Researchers want to use gravitational waves to learn about dark matter

When two sufficiently massive objects collide — such as when two black holes merge — the forces can actually bend space-time, creating ripples called gravitational waves. These gravitational waves can be detected even from millions of light-years away, making them a way to learn about distant, dramatic events in far-off parts of the universe. And now, a team of astronomers has come up with a method for using gravitational waves to study the mysterious phenomenon of dark matter. The idea of the research was to create different computer models of what gravitational waves from black hole mergers would look like in universes with different types of dark matter. By comparing the models to what is seen in the real world, we can learn more about what type of dark matter is most likely. Scientists know that dark matter doesn’t interact with light, but some people think that it could interact with a type of particle called a neutrino. That means that neutrino collisions could prevent dark matter from forming into the structures which are the basis for galaxies, so these particles could stop galaxies from forming. If we could find these “missing” galaxies, that would support the idea that dark matter can be affected by neutrinos. It’s hard to see a galaxy that didn’t form, though. That’s why the researchers suggest using gravitational waves created in black hole mergers as a measure instead. With fewer galaxies there are fewer mergers, and therefore fewer gravitational waves. Simulations show that this could be an effective method for learning about dark matter. Current gravitational wave detectors aren’t powerful enough to detect these small effects, but the next generation of instruments could be used for this purpose. “Dark matter remains one of the enduring mysteries in our understanding of the universe,” said one of the researchers, Sownak Bose of Durham University, in a statement. “This means it is especially important to continue identifying new ways to explore models of dark matter, combining both existing and new probes to test model predictions to the fullest. Gravitational wave astronomy offers a pathway to better understand not just dark matter, but the formation and evolution of galaxies more generally.” The research was presented at the 2023 National Astronomy Meeting on 5 July. One of the big challenges of Mars exploration is something very small: dust. Fine dust covers much of the martian surface, and high winds and low gravity mean the dust is easily whipped up off the surface, covering solar panels and gumming up components. The Ingenuity helicopter has had its own problems with dust on its solar panels, limiting the amount of power it could draw from the sun. Now, researchers have used data from Ingenuity to understand more about how dust moves in the martian air, learning about the dynamics of dust, which could help future missions deal with this ongoing problem. With Halloween coming up tomorrow, the Hubble Space Telescope team is celebrating by releasing a new Hubble image showing the dark cobwebs of galaxy cluster Abell 611. Located an incredible 3.2 billion light-years away, this view shows hundreds of galaxies that are bound together by gravity into one enormous structure. Taken using Hubble’s Advanced Camera for Surveys and Wide Field Camera 3 instruments, the image combines both visible light and infrared observations. Black holes are some of the most mind-bending objects in the universe. They are so dense that anything which passes their event horizon, even light, can’t escape. That’s where they get their name, as the black hole itself is impossible to see. Fortunately for researchers, many black holes have material like dust and gas around them, and when this material falls into a black hole it can give off bursts of X-rays which allow them to locate the black hole. But this isn’t the case for every black hole. Some are not taking in material, meaning they don’t give off X-rays and are much harder to locate. Now, a citizen science project is inviting members of the public to help search for these “hidden” black holes.