As fascinating as astronomy is to some of us, it obviously doesn’t get onto the front page of newspapers and the start of news broadcasts very often. These past few days were a startling exception.
A very small asteroid gained major media attention because it was making a surprisingly near pass of Earth last week. But then, only about 16 hours before the asteroid’s closest approach, an unpredicted meteor about one-third the asteroid’s size — and totally unrelated — entered Earth’s atmosphere at a speed of roughly 40,000 mph and exploded over the Chelyabinsk region of Russia.
The terrifying shock wave from that explosion injured more than a thousand people, most of whom were struck by flying broken glass, and damaged roughly 3,000 buildings in six cities.
Today, I want to give you some information about the meteor and asteroid you might not get elsewhere. And I’ll also tell you about some really lovely sights we can see in our skies these next two weeks.
Close-passing asteroid seen locally: As I write these words, we still don’t have the amazing radar images that NASA will soon be providing of asteroid 2012 DA14. At around 2:25 p.m. Friday, this 150-foot-wide chunk of rock passed its closest to Earth, about 17,200 miles above Indonesia.
By the time Earth rotated New Jersey into night, the asteroid was departing but still close and amazing to see — if you could pull off the observation.
The biggest problem with seeing this asteroid was that its closeness placed it at radically different positions relative to the starry background from wherever you were located. Locally, I’m only aware of a few expert observers who got precise calculations of the asteroid’s position and were able to see it.
One was Ray Maher, observing the asteroid from Port Elizabeth with sizable telescopes. He watched as the asteroid went almost directly in front of a much-brighter star in the constelation Ursa Minor (the little bear) and could detect the asteroid’s motion during the course of just 10 seconds.
Meanwhile, at Atsion Field at Batsto, the calculations Joe Stieber generated helped him, Jim Castelli and Dawn Castelli sight the asteroid. Jim Castelli mentioned the group also observed two shadows of moons on the face of Jupiter.
The frightening Russian meteor event: We don’t yet know how many pieces of meteorite were produced by the object that exploded over the Chelyabinsk region of Russia, though one apparently caused a 20-foot-wide crater.
We do know that it entered our atmosphere as a meteoroid approximately 49 feet across, weighing about 7,000 tons and producing a meteor brighter than the sun as seen from near its path.
We also know that the meteor shattered from air pressure when about 10 to 15 miles above ground level in an explosion that may have released about 20 to 30 times as much energy as the Hiroshima atomic bomb.
And that last fact brings us to the really scary part of this story.
Soon after the explosion, a Russian nationalist went public with his belief that the event was actually an American weapons test. As Sky & Telescope magazine’s Robert Naeye writes (see skyandtelescope.com), the U.S. Air Force trackers can quickly distinguish between a ballistic missile and a meteor, which typically travels dozens of times faster than a missile — but the radar experts of some nations cannot do so quickly.
Although the Chelyabinsk meteor was the biggest explosion of this sort since the much stronger Tunguska event of 1908, is it possible that the next such object could create confusion that would set off a nuclear war?
Two lovely moon pairings: Tonight the moon forms a fairly close duo with brilliant Jupiter. But if you go out between midnight and 2 a.m. March 1, you’ll see the moon less than one moon-diameter from bright star Spica — a striking sight.
Fred Schaaf is a local author and astronomer. He can be reached at email@example.com