保护地球，探索宇宙，发现文明
The solar system might be a lot hairier than we thought. This illustration shows Earth surrounded by theoretical filaments of dark matter called “hairs.” Dark matter is an invisible, mysterious substance that makes up about 27 percent of all matter and energy in the universe. The regular matter, which makes up everything we can see around us, is ...
What is a black hole? A black hole is an astronomical object with a gravitational pull so strong that nothing, not even light, can escape it. A black hole’s “surface,” called its event horizon, defines the boundary where the velocity needed to escape exceeds the speed of light, which is the speed limit of the cosmos. Matter and radiation fall in, but they ca...
2020年11月4日 Fifty Gravitational Wave Events Illustrated Image Credit: LIGO Virgo Collaborations, Frank Elavsky, Aaron Geller, Northwestern U. Explanation: Over fifty gravitational wave events have now been detected. These events mark the distant, violent collisions of two black holes, a black hole and a neutron star, or two neutron stars. Most of the 50 event...