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A new study has found that space probes that fly close to the sun could one day help discover the nature of dark matter.
Dark matter it is an invisible and largely intangible substance that scientists estimate is about five-sixths of all matter in the universe. Although dark matter has not been directly observed, its existence is indicative of its gravitational influence on the motions of stars and stars galaxies. However, what dark matter might consist of remains a mystery.
“The discovery of dark matter would be one of the greatest achievements in human history,” lead study author Yu-Dai Tsai, a physicist at the University of California, Irvine, told Space.com.
Related: Can the Large Hadron Collider discover dark matter?
In a new study, a research team has proposed a new way to discover the nature of dark matter, using the most precise watches ever created: atomic clocks. While grandfather clocks keep track of swinging pendulums, atomic clocks monitor the quantum vibrations of atoms. Currently, the best atomic clock is so precise that it will basically only lose that much one second in 300 billion years.
Atomic clocks are regularly sent into space. For example, GPS satellites rely on atomic clocks to send exact time messages that each GPS receiver uses to determine its location.
In a new study, physicists suggest launching a mission, tentatively named SpaceQ, into orbit nearby Sun. Recently, NASA sent the so-called Parker solar probe closer to the Sun than any other spacecraft. In 2021, the spacecraft flew through the solar corona – its ultra-hot upper atmosphere – for the first time and continues to orbit closer and closer to our star.
“There are certainly technical challenges to accomplishing a mission like the one we are proposing and not [the] the least of which is how best to protect sensitive quantum sensors from the extreme environments found near the sun,” study co-author Joshua Eby, a physicist at the University of Tokyo, told Space.com. “But missions like the Parker Space Probe show that amazing things are possible and there seem to be no absolute obstacles. It will take some research and development [research and development]but let’s hope this work is just the beginning of the process.”
The leading dark matter candidates are spectral ultralight particles. For example, a hypothetical particle known as an axion might have a mass less than one billionth of an electron. Theoretical physicists originally proposed existence axions help explain why interactions are visible between some particles and not others.
“If this kind of dark matter exists, you can imagine us basking in waves of dark matter,” Tsai said.
If dark matter consists of ultra-light particles, their intangible nature would make them extremely difficult to detect, which explains why they have so far eluded detection. However, since the sun is much heavier than that Earth — about 330,000 times the mass of our planet — has a stronger gravitational pull. In principle, this means that the Sun can store much more dark matter than the Earth. This higher density could make it easier for probes to get closer to the Sun – closer than that Mercuryorbits – to detect these ghostly particles.
The Parker Solar Probe “showed that you can send a satellite very close to the Sun, sensing new conditions and making discoveries,” said study co-author Marianna Safronova, a physicist at the University of Delaware. statement. “That’s much closer to the Sun than what we’re proposing here.”
In principle, waves of ultralight dark matter particles can induce changes in fundamental constants of nature, such as mass electron or the strength of the electromagnetic force. This, in turn, would change the way atomic clocks tick, an effect that depends on the atoms the clock uses. By comparing how two different atomic clocks keep time near the sun, scientists can find dark matter. Comparable effects can also be seen in future timekeepers, which may prove even more accurate than atomic clocks, such as the so-called nuclear clocks.
“If ultralight dark matter were detected during such a mission, it would be a direct probe of both the density of dark matter near the Sun and its couplings with ordinary matter,” Eby said.
The researchers noted that the SpaceQ mission would require clocks, which are still in development. Also, even if it detected dark matter signals, scientists would need independent experiments to verify their findings, Tsai noted.
However, “basically, if we can measure dark matter in different places, we can map the density distribution,” Tsai said. “And if the signal becomes stronger towards the sun, it will be a convincing signature of a smoking gun to be discovered.”
The researchers detailed their findings online December 5 in the journal Nature astronomy (opens in a new tab).
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