It took every ounce of self control in my being not to have Officer Hotlips say “Still feelin' lucky, PUNK?!” In that fourth panel. Too cheesy, even for me!
So, it looks like the security goons may be getting the upper hand over Panzer… but Woody's already done her damage. Is it too late for the good guys to turn things around?
More to come, next week! See ya then!
Supernovae are some of the most visually stunning events in all the cosmos. They're also terrifying. If you ask a space nerd to list their top five scariest doomsday scenarios for our solar system, getting fried by a supernova is probably somewhere on that list. But how likely are we to get caught up in the wake of an exploding neighbor star, and just how much damage would it actually do?
There are over 414 stars within 10 parsecs (32.6 light years) of our solar system. That's roughly the “Danger Zone” within which a Type II supernova can do significant damage to us. Among those stars, none of them are currently candidates for a Type II supernova. The closest potential Type II supernova candidate is Spica, the brightest star in the Virgo constellation, about 75 parsecs away from us (that's 250 light years).
However, astronomers have recently discovered literally thousands of white dwarf stars in our vicinity, and those guys are a problem because under the right (or wrong) circumstance, they can sometimes form these doomed binary systems where one star gobbles up mass from its partner until it exceeds the maximum stable mass for a white dwarf star (the so called Chandrasekhar limit). At that point, it explodes in what is known as a Type 1a supernova. Type 1a supernovae are not as big and powerful as Type II supernovae, but because there are so many white dwarfs out there (nearly 14,000 of them within 100 parsecs of us), and they're relatively dim, it's very hard to keep track of all of them. One could go nova tomorrow. The nearest known white dwarf to us is Sirius B and, at 2.6 parsecs, it's basically right in our backyard. Sirius B is a binary, but fortunately, it's a stable binary and there's no risk of it exploding any time soon. The nearest known white dwarf at risk of a Type 1a supernova is IK Pegasi, 50 parsecs away (150 light years). It's no risk to us at all.
So, as far as we're aware, there are no immediate threats of a supernova going off close to us in the near future. But statistically, they do occur regularly. Within the Danger Zone of 10 parsecs, they happen maybe as often as once every 100 million years. So just by the numbers, Earth has been whacked by quite a few close ones, and absorbs radiation from more distant ones on a constant basis.
What actually happens to the Earth if a star goes supernova within the Danger Zone? It seems to depend on who you ask. The popular depiction seems to be of a cataclysmic event, with the atmosphere burned away, the oceans boiled off, and all carbon based life burned to cinders. This is what you'd get if our sun went supernova – which will never happen – but that's way extreme for the secondhand effects of a distant stellar explosion. The main hazard is that we'd be hit by a massive wave of ionizing radiation that would blast away much of the ozone layer. Many scientists describe this as an extinction level event, but there's reason to be skeptical about that dire prediction. Astronomers John Scalo and Craig Wheeler believe that supernovae and other energetic events strip away the Earth's ozone layer regularly about every 20.000 years or so. It always comes back, and these periods are associated with rapid mutation of terrestrial life forms. We also know from isotopes in sediment layers that a supernova occurred within 5 parsecs of the Earth – well within the Danger Zone – about 5 million years ago. There are no mass extinctions associated with that event.
As it turns out, the Earth's atmosphere, even temporarily bereft of its ozone layer, is still very effective at blocking gamma radiation. As science author Andrew Karam points out, 1 kilogram of air offers the same protection as 90 cm of lead shielding. So yeah, you'd get lots of genetic mutations and increased incidences of skin cancer, but the world wouldn't end. Supernovae are bad for your DNA, but they're probably not as bad as getting sucker punched by a comet.
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