Every day, the Earth receives around 100 tons of extraterrestrial matter in the form of grains of dust. 99% of these grains have an approximate size of between 0.05 and 0.5 millimeters .
Due to their size, all of them disintegrate upon re-entry into the Earth’s atmosphere, originating the so-called shooting stars; and only a few, larger ones, reach the earth’s surface. The largest known is 2.7 meters long by 2.4 meters wide and has an estimated mass of 59 tons. It was found in West Hoba, in Namibia.
The fastest meteoroids travel at 42 kilometers per second (km / s) . However, those that do make it through the atmosphere reach the surface at much slower speeds: for example, the Cañón del Diablo meteorite, which measured 50 meters in diameter and had a mass of approximately 30,000 tons, is estimated to have impacted 50 years ago. 000 years against the earth’s surface at a speed of 12 km / s. However, there could be, theoretically, a series of objects, not yet detected, that would travel at a much higher speed: at a fraction of the speed of light .
At 1% of the speed of light
A relativistic speed is considered to be one that represents a significant percentage of the speed of light and therefore forces us to take into account the effects of special relativity. These objects that would impact the Earth’s atmosphere at 1% of the speed of light would likely be subject to these effects. We are talking about a speed of 3 000 km / s.
This is what Harvard University astronomers have proposed in a new study. These meteorites would be between 1 and 10 centimeters in diameter and could be the result of nearby supernovae that cause the particles to accelerate to sub-relativistic or even relativistic speeds, that is, several thousand times the speed of sound or a fraction of the speed of light.
As one of the study’s authors, Amir Siraj , explains:
“Empirical evidence indicates that at least one supernova has caused heavy elements to precipitate on Earth in the past” […] The mass fraction contained in small groups is unknown, but only 0.01% of the ejection of dust is contained in objects of millimeter size or larger, we would expect one to appear in Earth’s atmosphere as a sub-relativistic meteorite every month, depending on the rate of supernovae in the Milky Way. “
To confirm that these fast meteorites are real, it would require an infrastructure that does not yet exist and that, among other elements, should incorporate microphones to capture infrasound and infrared temperature measurement instruments . These are important elements that could detect the acoustic signature and optical flashes of meteorites, since at such speeds it is to be assumed that they would originate a shock wave, which could be picked up by a microphone, and also a bright flash of visible radiation, picked up. by infrared temperature measuring instrument. According to the calculations, a global network of about 600 detectors would be necessary to register these fast theoretical objects.
These bodies would also be the object of relativistic effects such as those that take place in, for example, artificial satellites that orbit the Earth: for this reason, atomic clocks are used in GPS satellites both on the ground and on the satellite itself, in order to calculate the jet lag and thus avoid losing the calibration (this lag, in the course of a single day, would accumulate an error of kilometers in the GPS measurements).
