Astronomers working on the Dark Energy Survey recently announced the discovery of over 100 new small planets located at the edge of our solar system. All the objects are positioned past the planet Neptune, lending them the name of trans-Neptunian objects (TNOs).
According to Science Alert, 139 TNOs were found it total — ironically, it was by accident. The astronomers behind the discovery were working on the Dark Energy Survey, a mission that ran from August 2013 to January 2019 that collected infrared data on the southern sky to see how dark energy influenced the accelerating expansion of the universe.
However, the techniques behind mapping dark energy ended up helping the astronomers find these TNOs, as it involved looking at vast regions of the sky.
"The number of TNOs you can find depends on how much of the sky you look at and what's the faintest thing you can find," explained Gary Bernstein of the University of Pennsylvania.
However, such a large canvas unsurprisingly led to a lot of data, and astronomers had to tackle around seven billion dots to figure out which were just noise and which were actually planets.
On top of that, TNOs are notoriously difficult to find. Apart from the fact that they are small, they are in patches of the solar system that are incredibly dark — meaning they reflect little light.
Moreover, they are incredibly far away from Earth. To put it in perspective, Pluto is 40 Astronomical Units (AU) from our planet. In contrast, the distance of some of the more extreme TNOs found were an eye-watering 150 AU.
Astronomers are hoping that the new discovery will help lead them to Planet Nine. Planet Nine is a long-hypothesized object that exists at the farthest edge of our universe but has so far evaded detection. Scientists believe it is lurking around 200 AU away — meaning it is 200 times the distance of the Earth to the Sun.
"There are lots of ideas about giant planets that used to be in the Solar System and aren't there anymore, or planets that are far away and massive but too faint for us to have noticed yet," Bernstein added.
But for now, scientists are pleased the new data will help better understand the solar system.
"Making the catalogue is the fun discovery part. Then when you create this resource; you can compare what you did find to what somebody's theory said you should find," Bernstein concluded.