Subtitles section
Repeat sentence
Subtitles mode
Full screen
Previous
Next
x 1.0
Playback speed
More

What causes precession and other orbital changes | Cosmology & Astronomy | Khan Academy

Video vocabulary

right

Copy vocabulary

US / raɪt /

UK / raɪt /

A1
  • adjecitve
  • Correct or true
  • The south side of you looking at the rising sun
  • adverb
  • Exactly in a place or time
  • Being appropriate for a particular event
  • In a straight or direct manner
  • noun
  • Something you are legally or morally allowed to do
  • Ideal of what is just and good
  • Political view based on conservatism
  • verb
  • To fix something previously wrong or unjust
  • To make upright, as a boat that has turned over

tell

Copy vocabulary

US / tel /

UK / tɛl /

A1
  • verb
  • To (strongly) advise a person to do something
  • To be able to guess
  • To say or communicate information to someone
  • To inform, but without speaking; indicate
  • To have a negative effect on someone
  • To order someone to do something; command
  • To recognize something based on certain signs
  • To report something to an authority
  • To explain something or teach someone something

type

Copy vocabulary

US / taɪp /

UK / taɪp /

A1
  • noun
  • Printed letters or blocks used for printing them
  • Group of things or people sharing common features
  • verb
  • To identify something belonging to a group
  • To write by touching keys on a keyboard

about

Copy vocabulary

US / ə'baʊt /

UK / əˈbaʊt /

A1
  • adverb
  • To be ready to; going to
  • Nearly; approximately; roughly
  • Near; next to; close to
  • In every direction; in the area of
  • preposition
  • Concerning or of (a topic)

again

Copy vocabulary

US / ə'ɡen /

UK / əˈɡɛn /

A1
  • adverb
  • One more time, once more

that

Copy vocabulary

US / ðæt /

UK / ðæt, ðət /

A1
  • adjecitve
  • The person or thing being talked about
  • Used to identify something both the speakers know
  • adverb
  • Used to reinforce adjectives and adverbs
  • To such a degree
  • conjunction
  • Used to connect a noun clause
  • Used to introduce an adverbial clause
  • Used to introduce a noun clause
  • determiner
  • Used as a noun to refer to something
  • pronoun
  • Referring an object far away
  • Used to refer to the relative pronoun ‘which’

cause

Copy vocabulary

US / kɔ:z /

UK / kɔz /

A2
  • noun
  • Belief, goal or organization that people support
  • Reason for
  • verb
  • To make something happen; create effect or result

happen

Copy vocabulary

US / 'hæpən /

UK / ˈhæpən /

A1
  • verb
  • To take place or occur

ellipse

Copy vocabulary

US / ɪˈlɪps /

UK / ɪˈlɪps /

C1
  • noun
  • Plane curve made by cone and plane intersecting

change

Copy vocabulary

US / tʃeɪndʒ /

UK / tʃendʒ /

A1
  • noun
  • Exchange of one set of clothes for another
  • Money in the form of coins instead of paper
  • Money returned after giving too much
  • Act of making or becoming something else
  • verb
  • To exchange one set of clothes for another
  • To exchange one kind of money for another
  • To replace something with another thing
  • To make or become something else
  • To go from one train, bus, etc. and go to another

solar

Copy vocabulary

US / 'səʊlə(r) /

UK / ˈsolɚ /

B1
  • adjecitve
  • Concerning the sun, or its heat

bit

Copy vocabulary

US / bɪt /

UK / bɪt /

A1
  • noun
  • Device put in a horse's mouth to control it
  • Small piece of something
  • verb
  • (E.g. of fish) to take bait and be caught

kilometre

Copy vocabulary

US / ˈkɪləmi:tə(r) /

UK / ˈkɪləmiːtər /

A1
  • noun
  • A metric unit of length equal to 1000 metres

moon

Copy vocabulary

US / mu:n /

UK / mun /

A2
  • noun
  • Round object circling the Earth at night
  • verb
  • To expose your buttocks as a joke

between

Copy vocabulary

US / bɪˈtwi:n /

UK / bɪˈtwin /

A1
  • preposition
  • From one person, thing, or place, to another
  • In the space that separates two objects
  • Among two or more people who share something

they

Copy vocabulary

US / ðeɪ /

UK / ðe /

A1
  • pronoun
  • Two or more people, animals, or things

due

Copy vocabulary

US / dju: /

UK / du, dju /

A1
  • adjecitve
  • When something is required or expected
  • Owed to a person as a right
  • noun
  • Something you deserve; something you can expect

fat

Copy vocabulary

US / fæt /

UK / fæt /

A1
  • adjecitve
  • Having too much weight for the body size
  • Bringing or having a large amount of money
  • noun
  • Amount beyond what is usual or necessary
  • Oily part of meat

all

Copy vocabulary

US / ɔ:l /

UK / ɔl /

A1
  • adverb
  • Completely; totally
  • determiner
  • Being every one of something
  • pronoun
  • 100% of something; the complete amount

its

Copy vocabulary

US / ɪts /

UK / ɪts /

A1
  • adjecitve
  • Referring to or belonging to ‘it’
  • determiner
  • Of something; belonging or related to something
  • other
  • Possessive form of “it”

bulge

Copy vocabulary

US / bʌldʒ /

UK / bʌldʒ /

B2
  • noun
  • Rounded full or fat lump on the surface of a thing
  • Rapid increase in size
  • verb
  • To curve outward from the surface, as when full

into

Copy vocabulary

US / 'ɪntə /

UK / ˈɪntu /

A1
  • preposition
  • Moving or going inside something
  • In the same direction as; in the direction of
  • So as to become; taking the state of

other

Copy vocabulary

US / 'ʌðə(r) /

UK / ˈʌðər /

A1
  • adjecitve
  • A thing different from that mentioned
  • determiner
  • (Something) else; not the first (one)
  • pronoun
  • Being the one and only thing of that category

noticeable

Copy vocabulary

US / ˈnəʊtɪsəbl /

UK / ˈnoʊtɪsəbl /

B1
  • adjecitve
  • Being easy or likely to be sensed or noticed

perfect

Copy vocabulary

US / 'pɜ:fɪkt /

UK / ˈpɚfɪkt /

A1
  • adjecitve
  • So good it cannot be improved
  • verb
  • To do something so well, it cannot be done better

pull

Copy vocabulary

US / pʊl /

UK / pʊl /

A1
  • noun
  • Act of breathing in smoke, as from a pipe
  • Force something has that draws other things to it
  • Using your hands to move something to you
  • verb
  • To breathe in smoke, as from a pipe
  • To hold something and move it toward you
  • To remove something by force

one

Copy vocabulary

US / wʌn /

UK / wʌn /

A1
  • pronoun
  • You; we; people in general; someone
  • The thing or person previously referred to
  • adjecitve
  • Used to refer to people generally
  • Being a strong example of (something mentioned)
  • number
  • Number 1

turn

Copy vocabulary

US / tɜ:n /

UK / tɚn /

A1
  • noun
  • Place where changing of direction happens
  • Your time or chance to perform a duty
  • Your chance to play or do in say a game
  • Unexpected change, as in the weather
  • verb
  • To become (a particular age)
  • To become a different quality, color, etc.
  • To change the direction of something, e.g. a car
  • To move in an opposite direction or position
  • To shape metal with a spinning tool

than

Copy vocabulary

US / ðən /

UK / ðən /

A1
  • conjunction
  • Used to compare two things that are not equal

symmetrical

Copy vocabulary

US / sɪˈmetrɪkl /

UK / sɪˈmɛtrɪkəl /

B2
  • adjecitve
  • Having parts that are exactly the same

this

Copy vocabulary

US / ðɪs /

UK / ðɪs /

A1
  • adjecitve
  • Used to indicate something already been discussed
  • Used to indicate something happening around now
  • adverb
  • An indication by a physical motion or gesture
  • A specific amount of
  • determiner
  • Person, thing, or idea near you
  • pronoun
  • Person, thing that has already been discussed

term

Copy vocabulary

US / tɜ:m /

UK / tɚm /

A1
  • noun
  • Conditions applying to an agreement, contract
  • Length of time something is expected to happen
  • Fixed period of weeks for learning at school
  • The (precise) name given to something
  • verb
  • To call; give a name to

less

Copy vocabulary

US / les /

UK / lɛs /

A1
  • adjecitve
  • Smaller in amount or degree
  • adverb
  • To a smaller degree
  • noun
  • A smaller amount
  • preposition
  • With the subtraction of

also

Copy vocabulary

US / 'ɔ:lsəʊ /

UK / ˈɔlso /

A1
  • adverb
  • In addition; too; in a similar way

year

Copy vocabulary

US / jə: /

UK / jɪr /

A1
  • noun
  • Unit of time equal to 12 months or 365 or 366 days
  • Used to refer to the age of a person

you

Copy vocabulary

US / jʊ /

UK / ju /

A1
  • pronoun
  • Person someone is speaking or writing to
  • Person or people in general

let

Copy vocabulary

US / let /

UK / lɛt /

A1
  • verb
  • To allow someone to do something
  • Introducing a suggestion to do something together
  • To rent a house, etc. to others

little

Copy vocabulary

US / 'lɪtl /

UK / ˈlɪtl /

A1
  • adjecitve
  • Being short in length of time
  • Not great in size, amount, or degree; small
  • Being very young or younger than others
  • adverb
  • By an amount or degree that is not very much
  • Not often; rarely
  • noun
  • A person's name

the

Copy vocabulary

US / ðə /

UK / ðə /

A1
  • article
  • Used to refer to something already mentioned
  • Used to show there is only one of something
  • determiner
  • Used to describe all of a family

cycle

Copy vocabulary

US / ˈsaɪkl /

UK / ˈsaɪkəl /

A2
  • noun
  • Series of regular and repeated actions
  • Bicycle, bike
  • verb
  • To go through a series of events repeatedly
  • To ride on a bicycle

precession

Copy vocabulary

US / prɪ'seʃən /

UK / prɪ'seʃən /

C2
  • noun
  • (Formal) going first in time, order or rank

talk

Copy vocabulary

US / tɔ:k /

UK / tɔk /

A1
  • noun
  • Style of speaking
  • Discussion between two countries
  • Giving information in front of people; lecture
  • Saying things or ideas to someone with words
  • verb
  • To make a formal speech about something
  • To say things or ideas to someone with words

object

Copy vocabulary

US / 'ɒbdʒɪkt /

UK / ˈɑbdʒɪkt /

A2
  • noun
  • Something you can see or touch, but is not alive
  • Goal or purpose of a particular plan or activity
  • The thing that the action of a verb acts upon
  • verb
  • To disagree; to protest against an idea or plan

discussion

Copy vocabulary

US / dɪˈskʌʃn /

UK / dɪˈskʌʃən /

A2
  • noun
  • Any long communication about a particular topic

time

Copy vocabulary

US / taɪm /

UK / taɪm /

A1
  • noun
  • Speed at which music is played; tempo
  • Point as shown on a clock, e.g. 3 p.m
  • Number of hours, minutes needed to do something
  • Occasion when something happens
  • Period or occasion that something occurred
  • Period in history or the past
  • Something measured in minutes, hours, days, etc.
  • How long an event takes; duration
  • verb
  • To check speed at which music is performed
  • To choose a specific moment to do something
  • To measure how long an event takes, e.g. a race
  • To schedule something to occur at a specific moment

why

Copy vocabulary

US / waɪ /

UK / hwaɪ, waɪ /

A1
  • adverb
  • Question word to ask for a reason
  • exclamation
  • (Used to express surprise or approval)

fact

Copy vocabulary

US / fækt /

UK / fækt /

A1
  • noun
  • Something that is known or proved to be true

earth

Copy vocabulary

US / ɜ:θ /

UK / ɚθ /

A1
  • noun
  • Wire connecting an electrical device to the ground
  • The planet we live on
  • Soil in which we grow plants

system

Copy vocabulary

US / 'sɪstəm /

UK / ˈsɪstəm /

A1
  • adjecitve
  • Working in an organized, logical way
  • noun
  • Set of organized, planned ideas that work together

asymmetry

Copy vocabulary

US / ˌeɪ'sɪmətrɪ /

UK / eˈsɪmɪtri /

B2
  • noun
  • Being different on one side than the other

math

Copy vocabulary

US / mæθ /

UK / mæθ /

A2
  • noun
  • Study or science of numbers and shapes

those

Copy vocabulary

US / ðəʊz /

UK / ðoz /

A1
  • determiner
  • The people or things we are talking about
  • pronoun
  • The objects far from the speaker

pole

Copy vocabulary

US / pəʊl /

UK / pol /

B1
  • noun
  • One of two opposite ideas, qualities or positions
  • Most northern or most southern point on a planet
  • A long, narrow piece of metal or wood
  • One of two opposite magnetic forces
  • An upright long thin structure to support things
  • verb
  • To move a boat with a stick or pole

video

Copy vocabulary

US / 'vɪdɪəʊ /

UK / ˈvɪdiˌo /

A2
  • adjecitve
  • Of a moving film, with sound
  • noun
  • Recording capturing action with sound
  • verb
  • To make a moving film of, with sound

axial

Copy vocabulary

US / ˈæksiəl /

UK / ˈæksiəl /

A1
  • adjecitve
  • Forming or rotating around an axis

our

Copy vocabulary

US / 'aʊə(r) /

UK / aʊr /

A1
  • determiner
  • Belonging to us

not

Copy vocabulary

US / nɒt /

UK / nɑt /

A1
  • adverb
  • Word indicating the negative
  • (Used to form the negative of verbs)

whole

Copy vocabulary

US / həul /

UK / hol /

A1
  • adjecitve
  • Complete or full; all of
  • Being in a good condition
  • noun
  • Complete amount or sum; total

north

Copy vocabulary

US / nɔ:θ /

UK / nɔ:rθ /

A1
  • adjecitve
  • Coming from the opposite direction to the south
  • noun
  • Direction to your left when facing the rising sun

really

Copy vocabulary

US / ˈri:əli /

UK / ˈriəˌli, ˈrili /

A1
  • adverb
  • Used to stress something that is said; definitely
  • In a true or accurate manner
  • Very

physics

Copy vocabulary

US / ˈfɪzɪks /

UK / ˈfɪzɪks /

A1
  • other
  • The study of heat, light, and energy on objects

measure

Copy vocabulary

US / ˈmeʒə(r) /

UK / ˈmɛʒɚ /

A1
  • noun
  • Plan to achieve a desired result
  • Tool used to calculate the size of something
  • verb
  • To determine the value or importance of something
  • To calculate size, weight or temperature of

planet

Copy vocabulary

US / 'plænɪt /

UK / ˈplænɪt /

A2
  • noun
  • One of the bodies that orbit the sun

south

Copy vocabulary

US / saʊθ /

UK / saʊθ /

A1
  • adjecitve
  • Direction to your right when facing the rising sun
  • Coming from the opposite direction from north
  • noun
  • The direction to your right of the rising sun

tall

Copy vocabulary

US / tɔ:l /

UK / tɔl /

A1
  • adjecitve
  • High in height

but

Copy vocabulary

US / bət /

UK / bʌt,bət /

A1
  • conjunction
  • Used before you say something different, opposite

could

Copy vocabulary

US / kəd /

UK / kʊd /

A1
  • other
  • Past form of 'can' to mean have ability
  • Used to ask for something politely, or to offer

diameter

Copy vocabulary

US / daɪˈæmɪtə(r) /

UK / daɪˈæmɪtɚ /

B1
  • noun
  • Distance across the center of an object

see

Copy vocabulary

US / si: /

UK / si /

A1
  • verb
  • To go on a date with someone
  • To predict whether something is, or will be true
  • To understand what someone says
  • To use your eyes to look at something
  • To visit a place often for sightseeing or pleasure
  • To visit or meet with someone
  • To find out by waiting or looking
  • To watch (a game, movie or TV show)

have

Copy vocabulary

US / həv /

UK / hæv /

A1
  • verb
  • To drink, smoke, eat or use something
  • To experience the effects of something
  • To organize an event, or join in an activity
  • To own, possess, or hold something
  • To cause to happen or produce a particular effect

next

Copy vocabulary

US / nekst /

UK / nɛkst /

A1
  • adverb
  • The one that follows another in time or order
  • At a time or place directly after the present one
  • noun
  • The one that follows after
  • adjecitve
  • Immediately after the previous one
  • First occurrence after the present one

orbit

Copy vocabulary

US / 'ɔ:bɪt /

UK / ˈɔrbɪt /

B2
  • noun
  • Path an object takes as it circles another object
  • verb
  • To go around another object (often in space)

with

Copy vocabulary

US / wɪð /

UK / wɪð, wɪθ /

A1
  • preposition
  • As an employee of a certain company
  • Against something or someone
  • By using something as a means
  • Due to; because of
  • Including
  • Possessing as a feature
  • Related to
  • (Of the manner/attitude by which you do something)
  • Used to express that people or things are together

draw

Copy vocabulary

US / drɔ: /

UK / drɔ /

A1
  • noun
  • Something that attracts people to visit a place
  • A lottery or prize
  • Result of a game, contest where the score is equal
  • verb
  • To attract attention to someone or something
  • To get closer to or approach something or someone
  • To influence a person's involvement in something
  • To move an object by pulling
  • To create an image using pen or pencil and paper
  • To take one thing out of a container, etc.
  • (Of 2 teams) to finish a game with the same score

byproduct

Copy vocabulary

US / 'baɪˌprɒdʌkt /

UK / ˈbaɪˌprɑdəkt /

C1
  • noun
  • A waste product made from making something else

sun

Copy vocabulary

US / sʌn /

UK / sʌn /

A1
  • noun
  • Light and heat coming from a large star in the sky
  • Hot shining star the Earth moves around
  • verb
  • To lie in the sunshine and enjoy its warmth

approximately

Copy vocabulary

US / əˈprɒksɪmətli /

UK / əˈprɑksəmɪtlɪ /

A2
  • adverb
  • Around; nearly; almost; about (a number)

equator

Copy vocabulary

US / ɪ'kweɪtə(r) /

UK / ɪˈkwetɚ /

B1
  • noun
  • Geographical line at zero degrees latitude

call

Copy vocabulary

US / kɔ:l /

UK / kɔl /

A1
  • noun
  • A order or request for action
  • The sound an animal makes, often when in danger
  • A correct prediction, e.g. a decision in a game
  • A short visit to a place or person
  • A decision by a referee or umpire in a game
  • verb
  • To make a request or order for action
  • (Animal) to make sounds to warn of danger
  • To announce the date of an election
  • To make a judgment about something
  • To give someone or something a name
  • To guess in advance the result or outcome
  • To visit a place or person for a short time
  • To phone someone
  • To speak, announce or shout in a loud voice

beyond

Copy vocabulary

US / bɪ'jɒnd /

UK / biˈɑnd, bɪˈjɑnd /

A2
  • adverb
  • On or to the farther side
  • In addition to
  • preposition
  • Later in time than
  • Out of the limits of

along

Copy vocabulary

US / əˈlɒŋ /

UK / əˈlɔ:ŋ /

A1
  • adverb
  • As a companion; taken with someone
  • preposition
  • At a point on a line

from

Copy vocabulary

US / frəm /

UK / frʌm, frɑm,frəm /

A1
  • preposition
  • Starting at a particular place, time or level

out

Copy vocabulary

US / aʊt /

UK / aʊt /

A1
  • adverb
  • No longer stylish (e.g. fashion)
  • Away from home, business, or the usual place
  • In a direction/movement away from inside or center
  • noun
  • Act when a batter cannot continue playing
  • verb
  • To tell people a secret

over

Copy vocabulary

US / 'əʊvə(r) /

UK / ˈovɚ /

A1
  • adverb
  • Finished; no longer happening
  • Towards the ground/away from a standing position
  • noun
  • A set of six consecutive balls bowled in cricket
  • other
  • Finished
  • preposition
  • Showing the relation when a thing is above another
  • On or covering something
  • Above or across something
  • More than you need
  • From one side to the other
  • In the direction of; toward

and

Copy vocabulary

US / ənd /

UK / ənd, ən,ænd /

A1
  • conjunction
  • Used to refer to two or more things
  • Plus; in addition; on top of that
  • Used to introduce an action that follows another

lot

Copy vocabulary

US / lɒt /

UK / lɑt /

A1
  • noun
  • What happens to a person in life from chance; fate
  • A group of people seen together
  • Item for sale at an auction
  • Small area of land used for a purpose e.g. parking

completely

Copy vocabulary

US / kəmˈpli:tli /

UK / kəmˈpliːtli /

A1
  • adverb
  • In every way or as much as possible

only

Copy vocabulary

US / ˈəunli /

UK / ˈonli /

A1
  • adverb
  • Just one; just that amount or thing; not more than
  • Not very important or serious
  • Just that type of thing, person
  • Short time ago; not before a certain time
  • conjunction
  • Except; but

put

Copy vocabulary

US / pʊt /

UK / pʊt /

A1
  • phrasal verb
  • to make a light stop shining by pressing or moving a switch
  • verb
  • To move or place a thing in a particular position
  • To rate something in importance or value
  • To write or say something in a certain manner

guess

Copy vocabulary

US / ɡes /

UK / ɡɛs /

A1
  • noun
  • Answer given when you don't know if it is correct
  • verb
  • To give an answer without knowing if it is correct

thousand

Copy vocabulary

US / ˈθaʊznd /

UK / ˈθaʊzənd /

A1
  • number
  • Number 1,000

will

Copy vocabulary

US / wɪl /

UK / wɪl /

A1
  • noun
  • Desire or choice of someone
  • Document saying who gets your money when you die
  • Strong desire to do something; determination
  • Desire to do something; strong wish to do
  • other
  • Used with verbs to express the future
  • verb
  • To leave property to someone after your death
  • To use mental effort to make something happen
  • Am (is, are) likely to do
  • To influence someone to do something
  • To make something happen by strongly wanting it

here

Copy vocabulary

US / hɪə(r) /

UK / hɪr /

A1
  • adverb
  • In this place; at this location, position or time

actually

Copy vocabulary

US / ˈæktʃuəli /

UK / ˈæktʃuəli /

A1
  • adverb
  • Used to add new (often different) information

equatorial

Copy vocabulary

US / ˌekwəˈtɔ:riəl /

UK / ˌikwəˈtɔriəl, -ˈtor-, ˌɛkwə- /

B1
  • adjecitve
  • Concerning or at an equator; having hot weather

gravity

Copy vocabulary

US / ˈgrævəti /

UK / ˈɡrævɪti /

B1
  • noun
  • (Of a situation) extreme seriousness
  • Force making things fall towards the ground

inside

Copy vocabulary

US / ˌɪn'saɪd /

UK / ɪnˈsaɪd, ˈɪnˌsaɪd /

A2
  • adjecitve
  • Being in something
  • Being in a building
  • adverb
  • Into a house; indoors
  • noun
  • Inner part or surface of something

once

Copy vocabulary

US / wʌns /

UK / wʌns /

A1
  • adverb
  • One time; one instance
  • At a time in the past
  • conjunction
  • When; as soon as

inclination

Copy vocabulary

US / ˌɪnklɪˈneɪʃn /

UK / ˌɪn.klɪˈneɪ.ʃən /

B1
  • noun
  • Feeling or desire to do something; a habit
  • Subtitles section
  • I've talked a lot about precession and the changes in the inclination of Earth's orbit, but I haven't told you why they are happening.
  • And I'm not going to go into the physics of it.
  • It's a little bit beyond this discussion right over here.
  • But they're really a byproduct of the Earth and sun's interactions with Earth and with the fact that Earth is not a perfect sphere.
  • So if I draw Earth-- so this is my little drawing of Earth, and let me put the poles over here, North Pole and South Pole, it actually turns out that Earth is fatter than it is taller.
  • So if you were to measure Earth's diameter along the equator, it is 43 kilometers, which is approximately 27 miles longer than if you were to measure its diameter from pole to pole.
  • So longer than the pole to pole diameter.
  • And the fact that Earth has this equatorial bulge, that it's not a perfect sphere-- and once again, I'm not going to go into the math here-- it's the interactions between that, I guess you could call it, that one asymmetry of the Earth,
  • it's that interaction between that and the pull of gravity between the Earth and the sun and the moon that causes these long term cycles, this axial precession and other less noticeable changes in Earth's orbit.
  • And as we'll see in the next video, these aren't the only types of changes in orbits we have.
  • We also have changes in the actual ellipse that Earth's orbit has actually rotates over time.
  • But that's due more to interactions with Earth's orbit, and the orbit of other planets in our solar system.
  • And once again, it's one of those things that happened over thousands and thousands of years.
  • So all of these changes, they're because Earth isn't completely symmetrical, more fat than it is tall, those interactions between the gravity of the sun and the moon.
  • And Earth's orbit, as a whole, changes because of interactions with other objects inside of our solar system.