A small, dark object hiding within an “Einstein ring” was found recently, and it could help researchers pinpoint mysterious dark matter.
The object was discovered within B1938+666, an Einstein ring located about 10 billion light-years from Earth. The record-breaking find is likely a clump of invisible dark matter.
The light that makes up an Einstein ring comes from a distant galaxy. A phenomenon called gravitational lensing causes the light to bend around a closer galaxy in the foreground, which is what produces the Einstein ring’s halo shape.
Gravitational lensing was first proposed by Albert Einstein’s theory of general relativity in 1915. Not only does gravitational lensing warp light, but it also magnifies it.
An Einstein ring occurs when the lensing object is aligned perfectly between the distant object and the observer. As a result, the light bends in a circle. When the alignment is off, other shapes can be seen, such as zig-zags, crosses, and question marks.
B1938+666 was discovered in the 1990s, but it was only recently that researchers spotted a gravitational disturbance within radio waves in the outer ring caused by a hidden object.
“From the first high-resolution image, we immediately observed a narrowing in the gravitational arc, which is the telltale sign that we were onto something,” said John McKean, an astronomer from the University of Groningen in the Netherlands and the University of Pretoria in South Africa.
“Only another small clump of mass between us and the distant radio galaxy could cause this.”
The object is approximately one million times more massive than the sun, which makes it around 100 times smaller than the previous object that held the record for the smallest object detected through gravitational lensing.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
The researchers combined data from radio observatories around the world and detected a subtle disturbance. But there was so much data that they had to develop a new method of organizing it.
They believe that the small object is a clump of dark matter, although they have no way of confirming it. Dark matter makes up 27% of the known universe. It does not interact with light, so it is invisible to the human eye.
This clump of dark matter could help with testing the “cold dark matter theory.” The theory states that dark matter can only clump together if it moves at slow speeds. As a result, it would generate low amounts of energy.
It is thought that these clumps are more common than we realize.
“We expect every galaxy, including our own Milky Way, to be filled with dark matter clumps, but finding them and convincing the community that they exist requires a great deal of number-crunching,” said Simona Vegetti, an astronomer at the Max Planck Institute for Astrophysics in Germany.
Currently, only three other similar potential small dark matter clumps have been discovered. The latest findings were published in the journals Nature Astronomy and Monthly Notices of the Royal Astronomical Society.
You can check out a photo of the record-breaking dark matter clump here.
By Emily Chan
Emily Chan is a writer who covers lifestyle and news content. She graduated from Michigan State University with a degree in... More about Emily Chan
