(ORDO NEWS) — Scientists have shown that the fireball that exploded over Canada in 2021 was hard and rocky.
This is extremely unexpected, because he flew from the Oort Cloud – a distant region, where, as it is believed, there are only fragile ice bodies.
In February 2021, a fireball exploded in the skies over Canada . An analysis of its trajectory and death showed that it was a rocky celestial body that arrived from the Oort Cloud, where, theoretically, only icy comets should be present.
The discovery forces us to reconsider some ideas about what is happening on the far periphery of the solar system.
The Oort Cloud is a hypothetical region of the solar system, a spherical cloud of icy celestial bodies. It covers space in a whole light year, although its existence has not yet been directly confirmed: we receive all knowledge about the Oort Cloud only indirectly.
In particular, if a random game of gravity gives an unexpected boost to one of its objects, it can become a long-period comet passing through the inner solar system as well.
In 2016, scientists noticed one of these bodies with a suitable trajectory, but outwardly completely different from the object of the Oort Cloud. It had a faint luster and did not form a long, sparkling tail, and looked more like a rocky asteroid than an icy comet.
Since then, several more similar observations have been made, although all of them have not been strictly confirmed: such objects are too small and fast. Now one of them has been spotted in the Earth‘s atmosphere, in Canada.
Denis Vida and his colleagues have collected and studied hundreds of random testimonies, CCTV footage, as well as data from the Global Fireball Observatory network, specially deployed to record such events, and satellite imagery.
Based on this, scientists were able to calculate the trajectory of the object and show that it comes from the Oort Cloud.
However, it did not look like an ordinary comet. Fragile comets break up and burn up in the upper atmosphere, but this body, moving at a speed of about 62 kilometers per second, penetrated to a decent depth. Its decay occurred in two stages, as is typical for asteroids.
In addition, the researchers analyzed archival data, finding at least one more similar event recorded in 1979. Based on this, astronomers have suggested that the Oort Cloud may contain not only icy comets, but from one to 20 percent of its objects are rocky asteroids.
Perhaps these estimates are greatly overestimated. In the end, the conclusions are drawn based on too few events, moreover, due to the greater resistance of stony meteorites, their death is more easily detected during monitoring.
But even if we take the lower limit of the specified range – one percent – this makes us seriously think about the appearance and composition of the Oort Cloud.
The presence of rocky bodies there may testify in favor of the “ large tack hypothesis ”, according to which Jupiter formed relatively close to the Sun, after which it approached it, and only then migrated to its current orbit.
In these movements, the massive planet twice destroyed the asteroid belt, and some of its objects could be ejected to the periphery, up to the distant Oort Cloud.
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