In the summer of 1908, a fireball appeared over Tunguska, in northern Siberia. Eyewitnesses described a column of blue light moving across the sky, followed by an extraordinary explosion that washed away trees over 2,000 square kilometers .
The space rock responsible for that deflagration could have bounced off the atmosphere and would still orbit the Sun today, according to new research that attributes the absence of debris from the asteroid that caused the big explosion to this fact .
Bounce theory
Given the size of the impact region, it is estimated that the original asteroid was almost 70 meters. But no impact crater or remains have been found . The theory that it has bounced, then, is plausible, and it would not be the first time that it would happen.
One such example was the 1972 Great Daylight Fireball, a truck-sized rock that leapt through the upper atmosphere and was seen in parts of Utah and Wyoming:
In the aforementioned research, several scenarios were modeled, considering bodies that vary in size from 50 to 200 meters and are composed of ice, stone or iron.
Finally, it was found that the most likely scenario is an iron asteroid about 200 meters in size : if the object had a surface impact in the atmosphere, reaching less than 10 kilometers from the Earth’s surface, it would have remained practically undamaged and it would have returned to space to enter a near-solar orbit.
Tons of matter from space fall on Earth every day, although most of it disintegrates upon re-entry into the Earth’s atmosphere . Specifically, the Earth receives around 100 tons of extraterrestrial matter in the form of grains of dust per day. 99% of these grains have an approximate size of between 0.05 and 0.5 millimeters. Some, however, are larger. And they come from the moon, or from Mars.