Lecture 7 Flashcards Preview

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Flashcards in Lecture 7 Deck (36):
1

What asteroid will Osiris Rex visit?

Bennu, to pick up some soil samples

2

What did ancient civilizations use astronomy for?

Measuring time and space

3

When was Stonehenge built?

1550 BCE

4

What were the first clocks/calendars based on?

The sun (Sundials)

5

What were the three things that allowed Greek civilization to develop astronomy?

1. tradition to understand nature w/out the supernatural 2. mathematics 3. Reasoning based on observations

6

Who developed the geocentric model in 400 bc?

the greeks

7

How many planets did the Greeks expect?

7 planets

8

What was unique about Thales' model of the universe?

The first one that didn't rely on supernatural forces

9

What Anaximander's model of the universe?

A cylinder floating in space surrounded by the celestial sphere

10

What did Pythagoras change about Anaximander's model?

The earth is a SPHERE

11

What were Anaxagoras's key hypotheses?

Earth and Heavens are made from the same elements and that the moon reflects light

12

Who first thought that the Earth rotates?

Heracleides Ponticus

13

Who proposed heliocentric?

Aristarchus

14

What did Eratosthenes measure?

The circumference of the Earth

15

Who proposed epicycles?

Hipparchos

16

What did Ptolemy do?

He made many predictions, recorded in his Almagest

17

Who revived Aristarchus's sun-centered model?

Copernicus

18

How did Copernicus deal with the inaccuracy of circular orbits?

He added epicycles

19

What was Tycho Brahe's contribution?

He recorded the best naked eye observations, hired Kepler, and began to dismantle the stellar parallax, and discovered that planets go around the sun (with earth in the center)

20

What did Kepler finally decide?

Orbits had to be ellipses

21

Is the perihelion the short or long side?

Short

22

Is the aphelion the short or long side?

Long

23

What is Kepler's first law?

The orbit of each planet is an ellipse with the sun at one focus, which dispelled heavenly perfection

24

What is Kepler's second law?

A planet sweeps out equal distances at equal times (slower when further away)

25

What is Kepler's third law?

a planet orbiting further out orbits slower (p^2=a^3)

26

What was Thomas Digges's contribution?

He dismantled the stellar parallax, and proved that the universe was infinitely large with infinite stars at various distances

27

What three things did Galileo dismantle?

1. stellar parallax 2. non-circular orbits 3. Earth could not be moving because air would be left behind

28

How did Galileo prove that the heavens were imperfect?

He detected sunspots on the sun and mountains on moon

29

How did Galileo prove heliocentricity?

He used the phases of Venus

30

What did the Julian calendar add?

Leap years

31

What did the Gregorian calendar add?

Fixed leap years and timing

32

What is the sidereal period?

The time it takes for a planet to orbit the sun

33

What is the apparent solar time?

The time when the sun appears highest

34

What is the mean solar time?

Average of all apparently solar times

35

What is the synodic period?

Time between when a planet is lined up with the sun and when it is lined up again

36

What is a tropical year?

time from one spring equinox to the next