At the edge of our solar system lies the Kuiper Belt, which is almost 60 times farther from the Sun than Earth, but a new discovery raises the possibility it’s bigger than we thought.
The latest readings defy previous models, making scientists scratch their heads over how far the Kuiper Belt stretches.
The New Horizons Venetia Burney Student Dust Counter (SDC) instrument has been detecting higher than expected levels of dust – made up of tiny frozen remnants of collisions and particles kicked up from Kuiper Belt objects (KBOs) from outside the solar system.
Previous theories say the KBO population and density of dust should start to decline a billion miles inside that distance, but new data suggests otherwise. Now, it’s believed the outer edge of the Belt could extend billions of miles farther than the original estimates – or even, NASA, says, there could be a second belt we never knew about.
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The research was published in Astrophysical Journal Letters on February 1.
“New Horizons is making the first direct measurements of interplanetary dust far beyond Neptune and Pluto, so every observation could lead to a discovery,” said Alex Doner, lead author of the paper and a physics graduate student at the University of Colorado Boulder who serves as SDC lead.
“The idea that we might have detected an extended Kuiper Belt — with a whole new population of objects colliding and producing more dust – offers another clue in solving the mysteries of the solar system’s most distant regions.”
The SDC instrument, designed and built by students at the Laboratory for Atmospheric and Space Physics, at the University of Colorado Boulder, detected dust grains produced by collisions among asteroids, comets and KBOs. These were found along the New Horizons’ 5-billion mile. The SDC counts and measures the size of dust particles, to learn more about collisions in our outer solar system.
The latest results were compiled over three years, as New Horizons traveled from 45 to 55 astronomical units from the Sun – roughly 93 million miles or 140 million kilometers.
One possibility on the new findings is that radiation pressure and other factors push dust from the Belt out farther, another is that the new findings are shorter-lived particles that can’t reach the inner solar system so were not accounted for in current estimates.
New Horizons is onto its second extended mission, to have enough power through the 2040s, to travel far beyond 100 AU from the Sun.
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