Jakarta –
As far as astronomers who study the observable universe know, only about 5% is made up of matter. The rest, or most of it, consists of dark matter or dark matter (around 27%) and dark energy (around 68%).
Dark matter is invisible matter that does not emit its own light and only interacts with normal matter through gravity, evidence of which we can see in galaxies and galaxy clusters. But considering that it is five times more abundant than ordinary matter, scientists are of course looking for direct evidence of its existence.
One approach to finding it, perhaps counterintuitive because dark matter explains what we see in stars and galaxies, is to head underground.
There are several underground facilities around the world where physicists look for signs of Weakly Interacting Massive Particles (WIMPs), such as measuring neutrino impacts, among other things.
The idea is that WIMPs should pass by Earth all the time as they move through space, so to detect them we just need a detector sensitive enough to pick up such weak interactions.
“In the Stanford LUX-ZEPLIN experiment, two large electrical networks applied an electric field across the volume of the liquid, which pushed the released electrons to the surface of the liquid,” said Hugh Lippincott, Associate Professor of Physics at the University of California, Santa Barbara, quoted from The Conversation.
“As they penetrate the surface, they are drawn into the space above the liquid, which contains xenon gas, and accelerated by another electric field to create a second flash of light. Two large arrays of light sensors collect these two flashes of light, and together they allow researchers to reconstruct the position, energy, and the type of interaction that occurs,” he said again.
These detectors are impressive, and even if they don’t know what dark matter is, they can help constrain what dark matter isn’t. But the problem is that if you place them on the surface, they will detect too much noise.
“However, on Earth, we are constantly surrounded by low levels and harmless radioactivity originating from trace elements, especially uranium and thorium in the environment, as well as cosmic rays from outer space,” Lippincott continued.
“The goal of hunting for dark matter is to build detectors that are as sensitive as possible, so they can see dark matter, and place them in places as quiet as possible, so that dark matter signals can be seen against the background of radioactivity,” he explained.
Therefore, dark matter detectors are placed deep underground. In Ontario, Canada, scientists must travel every day 2 kilometers underground, then walk deeper into a working mine to reach SNOLAB, the world’s deepest clean laboratory.
Events recorded from the LUX-ZEPLIN experiment, deep beneath the Black Hills in South Dakota, occur about five times a day, far lower than the trillions of events detected at the surface.
However, scientists have ruled out dark matter as a potential cause of all this. But as the experiments continue, there is hope that they can find evidence of all the missing objects in the universe, deep underground.
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(rns/afr)
2024-03-16 04:19:34
#reason #scientists #dig #earth #dark #matter
