In January 2018, scientists gazing out beyond the known objects of the Solar System spotted something new: A small object, seemingly bound in orbit around the Sun. Scientists nicknamed this speck 'Farfarout,' for its distant location from the star — about four times farther than Pluto is from the Sun.
Now, after years of follow-up observations, we can finally confirm: Farfarout is in fact a planetoid, and the most distant object in the Solar System.
HERE'S THE BACKGROUND — Using the Subaru Telescope, an 8-meter telescope located on top of the dormant volcano Mauna Kea in Hawaii, scientists spotted the planetoid Farfarout.
A planetoid is a kind of hybrid, somewhere between a planet and an asteroid — a small piece of ice, rock, and dust orbiting around the Sun.
Follow-up observations of the object determined its orbit, confirming that it is the furthest known object of the Solar System.
Of course, the latest object is not to be confused with 'Farout,' the previous record holder of the most distant object of the Solar System. Unfortunately for Farout, Farfarout is much further out, located deep inside the Kuiper Belt.
The planetoid is located a whopping 132 astronomical units (AU) away from the Sun. One astronomical unit is the distance between the Earth and Sun, approximately 91.757 million miles.
For comparison, the dwarf planet Pluto is located 34 AU from the Sun.
WHAT'S NEW — By tracking Farfarout's motion around the Sun, the team of scientists were able to determine its orbit — and it is certainly a doozy.
The object completes one orbit around the Sun in a thousand years.
At the furthest point in its orbit, Farfarout is at a 175 AU away from the Sun. As it journeys around the star, it does loop a little closer in, eventually creeping in even closer than the planet Neptune, at only 27 AU away from the Sun.
"A single orbit of Farfarout around the Sun takes a millennium," David Tholen, an astronomer at the Institute for Astronomy of the University of Hawaii, and a member of the team behind the discovery, said in a statement.
"Because of this long orbital period, it moves very slowly across the sky, requiring several years of observations to precisely determine its trajectory."
Due to it crossing paths with Neptune, the scientists behind the discovery believe Farfarout may have at one point been a much more close member of our planetary neighborhood. At some point in the past, Farfarout may have been ejected from the inner bosom of our system, out into the outer realms of the Solar System. This may have occurred after the planetoid got too close to Neptune for comfort during the chaotic early years of the Solar System.
WHAT'S NEXT — The team of scientists will continue to observe Farfarout. One thing Farfarout needs, for example, is an official name (no, we can't keep calling it that), which they will determine after they have a better understanding of its orbit.
At the same time, Farfarout raises the bar on furthest object from the Sun — the scientists behind this discovery are also hoping to discover more distant objects in the outer Solar System. This will become increasingly possible as our Earthly telescopes continue to advance, allowing us to seek out more distant worlds which share our host star.