Skip to main content

Researchers come up with new method to ‘see’ dark matter

Scientists know that just over a quarter of all that exists in the universe is in the form of dark matter, something we can’t see directly. We know that dark matter must be there because of the ways that galaxies move, which shows they have a lot more mass than we can observe. So we call the remaining unknown mass dark matter.

But how do you study something you can’t see? The next generation of dark matter instruments will use new techniques and extremely accurate hardware to measure the movements of distant galaxies. But for now, a small group of astronomers from the Swinburne University of Technology have come up with a way to “see” dark matter using current telescopes.

Recommended Videos

The method works by looking for the gravitational effects of dark matter, rather than the presumed particles themselves. “It’s like looking at a flag to try to know how much wind there is,” lead author Pol Gurri explained in a statement. “You cannot see the wind, but the flag’s motion tells you how strongly the wind is blowing.”

Artist's impression of a galaxy surrounded by gravitational distortions due to dark matter. Galaxies live inside larger concentrations of invisible dark matter (coloured purple in this image), however the dark matter's effects can be seen by looking at the deformations of background galaxies.
Artist’s impression of a galaxy surrounded by gravitational distortions due to dark matter. Galaxies live inside larger concentrations of invisible dark matter (colored purple in this image), however the dark matter’s effects can be seen by looking at the deformations of background galaxies. Swinburne Astronomy Productions - James Josephides

The research uses a technique called weak gravitational lensing, in which they observe distant galaxies and wait for another galaxy to pass between it and us. When this happens, the in-between galaxy bends the light waves from the distant galaxy due to its gravity. “The dark matter will very slightly distort the image of anything behind it,” explained Associate Professor Edward Taylor, who was also involved in the research. “The effect is a bit like reading a newspaper through the base of a wine glass.”

Please enable Javascript to view this content

This technique has been used before to investigate dark matter. But it usually requires highly accurate telescopes, which measure the shape of the distant galaxies. The team’s innovation was to look at how galaxies rotate instead.

“Because we know how stars and gas are supposed to move inside galaxies, we know roughly what that galaxy should look like,” Gurri said. “By measuring how distorted the real galaxy images are, then we can figure out how much dark matter it would take to explain what we see.”

This means that even older telescopes, like the ANU 2.3m Telescope in Australia, can be used to “see” dark matter, in a more accurate way than if they were not looking at rotation.

“With our new way of seeing the dark matter,” Gurri said, “we hope to get a clearer picture of where the dark matter is, and what role it plays in how galaxies form.”

Georgina Torbet
Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…
See the stunning first images taken by the dark matter-hunting Euclid telescope
The Horsehead Nebula, also known as Barnard 33, is part of the Orion constellation. About 1,375 light-years away, it is the closest giant star-forming region to Earth. With Euclid, which captured this image, scientists hope to find many dim and previously unseen Jupiter-mass planets in their celestial infancy, as well as baby stars.

The European Space Agency (ESA) has released the first full-color images taken by Euclid, a space telescope that was launched earlier this year to probe the mysteries of dark matter and dark energy. Euclid will image a huge area of the sky to build up a 3D map of the universe, helping researchers to track the dark matter that is clustered around galaxies and the dark energy that counteracts gravity to push galaxies apart.

The Horsehead Nebula, also known as Barnard 33, is part of the Orion constellation. About 1,375 light-years away, it is the closest giant star-forming region to Earth. With Euclid, which captured this image, scientists hope to find many dim and previously unseen Jupiter-mass planets in their celestial infancy, as well as baby stars. ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi; CC BY-SA 3.0 IGO

Read more
Dark matter hunting telescope Euclid has a problem with its guidance system
Graphic rendering of the Euclipd space telescope.

The European Space Agency's (ESA) Euclid space telescope, which launched in July this year to investigate the mysteries of dark matter and dark energy, has run into issues during its commissioning phase. Although the early calibration images looked good, since then the telescope has had problems with the instrument that helps it position itself by locking onto particular stars, called the Fine Guidance Sensor.

The Fine Guidance Sensor has been intermittently failing to lock onto stars, which is making it difficult to orient the telescope in the right direction. When working correctly, data from the Fine Guidance Sensor goes to the spacecraft's attitude and orbit control system which keeps it in the right orientation. However as this has not been working as intended, the commissioning phase for the telescope has been extended so teams can investigate the issue.

Read more
See the sparkling Terzan 12 globular cluster in new Hubble image
This colorful image of the globular star cluster Terzan 12 is a spectacular example of how dust in space affects starlight coming from background objects.

A new image from the Hubble Space Telescope shows a stunning field of thousands of stars, part of a globular star cluster called Terzan 12. These groups of stars are bound together by gravity, in a packed configuration that is roughly spherical. This particular cluster is located within the Milky Way, in the constellation of Sagittarius, and is around 15,000 light-years away from us here on Earth.

This colorful image of the globular star cluster Terzan 12 is a spectacular example of how dust in space affects starlight coming from background objects. NASA, ESA, ESA/Hubble, Roger Cohen (RU)

Read more