Asteroids!
“An asteroid that was discovered just two weeks ago is expected to make its nearest pass to Earth on Halloween and will be closer to our planet than any other object since 2006.”
As a recent news item, I found this to be a very odd statement. In any given year there are numerous reports of small asteroids passing close to Earth and within the orbit of the moon, I checked and found 19 so far this year, (Nineteen). The average size of these is of a house and larger, a big enough object to cause some damage if it were to strike the Earth.
“Identified as 2015 TB145, it was first located on October 10. Measuring somewhere between 920 and 2,034 feet in diameter, it’s about the size of a large skyscraper. But don’t worry. This asteroid is not a threat to our planet. It will pass by roughly 1.3 lunar distances from Earth; in other words, it will never come closer to the planet than the Moon. Although no human is known to have been killed directly by an impact, over 1000 people were injured by the Chelyabinsk meteor airburst event over Russia in 2013.”
Yes, don’t worry, be happy. The Chelyabinsk meteor, (an asteroid becomes a meteor when it enters the atmosphere of our planet), is said to be the largest natural object to have hit Earth since the 1908 Tunguska event which destroyed a large, remote forested area in Northern Siberia. I also checked on that as well and found it to be basically true. However, there have been some 556 incidents in the 20 years between 1994 and 2013 that the Earth has been hit by small asteroids from 1 meter to almost 20 meters, (60 feet wide) in size! (Source: NASA). The Chelyabinsk meteor is thought to have been 20 meters wide. So what about all those other hits? And not to mention the near misses, an estimated 30 per year! Okay, I don’t mean to get excited about this, but clearly not too many people are aware of the magnitude of these events. What is also scary about the Chelyabinsk meteor strike is that on the same day, 16 hours later, another asteroid passed close to Earth. This was a 30-meter object in a different orbit. So first the good news, objects this size almost always burn and break up in the atmosphere before hitting the ground. The bad news is that the large ones can create an ‘airburst’ equal to a small atomic bomb. Some 7,200 buildings in six cities were damaged by the shock wave from the Chelyabinsk meteor. It would take a rock a half to a mile wide in size to really do some damage to our planet and these are supposedly easier to see and track in space. There is some effort being made by NASA to keep an eye on these objects, so that is some comfort. But remember, the dinosaurs were wiped out by a large asteroid strike on Earth long ago. What happened then could always happen again. (Below, an old painting of mine, showing an asteroid being explored by spacecraft over Europa.)
