Red Sky at Night

I was reading in the hot tub tonight, using the green underwater tub light. I finished the story I was reading, put the book aside, turned off the light, and lay back to gaze at the stars. My heart caught and I gulped. The familiar stars glared orange and baleful from an angry blood-red sky. It took only a second, of course, to realize the source of the startling vision: the long exposure to the green light had temporarily exhausted the green receptors in my retina, leaving only the red to send signals to my brain. Nonetheless, it took many minutes for the effect to pass, and I had some time to gaze at the sanguine firmament.

Is this what it will be like, I wondered, when the sun has exhausted its fuel at last and slowly bloats to a red giant? It will expand enormously, first slow-roasting Mercury, then Venus, then Earth. The seas will boil, the atmosphere will burn off, the crust of the Earth will melt and run. Finally, our friendly sun will expand to the orbit of the Earth and swallow the planet whole and without a trace.

And of course this is no science fiction fantasy. There is nothing anyone could possibly do to stop it. The planet is clearly doomed. All that we see about us will inevitably be destroyed, whether or not there is anything like us, or even anything of life, here to see it.

This less-than-happy thought is quickly replaced, if not alleviated, by another. The slow roast is indeed bound to happen - unless of course, one of those friendly sparks of light up there were to suddenly go supernova. Then the expanding shock wave would sweep across dozens of light years, vaporizing and obliterating any solar systems in its path. But of course, if that were to happen, the shock wave would strike us at nearly the speed of light, and we would not see the flaming sky before the Earth was incinerated. Come to think of it, one of those stars could have already exploded, and we would have no way of knowing. Cheery old Sirius, twinkling blue and red and green up there, for example, is only around ten light years away. It could have blown up nine years ago, and the massive wave of radiation could even now be streaking the last few miles toward us. Perhaps the gibbous moon floating so peacefully over there has already been raked by the blast a second ago and this could be our last second to live. Or perhaps this second, or this second, or this. The fact that seconds continue to tick safely past in no way lessens the likelihood that annihilation will arrive the next. And there are so very many stars up there, any one of which could be our nemesis.

Betelguese, for example, that friendly red light in just up there in Orionís shoulder, like a distant campfire in the night, is already in its death throes. Itís already expanded into a red giant 650 times the diameter of the sun, and has already consumed any planets and civilizations it may have once harbored. Itís highly unstable, pulsates irregularly, and is not expected to last much longer. It could explode any minute. Of course, it is around 427 light years away, so weíre seeing it the way it looked when Elizabeth the First was Queen of England. If it was so unstable back then, it would be a miracle if it hasnít exploded in the last four hundred years. If it did, its massive shock wave is already on its way toward us.

I should perhaps have placed this warning in the first paragraph: this essay should not be read by those who tend to worry about unavoidable, unpreventable, and unknowable disasters. You know the kind of people you are: the ones who shouldnít hear about the large number of Earth-crossing asteroids discovered each year, after they have passed us and become detectable. Oh, sorry.

copyright 1988 by Brian K. Crawford