The doughnut-shaped Kuiper belt, which is already one of the largest structures in the solar system, may extend farther than previous estimates. During its journey across the edge of the solar system, the New Horizons probe captured a trail of dust made up of ice debris, which could indicate that the Kuiper Belt – once home to the planet Pluto and countless other objects – is much larger than we thought.
New observations from NASA missions suggest that the vast doughnut-shaped outer region of the solar system, known as the Kuiper Belt, could extend billions of miles more outward than current estimates. According to a study published in Astrophysical Letters, there may even be a second outer band altogether.
New Horizons became the first spacecraft to visit Pluto in 2015 and has been on an extended mission of the Kuiper Belt ever since, traversing a region filled with frozen debris left over from the early days of the solar system. The Venetia Burney Student Dust Counter (SDC) on the spacecraft detected dust levels that exceeded expectations. The dust is the remains of a violent collision between objects within the Kuiper Belt.
Previous models of the bands showed that the amount of dust should have begun to decline after extending outward for a billion miles. However, the density of dust detected by New Horizons challenges these models, suggesting that the Kuiper Belt may extend further than scientists believe. The outer edge of the band, where the density of objects begins to decline, was originally thought to be about 50 astronomical units from the Sun (one astronomical unit is the distance between the Earth and the Sun, about 93 million miles or 1.).400 million kilometers), but new evidence suggests that the Kuiper Belt may extend to 80 AU or beyond, with Neptune, the farthest planet from the Sun, located at 30 AU.
"We may have detected an extended Kuiper Belt — with entirely new groups of objects colliding with each other and producing more dust — that provides another clue to unravel the mysteries of the farthest reaches of the solar system," Alex Donal, a graduate student in physics at the University of Colorado Boulder and lead author of the new **, said in a statement. The evidence provided by New Horizons is also supported by observations from the ground at the Japan Pleiades Telescope in Hawaii, which discovered a number of Kuiper Belt objects located on what is believed to be the outer edge. Scientists are making more observations of the belt and exploring other explanations, such as a second belt that has yet to be discovered. Another possibility is that radiative pressure and other factors pushed the dust generated by the Neicoiper belt beyond the edge of 50 astronomical units.
New Horizons was launched on 18 January 2006. The mission was originally scheduled to end in 2024, but NASA recently decided to extend it until the spacecraft leaves the Kuiper Belt, which is expected to happen as early as 2028.