Chapter 2
Space and Time
1.impulse/ˈɪmpʌls/
Before them people believed Aristotle, who said that the natural state of a body was to be at rest and that it moved only if driven by a force or impulse.
1.N-VARAnimpulseis a sudden desire to do something.
Unable to resist the impulse, he glanced at the sea again.
2.N-COUNTAnimpulseis a short electrical signal that is sent along a wire or nerve or through the air, usually as one of a series.
It works by sending a series of electrical impulses which are picked up by hi-tech sensors.
3.ADJAnimpulsebuy orimpulsepurchase is something that you decide to buy when you see it, although you had not planned to buy it.
The curtains were an impulse buy.
4.PHRASEIf you do somethingon impulse, you suddenly decide to do it, without planning it.
词根：impulse
adj. impulsive冲动的；受感情驱使的；任性的
adv. impulsively有推动力地
n. impulsiveness冲动 impulsion冲动；冲击；原动力
2.gravitational/ˌɡrævɪˈteɪʃənəl/
Newton’s law of gravity says that the gravitational attraction of a star is exactly one quarter that of a similar star at half the distance.
ADJGravitationalmeans relating to or resulting from the force of gravity.
If a spacecraft travels faster than 11 km a second, it escapes the Earth's gravitational pull.
3.accuracy/ˈækjʊrəsɪ/
This law predicts the orbits of the earth, the moon, and the planets with great accuracy.
1.N-UNCOUNTTheaccuracyofinformation or measurements is their quality of being true or correct, even in small details.
Every care has been taken to ensure the accuracy of all information given in this leaflet.
2.N-UNCOUNTIf someone or something performs a task, for example, hitting a target,withaccuracy, they do it in an exact way without making a mistake.
...weapons that could fire with accuracy at targets 3,000 yards away.
4.elliptical/ɪˈlɪptɪkəl/
If the law were that the gravitational attraction of a star went down faster or increased more rapidly with distance, the orbits of the planets would not be elliptical, they would either spiral in to the sun or escape from the sun.
1.ADJSomething that isellipticalhas the shape of an ellipse.
...the moon's elliptical orbit.
2.ADJEllipticalreferences to something are indirect rather than clear.
...elliptical references to problems best not aired in public.
5.spiral/ˈspaɪərəl/(spiralling,spiralled,spirals)
If the law were that the gravitational attraction of a star went down faster or increased more rapidly with distance, the orbits of the planets would not be elliptical, they would either spiral in to the sun or escape from the sun.
1.N-COUNTAspiralis a shape which winds around and around, with each curve above or outside the previous one.
The maze is actually two interlocking spirals.
2.ADJSpiralis also an adjective.
...a spiral staircase.
3.V-T/V-IIf somethingspiralsoris spiralledsomewhere, it grows or moves in a spiral curve.
Vines spiralled upward toward the roof.
4.N-COUNTSpiralis also a noun.
Larks were rising in spirals from the ridge.
5.V-IIf an amount or levelspirals, it rises quickly and at an increasing rate.
Production costs began to spiral.
6.N-SINGSpiralis also a noun.
...an inflationary spiral.
7.V-IIf an amount or levelspiralsdownward, it falls quickly and at an increasing rate.
House prices will continue to spiral downwards.
8.N-SINGSpiralis also a noun.
...a spiral of debt.
6.rotation/rəʊˈteɪʃən/
For example, if one sets aside for a moment the rotation of the earth and its orbit round the sun, one could say that the earth was at rest and that a train on it was traveling north at ninety miles per hour or that the train was at rest and the earth was moving south at ninety miles per hour.
1.N-VARRotationis circular movement. Arotationis the movement of something through one complete circle.
...the daily rotation of the earth upon its axis.
2.N-UNCOUNTTherotationof a group of things or people is the fact of them taking turns to do a particular job or serve a particular purpose. If people do somethingin rotation, they take turns to do it.
He grew a different crop on the same field five years in a row, what researchers call crop rotation.
7.track/træk/(tracking,tracked,tracks)
To someone on the track, the two bounces would seem to take place about forty meters apart, because the train would have traveled that far down the track between the bounces.
1.N-COUNTAtrackis a rough, unpaved road or path.
We set off once more, over a rough mountain track.
2.N-COUNTAtrackis a piece of ground, often oval-shaped, that is used for races involving running, cars, bicycles, horses, or dogs called greyhounds.
...the athletics track.
3.N-COUNTRailwaytracksare the rails that a train travels along.
A cow stood on the tracks.
4.N-COUNTAtrackis one of the songs or pieces of music on a CD, record, or tape.
I only like two of the ten tracks on this CD.
5.N-PLURALTracksare marks left in the ground by the feet of animals or people.
The only evidence of pandas was their tracks in the snow.
6.V-TIf youtrackanimals or people, you try to follow them by looking for the signs that they have left behind, for example, the marks left by their feet.
He thought he had better track this wolf and see where it lived.
7.V-TTotracksomeone or something means to follow their movements by means of a special device, such as a satellite or radar.
Our radar began tracking the jets.
8.irrational/ɪˈræʃənəl/
He was severely criticized for this irrational belief by many people, most notably by Bishop Berkeley, a philosopher who believed that all material objects and space and time are an illusion.
1.ADJIf you describe someone's feelings and behaviour asirrational, you mean they are not based on logical reasons or clear thinking.
...an irrational fear of science.
9.notably/ˈnəʊtəblɪ/
He was severely criticized for this irrational belief by many people, most notably by Bishop Berkeley, a philosopher who believed that all material objects and space and time are an illusion.
1.ADVYou usenotablyto specify an important or typical example of something that you are talking about.
The divorce would be granted when more important problems, notably the fate of the children, had been decided.
2.ADVYou can usenotablyto emphasize a particular quality that someone or something has.
Old established friends are notably absent, so it's a good opportunity to make new contacts.
词根：noted
adj. notable值得注意的，显著的；著名的 noted著名的；显著的；附有乐谱的
n. notable名人，显要人物 notability显著；显要人物
v. noted注意；记下（note的过去式和过去分词）
10.refute/rɪˈfjuːt/(refuting,refuted,refutes)
When the famous Dr. Johnson was told of Berkeley’s opinion, he cried, “I refute it thus!” and stubbed his toe on a large stone.
1.V-TIf yourefutean argument, accusation, or theory, you prove that it is wrong or untrue.
It was the kind of rumour that it is impossible to refute.
2.V-TIf yourefutean argument or accusation, you say that it is not true.
Isabelle is quick to refute any suggestion of intellectual snobbery.
11.stub/stʌb/(stubbing,stubbed,stubs)
When the famous Dr. Johnson was told of Berkeley’s opinion, he cried, “I refute it thus!” and stubbed his toe on a large stone.
1.N-COUNTThestubof a cigarette or a pencil is the last short piece of it which remains when the rest has been used.
He pulled the stub of a pencil from behind his ear.
2.N-COUNTA ticketstubis the part that you keep when you go in to watch a performance.
Fans who still have their ticket stubs should contact the box office by July 3.
3.N-COUNTA chequestubis the small part that you keep as a record of what you have paid.
I have every cheque stub we've written since 1959.
4.V-TIf youstubyourtoe, you hurt it by accidentally kicking something.
I stubbed my toes against a table leg.
词根：stub
adj. stubby短而粗硬的；又短又秃的；断株样的 stubbly短而硬的；断株样的；短而粗的
n. stubble残株；发茬，须茬
12.interval/ˈɪntəvəl/
That is, they believed that one could unambiguously measure the interval of time between two events, and that this time would be the same whoever measured it, provided they used a good clock.
1.N-COUNTAnintervalbetween two events or dates is the period of time between them.
The process is repeated after a short interval of time.
2.N-COUNTAnintervalduring a concert, show, film, or game is a short break between two of the parts.
...during the interval of the musical "Steppin' Out."
3.PHRASEIf something happensat intervals, it happens several times with gaps or pauses in between.
She woke him for his medicines at intervals throughout the night.
4.PHRASEIf things are placedatparticularintervals, there are spaces of a particular size between them.
Several red and white barriers marked the road at intervals of about a mile.
time interval时间间隔 at intervals时时；相隔一定距离（或时间）
confidence interval置信区间，可靠区间
13.notion/ˈnəʊʃən/
Although our apparently commonsense notions work well when dealing with things like apples, or planets that travel comparatively slowly, they don’t work at all for things moving at or near the speed of light.
1.N-COUNTAnotionis an idea or belief about something.
We each have a notion of just what kind of person we'd like to be.
2.N-PLURALNotionsare small articles for sewing, such as buttons, zips, and thread.
14.remarkable/rɪˈmɑːkəbəl/
Nevertheless, Roemer’s achievement, in not only proving that light travels at a finite speed, but also in measuring that speed, was remarkable – coming as it did eleven years before Newton’s publication of Principia Mathematica.
ADJ Someone or something that isremarkableis unusual or special in a way that makes people notice them and be surprised or impressed.
He was a remarkable man.
Principia Mathematica 《数学原理》
15.propagation[,prɔpə'ɡeiʃən]
n.1.the spreading of something (a belief or practice) into new regions
同义词：extension
2.the act of producing offspring or multiplying by such production
3.the movement of a wave through a medium
16.ripple/ˈrɪpəl/(rippling,rippled,ripples)
Maxwell’s equations predicted that there could be wavelike disturbances in the combined electromagnetic field, and that these would travel at a fixed speed, like ripples on a pond.
1.N-COUNTRipplesare little waves on the surface of water caused by the wind or by something moving in or on the water.
Gleaming ripples cut the lake's surface.
2.V-T/V-IWhen the surface of an area of waterripplesor when somethingripplesit, a number of little waves appear on it.
You throw a pebble in a pool and it ripples.
3.V-IIf something such as a feeling ripples over someone's body, it moves across it or through it.
A chill shiver rippled over his skin.
4.N-COUNTIf an event causesripples, its effects gradually spread, causing several other events to happen one after the other.
If Brazil defaults on its foreign debt, it will cause ripples throughout the world.
5.Na special kind of comb designed to separate the seed from the stalks in flax, hemp, or broomcorn 麻梳(用来梳除亚麻茎、棕榈或高粱上籽的粗钢梳)
6.Vto comb with this tool (用麻梳)梳理
17.crest/krɛst/
If the wavelength of these waves (the distance between one wave crest and the next) is a meter or more, they are what we now call radio waves.
1.N-COUNTThecrestofa hill or a wave is the top of it.
2.PHRASEIf you say that you areon the crest of a wave, you mean that you are feeling very happy and confident because things are going well for you.
The band is riding on the crest of a wave with the worldwide success of their number-one-selling single.
3.N-COUNTA bird'screstis a group of upright feathers on the top of its head.
Both birds had a dark blue crest.
4.N-COUNTAcrestis a design that is the symbol of a noble family, a town, or an organization.
On the wall is the family crest.
wave crest n. 波峰
18.infrared/ˌɪnfrəˈrɛd/
Shorter wavelengths are known as microwaves (a few centimeters) or infrared (more than a ten-thousandth of a centimeter).
1.ADJInfraredradiation is similar to light but has a longer wavelength, so we cannot see it without special equipment.
This information is encrypted within the Smartpen and then sent out through an infrared transmitter.
2.ADJInfraredequipment detects infrared radiation.
...searching with infrared scanners for weapons and artillery.
infrared spectroscopy红外光谱法；红外线分光镜 near infrared近红外（线）
19.confine/kənˈfaɪn/(confining,confined,confines)
For this reason, any normal object is forever confined by relativity to move at speeds slower than the speed of light.
1.V-TToconfinesomethingtoa particular place or group means to prevent it from spreading beyond that place or group.
Health officials have successfully confined the epidemic to the Tabatinga area.
2.V-TIf youconfinesomebody or something, you prevent them from leaving or escaping.
He was confined in an internment camp in Utah.
3.V-TIf youconfineyourselfor your activitiestosomething, you do only that thing and are involved with nothing else.
He did not confine himself to the one language.
词根：confine
adj. confined狭窄的；幽禁的；有限制的；在分娩中的 confining受限的；狭窄的；拘束的
n. confinement限制；监禁；分娩
v. confined限制（confine的过去式和过去分词）
20.intrinsic/ɪnˈtrɪnsɪk/
Only light, or other waves that have no intrinsic mass, can move at the speed of light.
ADJIf something hasintrinsicvalue orintrinsicinterest, it is valuable or interesting because of its basic nature or character, and not because of its connection with other things.
Diamonds have little intrinsic value and their price depends almost entirely on their scarcity.
此处应有思维导图。
时间简史这本书的语言真的比较简单，用词简单，除了专业单词不认识之外都能认识。但是不是很能够看懂，要反复理解阅读才行。对逻辑的理解要很深刻才能行。
