Seeing dark matter in a new light

Scientists presently estimate that as much as 85% of the mass within the universe is successfully invisible. This ‘darkish matter’ can’t be noticed immediately, as a result of it doesn’t work together with mild in the identical method because the peculiar matter that makes up stars, planets, and life on Earth.

So how can we measure what can’t be seen? The secret is to measure the impact of gravity that the darkish matter produces.

Pol Gurri, the PhD pupil at Swinburne College of Expertise who led the brand new analysis, explains: “It is like a flag to attempt to know the way a lot wind there may be. You can’t see the wind, however the flag’s movement tells you ways strongly the wind is blowing.”

The brand new analysis focuses on an impact referred to as weak gravitational lensing, which is a characteristic of Einstein’s basic concept of relativity. “The darkish matter will very barely distort the picture of something behind it,” says Affiliate Professor Edward Taylor, who was additionally concerned within the analysis. “The impact is a bit like studying a newspaper by means of the bottom of a wine glass.”

Weak gravitational lensing is already one of the crucial profitable methods to map the darkish matter content material of the Universe. Now, the Swinburne group has used the ANU 2.3m Telescope in Australia to map how gravitationally lensed galaxies are rotating. “As a result of we all know how stars and gasoline are supposed to maneuver inside galaxies, we all know roughly what that galaxy ought to seem like,” says Gurri. “By measuring how distorted the true galaxy pictures are, then we are able to determine how a lot darkish matter it might take to clarify what we see.”

The brand new analysis reveals how this velocity data allows a way more exact measurement of the lensing impact than is feasible utilizing form alone. “With our new method of seeing the darkish matter,” Gurri says, “we hope to get a clearer image of the place the darkish matter is, and what position it performs in how galaxies kind.”

Future area missions akin to NASA’s Nancy Grace Roman Area Telescope and the European Area Company’s Euclid Area Telescope are designed, partly, to make these sorts of measurements primarily based on the shapes of a whole bunch of hundreds of thousands of galaxies. “Now we have proven that we are able to make an actual contribution to those international efforts with a comparatively small telescope constructed within the 1980s, simply by fascinated about the issue differently,” provides Taylor.

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Materials offered by Royal Astronomical Society. Notice: Content material could also be edited for fashion and size.