1 . The US space agency NASA has revealed an astonishing picture revealing new secrets of the Earth’s home galaxy (星系), the Milky Way. The sun is just one of hundreds of billions of stars that form the huge shape of our galaxy. Our solar system sits in an outlying region but the new image focuses on the centre of the Milky Way, a “noisy” area because of all the crowded stars. Light from this region takes about 26,000 years to reach Earth. For comparison, light takes just eight minutes to reach us from the sun.

The researchers use the data collected by two telescopes that see the sky in ways that are very different from the visible light our eyes can see to form the new image. Most of the data comes from 370 different pictures taken over the past 20 years by NASA’s Chandra X Observatory. This satellite telescope detects X-rays out in space. X-rays are a from of radiation that is sent out when violent events heat matter to temperatures of millions of degrees. Other data comes from the MeerKAT telescope in South Africa, which can detect radio waves from space. These waves have much less energy than X-rays. They are usually produced by cooler material, such as huge clouds of gas between the stars.

The brightest sources include neutron stars which are the cores of huge stars that ran out of fuel and collapsed to city-sized balls of super hot matter. Many neutron stars and black holes jet out gases that appear in the picture as purple streaks (斑纹). Powerful magnetic fields in the area cause the jets to bend as they get further from their source. Astronomer Dr Daniel Wang, who has worked on the image over the past year, said the new picture described “a violent or energetic ecosystem”.