An asteroid between 150-160 meters in diameter will pass within 540,000 kilometers (334,000 miles) of Earth on January 29 at 08:33 UT (3:33 EST). Hopefully this news won’t cause any alarmist cries of doom, as the asteroid has no chance of hitting Earth. But there is one reason to get excited about this close approach by an asteroid: it will be close enough to likely be visible to amateur astronomers.
Asteroid 2007 TU24 was discovered by the Catalina Sky Survey on October 11, 2007 and will approach the Earth to within 1.4 lunar distances. During its closest approach, it will reach an approximate apparent magnitude 10.3 on Jan. 29-30 before quickly becoming fainter as it moves further from Earth. So, for a brief time the asteroid will be observable in dark and clear skies with amateur telescopes of 3 inch apertures or larger.
According to NASA’s Near Earth Object Program, since the estimated number of near-Earth asteroids of this size is about 7,000 discovered and estimated undiscovered objects, an object the size of 2007 TU 24 would be expected to pass this close to Earth, on average, about every 5 years or so. They also say the average interval between actual impacts of Earth for an object of this size would be about 37,000 years. But rest assured, for the January 29th encounter, near Earth asteroid 2007 TU24 has no chance of hitting, or affecting, Earth.
2007 TU24 will be the closest currently known approach by an asteroid of this size or larger until 2027. Plans have been made for the Goldstone planetary radar to observe this object Jan 23-24 and for the Arecibo radar to observe it Jan 27-28, as well as Feb 1-4. The NEO office says they should be able to image the object with high resolution radar, and if so, 3-D shape reconstruction images should be possible. Way cool.
The illustration below is courtesy of amateur astronomer Dr. Dale Ireland from Silverdale, WA. The illustration shows the asteroid’s track on the sky for 3 days near the time of the close Earth approach as seen from the city of Philadelphia. Since the object’s parallax will be a significant fraction of a degree, observers are encouraged to use the NEO office’s on-line Horizons ephemeris generation service for their specific locations.
Now, we’re aware that there are some alarmists out there trying to freak people out about this asteroid visit. They’re posing the usual conspiracy theories about the astronomy community’s cover up. Don’t worry, there’s absolutely nothing to fear except a little cold weather as you stand outside, hoping to see the asteroid pass by with your telescope. If you want a more detailed debunking of this myth, check out Bad Astronomy’s excellent coverage.
Original News Source: NEO Program Press Release