国内英语资讯:Chinese satellite detects mysterious signals in search for dark matter_时事

国内英语资讯:Chinese satellite detects mysterious signals in search for dark matter

Dark matter, which cannot be seen or touched, is one of the great mysteries of science. Scientists calculate that normal matter, such as galaxies, stars, trees, rocks and atoms, accounts for only about 5 percent of the universe. However, about 26.8 percent of the universe is dark matter and 68.3 percent dark energy.

China sent DAMPE into an orbit of about 500 kilometers above the earth on December 17, 2017, to look for evidence of the annihilation or decay of dark matter particles in space.

DAMPE has the widest energy range coverage and the highest energy resolution of all the dark matter probes currently in space. Based on the satellite's data, scientists drew the cosmic ray electron and positron spectrum.

To their surprise, scientists found a break at around 0.9 TeV and a strange spike at around 1.4 TeV on the spectrum. "We never expected such signals," Chang said.

"The spike might indicate that there exists a kind of unknown particle with a mass of about 1.4 TeV," said Chang.

"All the 61 elementary particles predicted by the standard model of particle physics have been found. Dark matter particles are beyond the list. So if we find a new elementary particle, it will be a breakthrough in physics," he added.

"The spike is very unusual," said Fan Yizhong, deputy chief designer of the scientific application system of DAMPE. "The signals might have originated from either dark matter or pulsars. Even if they were from pulsars, it would be quite a strange astrophysical phenomenon that nobody had known before."