Solar Systems

Question 1

Give some differences between terrestrial and jovian planets.

Answer 1

Terrestrial: Less than 2AU from Sun
Small
Mostly rocky materials
High Density

Jovian: More than 5AU from Sun
Large
Mostly light H and He
Low Density

Question 2

T or F. Mercury has no atmosphere.

Answer 2

True.

Question 3

What is the primary element in the atmosphere of Venus and Mars?

Answer 3

Carbon Dioxide.

Question 4

Formula for kinetic energy of a gas atom or molecule.

Answer 4

E = ( 3 / 2 )* (B) * T

E = energy
T = temperature
B = Boltzmann Constant

Question 5

Formula for average speed of a gas atom or molecule.

Answer 5

root( 3 * (B) * T / m)

where T = Temperature
m = mass
B = Boltzmann Constant

Question 6

T or F. All the jovian planets have rings.

Answer 6

True.

Question 7

How are planetary rings formed?

Answer 7

When a satellite passes inside the roche limit, the tidal forces overwhelm the gravitational forces that hold the satellite together. The fragments are spread about the planet by Kepler’s third law.

Question 8

How is the Roche limit of a planet calculated?

Answer 8

2.4 * radius

Question 9

Name two features of Jupiter.

Answer 9

Aurorae on its poles
Great red spot

Question 10

T or F. Jupiter’s atmosphere does not seem to suffer significant changes over the years.

Answer 10

False.

Question 11

T or F. The smallest size of the Great Red Spot is one earth diameter.

Answer 11

True.

Question 12

What is unique about Uranus?

Answer 12

Its axis of rotation is fully tilted with the equatorial plane perpendicular to the orbital plane.

Question 13

T or F. Despite its rotation being tilted, all of Uranus’ satellites still orbit around Uranus along the orbital plane.

Answer 13

False.

Question 14

Why are features not easily seen on the surface of Uranus?

Answer 14

Features form in the troposphere closer to the surface.

Question 15

T or F. If you wanted to see planets in Dublin’s night sky you should look at the ecliptic?

Answer 15

True.

Question 16

T or F. From the terrestial planets, only Venus and Earth have atmospheres.

Answer 16

False.

Question 17

T or F. Venus has no magnetic field.

Answer 17

True.

Question 18

T or F. Mars and Mercury have magnetic fields though weak.

Answer 18

True.

Question 19

T or F. The magnetic field of Earth is of moderate strength like Mars.

Answer 19

False.

Question 20

Name four methods for detecting exoplanets.

Answer 20

Radial velocity or ‘stellar wobble’ method.
Astrometric method
Transit Photometry
Direct Imaging

Question 21

Explain how radial velocity method works.

Answer 21

If a star has companions, then the wavelengths of the stars spectral lines get Doppler shifted, since the star has motion relative to the centre of mass of the solar system.

The magnitude of the wobble determines the companion minimum mass, the period determines the semimajor axis.

Question 22

Explain how transient method works.

Answer 22

When the planets passes in front of the star, the amount of dimming tells us the planet’s diameter, additional absorption features reveal the composition of its atmosphere.

When the planet moves behind the star the amount of infrared dimming tells us the planet’s surface temperature.

Question 23

What is the habitable zone for our solar system?

Answer 23

0.95 Au to 1.37AU

Question 24

T or F. The transient method can help us measure mass, radius, density, orbit and atmosphere of a planet around a star.

Answer 24

True.

Question 25

T or F. The habitable zone is a fixed range of distance for any one star.

Answer 25

False. As temperature/size of star fluctuates so does this zone.

Question 26

Give the four conditions for a dwarf planet.

Answer 26

a) is in orbit around the Sun b) nearly round shape c) has not cleared the neighborhood around its orbit d) Is not a satellite

Question 27

What is unique about Pluto?

Answer 27

Pluto is a dwarf planet which forms a binary system with Charon a moon, where Charon's gravitational pull is not negligible compared to Pluto's.

Question 28

Size range for asteroids.

Answer 28

between few kilometres up to 1000km in diameter.

Question 29

What does it mean for a comet to be active?

Answer 29

Means near the sun.

Question 30

What is sublimation?

Answer 30

Heating of icy nucleus to form coma, ion tail created by solar wind and dust tail created by solar wind and sunlight.

Question 31

T or F. Comet tails always point away from the sun.

Answer 31

True.

Question 32

What is a prograde orbit? Which comet is more likely to have a prograde orbit near ecliptic plane?

Answer 32

When orbitting body moves with same direction of rotation as what it orbits. Short-period.

Question 33

T or F. Retrograde orbit comet originates in Oort Cloud.

Answer 33

True.

Question 34

Age range for short period comet.

Answer 34

< few centuries

Question 35

What is a sungrazing comet?

Answer 35

Comet with perihelion at less than 0.01AU

Question 36

How far does the Oort cloud extend?

Answer 36

50000AU

Question 37

Define meteoroid.

Answer 37

A meteoroid is a small object moving across the Solar System.

Question 38

Define meteor.

Answer 38

A meteor is the brief flash of light that is visible when a meteoroid enters Earth's atmosphere. For meteoroids less than 10m wide heat vaporises it.

Question 39

What is a meteorite?

Answer 39

Piece of rock that has survived the descent through Earth's atmosphere and has reached the ground.

Question 40

What is meteor swarm?

Answer 40

The residual dust and rock fragments left by the tail of a comet are called meteor swarm. Lead to meteor showers.

Question 41

T or F. Dwarf planets have in common that they have orbital inclinations greater than that of the main planets.

Answer 41

True.

Question 42

What are the Kirkwood gaps?

Answer 42

Regions with fewer asteroids.

Question 43

Formula showing how we calculate planets radius using transient method.

Answer 43

fraction of light blocked = (R planet / R star )^2

Question 44

T or F. Jovian planets spin much slower than Earth.

Answer 44

False.

Question 45

Why do the Jovian planets primarily retain their atmospheres?

Answer 45

Large mass

Question 46

What is the name used to describe the dark bands encircling Jupiter?

Answer 46

Belts

Question 47

Why has direct imaging found so few exoplanets?

Answer 47

Exoplanets are faint and are usually close to their parent stars.

Question 48

Space telescopes looking for transiting planets look for small drops in brightness; these drops are:

Answer 48

Less than 0.01%

Question 49

The habitable zone is the area around a star where:

Answer 49

temperatures are suitable for planets to have liquid water

Question 50

When looking for the radial velocity changes or ʺwobblesʺ detected due to Doppler shifts, which mass combination is most likely to be detected? Question options: high mass star, high mass planet a high mass planet, the mass of the star is irrelevant low mass star, high mass planet low mass star, low mass planet high mass star, low mass planet

Answer 50

low mass star, high mass planet

Question 51

Neptune and Uranus have a bluish tint because: Question options: their atmospheres contain hydrogen and helium at their distances, the Sun appears blue, the red absorbed by dust in the ecliptic their atmospheres contain methane, which absorbs red light ammonia ice reflects blue light better than any other color. they are far away and distance makes objects appear bluish

Answer 51

their atmospheres contain methane, which absorbs red light

Question 52

Why is it easier to discover transiting exoplanets, especially small ones, with a telescope in space than with a ground-based telescope? Question options: A.- Because of the longer exposure times available in space C. - Because we can build larger telescopes B.- Because of the lack of atmosphere A and B B and C The original statement is wrong, ground-based telescopes are better

Answer 52

A and B

Question 53

A moon that goes inside the Roche Limit will: Question options: become a planet. get heated by the strong magnetic fields. be torn apart by the planetʹs tidal forces. escape its planetʹs gravity. collide with a major satellite.

Answer 53

get heated by the strong magnetic fields.