time and space

阅读时间：50分钟

1.the leaning tower of Pisa 比萨斜塔

2.air resistance 空气阻力

3.Newton’s first law 牛顿第一定律

4.gravitational attraction， gravity, gravitation

5.refute

    1. to say that a statement is not true or accurate without giving proof

    The police said he was drunk, a claim refuted by his attorney.

    2. to prove that a statement is false

    The evidence refutes all claims that the student loan scheme is not working.

He observed that the times at which the moons of Jupiter appeared to pass behind Jupiter were not evenly spaced, as one would expect if the moons went round Jupiter at a constant rate.

6.moon 卫星

7.space

    v [Tn, Tn.p] ~ sth (out) set sth out with regular spaces between

     将某事物均匀隔开:

    space out the posts three metres apart

    把这些柱子间隔三米排开 *

8.propagation 传播

9.wave crest 波峰

10.thousandth 千分之一

11.ether 以太

The fundamental postulate of the theory of relativity, as it was called, was that the laws of science should be the same for all freely moving observers, no matter what their speed.

12.postulate

an idea that is an important part of a theory, argument, or explanation 假定，基本原理

13.the special / general theory of relativity      狭义/广义相对论

Only light, or other waves that have no intrinsic mass, can move at the speed of light.

14. intrinsic:

    relating to the essential qualities or features of something or someone

    the intrinsic beauty of the Italian language

15.pulse 脉冲

16.velocity

the speed that something moves at in one direction速度

17.cesium clock 铯原子钟， 铯钟

18.铂杆（platinum metre bar），以此杆两端之间的距离定为1米

19.坐标系 Coordinate system

20.Piccadilly Circus 皮卡迪利圆环

皮卡迪利圆环（Piccadilly Circus），伦敦最有名的圆形广场，兴建于1819年，早期是英国零售商店所在地，今日为英国伦敦市中心购物街道的圆心点，有五条主要道路交错于此。

21.diagonal line对角线

22.radius 半径

23.snapshot n,快照

24.geodesic 测地线

25.elongated

    longer and narrower than is normal or natural

    elongated fingers

26.curvature 弯曲

Brilliant ideas:

In Newton’s theory, if a pulse of light is sent from one place to another, different observers would agree on the time that the journey took (since time is absolute), but will not always agree on how far the light traveled (since space is not absolute). Since the speed of the light is just the distance it has traveled divided by the time it has taken, different observers would measure different speeds for the light.

In relativity, on the other hand, all observers must agree on how fast light travels. They still, however, do not agree on the distance the light has traveled, so they must therefore now also disagree over the time it has taken.

The theory of relativity put an end to the idea of absolute time!!!

That space-time is not flat, as had been previously assumed: it is curved, or “warped,” by the distribution of mass and energy in it.

The mass of the sun curves space-time in such a way that although the earth follows a straight path in four-dimensional space-time, it appears to us to move along a circular orbit in three-dimensional space.