NASAs New horizons mission, which we encountered Pluto in 2015 now rides through the deepest depths of the Kuiper beltfaces a cosmic dust storm that suggests there may be more going on in Earth’s outer reaches solar system than we imagine.
Space is filled with dust made up of tiny particles just microns – a millionth of a meter – in size. Much of the dust in our solar system is a remnant of the formation of the planets, a violent affair in which large numbers of objects collided. Today, this ancient dust is also accompanied by fresh dust spewed from the surfaces asteroids And Come eat by micrometeorite impacts. This content of dust, both fresh and old, gives rise to the enigmatic ‘Zodiacal Light’. The dust extends to the farthest reaches of the solar system. Astronomers are still not entirely sure about the composition of this final frontier.
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The Kuiper Belt (or the Kuiper-Edgeworth Belt, named after astronomers Gerard Kuiper and Kenneth Edgeworth, who independently proposed its existence) is so far away, and its icy inhabitants are so small and weak, that it was not discovered until 1992 lasted for the Kuiper Belt to form. the first Kuiper Belt Object (KBO) beyond Pluto was discovered. That discovery was made by astronomers Dave Jewitt and Jane Luu of the University of Hawaii. But since then, thousands of KBOs have been spotted and astronomers have tentatively succeeded in mapping the outer solar system.
Beyond the Kuiper Belt is the Scattered Disk, populated by KBOs spread from the Kuiper Belt by gravitational tides originating from the solar system’s outer planet. Neptune. Objects in the scattered disk tend to have highly elliptical orbits that are highly inclined to the plane of the Solar System and can be up to hundreds of AUs from the Sun. One AU, or astronomical unit, is equal to the distance between the Earth and the sun.
Far beyond the Kuiper Belt and the Scattered Disk lies the Oort cloud, a vast spherical region of frozen objects stretching about a light-year from the Sun. Although its distance means the Oort Cloud has never been directly observed, scientists know it exists because the orbits of long-period comets can be traced back to it.
Now, however, new findings from New Horizons threaten to upend much of what we thought we knew about the outer solar system.
“New Horizons makes the first direct measurements of interplanetary dust far beyond Neptune and Pluto, so any observation could lead to a discovery,” astronomer Alex Doner of the University of Colorado, Boulder, said in a statement. rack.
The distance between the outer edge of the Kuiper Belt and the Sun was thought to be about 50 astronomical units (one AU is also equal to 149.5 million kilometers or 93 million miles). On January 1, 2019, New Horizons encountered the KBO Arrokoth, which is located at a distance of 44.5 AU from the Sun; Today New Horizons is 58.25 AU from the Sun, after crossing the 50 AU mark in April 2021. For the past five years, New Horizons should have sailed over the edge of the Kuiper Belt. However, because the KBOs were millions of miles apart, New Horizons would not visually notice that it had left them behind. Instead, the sign would be a drop in interplanetary dust levels.
Yet the spacecraft’s Venetia Burney Student Dust Counter (SDC) is named after it the little girl who named Pluto in 1930, this decline has not been observed. In fact, there is as much dust as ever before, which baffles astronomers.
The SDC is mounted on the front of the New Horizons spacecraft. It consists of 14 plastic film detectors, each 14.2 by 6.5 centimeters (5.6 by 2.6 inches) in size and only 28 microns thick. A dozen of the detectors are exposed to space, while the other two are shielded so they can act as reference detectors, recording events unrelated to dust impacts to rule out false positives. Every time a dust particle hits one of the detectors, the impact leaves a small pit in the plastic film that subtly changes the way their surfaces conduct electricity.
One possibility is that the excess dust was actually produced closer to the Sun and blown out of the Kuiper Belt thanks to the pressure of sunlight acting on the particles. However, Doner’s team considered this theory unlikely. Instead, a more attractive option is preferred, they say.
There may simply be more to the Kuiper Belt than astronomers had realized.
The continued presence of dust implies that New Horizons is still within the Kuiper Belt, and that the Kuiper Belt is much more extensive than anyone knew, stretching billions of miles further from the Sun than our maps currently estimate.
It’s not just the dust counts that tell us this. Astronomers have taken advantage of it machine learning algorithms to search observations made by the 8.2-meter Subaru Telescope on Mauna Kea in Hawaii, and the Victor M. Blanco four-meter telescope at the Cerro Tololo Inter-American Observatory in Chile, to look for more icy objects that New Horizons could explore. They have so far found 154 objects in the direction New Horizons is headed, including about 20 that the spacecraft will come within a few million miles, close enough for some rudimentary observations. Yet some of those 154 objects appear to be outside the Kuiper Belt, and not in the kind of eccentric orbit reminiscent of the Scattered Disk, but in the ecliptic plane also shared by the Kuiper Belt.
Are they members of a broader Kuiper Belt, or perhaps even a second belt?
“The idea that we may have discovered a vast Kuiper Belt – with a whole new population of objects colliding and producing more dust – offers another clue to solving the mysteries of the solar system’s most remote regions,” says Doner.
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– NASA’s Voyager 1 glitch leaves scientists sad but hopeful: ‘Voyager 2 is still going strong’
— Which cosmic object ‘Arrokoth’ can tell us about the formation of our solar system
– Could an ‘Earth-like’ planet be hiding in the outer reaches of our solar system?
New Horizons sails through uncharted waters. Only four spacecraft have passed this route before: Pioneer 10 and 11, and Traveler 1 And Traveler 2; none were equipped with a dust counter like New Horizons.
While the Pioneers have been inactive for a long time and with the Voyager 1 spacecraft starts to waverNew Horizons has enough fuel and power to survive well into the 2040s, when its distance from the Sun could be well above 100 AU. By the time its power wanes, it will likely have completely redrawn the map of the outer solar system.
The new results of the SDC were published on February 1 in the Astrophysical diary letters.