Explanation - a fragment that escaped from the moon
Avi Blizovsky
A fragment of an asteroid, about 50 meters in diameter, was discovered orbiting the Sun in an orbit almost parallel to that of the Earth. The object, discovered on February 10 by an automated asteroid hunter (a telescope connected to a computer that is programmed to look for small near-Earth bodies) in New Mexico,
It is apparently a rock that broke off from the moon. This is what the New Scientist magazine reported at the end of last week
A team of astronomers at the Institute of Astrophysics of the Harvard Smithsonian Center observed the object for six consecutive nights and according to their calculations, the object revolves around the sun for about a year and a month, in an almost circular orbit nine million kilometers from the Earth's orbit.
The search for near-Earth objects has gained momentum in recent years, following the discovery of several asteroids whose orbit brought them almost into collision with the Earth. Astronomy enthusiasts (this field is treated unsympathetically by professional astronomers) have rallied to this cause, and they devote a significant portion of their time to locating such objects. The goal is to find those among them who threaten the inhabitants of the earth. According to a popular theory, a large asteroid that collided with the Earth about 65 million years ago is this
which caused the extinction of the dinosaurs and most of the other animal species that existed at the time. Research institutes conduct automated observations of the sky to discover near-Earth objects.
The bone track is unusual. Comets and asteroids that cross Earth's orbit usually move in eccentric (ie, highly elliptical) orbits. So far, only one asteroid has been discovered that moves in an orbit similar to that of the Earth - 1991-VG. When it was discovered eight years ago, astronomers believed that it was a spaceship that had been released from the Earth's gravity.
The new object, 1999-CG9, is brighter than the previous one. That means it's also bigger, says Brian Marsden of the Harvard-Smithsonian Center. He estimates that its diameter varies between 30 and 50 meters - too large to be the third stage of a rocket that flew too high, and in his opinion it is a rock that was splashed from the moon.
The chairman of the Israeli Astronomical Society, Yigal Fatal, explains that these objects are actually the lunar material that was splashed when a meteorite crashed on the surface of the moon. As a result of the collision, a crater was formed. Most of the material remains in the vicinity of the crater, but sometimes the intensity of the collisions is so great that
that scatter in space in fragments with a diameter of about 50 meters. According to the calculation, it is a bone that weighs about a quarter of a million tons. This is how it is assumed that the stones that, according to the explanation, came from Mars, and in which fossils of bacteria were found: a large body landed on Mars, created a crater and threw the rock into a trajectory that took it outside of Mars and eventually - to Earth.
In 1908, an object of a similar size - several tens of meters - hit Tunguska in Siberia and caused complete destruction in a radius of several tens of kilometers. Fortunately, it was an uninhabited area. If this happened in the center of a big city like New York, millions of people would be killed.
"Objects fired from the moon continue to revolve around the sun in a similar orbit to those of the moon and the earth," adds Marsden. He hopes that after scientists study the composition of the materials of the new asteroid - which will be done by observing its spectrum - it will be possible to know if it actually originated from the moon.
NASA delayed for two weeks the publication of the news about the discovery of the bone.
According to Fatal, NASA wanted to thoroughly check the orbit of the object before publication, so as not to repeat the error in the case of the asteroid 1997-XF11. At that time, it was reported that it was going to come as close as several tens of thousands of kilometers from the Earth and possibly even collide with it in the 21s. XNUMX But repeated calculations revealed that it would miss the Earth by a million kilometers.
Published in "Haaretz" on 01/03/1999
