Lecture 7 Flashcards Preview

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Flashcards in Lecture 7 Deck (36)
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1
Q

What asteroid will Osiris Rex visit?

A

Bennu, to pick up some soil samples

2
Q

What did ancient civilizations use astronomy for?

A

Measuring time and space

3
Q

When was Stonehenge built?

A

1550 BCE

4
Q

What were the first clocks/calendars based on?

A

The sun (Sundials)

5
Q

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

A
  1. tradition to understand nature w/out the supernatural 2. mathematics 3. Reasoning based on observations
6
Q

Who developed the geocentric model in 400 bc?

A

the greeks

7
Q

How many planets did the Greeks expect?

A

7 planets

8
Q

What was unique about Thales’ model of the universe?

A

The first one that didn’t rely on supernatural forces

9
Q

What Anaximander’s model of the universe?

A

A cylinder floating in space surrounded by the celestial sphere

10
Q

What did Pythagoras change about Anaximander’s model?

A

The earth is a SPHERE

11
Q

What were Anaxagoras’s key hypotheses?

A

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

12
Q

Who first thought that the Earth rotates?

A

Heracleides Ponticus

13
Q

Who proposed heliocentric?

A

Aristarchus

14
Q

What did Eratosthenes measure?

A

The circumference of the Earth

15
Q

Who proposed epicycles?

A

Hipparchos

16
Q

What did Ptolemy do?

A

He made many predictions, recorded in his Almagest

17
Q

Who revived Aristarchus’s sun-centered model?

A

Copernicus

18
Q

How did Copernicus deal with the inaccuracy of circular orbits?

A

He added epicycles

19
Q

What was Tycho Brahe’s contribution?

A

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
Q

What did Kepler finally decide?

A

Orbits had to be ellipses

21
Q

Is the perihelion the short or long side?

A

Short

22
Q

Is the aphelion the short or long side?

A

Long

23
Q

What is Kepler’s first law?

A

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

24
Q

What is Kepler’s second law?

A

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

25
Q

What is Kepler’s third law?

A

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

26
Q

What was Thomas Digges’s contribution?

A

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

27
Q

What three things did Galileo dismantle?

A
  1. stellar parallax 2. non-circular orbits 3. Earth could not be moving because air would be left behind
28
Q

How did Galileo prove that the heavens were imperfect?

A

He detected sunspots on the sun and mountains on moon

29
Q

How did Galileo prove heliocentricity?

A

He used the phases of Venus

30
Q

What did the Julian calendar add?

A

Leap years

31
Q

What did the Gregorian calendar add?

A

Fixed leap years and timing

32
Q

What is the sidereal period?

A

The time it takes for a planet to orbit the sun

33
Q

What is the apparent solar time?

A

The time when the sun appears highest

34
Q

What is the mean solar time?

A

Average of all apparently solar times

35
Q

What is the synodic period?

A

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

36
Q

What is a tropical year?

A

time from one spring equinox to the next