Where is the dark matter?Looking for a suspiciously warm planet


We are taking a bath The uncertain universe. Astrophysicists generally believe that about 85% of the mass in the universe comes from strange particles that are still assumed to be dark matter. Our Milky Way galaxy, which looks like a bright disk, lives in their huge sphere-a halo, which is particularly dense towards the center. But the nature of dark matter determines that it is elusive. It does not interact with electromagnetic forces such as light, and any potential collisions with matter are rare and difficult to detect.

Physicists got rid of these difficulties.They have Designed detector Creatures on earth made from silicon chips or a bath of liquid argon to directly capture these interactions.They look at how deep the dark matter is May affect neutron stars. When other celestial bodies are floating, they are looking for it. “We know that we have stars and planets, and they are full of light throughout the halo,” he said Rebecca LeaneHe is an astrophysicist at the SLAC National Accelerator Laboratory. “As long as they pass through the halo, they can interact with dark matter.”

Therefore, Leane suggests that we look for them in the outer planets of the Milky Way or a large number of planets outside the solar system. Specifically, she believes that we should use a lot of gas giants, like planets like our own Jupiter. Dark matter may get stuck in the gravity of the planet, just like quicksand. When this happens, the particles collide and extinguish, thereby releasing heat. This heat will accumulate and heat the planetary pipes, especially the planets near the dense center of the Milky Way. In April, Leane and her co-author, Yuri Smirnov From Ohio State University Published a dissertation Medical letter It proposed that measuring the temperature array of exoplanets in the center of the Milky Way could reveal this obvious trace of dark matter: unexpected heat.

Their paper is based on calculations, not observations.But the temperature peaks predicted by Leane and Smirnov are obviously large, and we will soon have a cutting-edge thermometer: NASA’s new thermometer James Webb Space telescope It is expected to be launched this fall. JWST is an infrared telescope and the most powerful space telescope ever.

“This is a very surprising and creative method of detecting dark matter,” he said. Joseph BramantHe is a particle physicist at Queen’s University and the McDonald’s Research Institute in Ontario, but did not participate in this research. Bramante has previously studied the possibility of detecting dark matter on planets. He said that the detection of an unusually hot planet pointing to the center of the Milky Way “will be a very striking feature of the dark matter smoking gun.”

It has been less than 30 years since astronomers detected the first exoplanet. Because they are much dimmer than the stars they orbit, it is difficult to see them alone.They usually just show themselves only Cover up the light of those stars.Astronomers also use similar techniques to find exoplanets and determine their size Micro lens. (The gravity of one star distorts our view of the light of another star, and the planet in between creates a flicker that effect. ) Exoplanet Tally At 4,375, But some 300 billion It might be there.

Dark matter usually moves freely between these “normal” islands of matter, which means it slides over objects without interaction. But when a dark matter particle happens to push ordinary particles like protons, it will slow down due to neutron particles. “It’s like billiards,” Lane said. “As soon as it comes in, it hits it and then rebounds. But it can rebound with less energy.”

Accumulating enough of these collisions will slow them down so that they cannot escape the planet’s gravity. Physicists expect that when this “scattering” and trapping occurs, dark matter particles will collide with each other and annihilate. Dark matter that was once full of vitality will break down into other particles and heat. Lane said: “When they shattered together, it brought energy into the planet.”


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