Astronomers Have Spotted A Mysterious Object Floating At The Edge Of The Solar System

ASA / ESA / G. Bacon (STScI)Wikimedia Commons / Cropped and Resized

Astronomers have discovered an enigmatic object at the fringes of our solar system. The newfound object is only 1.6 miles wide (1.3 kilometers in radius) and was spotted by Japanese researchers all the way in the Kuiper Belt — the distant disk of rocky and icy bodies swarming beyond the orbit of Neptune.

Although tiny, especially in comparison to other, more famous Kuiper Belt objects (KBOs) — such as the dwarf planet Pluto, which measures a whopping 1,477 miles in diameter, and the 20-mile-wide Ultima Thule recently photographed by NASA — the newly discovered object is of tremendous importance to science.

According to the National Astronomical Observatory of Japan (NAOJ), the newfound object – which has been dubbed a planetesimal – actually belongs to a new class of “kilometer-sized” KBOs, ranging between one and 10 kilometers in radius. These objects have been theorized to exist for more than 70 years, although no successful detections had been made until now. This makes the newly discovered object the first one of its kind to ever be uncovered by astronomers.

Given these objects’ small size and dimness, kilometer-sized KBOs are nearly impossible to pick up by even the sharpest of our telescopes. However, NAOJ astronomers believe they have found evidence of a planetesimal with a 0.8-mile radius orbiting the sun at a distance of 32 astronomical units (AU).

One AU represents the average distance between Earth and the sun and is equivalent to about 93 million miles. This places the newfound object within Pluto’s orbital range, which is between 29 and 49 AU, notes Science Alert.

This incredible object was detected through a method called occultation. Since kilometer-sized KBOs are too small to be observed directly with the telescope, the team chose to go a different way and look at the stars instead.

The astronomers picked 2,000 stars and observed them for a total of 60 hours, lying in wait for an object to pass in front of any of these stars and block some of its light. Their efforts eventually paid off when they stumbled upon the tiny KBO — a feat rendered all the more extraordinary given the meager means at their disposal.

As Space points out, the Japanese astronomers did all the work “on the cheap” by installing two small, 11-inch-wide telescopes on the rooftop of a school in Okinawa.

“This is a real victory for little projects,” said team leader Ko Arimatsu, who published the results in a study.

“Our team had less than 0.3 percent of the budget of large international projects [..] Yet we still managed to make a discovery that is impossible for the big projects.”

Just like the rest of the Kuiper Belt residents lurking at the edge of the solar system, the newfound space rock is believed to date back to the early days of planet formation. What’s more, the tiny object is being hailed as the “missing link in planet evolution.”

As NAOJ explains, the tiny planetesimal was born from the same protoplanetary disk that gave birth to the solar system’s planets. However, the 1.6-mile-wide object represents an early stage of planetary formation — a primordial clump of dust and gas particles that never got to coalesce into a bigger object with a strong enough gravity that would allow it to attract even more material and eventually snowball into a planet-sized body.

“If this is a true KBO detection, this implies that planetesimals before their runaway growth phase grew into kilometer-sized objects in the primordial outer solar system and remain as a major population in the present-day Kuiper Belt,” the authors wrote in their paper, published on Monday in the journal Nature Astronomy

Now that they have tested their system, the astronomers plan to look even further out into the cosmos to hunt for hidden planetesimals, said Arimatsu. The team has set their sights on the distant Oort Cloud — a spherical shell of icy comets that begins at 1,000 AU from the sun, as previously reported by the Inquisitr.