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