in Boulder, Colorado, are taking to the skies to learn more about comets, meteor showers and asteroids. Strapped into the backseat of a high-performance jet aircraft, a scientist can simply look out the canopy to spot possible leftovers from the solar system's formation. These leftovers are rocky debris called "Vulcanoids" thought to circle the sun inside Mercury's orbit.
The innovative airborne astronomy idea is making use of NASA-provided aircraft, including an F 18 fighter jet, outfitted with special gear.
This astronomy-on-the-fly operation is the latest twist in a century-long search for asteroid-like Vulcanoids, chunks of flotsam believed to be leftovers from the creation of the planet Mercury. Some of these objects are thought to have crashed into Mercury long ago, leaving deep craters on its surface.
"Looking for these objects goes back some 150 years," said Alan Stern, head of the institute's department of space studies in Boulder. "In the 19th century, there were numbers of reports of people seeing what looked like little asteroids going across the sun. But they all turned out to be bogus."
More recently, computer calculations suggest that a reservoir of small-sized Vulcanoids may indeed exist in a region inside Mercury's orbit. Work by Stern and colleague Daniel Durda suggest that a few hundred such objects could reside in the sector, most of them less than a mile in diameter.
"These objects are zipping along faster than any bullet on Earth. They are small because they have been running into each other. You can imagine if a mountain hits a mountain at those speeds. Just smithereens is all you've got left," Stern told space.com.
During the last few weeks, Stern and Durda have been poring over data collected by the U.S. European Solar and Heliospheric Observatory or
. Using special computer software, 40 days of SOHO imagery is being analyzed in an attempt to tell if any Vulcanoids have darted across the sun's face. 
"These objects are zipping along faster than any bullet on Earth."
Stern and his colleagues already are hard at work on another way to search for Vulcanoids, using an Air Force two-seater U 2 aircraft. The vintage Cold War spy plane, originally used for photo reconnaissance missions over the former Soviet Union and other countries, can fly as high as 70,000 feet above Earth.
At that altitude, the U 2 can slip above the light-blurring effects of Earth's atmosphere. Timed to fly in a zone of twilight against a black sky, the aircraft can tote a scientist and an array of astronomical equipment to look near and at the sun in a dedicated search for Vulcanoids.
"Using the U 2, you can have a much better twilight than any observatory on the ground. Because the airplane can make pretty good speed, the twilight can be prolonged long enough to do enough imaging in flight to be meaningful," Stern said. "We know that we can nail this problem from a U 2."
The institute has been using high-altitude, high-performance aircraft to carry out low-cost astronomical surveys since 1997. More than a dozen missions with NASA have been flown.
In one of them, an airborne ultraviolet imaging system recently was used to watch an asteroid passing in front of a star.
"It was a great run," said Durda, who flew in the backseat of a NASA F 18 on that January 9 mission. "We're furiously reducing the data we got." From the information scientists should be able to tell the shape of the asteroid and better estimate its size.
Using high-performance aircraft to look for Vulcanoids and other objects is both practical and scientifically important.
"The discovery of even a single Vulcanoid would be the culmination of a century-long search by a number of dedicated astronomers," Durda said. "It could possibly teach us a great deal about the condensation of material close to the early sun that formed the inner planets and about the bombardment history of
advertisement
