Professional and backyard astronomers were surprised by the apparent speed of an asteroid they watched recently as it zoomed past Earth close enough to be observed in small telescopes.
Students from Yale University used a 3-foot (0.9-meter) telescope at Kitt Peak National Observatory to capture a series of still images of asteroid 2002 NY40 on August 15-16, two nights before its closest approach to Earth. The images were converted into a short movie that represents two hours of observations condensed. [Watch the video of the images here.]
Undergraduate student Brandy Heflin and graduate student Bing Zhao were at Kitt Peak conducting research on binary stars when they decided to interrupt their work to observe this unique event.
The observations were possible because a consortium of universities took over operation of the telescope from the National Science Foundation last March, in order to give their students more hands-on research time.
"These unplanned observations reflect the exact reasons that the university partnership took over operational responsibility for the telescope," said astronomer Charles Bailyn, Heflin and Zhaos research mentor at Yale. "They took me a bit by surprise, but we want to encourage students to take the initiative, and they did a very nice job. There is also some real science to be gleaned from these observations, in terms of brightness fluctuations and the rotational period of the asteroid."
Asteroid 2002 NY40 crossed an area of the sky about equal to the full Moon during the time period of the movie. Two nights later, during its closest approach to Earth, the asteroid was moving across the sky about 20 times faster. It was not visible without the aid of binoculars or a telescope.
Other backyard astronomers described the asteroid as appearing in their telescopes like a slow-moving, distant satellite.
Discovered on July 14, asteroid 2002 NY40 has an estimated diameter of about 0.43 miles (700 meters). It passed safely by Earth on the night of August 17-18 at a distance of approximately 326,000 miles (524,000 kilometers), about 1.3 times the distance from Earth to the Moon.
Despite a few press reports that had claimed the asteroid had a small chance of hitting Earth in the future, NASA and other astronomers said there is no such chance. Such close passes by large asteroids, however, provide viewing opportunities like this only every few decades, astronomers say.
The staff of National Optical Astronomy Observatory (NOAO) in Tucson, AZ created the digital movie of 2002 NY40.
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