NASA's New Horizons spacecraft, together with Japan's Subaru telescope, has discovered a hitherto unknown part of the Solar System: according to recent data, there is another asteroid field outside the Kuiper Belt.
The Kuiper Belt is a region beyond Neptune, 4.5 to 7.5 billion kilometers away, at the outer edge of the Solar System. The existence of the belt was proposed by Gerard Kuiper in 1951. Observations in subsequent decades have found thousands of celestial bodies here, but in reality there are billions of smaller asteroids and hundreds of thousands of asteroids larger than 50 kilometers. These are icy asteroids composed largely of methane, ammonia, or frozen water. Many strange asteroids orbit here, such as Pluto, Charon, Orcus, Haumea, Quasar, Makemake, Arrokoth, and the snowman-shaped Ultima Thule.
(It is worth noting here that a year before Kuiper, in 1950, the Dutch astronomer Jan Oort described another possible region – the Oort cloud, not to be confused with the Kuiper belt, which surrounds it at a farther distance, at a distance of 0.03-3 light years from the solar system.)
empty space
NASA's New Horizons probe, launched in 2006, has been exploring Pluto and the Kuiper Belt for a decade. The instrument is the fifth body, along with the Pioneer and Voyager probes each, to gain sufficient escape velocity to eventually leave the solar system.
Since all of its systems were still working flawlessly in 2021, and the radioisotope power supply would last until the 2030s, its mission was extended. After flybys of Uranus, Neptune, Pluto, and Arrokoth, starting in 2020, the Subaru telescope was used to search for an asteroid that New Horizons could launch and examine in orbit, but they didn’t find a suitable target for years. Now we know why.
Calculations based on the new observations show that outer space is almost completely empty between 8.2 and 10.4 billion kilometers from the Sun, but beyond that, a thinner, rarer asteroid belt begins that appears to be a continuation of the Kuiper Belt.
Subaru and New Horizons have found 263 unknown objects in this region in recent years, but 11 of them have been found orbiting far beyond the outer boundary of the Kuiper Belt, which is 70 astronomical units away.
We have known for some time that the Kuiper Belt in the solar system is very small compared to other planetary systems, and based on the results we have only been deceived by distorting our observations.
Wesley Fraser, a Canadian member of the international team exploring the area, said.
Alan Stern, an employee of the Southwest Research Institute, who also participated in the research, stressed that the result is not only surprising, but a major breakthrough, made possible by the unique capabilities of the 8.2-meter Subaru telescope in Hawaii.
The discovery casts doubt on ideas about the formation of the solar system, according to which the history of our immediate cosmic environment began with a disk of matter much larger than previously thought. However, if the Kuiper Belt is not much smaller than other stars, then the solar system is not exceptional in this respect – and this increases the chances of life emerging in other, less exceptional star systems.
(Science Alert, Space.com website, Wikipedia)
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