点击这里查看首页

两个视频读懂黑洞


来源:网络转载
发布时间:2019-04-14 15:27:00
查看次数:

内容提要:两个视频读懂黑洞


Black holes are among the most fascinating objects in our universe, and also the most mysterious.

A black hole is a region in space where the force of gravity is so strong not even light – the fastest known entity in our universe – can escape.

The boundary of a black hole is called the event horizon, a point of no return, beyond which we truly cannot see.

Once something crosses the event horizon, it collapses into the black hole’s singularity: an infinitely small, infinitely dense point where space, time, and the laws of physics no longer apply.

Scientists have theorized several different types of black holes, withstellar and supermassive black holes being the most common.

Stellar black holes form when massive stars die and collapse. They’re roughly 10 to 20 times the mass of our Sun and scattered throughout the universe. There could be millions of these stellar black holes in the Milky Way alone.

Supermassive black holes are giants by comparison, measuring millions, even billions of times more massive than our Sun. Scientists can only guess how they form, but we do know they exist at the center of just about every large galaxy…including our own.

Sagittarius A, the supermassive black hole at the center of the Milky Way, has a mass of roughly 4 million suns and has a diameter about the distance between Earth and our Sun.

Because black holes are invisible, the only way for scientists to detect and study them is to observe their effect on nearby matter.

This includes accretion disks, a disk of particles that form when gases and dust fall toward a black hole and quasars, jets of particles that -out of supermassive black holes.

Black holes remained largely unknown until the 20th century.

In 1916, using Einstein’s General Theory of Relativity, a German physicist named Karl Schwartzschild calculated that any mass could become a black hole if it were compressed tightly enough.

But it wasn’t until 1971, when theory became reality. Astronomers, studying the constellation Cygnus, discovered the first black hole.

An untold number of black holes are scattered throughout the universe…

Constantly warping space and time, altering entire galaxies, and endlessly inspiring both scientists and our collective imagination.


相关文章
·英文版《伊索寓言》 22 农夫与老鹰03-09
·米歇尔奥巴马北京大学演讲视频03-29
·英文版《西游记》37-39集(耳濡目染,用简单快乐的方式学习英语)11-24
·英文版《西游记》16-18集(耳濡目染,用简单快乐的方式学习英语)11-17
·名师微课| 初高衔接(二十四) 策略灵活用,巧拼完形图09-09
·如何避免在压力之下发挥失常?(TED)04-20
·震撼演讲:好爸爸不缺席(来自电影《勇气》)06-17
·3分钟中国共产党英文宣传片为何火爆全世界?看完你就懂!07-01
·Happy Teachers' Day 教师节快乐!09-10
·6分钟不到就能燃起你斗志的英文短片10-04
最新文章
·模仿朗读︱西夏陵申遗成功07-12
·模仿朗读︱如何用英文介绍小暑07-07
·双语阅读 用英语介绍夏至06-21
·父爱如山 父亲节快乐 Happy Father's Day06-15
·Happy Children's Day 儿童节快乐!06-01
·双语视频︱用英语介绍端午节和赛龙舟05-31
·模仿朗读︱二十四节气:小满05-21
·妈妈,您辛苦啦!祝所有妈妈节日快乐05-11
·模仿朗读 用英语介绍立夏05-05
·To Youth 致青年05-04
阅读排行