Kenneth Glad
Staring up at the night sky, it is easy to think we know our cosmic neighbourhood. Generations of dedicated researchers have mapped the dark corners of space. But every so often, a truly massive surprise hides right out in the open.
A giant space rock is circling the sun far beyond Pluto. It could soon join a very exclusive club.
Astronomers recently spotted the distant object from a high-tech facility in Chile. Right now, it goes by the simple temporary code name of ED138.
Experts estimate the rocky body stretches anywhere from 600 to 1500 kilometres across, according to New Scientist. Because of that incredible scale, it ranks as one of the largest solar system discoveries in recent years.
To earn the title of a dwarf planet, an object must pack enough mass to pull itself into a round shape. A 600-kilometre diameter usually does the trick.
Hiding in plain sight
Authorities currently recognise just five official dwarf planets. Pluto remains the most famous, but a few unofficial members wait in the wings.
You might wonder how something so massive went unnoticed for so long. The answer lies entirely in the background lighting.
The newly discovered rock sits near the crowded plane of the Milky Way. When past observers looked in that direction, telescopes simply could not pick it out against the glare.
That dynamic changed when the Vera C. Rubin Observatory turned its powerful lenses to the sky.
Digging through the past
Mario Jurić from the University of Washington explained the breakthrough in a recent statement.
“Rubin is giving us an unprecedented capacity to explore the sky through a combination of speed, depth, and precision,” Jurić said, accordng to ScienceSprings.
Researchers realised they had actually captured the distant rock before. Digging into the archives, old data showed clear signs of the icy giant back in 2017.
By tracking those older images, the science team mapped the exact path the rock takes around our sun.
Just the beginning
The massive rock takes 281 years to complete a single trip around our solar system. Its tilted orbit suggests that Neptune pushed it off course long ago.
Astronomer Matthew Holman first spotted the object. He noted in a public release that the team expects to find much more out there.
“Rubin will image the whole southern sky again and again for ten years, so any others hiding in the places earlier surveys skipped are now within reach,” Holman said.
Scientists must gather extra data to lock down the exact dimensions of this distant world. Stargazers will just have to wait.
