For years, the American space agency NASA has relied on amateur astronomers to search for asteroids - huge chunks of space rock that may be on a collision course with the planet Earth. Many professional telescopes are well suited to scanning large portions of the sky and picking out new asteroids. But hundreds of amateur observatories around the globe use their narrower telescopes to zero in on the new discoveries, and track their progress through space. From the Great Plains state of South Dakota, Curt Nickisch recently joined one such amateur astronomer on the hunt.
Western South Dakota is perhaps better known for paleontology than astronomy. It's one of the world hotspots for dinosaur fossils. Some scientists believe the dinosaurs died out suddenly 65 million years ago when a colossal asteroid smashed into the Earth, drastically changing the climate. It's here, at the edge of rugged outcroppings called the South Dakota Badlands, that Ron Dyvig is searching for the next killer asteroid.
Mr. Dyvig retired from his job at a used car lot five years ago to build this observatory at an abandoned medical building in the town of Quinn. The town's 44 residents were happy to find a use for the building, and hoped the Badlands Observatory would put Quinn on the map. With plywood and planks, Ron Dyvig and a few friends constructed the geometric dome that caps the white cement building like a tank turret. A hand-crank opens the dome to the night sky.
"It's very good to have the temperature inside the same as the outdoor temperature," explains Mr. Dyvig, "because the difference in temperature between the air column in front of the telescope and outside can create thermal waves that basically blur the image. That's what causes stars to twinkle at night and it's great for romance, but it's not good for astronomy!"
At first, Mr. Dyvig had to brave the cold weather here to make observations. Now he can direct the four-meter-long telescope with computers from a heated control room downstairs. Motors turn the dome to keep the opening in front of the telescope as it tracks across the sky.
"These motors actually came from a vending company. I believe that they're motors that were originally used out of Coke machines. They're geared down and they're very powerful at slow RPMs," he told a visitor, referring to revolutions per minute.
It took three years and $25,000 to build what now is a culmination of a lifelong love of astronomy. Mr. Dyvig says he got hooked when spotting the planet Mars with the naked eye on a Boy Scout camping trip 50 years ago. Now the telescope he's built detects objects more than a million times fainter than Mars. That makes the Badlands Observatory particularly good at detecting rock masses careening through the solar system, asteroids whose orbits might one day crash them into the Earth.
These guys are really having a lot of fun," says Steve Chesley, a senior engineer at a NASA center in Pasadena, California. It's his job to analyze observations from the hundreds of amateur astronomers all around the world who spot and track such asteroids. "They like to observe. They like to go without sleep. And instead of just pointing their telescopes at galaxies and planets and saying 'ooh, ah, look at that,' they are pointing them at asteroids and doing something that's really valuable."
It's easier to spot the asteroids moving at the threshold of visibility when the sky is extremely dark. That's why Ron Dyvig chose the South Dakota Badlands, one of the darkest areas in the United States. He even convinced the town council to install hoods over the streetlights in Quinn, and a switch on the one closest to the observatory. Before looking for asteroids each night, he trudges through the snow to switch the streetlamp off.
On a dark night like this two years ago, Mr. Dyvig re-discovered an asteroid heading towards Earth that was first observed briefly back in 1987 before disappearing from view. That sighting helped other astronomers plot its course and determine that it would pass Earth at a safe distance. He's also discovered 27 asteroids that orbit beyond Mars. One of them was officially named after South Dakota.
Tonight, however, Ron Dyvig is getting a break from his self-appointed task. Clouds passing over the Badlands prevent him from detecting any asteroids moving through the starry heavens. So he reluctantly directs the computer to steer his telescope back into its stow position and looks forward to another night, and another hunt for faint, but potentially dangerous asteroids.