"We have also detected a gravitational wave incident." On the morning of June 16, Beijing time, at a press conference of the 228th meeting of the American Astronomical Society, Gabriella, spokesman for the Scientific Cooperation Organization of the United States Laser Interferometry Graviation Wave Observatory (LIGO) Gonzalez officially announced the news and played the sound of the gravitational waves they captured. Although this signal is much weaker than the gravitational wave signal it first detected, its confidence is as high as 5 sigma. This is the second announcement of the gravitational wave signal since they announced the first detection of the gravitational wave signal in February of this year, which means that mankind has opened up a completely new era of gravitational wave astronomy. Gonzalez said the gravitational waves detected this time were caused by two black holes with initial mass of about 14 times the sun's mass and about 8 times the mass of the sun, respectively, combined into a rotating black hole of about 21 times the mass of the sun. After 1.4 billion years of long travel, this signal was detected by two twin gravitational LIGO detectors at 3:38:53, December 26, 2015, World Time Standard, and was named GW151226. The gravitational wave incident was also affectionately described by researchers as "a Christmas gift from Einstein." Due to the lighter quality of the two black holes, the speed of approaching the two black holes is much slower than the previous one. For the same reason, the number of turns before the black hole coalesces is much larger than the first time. In about 1 second , The two black holes revolve around each other by 55 laps, giving scientists a chance to take a fresh look at general relativity. In the meantime, the researchers also captured the third "suspected signal," but the signal was too weak to confirm. Gonzalez said that once again detecting the gravitational wave signal, it means that the detection probability of gravitational wave events is much higher than people expected before. There are reasons to believe that there will be more cases in the future. Gravitational waves are an effect of space-time bending, first proposed by Einstein 100 years ago. Direct detection of gravitational waves is the most important and final "puzzle" to test the correctness of general relativity, and gravitational waves themselves are also considered as new tools for mankind to explore unknown universes. The first LIGO team in February this year to find the news of gravity waves caused a sensation in the world has brought a variety of questions. One of the most representative of this is that this is a rare event of small probability, difficult to repeat.