Studying asteroids that approach Earth
On June 30, 1908, a large explosion occurred near the Tunguska River in Russia at the beginning of the day. There was no causation, but the witnesses reported a bright blue flash, followed by a thunder and a glare of windows.
Almost 10 years later, the scientists led an expedition. They observed unusual features like trees that seemed to have been burned, standing without branches.
The team was disappointed not to have found a crater or meteorite.
Since then, much research has focused on this “impact” – it is important to be the only test case for impact assumptions.
The newspaper reports that appeared during the days following the impact were collected to put in place the side effects – an earthquake on Richter Scale 5 was recorded. The shock waves were detected.
The devastated area was about eight kilometers wide. The atmospheric effects have also been reported. The people of about 100 km had seen a column of luminous blue cylindrical fire going down near the horizon just before the earthquake shook the buildings.
Impact is a concern for all of us. A study of this kind is important for us to survive. Several hypotheses have been developed. While it is said that these are comets, another says it was a sudden release of natural gas from the earth itself.
The possibilities of these studies are rather rare. An asteroid collision in Chelyabinsk on February 15, 2013 gave another opportunity: the asteroid roughly the size of a small plane and it exploded without creating a crater. The effect of the impact was 500 kilotonnes in the air explosion.
Eugene Shoemaker, an Americangeologist and one of the founders of the field of planetary science, who proposed the impact theory of lunar craters has also made estimates of impact energy.
The effects on the atmosphere, on the biosphere, are well studied. It is established that an impact was responsible for the mass extinction of dinosaurs 65 million years ago.
The impact crater is identified by an enormous circular region called the KT boundary near Mexico.
The importance of the study of these asteroids approaching the Earth was realized some time ago and special investigation projects were initiated. Near-Earth asteroid (NEAT) monitoring, astronomy research near Lincoln Land (LINEAR) and others like this use robotic telescopes to explore the sky for the rapidly moving body near Earth.
Near-Earth asteroids may be too small to be visible even with moderately sized telescopes. A register of potentially dangerous near-Earth ash- eroses (PHNEA) is maintained and these objects are tracked.
The list of PHNEAs is increasing rapidly with the arrival of new detectors and new survey telescopes. There are still a million asteroids to identify that could fit into this list. Approach distance is usually given in LD units, which is the lunar distance (384,000 km). For example, the asteroids designated 2014 BS5 move in front of the Earth at a distance of 3.12 LD on 23 July.
It is about 30 to 50 m in diameter (if circular) and will be a good target for the study using radar imagery.
Thus, PHNEAs pose a risk to the Earth, and the consequences of an impact can be severe. We have the technological capability to detect. More recent ideas on tracking and diverting dangerous people away from the impact of the earth are experienced.
There are only a handful of asteroids whose accident on earth was known.
Some of them had names like Lost City, Pribram, Peekskill and Innisfree. They were very small and their impact did not do much damage. However, there are larger bodies that are known whenever they are landed once every three or five years. The closest approach to Apophis, about 370 km, is scheduled for April 13, 2029, when it is probable Within a distance of 36,000 km ….