Solar System and the Sun

Question 1

What is the solar nebula?

Answer 1

A collection of gas and dust from which the Solar System formed.

Question 2

What is a planetesimal?

Answer 2

A body of accreted gas and dust.

Question 3

What is accretion?

Answer 3

The process of growth by the gradual build-up of matter.

Question 4

What started the solar nebula collapse?

Answer 4

A trigger event such as a supernova explosion.

Question 5

Why do scientists believe that the solar nebula is a remnant of an earlier supernova explosion of a high mass star?

Answer 5

The gas and dust in the solar nebula included elements besides hydrogen and helium.

Question 6

How does the motion of planets and asteroids support the nebular hypothesis?

Answer 6

The orbits of planets and asteroids are counterclockwise in a relatively flat plane.

Question 7

What is the first step to the formation of planets?

Answer 7

Material outside the protostar begins to clump and stick together by electrostatic attraction.

Question 8

What is the second step that changes planetesimals into planets?

Answer 8

Larger particles form by collisions and gravitational attraction.

Question 9

What two properties define a planet?

Answer 9

Planets have a spherical shape and have gravitationally cleared the area around their orbit.

Question 10

What two characteristics got Pluto demoted from planet to dwarf planet status?

Answer 10

Pluto is too small and its orbit is highly irregular (too elliptical)

Question 11

What are two properties of the inner planets?

Answer 11

They are made from mostly silicates and metals (rocky planets). They are smaller than the outer planets.

Question 12

What are properties of the outer planets?

Answer 12

They are made from small hydrogen compounds in the gas state. They are large, have many moons and have ring systems.

Question 13

Which planets are considered inner planets?

Answer 13

Mercury, Venus, Earth and Mars

Question 14

Which planets are considered outer planets?

Answer 14

Jupiter, Saturn, Uranus, and Neptune

Question 15

What is the Kuiper Belt

Answer 15

An area of the solar system beyond the orbit of Neptune believed to contain dwarf planets, small rocky bodies, and some comets.

Question 16

What is the Oort Cloud?

Answer 16

An area at the outer part of the solar system from which many long-period comets originate

Question 17

What is a comet?

Answer 17

A ball of ices and dust that orbits the Sun

Question 18

How does the Sun generate energy?

Answer 18

Nuclear fusion of hydrogen into helium in its core

Question 19

What is the layer of the Sun outside its core? How does energy move through this layer?

Answer 19

The radiative zone is outside the core. Energy slowly radiates (plasma absorbs and emits photons of energy) from the core towards the convective zone.

Question 20

What is the outer layer of the Sun’s interior? How does energy move through this layer?

Answer 20

The convective zone is outside the radiative zone. Energy moves through the convective zone by convection (warm plasma rises and cool plasma sinks)

Question 21

What layer is considered the Sun’s surface?

Answer 21

The photosphere

Question 22

What layer of the Sun’s atmosphere is outside the photosphere?

Answer 22

The chromosphere

Question 23

What layer is considered the outer layer of the Sun’s atmosphere?

Answer 23

The corona

Question 24

What are features associated with the Sun’s magnetic field?

Answer 24

Sunspots, prominences, solar flares, and streamers

Question 25

Why does the Sun have a tangled magnetic field?

Answer 25

The “polar” areas of the Sun rotate at a different speed than the equator (differential rotation)

Question 26

What is a sunspot?

Answer 26

A cooler area on the Sun’s surface

Question 27

What is the sunspot cycle?

Answer 27

A change in the number of sunspots visible from nearly zero to over 100 then back to nearly zero over an 11 year period.

Question 28

Why is the fact that the corona has a higher temperature than the photosphere unique?

Answer 28

Temperature usually decreases as one moves away from the source of energy.

Question 29

Why do scientists monitor solar flares and coronal mass ejections?

Answer 29

Charged particles from the Sun can damage satellites, change orbits of satellites, and interfere with power transmission and electronics.

Question 30

What protects Earth from charged particles in the solar wind?

Answer 30

Earth’s magnetic field deflects most charged particles around the planet.

Question 31

What is an aurora?

Answer 31

An interaction of the solar wind with Earth’s atmosphere, which results in the emission of light