科学美国人60秒 SSS How to Find Loooong Gravitational Waves
时间：2019-01-20 作者：英语课 分类：2017年Scientific American(三)月
In 2016 the Laser Interferometer Gravitational-Wave Observatory 1, LIGO, made the first accepted detection of gravitational waves.
“So any time you move a mass it produces a gravitational wave…so black holes, like the ones LIGO detected, these are stellar mass black holes, about 10 times the mass of the sun. When they’re in orbit they’re accelerating constantly, so constantly producing gravitational waves.”
Sarah Burke Spolaor, of the National Radio Astronomy Observatory in New Mexico, at the annual meeting of the American Association for the Advancement 2 of Science in Boston on February 18th.
For gravitational waves produced by the acceleration 3 of even bigger masses, we’re going to need what’s called the Laser Interferometer Space Antenna 4, or LISA.
“Now if you think of much bigger masses, something like a million times the mass of the sun, these things are moving much more slowly, much more far apart, and they’re producing lower frequency gravitational waves. And this is what LISA can detect. So LIGO, which is operating at these very fast orbits, fast frequencies, is unable to detect these things that are moving much more slowly and are on a much bigger scale.”
And for even bigger masses, you get to what Burke Spolaor is working on: Pulsar Timing 5 Arrays.
“What we do with this technique is use radio telescopes to observe pulsars, which are neutron 6 stars that are rotating very rapidly and sending their beams of emission 7 across Earth, several hundred times per second…and the idea is of course if a gravitational wave is passing through Earth, the gravitational wave is stretching and squeezing our space time. And the tick that we see from these very, very regularly spinning pulsars is speeding up and slowing down.
“Just like we can scale the stellar mass black holes that LIGO can detect, to very, very intermediate mass very large black holes that LISA can detect, Pulsar Timing Arrays will probe the very massive end of this distribution and the most massive, so the billion to even 10 billion solar mass binary 8 black holes in the universe. So every time you get a galaxy 9 merger 10 you can get a binary supermassive black hole, which then will contribute signal to our Pulsar Timing Arrays by propagating through the galaxy.
“Of course, gravitational waves does not stop at detection. What we really want to do is astrophysics with gravitational waves. And use it as a new tool to observe the universe and understand our place in it.”
—Steve Mirsky
- Guy's house was close to the observatory.盖伊的房子离天文台很近。
- Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
- His new contribution to the advancement of physiology was well appreciated.他对生理学发展的新贡献获得高度赞赏。
- The aim of a university should be the advancement of learning.大学的目标应是促进学术。
- All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
- He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。
- The workman fixed the antenna to the roof of the house.工人把天线固定在房顶上。
- In our village, there is an antenna on every roof for receiving TV signals.在我们村里，每家房顶上都有天线接收电视信号。
- The timing of the meeting is not convenient.会议的时间安排不合适。
- The timing of our statement is very opportune.我们发表声明选择的时机很恰当。
- Neutron is neutral and slightly heavier than the proton.中子是中性的，比质子略重。
- Based on the neutron energy,the value of weighting factor was given.根据中子能量给出了相应的辐射权重因子的数值。
- Rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施，降低污染物排放总量。
- Finally,the way to effectively control particulate emission is pointed out.最后，指出有效降低颗粒排放的方向。
- Computers operate using binary numbers.计算机运行运用二进位制。
- Let us try converting the number itself to binary.我们试一试，把这个数本身变成二进制数。
- The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
- The company has a galaxy of talent.该公司拥有一批优秀的人才。