China’s Wukong Joins The Hunt For Dark Matter

Wukong is the most sensitive dark matter probe to date and China’s first mission focused purely on scientific discovery.

AsianScientist (Jan. 6, 2016) – China’s first dark matter probe satellite was launched on December 17, 2015, at 8:12am Beijing time. Officially called the Dark Matter Particle Explorer (DAMPE), the probe has been nicknamed Wukong after the Monkey King in the classic Chinese legend Journey to the West.

According to legend, the Monkey King had supernatural powers and was responsible for protecting a pilgrim on a journey to retrieve the Buddhist sutras from India. Also, ‘wu’ means comprehension or understanding and ‘kong’ means space, so Wukong the satellite has a mission to “understand space,” according to China’s National Space Science Center (NSSC).

At 1.5 meters long and wide and 1.2 meters high, the 1.9-tonne satellite has been lifted into sun-synchronous orbit 500 kilometers above the ground, and will remain there for three to five years searching for evidence of the existence of dark matter.

Wukong’s payload has four parts: a plastic scintillator array detector, a silicon array detector, a BGO calorimeter, and a neutron detector. They will measure high-energy electrons and gamma rays in space, which will lead to possible traces of dark matter particles’ annihilation or decay and help to reveal physical details and spacial distribution.

Like the Monkey King who can see through everything with his sharp eyes, the satellite has ten times the energy observation spectrum of the Alpha Magnetic Spectrometer mounted in the International Space Station, and four times the energy resolution of other similar detectors. It is the most sensitive and accurate detector for dark matter designed to date.

Chang Jin, Wukong’s chief scientist and vice director of the Purple Mountain Observatory, said China’s first space telescope could totally change the way we understand the universe, promising major breakthroughs in space science and an answer to a decades-old riddle for physicists and astronomers.

In the early 1930s, Swiss astrophysicist Fritz Zwicky found the mass we can see is not enough to hold the universe together. Without another kind of matter that we can’t see, galaxies would have disappeared long ago. He coined the term ‘dark matter’ to describe it.

In the 1970s, astronomic discoveries such as rotation curves of disk galaxies, X-ray observations of clusters and the gravitational lensing effect all suggested the existence of dark matter. However, it can’t be seen directly by optical or electromagnetic observation equipment, as it doesn’t take part in electromagnetic interaction.

From dark matter’s gravitational interaction with common matter, scientists calculate that dark matter and dark energy form 95 percent of universe mass, as the stars and planets we see account for just five percent. Any discoveries in this area could be as significant as heliocentric theory, the law of gravity, relativity theory and quantum mechanics.

China launched its first satellite in 1970, sent astronauts into space since 2003 and landed a rover on the moon in 2013. But unlike other leading space powers, China never developed satellites for pure science research—until now. Most of its satellites are designed for applications such as communication, navigation and remote sensing.

Wukong is just the start of China’s new stage in space exploration. The Space Science Pilot Projects initiated by NSSC under Chinese Academy of Sciences (CAS) in 2013 has developed four space science satellites. Another three will be launched in the near future.

Wukong is China’s first attempt to solve this enduring mystery. It is hard to predict when dark matter will be found or the applications of the discovery. Even so, exploration will continue despite uncertainties and setbacks.

“Only when we understand the nature of dark matter, can we find how it will change the future. But the development of fundamental physics will definitely boost science and technology,” said Chang.

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Source: Chinese Academy of Sciences.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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