Lectures 1-15

Question 1

“Pale Blue Dot” was taken by what spacecraft?

Answer 1

Voyager 1

Question 2

Earth’s first artificial satellite

Answer 2

Sputnik

Question 3

Define “bootstrapping”

Answer 3

taking a known, measures quantity, and using it to infer the value of another quantity

Question 4

How have we known the size and distance of the moon for 2200 years?

Answer 4

Aristarchus of Samos measured the time it took for the moon to pass through Earth’s shadow during an eclipse and compared it to the time it took for the moon to move its own diameter in the sky

Question 5

What assumptions did Aristarchus of Samos make when measuring the size and distance of the moon?

Answer 5

1) Earth was a sphere

2) the sun is very far away- Earth’s shadow is straight

Question 6

A star’s parallax is defined by

Answer 6

one-half of the angular shift of the star over the course of a year

Question 7

One parsec is

Answer 7

the distance equivalent to one arcsecond (1/3600 degrees)

Question 8

Equation for distance in parsecs is

Answer 8

d=1/p(in arcseconds)

Question 9

1 parsec= ___ light years

Answer 9

3

Question 10

What is Gaia?

Answer 10

ESA spacecraft to measure space

Question 11

What was the Vanguard Project?

Answer 11

American rocket program. Was reinvigorated after the Russian success of Sputnik

Question 12

What is Newton’s First Law?

Answer 12

A body in motion stays in motion

Question 13

What is Newton’s Second Law?

Answer 13

F=ma

Question 14

What is Newton’s Third Law?

Answer 14

For every action, equal and opposite reaction

Question 15

Newton’s Law of Gravity

Answer 15

F=(Gm1m2)/d^2

Question 16

Equation for uniform circular motion

Answer 16

F=(m1 v^2)/d

Question 17

Equation for orbital velocity

Answer 17

sqrt(G M_earth/d)

Question 18

Energy, or work, is equal to

Answer 18

Force x distance

Question 19

KE=

Answer 19

.5mv^2

Question 20

PE=

Answer 20

(GmM_earth)/R_earth

Question 21

Escape Velocity=

Answer 21

sqrt((2GM_earth)/R_earth)

Question 22

What was Luna 1

Answer 22

Launched by the USSR in 1959 with the goal of impacting the moon- missed but first spacecraft in heliocentric orbit

Question 23

What is the Kessler effect

Answer 23

a scenario where the density of objects in LEO is high enough to be the catalyst for generating more collisions, which would create more space debris, which would cause more collisions…

Question 24

Pros of elliptical orbit

Answer 24

Allows operation further from Earth with close approach for data downlink

Question 25

Pros of polar orbit

Answer 25

Good orbit for mapping and surveillance

Question 26

Geostationary orbit is

Answer 26

Orbit that has same rotation speed as Earth

Question 27

Equations to find geostationary orbit

Answer 27

d^3=(P^2*G*M_earth)/(4*pi^2) | d includes radius of earth=6400 km

Question 28

The mass of a typical rocket is about ___ to ___ fuel

Answer 28

80 to 90

Question 29

Reasons against space elevator:

Answer 29

1) materials too heavy- will snap 2) materials too weak- snap under their own weight (carbon nanotubes?) 3) power supply issue- conventional means will snap under weight (lasers?)

Question 30

Period of orbit=

Answer 30

2*pi*R(r_earth+altitude)/V_orbit | V_orbit= sqrt(GM/d(altitude+6400 km))

Question 31

The first paper on Special Relativity involved

Answer 31

Length contraction and time dilation

Question 32

The second paper on Special Relativity involved

Answer 32

E=mc^2

Question 33

What did Einstein win the 1921 Nobel Prize for

Answer 33

The light-quantum hypothesis (light hits like a particle)

Question 34

Einstein's assumptions

Answer 34

1) laws of physics take the same form in all uniformly moving reference frames 2) in any uniformly moving reference frame, the velocity of light is the same

Question 35

Time dilation equation

Answer 35

t=t_rest/sqrt(1-v^2/c^2)

Question 36

Distance traveled by light equation

Answer 36

=2*d | where d is vertical distance, =2*sqrt(x^2+d^2)

Question 37

what is the equivalence principle

Answer 37

gravity and acceleration are equivalent

Question 38

Theory of general relativity states

Answer 38

gravity=curved space

Question 39

general relativity predicts

Answer 39

1) starlight will bend around sun | 2) Mercury's orbit will precess at a different rate than predicted by Newton

Question 40

Testing relativity with 2 predictions:

Answer 40

1) light around star should bend- measurable during solar eclipse 2) solar spectral lines should redshift

Question 41

Why gps would fail without relativistic physics

Answer 41

clocks tick faster because less gravitational field further out. Less gravity = time moves faster, canceling out speed difference

Question 42

All large telescopes (D>1 m) are reflective. Why?

Answer 42

Lenses are heavy and glass flows over time.

Question 43

What is the value of a bigger telescope?

Answer 43

Better light collection

Question 44

Why put a telescope in space?

Answer 44

No light pollution No weather No atmospheric turbulence No day night cycle

Question 45

How does Hubble make colored pictures?

Answer 45

Uses CCDs- filters in camera to select range of wavelengths that will be observed

Question 46

What is the photoelectric effect?

Answer 46

The property of light hitting electrons like a particle would

Question 47

Planks law equations

Answer 47

E=hf Or E= (hc)/λ

Question 48

Spectroscopy is a technique for

Answer 48

Sorting light into component colors

Question 49

In terms of light, why put telescopes in space?

Answer 49

Certain wavelengths can’t penetrate Earth’s atmosphere

Question 50

The Chandra observatory studied what kind of light

Answer 50

X-rays

Question 51

The spritzer space telescope used what kind of light and is in what kind of orbit

Answer 51

Infrared | Heliocentric

Question 52

If we want to see deeper into a cloud of gas, use longer or shorter wavelengths?

Answer 52

Longer

Question 53

Kepler’s laws state that

Answer 53

More distant planets orbit more slowly

Question 54

Terrestrial planet key properties

Answer 54

Close to sun Short orbital periods High densities Few if any moons

Question 55

Differentiation in planets:

Answer 55

Heavy metallic elements sunk to core, lighter minerals rose to outer layers

Question 56

Star formation takes place in

Answer 56

Molecular clouds

Question 57

Molecular clouds contain

Answer 57

Helium Hydrogen Volatile compounds Refractory materials

Question 58

How do cosmic dust particles grow?

Answer 58

They stick together naturally in low gravity

Question 59

How do we classify cosmic dust as planetesimal

Answer 59

When the clump reaches 1 km in size and exerts it’s own gravity

Question 60

What was the pioneer program

Answer 60

Missions from the 50s to 70s that were designed to reach escape velocity and launch lunar orbiters

Question 61

What was the mariner program

Answer 61

Missions to explore mercury, Venus, and Mars

Question 62

Why did mariner 1 have to abort

Answer 62

Rocket veered off course due to missing hyphen in flight code

Question 63

What is the Oort Cloud

Answer 63

Spherical distribution of comets and other debris at the outer bounds of the solar system

Question 64

The Galileo missions were a joint effort between the US and ____ with the goal of _____

Answer 64

Germany Study Jupiter

Question 65

Why is Io so volcanically active

Answer 65

Interior heating from tidal forces from Jupiter

Question 66

Europa’s smooth surface implies

Answer 66

Surface is relatively new

Question 67

Largest moon in the solar system

Answer 67

Ganymede

Question 68

Callisto is as large as

Answer 68

Mercury

Question 69

2nd largest moon in the solar system

Answer 69

Titan

Question 70

The only landing on another moon besides our own

Answer 70

The Huygens probe on Titan

Question 71

Cassini discovered what on Enceladus

Answer 71

Water geysers

Question 72

At the Roche limit, the tidal forces on the moon are so strong that it begins to

Answer 72

Break up

Question 73

Inside the Roche limit, material in a ring or disk can’t clump together to form a single satellite, because

Answer 73

The tidal forces are too strong

Question 74

why haven’t Saturn’s rings dissipated?

Answer 74

One theory is that the big rings were formed by a collision between moons, and they will eventually dissipate. Rings are also fed by material ejected from moons

Question 75

In 2006, the International Astronomical Union convened in Prague to set the definition of a planet and settle the question A planet within the solar system is a celestial body that

Answer 75

1. Orbits the Sun 2. Is massive enough for its self- gravity to give it a nearly round shape 3. Has cleared the neighborhood around its orbit

Question 76

Why was Pluto downgraded?

Answer 76

It’s very small, its moon is very large, it has a highly elliptical and inclined orbit