Final Review

How large is the Sun's radius, compared to the Earth?

108/109 earths

what is the sunspot cycle?

11 yr. cycle that goes to maximum area

What is the temperature at the Sun's core?

15 Million Degrees

Full moon occurs every __________ days.

28

the sun will exhaust its nuclear fuel in about....

5 billion years

What is the temperature of the sun's photosphere?

6000 degrees

How long does it take for light to travel from the Sun to the Earth?

8 Light Minutes

Who used the gravitational force to describe the motion of planets around the sun?

Newton

Name the layers of sun above photosphere.

Photosphere, Chromosphere, Corona

Why is the sun's energy produced only in the core?

Requires extreme heat which can only be founded in the core--so that nuclear fusion takes place

The name of the star that appears brightest in the NIGHT sky is

Sirius

Star A has apparent brightness 2 and Star B has apparent brightness 8. Which star appears brighter in the sky?

Star A (less to more)

An astronomical unit (AU) is defined as

average distance between sun and earth

What can we say about the size of the sun in the next 2-3 billion years?

it does not change

The corona of the sun is only rarely visible because

it emits very little visible light compared to the sun's photosphere

Sun is known as a normal star, but it appears very bright because

it is very close to the earth

why don't we see chromosphere all the time?

light emitted from the photosphere is TOO bright therefore it blocks & cant be seen

Light pollution is caused by

light from objects OTHER than we intend to observe

The total amount of energy a star gives off

luminosity

absolute brightness (M) depends on the...

luminosity (NOT DISTANCE) @ 10 pc

Most stars plotted on the H-R- diagram would fall into a region called

main sequence

The sun is known as a ..... star

main sequence

Stars that lie in different places on the main sequence of the H-R- diagram different from each other mainly having different

mass

Shooting star is a

meteor

Compared to the Jovian planets, on the average, terrestrial planets are

more DENSE and less MASSIVE

A star has apparent brightness 3 and absolute brightness 1. The distance to this star from the earth is

more than 10 pc

What is convection?

movement of material (air or liquid) from one place to another

Phase of the moon during SOLAR ECLIPSE is

new moon

Which of the following is NOT a telescopic discovery of Galileo?

new planet Pluto

Most abundant element of the earth atmosphere is

nitrogen

Astronomers identify the main sequence of the H-R- diagram with what activity in the course of a star's life?

normal life fusing hydrogen in to Helium

The sun produce energy by means of

nuclear fusion

the source of energy responsible for the Sun's high luminosity is....

nuclear fusion

The number of confirmed stars in OUR SOLAR SYSTEM

only 1

What force balance the gravity of the sun?

outward radiation force

the visible part of the sun is called...

photosphere

What model did Copernicus and Kepler have in common?

planets move around the sun

Luminosity depends on...

size & temperature

Resolution of how well you can observe distinct objects thru telescope depends on

size of the telescope

what is granulation?

small grain-like features that cover entire solar surface except for the sunspot regions

White dwarfs compare to main sequence of stars of SAME MASS would always be:

smaller

chromosphere is visible only during...

solar eclipse

what features appear occasionally above the sun's surface?

solar flares, prominences, and sunspots

Why doesn't the Sun collapse under its own gravity?

state of equilibrium

what can you say about the mass of the sun?

sun constantly losing mass--decreases

What force keep planets in their orbit around the sun?

sun's gravity

Color of stars depend on its

temperature

The horizontal axis of H-R- diagram plots...of stars

temperature

Asteroids revolve around

the Sun

Comets revolve around

the Sun

what is the color of the sun?

white & yellow (at peak intensity)

How far is the Sun from the Earth?

1 AU

In which ways can heat be transferred from a hotter to a colder region (with out Medium)?

Convection

What is the hottest part of the entire sun?

Core

Where does the Sun produce most of its energy?

Core

What region has the highest temperature above photosphere?

Corona

What are sunspots?

Dark patches on the surface

Babylonians used deferent and epicycles to explain the retrograde motion of planets. True or False

FALSE

Circumpolar stars never appear ABOVE horizon. True or False.

FALSE

Color of light depends on how FAST light travels. True or False.

FALSE

During emission of light electrons in an atom move from lower orbits to higher orbits. True or False

FALSE

Galileo is the first astronomer to suggest the sun is at the center of the solar system. True or False.

FALSE

Path of the sun among stars is called zodiac. True or False

FALSE

The objects that exhibit retrograde motion are planets and nearby stars. True or False.

FALSE

Who use the telescope to observe the sky first?

Galileo

The largest planet in our solar system is

Jupiter

Which planets' composition is most similar to that of the Sun?

Jupiter

What temperature of stars are expected to live the longest?

M (coldest)

In our solar system, which planet is NOT a member of the Jovian planets>?

Mars

According to Kepler's second law planets move FASTER when they are closer to the sun. True or False.

TRUE

Relative to the horizon, stars rise in the east and set in the west every day. True or False

TRUE

What is the photosphere?

Visible part of the sun

how old is the sun?

about 5 billion yrs. old

The atmosphere of Venus is

about 95% carbon dioxide

The magnitude of a star, based on how luminous, is its

absolute magnitude

AM and PM stand for...

before and after sun crosses the meridian

Most asteroids in our solar system lie

between Mars and Jupiter

Two stars, A & B, has same color. This implies that

both stars have the same temperature

How do we classify stars?

by temperature: O B A F G K M

What causes the greenhouse effect?

carbon dioxide

Composition of asteroids mainly

carbonates, silicates, or metallic

What is the solar wind?

charged particles ejected from surface of the sun

What is the main function of a telescope?

collect more light than our eye capable of

what causes the granulation?

convection; tops of deep gas columns where energy transported by convection

why do sunspots appear dark?

cooler spots & temp drop to about 4000 degrees

Why is one part of the Sun's interior called Radiation Zone?

core energy travels to surface by electromagnetic radiation

How do we measure distance stars using parallax method? What 2 measurements are required?

d = 1/p and (parallax angle & baseline needed)

Light year is used to measure

distance

apparent brightness (m) depends on the...

distance & luminosity

Apparent brightness of a star depends on its

distance and luminosity

What are the granules on the sun's surface due to?

due to convection currents

Mercury is heavily cratered. But we don't see that many craters on the earth. This is because

earth has thick atmosphere compared to Mercury

According to Copernicus planets appear to retrograde when

earth overtakes planets

What causes the day and night on the earth?

earth's rotation about its axis

According to Kepler, planets move around the sun in _________ orbits.

elliptical

Why is one part of the Sun's interior called Convection Zone?

energy transferred by moving gases

Origin of Comets is most likely

frozen objects from outer solar system

What is the most abundant element in the Sun?

hydrogen

what are the 2 main gases in the sun?

hydrogen & helium

The main sequence lifetime of a star with HALF the MASS OF THE SUN

is LONGER than that of the Sun