endgroup$
    – Vincent
    Apr 11, 2015 at 1:45
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    $\begingroup$ The closest natural event I can think of that meets your criteria would be a gamma ray burst, but the one we've detected with the longest duration was only 30 minutes. See this. $\endgroup$
    – Frostfyre
    Apr 11, 2015 at 2:56
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    $\begingroup$ As for the shadow, polar areas have nights long enough to last anything that doesn't kill you even in shadow. So I think a base in Antarctic wondering about the weird aurora australis that cut off radio communications... People in Southern hemisphere would have a chance to make it to safety. Or you can swap to the Arctic, but the Antarctica has a continent full of ice to absorb the extra energy that must be causing rather extreme weather in everywhere else. Which makes flying kind of dangerous... $\endgroup$
    – Ville Niemi
    Apr 11, 2015 at 15:25

2 Answers 2

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Gamma-ray bursts

Let's not give up on the gamma-ray burst (GRB) idea so quickly. Sure, most GRBs are quite short, but there are exceptions: ultra-long gamma-ray bursts.

While normal GRBs last on the order of seconds - with some lasting for minutes - ultra-long GRBs can last for hours. Frostfyre cited a 28 minute-long GRB, GRB 101225A. It lasted for a whopping 28 minutes. Yet I mentioned hour-long bursts. There have been some observations of candidate ultra-long GRBs lasting for many hours.

We don't know much about GRBs in general, so it's difficult to figure why ultra-long GRBs last so long - or even what the events are that cause them. Gendre et al. (2013) explored the case of a blue supergiant undergoing a supernova, applying it to GRB 111209A. Their findings actually go against the magnetar model of a GRB, stating that magnetar formation from a supernova cannot account for data gathered from GRBs. Gender et al. mention numerous GRBs lasting for thousands of seconds, with one (Swift J1644+57) lasting for 2160000 seconds. That could have been a tidal disruption event, which I'll get to later.

Boer et al. (2014) briefly mention the progenitor possibilities, stating that an extremely massive progenitor would be necessary. Another promising hypothesis is that accretion from a massive star onto a companion object, not a supernova, could be the source of ultra-long GRBs. Virgili et al. (2013) also give a good overview of potential progenitors, noting that continuous accretion of the outer layers of the supergiant could be responsible for the duration.

The point of all this is that if you have the right progenitor, a GRB can last for hours and hours.

Tidal disruption events

I mentioned tidal disruption events earlier. Simply put, these happen when a star is ripped apart by tidal forces from a supermassive black hole. The result will be similar to a GRB, but it will last for a long time - perhaps days.

The one downside to using a tidal disruption event is that Earth is far from Sagittarius A*, the supermassive black hole at the center of the Milky Way.

Astrophysical jet

Another (more interesting) option is to use an astrophysical jet - the matter emitted along the polar axis of some objects accreting matter. These often come from supermassive black holes, but there's no reason that a massive intermediate-mass black hole couldn't emit them.

Bipolar outflows, coming from some young stars, are also astrophysical jets.

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  • $\begingroup$ Astrophysical Jet is what I was going to answer, though I didn't know the name. +1. $\endgroup$
    – Josiah
    Apr 11, 2015 at 23:11
  • $\begingroup$ A great answer! I'll accept it as soon as I get some opinions on the aircraft question also. $\endgroup$
    – Kelly Roadkill
    Apr 12, 2015 at 23:23
  • $\begingroup$ How about polar regions and underground/underwater locations - can one of these events sterilize them safely (at least the less deep fallout shelters), without disrupting the atmosphere too much (at least to keep it flyable on the other side for a while)? $\endgroup$
    – Kelly Roadkill
    Apr 12, 2015 at 23:29
  • $\begingroup$ @JoshK. A polar region could be hit if the burst/jet were directed near it. I think that underground areas would be fine, but I don't have any evidence for that. $\endgroup$
    – HDE 226868 ♦
    Apr 12, 2015 at 23:30
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The plane part of the answer:

You aren't going to be able to get around the equator...but if you move up in latitude the distance around the globe shrinks and this becomes possible.

21'000 km is around the largest deployment range for any aircraft I can locate...A Boeing 777-200LR. At 75 degree latitude, the circumference of the globe at that latitude is around 10'400km, which means this craft could push to get around the globe twice while flying at the 75 parallel. 75 degree is a long ways north (far north of canada and russia)...or a long ways south if you prefer, it's basically a circle around the antarctic.

The flight time to hit 21'000 km is in the 22-23 hour range, so you'd have to purposefully slow down a few times to conserve fuel...if you weren't careful you'd fly too fast and catchup to the burning ray of death on the other side of the globe. Unsure if a slower speed would still be able to hold the same range, you might have to go to a few degree's higher just to ensure your safety. If the land wasn't destroyed, there is the potential to have enough time to land and refuel.

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  • $\begingroup$ Thanks a lot! I'll upvote your answer as soon as I have enough reputation. $\endgroup$
    – Kelly Roadkill
    Apr 13, 2015 at 22:34
  • $\begingroup$ You might be able to get pretty creative with the aircraft route as well...swinging closer to the pole will make the distance less and moving away from the pole will make the distance longer. $\endgroup$
    – Twelfth
    Apr 13, 2015 at 23:17
  • $\begingroup$ @JoshK. - this might be helpful...just lists the distance you'd need to travel to get around the globe at a particular latitude/longitude. $\endgroup$
    – Twelfth
    Apr 14, 2015 at 18:16
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    $\begingroup$ I had written an answer and also came up with 75 degrees, so good work. I would suggest refueling on the dark side. There's military bases in both Russia and Canada on the way. But you'll have to be extremely lucky to be that far north to begin with, and have a boeing 7x7 series on hand. You might also be able to use the moon shadow creatively. $\endgroup$
    – Josiah
    Apr 16, 2015 at 15:17
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    $\begingroup$ whoops. my last comment should have had this home.online.no/~sigurdhu/Grid_1deg.htm $\endgroup$
    – Twelfth
    Apr 16, 2015 at 17:13

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