Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Where is the dark matter? Look for suspiciously warm planets

Where is the dark matter? Look for suspiciously warm planets



We take a bath an uncertain universe. Astrophysicists generally assume that about 85 percent of the total mass in the universe comes from exotic, still hypothetical particles called dark matter. Our Milky Way galaxy, which looks like a bright flat disk, lives in a huge sphere of things – a halo that becomes particularly dense toward the center. But the very nature of dark matter dictates 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 reduce these chances. They designed Earth detectors made of silicon chips or liquid argon baths to directly capture these interactions. They looked at how dark matter could affect neutron stars. And they seek it while it is carried by other celestial bodies. “We know we have stars and planets, and they̵

7;re just dotted with halos,” said Rebecca Lean, an astroparticle physicist at the National SLAC Accelerator Laboratory. “Only by moving through the halo can they interact with dark matter.”

For this reason, Lean suggests looking for them in the vast collection of exoplanets on the Milky Way or those outside our solar system. In particular, she believes that we should use large groups of gas giants, planets like our own Jupiter. Dark matter can get stuck in the gravity of the planets, as if in quicksand. When this happens, the particles can collide and destroy, releasing heat. This heat can build up to make the planet hot – especially those near the dense center of the galaxy. In April, Leane and co-author Yuri Smirnov of Ohio State University published an article in Physical examination letters which suggests that measuring multiple exoplanetary temperatures toward the center of the Milky Way may reveal this telltale trace of dark matter: unexpected heat.

Their report is based on calculations, not observations. But the temperature jumps that Leane and Smirnov predict are noticeably large, and we will soon have an avant-garde thermometer: James Webb’s new space telescope is expected to launch this fall. JWST is an infrared telescope and the most powerful space telescope ever built.

“This is a very surprising and inventive approach to detecting dark matter,” said Joseph Bramante, a particle physicist at the University of Queens and the MacDonald Institute in Ontario, who was not part of the study. Bramante had previously explored the possibility of finding dark matter on the planets. He says the discovery of unusually hot planets pointing to the center of the Milky Way “would be a very convincing signature of a smoking rifle of dark matter.”

It has been less than 30 years since astronomers discovered the first exoplanets. Because they are much darker than the orbiting stars, they are difficult to see on their own; they are usually revealed only with barely obscuring the light from these stars. Astronomers also find and resize exoplanets with tricks like a microlens. (The gravity of one star distorts our view of the light of another star and a planet between the two creates a flash that The effect.) The exoplanet is now 4375, but there may be about 300 billion.

Dark matter usually moves freely among these islands of “normal” matter, which means that it glides past objects without interacting. But when a particle of dark matter propels ordinary particles like protons, it is slowed by a stench. “Just like billiard balls,” says Lean. “He just walks in, literally hits him, and then bounces.” But it can bounce with less energy. “

The accumulation of enough of these collisions slows them down too much to escape the planet’s gravity. Physicists expect that when this “scattering” and capture occurs, the particles of dark matter can collide and destroy each other. Once the energetic dark matter breaks down into other particles – and heat. “When they break together,” says Lean, “it puts energy into the planets.”


Source link