Chapter 3

Question 1

Presolar Nebula

Answer 1

Condensed at about 4.6 Ga to give rise to our solar system.

Question 2

Hydrogen

Answer 2

Lightest and most abundant element in the universe.

Question 3

Jovian or outer planets

Answer 3

Largely made of hydrogen, with only small rocky cores.

Question 4

Terrestrial or inner planets

Answer 4

Iron cores surrounded by rocky mantles with denser elements like oxygen, iron, magnesium and silicon remaining in the inner part of the disk.

Question 5

Foci

Answer 5

Two special focus points, mathematically of an ellipse.

Question 6

Keplers third law

Answer 6

Length of time taken by objects to complete a single orbit around the Sun. He proposed that the square of the orbital period is proportional to the cube of the distance from the sun.

Question 7

1 astronomical unit

Answer 7

The average distance from the Earth to the Sun is about 150 million kilometres or 1.5 x 10 9 m.

Question 8

Comets

Answer 8

Mostly orbit very far out beyond the orbit of the planet Neptune, over 30 astronomical units from the Sun.

Question 9

Solar wind

Answer 9

Sun’s stream of energy and particles.

Question 10

Dwarf planets

Answer 10

Objects with diameters from about 850 km and up to about 2500 km. Includes Pluto.

Question 11

Asteroids

Answer 11

Objects that range in size from 1 m to about 850 km in diameter.

Question 12

Meteoroids

Answer 12

Chunks of solid material smaller than 1m in diameter.

Question 13

Meteors

Answer 13

Shooting stars as a result of meteoroids burning up as a result of friction with the atmosphere.

Question 14

Meteorite

Answer 14

A meteoroid or asteroid that makes it through the atmosphere to strike the Earth’s surface.

Question 15

Chondrites

Answer 15

Collections of small particles fused together, small sphere that appear to have been drops of liquid that existed in the presolar nebula or protoplanetary disk.

Question 16

Iron meteorites

Answer 16

Mixtures of iron and nickel and represent core of early asteroids, dwarf planets that disintegrated during early collisions in the Solar System

Question 17

Achondrite meteorites

Answer 17

Composed of silicate minerals - a combination of silicon, oxygen, iron, and magnesium mainly.

Question 18

Jovian planets

Answer 18

Neptune, Uranus, Saturn, Jupiter. Comprised of hydrogen and helium mostly.

Question 19

Terrestrial Planets

Answer 19

Mars, Earth (& Moon), Venus and Mercury. All have dense iron core mixed with nickel.

Question 20

Crust

Answer 20

The outer part of each planet, 5 to 120 km thick.

Question 21

Eccentricity of Earth’s Orbit

Answer 21

Ellipse with the sun at one focus.

Question 22

Milakovitch Cycle

Answer 22

Every 100,000 years, the eccentricity due to gravitational pull of Jupiter and Saturn varies between a low of .3% and a high of 6%.

Question 23

Obliquity of the axis

Answer 23

The axis is inclined to the place of the Earth’s orbit at an angle of 23.4 degrees.

Question 24

Earth’s shape

Answer 24

Oblate spheroid or ellipsoid of revolution, a slightly flattened sphere that looks circular when viewed from above the North or South Pole.

Question 25

Barycentre

Answer 25

Earth-Moon system rotates around its combined centre of gravity.

Question 26

Spring tide

Answer 26

when the Earth, Sun and Moon all lie in a straight line, the two effects reinforce each other. High tides are higher and low tides are lower.

Question 27

Neap tide

Answer 27

Then the Sun and the Moon are at 90 degrees apart in the sky, their effects work against each other. High tides are less high and low tides are less low.

Question 28

Plasma

Answer 28

A form of matter in which all electrons are separated from the atomic nuclei because of the high temperature.

Question 29

Sun

Answer 29

Radius is about 700,000 km, 109 times more than Earth. Mass is 300,000 times that of Earth or 10 to the 30th kg.

Question 30

Energy source of sun

Answer 30

Nuclear fusion.

Question 31

Photosphere

Answer 31

Visible surface of the sun.

Question 32

Sunspots

Answer 32

dark patches formed by turbulence within the Sun

Question 33

Solar Energy Flux or irradiance

Answer 33

Concentration of power is about 1365 W/m2 means every square metre of Earth’s surface could receive 1365 joules of energy per second.

Question 34

Insolation

Answer 34

Is the diluted energy flux that varies with latitude and with the seasons.

Question 35

Geothermal energy

Answer 35

Heat from within the earth. Either breakdown of radioactive substances inside the Earth, and leftover energy from the formation of the Earth during formation of the Solar System.

Question 36

Albedo

Answer 36

Incoming energy that is reflected back into space. For Earth it is about 30%

Question 37

Infra-red radiation

Answer 37

Heat that is reradiated also known as radiant heat.

Question 38

Greenhouse gases

Answer 38

Gases that absorb infra-red radiation

Question 39

Latent energy

Answer 39

Absorption of a lot of energy

Question 40

Photosynthesis

Answer 40

A process which occurs in the bodies of plants in which captured solar energy is used to split carbon dioxide from the atmosphere and store energy in carbon compounds.

Question 41

Respiration

Answer 41

The energy released to organisms in which carbon is recombined with oxygen and returned to the Atmosphere as carbon dioxide.