to David Freeman
A large asteroid and a small companion moon will harm the earth this weekend.
A so-called binary asteroid called KW4 in 1999 will make the closest approach at 7:05 pm. ET, when a paired object moves at about 50,000 miles per hour, about three million miles away from Earth.
In 1999, KW4 was designated as a potentially dangerous asteroid, but it is unlikely to hit Earth. Nonetheless, astronomers will use a combination of Earth and a space telescope to observe the flying distance. It is part of a continuing effort to improve planetary defenses against the violent asteroid strike seen in recent confusing simulations in Washington.
"It's one of the closest binary flyboys in recent history," said Bishnu Reddy, a planetary scientist at the University of Arizona in Tucson. "That's a very interesting goal."
In the closest approach, the asteroid will be visibly faint.
The asteroid 1999 KW4 was discovered on May 20, 1999 at LINEAR in the Lincoln Near-Earth asteroid study near Socorol, New Mexico, and has since been extensively studied.
Observations show that the primary (alpha) object is about 0.8 miles wide and has a spinning top with a noticeable ridge around the equator. A smaller, or Beta, object is approximately one-third the size of an Alpha object and is about 1.6 miles away from the latter.
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