Schol SPACE

Question 1

What gives a planet a magnetic field?

Answer 1

Mobile conductive fluids.

Eg. Earth’s outer core of molten iron and nickel

Question 2

What is implied if a planet has a strong magnetic field?

Answer 2

It has a large liquid core
The core is rich in metals
High rotation rate

Question 3

What does earth’s magnetic field do?

Answer 3

protects the earth from high levels of radiation 

Prevents erosion of the atmosphere

Question 4

How does the magnetic field affect solar wind?

Answer 4

Solar wind = stream of energetic charged particles from the sun

Mag field deflects the charged particles. Channels some charged particles into the Van Allen radiation belts.

Solar winds cause the magnetic field to be compressed on the side closest to the sun, and extend far out away from it.

Question 5

Lack of magnetic field results in…

Answer 5

Eg Mars
Solar winds not deflected, strips away atmosphere so it is very thin. Low surface pressure

Question 6

Why does venus and Mercury have a weak magnetic field

Answer 6

Both rotate slowly (compared to earth)

No evidence of tectonic activity on Venus

Weak mag field on Mars suggests circulation of a molten iron core (due to eccentric orbit and large tidal forces)

Question 7

Define ‘locking’
Give an example

Answer 7

An object has the same rotational period as it’s orbital period

Eg moons generally have synchronous rotation with the planet (1:1 tidal locking)

Question 8

Tidally locked planets in the solar system

Answer 8

Generally only planets within close proximity of a star can be tidally locked

Mercury 3:2, as orbit is eccentric
(Rotates 3 times for every 2 orbits)

Question 9

Define habitable zone

Answer 9

Area around a star where the temp allows LIQUID water to exist on the surface of a planet

Depends on the type of star (eg red dwarf zone is closer to the star, likely to be tidally locked)

Question 10

Define tidal flexing

Answer 10

Occurs when interior of orbiting body subjected to FRICTIONAL FORCES because of the gravity of the thing it’s orbiting.

Question 11

Effects of tidal flexing on moons around gas giants (Jupiter)

Answer 11

Huge planet, large grav forces.

Cold, but friction creates heat… perhaps some moons are habitable

Effects of tidal flexing are amplified if orbit is eccentric.
Eg tidal bulges on Io (Jupiter’s closest moon). Close to planet, large bulge.

Question 12

Tidal locking and Io

Answer 12

Elliptical orbit and huge tidal forces. Variation of orbit causes variation in flexing, causes further friction.

Causes frictional heating of rocks into magma and VOLCANISM on the surface.

The most volcanically active body in the solar system due to huge tidal forces from Jupiter AND other large moons (Europa, Ganymede)

Question 13

Tidal locking and Enceladus

Answer 13

Icy, high albedo. BUT may have ocean under ice because of heating by tidal flexing, keeps water under the surface in liquid form.
Evidenced by plumes of water vapour and salty ice.
Possibility of geothermal vents due to flexing

—> extremophiles: potential for Chemotropic (and halotrophic) life forms… similar to those around geothermic vents. Plumes of water contain CO2, source of carbon.

Question 14

Tidal flexing and Europa

Answer 14

Thick ice on surface.
May be liquid water ocean under ice

Possibility of underwater volcanoes as a result of tidal flexing

Question 15

Requirements for life

Answer 15

Conditions that allow liquid water to be present
(warmth from sun/geothermal activity/tidal flexing)

A carbon source (C compounds for catabolism/anabolism)

Energy source to ‘fix’ inorganic C to organic. (Photosynthesis / chemosynthesis)

Protection from harmful radiation, and TIME for life to evolve (4 billion years for earth)

Question 16

Define chemosynthesis

Answer 16

Instead of energy from the sun, organisms use energy from oxidation of inorganic compounds to fix it into organic molecules.

Eg. Methanotrophes use CH4.
in deep sea vents oxidise H2S as an energy source, CO2 to C.

Question 17

What are extremophiles?

Answer 17

Microbes that live in extreme conditions on earth
(Intense heat, cold, pressure, acidity, dryness)

Question 18

Prokaryotic organisms

Answer 18

Bacteria, archaea (many extremophiles in the Archaea domain)

Question 19

Describe the features of Titan and possibility of life

Answer 19

Biggest moon of Saturn and the solar system.
The only other object with solid land, flowing rivers and lakes of liquid METHANE
—> methanotropic (methane using) or methanogenic (methane producing) reactions could occur.
Possibility of syntrophic relationship.

Methane based organisms (due to low temp) rather than water based.

Organic compounds are less soluble in CH4 than water, concentration gradients difficult to set up.
Specialised active-transport across membranes

Question 20

What are two ways that a body can gain an atmosphere?

Answer 20

Solar nebula - primary atmosphere. Mostly H and He.
Very light, required large gravity, only gas giants kept much of the early atm.

Volcanic - secondary atm.
Gases from the interior of the planet released.
Heavier H2O, CO2 easily retained

Question 21

How is an atmosphere lost?

Answer 21

Size - smaller gravity, lower escape velocity
Heat - more Ek, more molecules escape
Impact - large impact can blow away atm (like Mars)
Loss to surface - dissolved or condensed
Solar wind - lack of mag field strips atm away

Question 22

what are coronal mass ejections

Answer 22

giant solar flares
cause strong geomagnetic storms
may affect electronics on earth

Question 23

what are sunspots

Answer 23

small, dark regions on the sun’s surface containing strong magnetic fields
cooler than the rest of the sun
number varies over an 11 year cycle

Question 24

describe a lunar eclipse

Answer 24

Earth completely blocks the moon from the sun
moon is located in the umbra
some sunlight is bent through earth’s atmosphere, giving the moon a coppery glow

Question 25

Mercury main features

Answer 25

No atmosphere
Very slow rotation
–> very hot on one side, very cold on the other (rocky surface absorbs / loses heat quickly)

Question 26

Venus main features

Answer 26

very high surface temp due to thick atmosphere, 97% CO2
Thick dense clouds made of sulphuric acid and CO2
backwards rotation

Question 27

moon main features

Answer 27

very big for earth’s size
same side faces Earth – locked
no atmosphere
very little water
many visible craters - no atm = no erosion

Question 28

Mars main features

Answer 28

may have had liquid water (river beds)
thin atmosphere, 95% CO2, some methane
strong winds
extinct volcanoes and Valles Marineris show possible tectonic activity
two moons – possibly captured asteroids
also on a tilt – has seasons

Question 29

Jupiter main features

Answer 29

Mostly H
high speed winds
Great Red Spot
faint rings