Death from the Skies! by Ph. D. Philip Plait Page B

which was far too late . . . not that advance knowledge would have helped.
    Within minutes of the event, automated observatories orbiting the Earth perk up. Astronomical satellites designed to observe high-energy light such as X-rays and gamma rays see a rise in detections. One by one, as they slew over to focus on the source of the particles, their detectors saturate with photons as the fierce light intensifies. Within minutes the satellites are blinded, overwhelmed with light, and lose track of the target.
    On the ground, across the night sky of Earth, thousands of amateur astronomers, truckers, police officers, and general night owls notice the light in the sky. It’s getting brighter by the minute. Some of the amateur astronomers momentarily think it’s an airplane, or the glint of reflected sunlight off an orbiting satellite. But many immediately realize what’s happening, and start taking data. Others send out e-mails, alerting astronomers all over the world. Get out your scopes! There’s a new supernova!
    But the e-mails are unnecessary. Within minutes, the “new” star is so bright that other stars in the sky can’t compete. Like the sunrise or the full Moon, the supernova is washing out the sky around it.
    Astronomers are beside themselves with glee. It’s been over four hundred years since the last naked-eye supernova in our galaxy, and this one will no doubt be a record breaker.
    But their joy is short-lived. In the middle of their observations, all their machines suddenly lose power. The images and data are all lost when the computers controlling the telescopes die. And before they can properly assess the problem, all the power goes out. One astronomer ventures outside to see what’s going on and realizes that the glow of the nearby city is gone. Normally, the combined luminescence of thousands of streetlights, buildings, spotlights, car dealerships, and house lights drowns out the fainter stars in the sky. In a huge ironic twist, the power is out everywhere and the sky is truly dark for the first time in years, yet she cannot observe because her power is off too. Her telescope is useless.
    She stares upward at the stars and, after a few minutes, realizes the sky isn’t as dark as it was earlier: the fierce eye of the supernova is glaring down on her, and the sky around it is blue. No other nearby star could possibly compete.
    Her attention is diverted when she sees another bright light in the sky, this one moving slowly across the ever-bluer sky. She realizes it’s the International Space Station. She laughs, glad to see something normal for a moment.
    What she doesn’t realize is that the astronauts on board are dead. Had she known, she certainly wouldn’t have smiled. But then, in a few years, everyone on Earth will be dead too. Humans were doomed from the instant the first rays of light from the supernova touched the atmosphere.
    Gamma rays from the supernova destroy vast amounts of ozone, which is quickly reduced to half its normal amount. When the Sun rises in the morning, its ultraviolet light will stream all the way through the atmosphere nearly unabated. Severe sunburn will be the least of the problems faced on Earth as the UV radiation kills off the ocean’s phytoplankton, which make up the base of the food chain. Animals that feed off phytoplankton find their food source dwindling and eventually disappearing in mere days, and animals that feed off those animals face the same dire problem a few days later. This die-off marches up the food chain, and it won’t stop until it reaches the top: us.
    It’s been a long time since an astronomical event touched off a mass extinction. But now, another one is under way.

A STAR IS BORN
    If you go outside on a dark, clear night, far from city lights, you can see thousands of stars sprinkled across the sky. They may seem unchanging, fixed—some people even refer to the night sky as the “starry vault,” implying a strength and permanence. Sure, the