SCI101 Unit 4 Test

A protostar heats up internally because

gravity increases the density, pressure, and temperature.

How can a red giant become brighter if it now has a lower surface temperature? It

has much more surface area radiating light

What are the two forces that keep a star in a balanced, stable condition while it is a main sequence star?

high temperature expansion and gravitational contraction

What is the difference between apparent magnitude and absolute magnitude?

(2 ANSWERS) -apparent magnitude is a measure of how bright a star appears in the sky -absolute magnitude calculates the brightness based on the stars being the same distance away

Why is it very unlikely that there is life on Mercury?

(3 ANSWERS) -Mercury has extreme temperatures. -Mercury's atmosphere is composed of inert gases. -Mercury has only a trace of atmosphere.

The giant planets

(3 ANSWERS) -are Jupiter, Saturn, Uranus, and Neptune. -are mostly composed of hydrogen, helium, and methane. -have deep layers of compressed gases over a rocky core.

Distinguish between asteroids and meteoroids.

(3 ANSWERS) -most asteroids follow orbits between Mars and Jupiter. -Meteoroids originate from outside of Neptune's orbit. -In general, asteroids are larger than meteoroids.

What remains uncertain in the protoplanet nebular model?

(3 Answers) -why the planets formed where they did -why the accretion disk did not remain a disk -why inner planets are rocky and outer planets are gaseous

Why are astronomical distances not measured with standard referent units of distance such as kilometers or miles?

-Astronomical distances are so large that kilometers or miles would result in huge numbers -Kilometers or miles would have little meaning since there are no referent points for comparison. -It makes more sense to measure astronomical distance in the terms of time, such as the light-year. -THE ANSWER IS ALL OF THE ABOVE

The Milky Way Galaxy has

-a spherical concentration of stars at the center called the galactic nucleus. -spirals in a disk about 100,000 light years across. -clusters of a thousand to a million stars that move together -(ANSWER IS ALL OF THE ABOVE)

The giant red spot on Jupiter

-has lasted at least for three hundred years -is the most powerful storm on Jupiter. -is the coldest place on Jupiter (ANSWER IS: ALL OF THE ABOVE)

What are "shooting stars"?

-mostly dust particles heated by atmospheric compression -a meteor burning in earth's atmosphere -particles hitting the atmosphere that melt into a visible trail of light and smoke (ANSWER IS ALL OF THE ABOVE)

Terrestrial planets do not have an atmosphere of hydrogen and helium becuase

-the sun blasted it away when fusion started -they never did have such an atmosphere -hydrogen and helium collected in the outer solar system. (ANSWER IS: ANY OF THE ABOVE MIGHT BE CORRECT)

The standard time zones of Earth's surface are how wide in units of time?

1 hour

The big bang that gave rise to our universe happened about

14 billion years ago

The standard time zones of Earth's surface are how wide in degrees?

15 degree

Examination of lunar rocks indicates that all igneous activity on the moon stopped about

3 billion years ago

What is the parallel of the Antarctic circle?

66.5 S

Why is an average star like the Sun unable to have carbon fusion reactions?

A more massive star is needed to reach critical temperature.

What event marks when a protostar becomes a star?

A nuclear fusion reaction begins

How do the orbits of the periodic comets compares in shape with the orbits of the planets?

All the orbits are ellipses, but those of comets are long and narrow whereas those of planets are more nearly circular.

What identifies the northern limit toward the equator where the Sun appears on the horizon all day for at least once during the summer?

Arctic circle

What is believed to be the origin of the asteroids?

Asteroids are believed to be leftover matter from the early solar system that never became part of a large body because of the gravitational influence of nearby Jupiter.

In what part of the star are gases heated from below, expand and rise, and then contract and sink again?

Convection Zone

What is the very hot part of an average star where nuclear fusion reactions release gamma and X-ray radiation?

Core

Which statement below correctly identifies the differences and similarities between planets, dwarf planets, and planetary satellite?

Dwarf planets are much small than. Planets and dwarf planets are spherical in shape and orbit the sun, but satellites do not orbit the sun. Both planets and dwarf planets can have satellites.

True or False: the most likely explanation for the origin of the moon states that the moon split away from Earth.

False

What evidence exists in the protoplanet nebular model that protoplanets underwent heating?

Heavy and light minerals are separated inside planets.

Why does a less massive star have a longer life span?

Higher pressure at the core of a massive star means a faster fusion reaction.

Where is the mass of the solar system concentrated?

In the sun

Which planets have rocky and iron cores surrounded by a thick layer of frozen hydrogen, a deep layer of liquid hydrogen, and then an atmosphere above with a banded appearance from a mixture of sulfur and organic compounds in ammonia clouds?

Jupiter and Saturn

What is a major, significant difference between the Sun and Jupiter?

Jupiter does not have enough mass to create the condition needed for fusion.

Which is the largest planet (in km)? The smallest? Which planet is nearest the sun?

Jupiter; Mercury; Mercury

How does the protoplanet nebular model account for the differences in terrestrial and giant planets?

Light gases of terrestrial planets were blasted away by flare-up of the Sun.

Oxygen is a major component of Earth's atmosphere, but not other planets. Why is this?

Living things that produce oxygen developed in Earth's ocean, but not on other planets.

What event must occur first according to the protoplanet nebular model?

Many stars live out their life cycles.

Considering the properties of planets other than the Earth, which seem to have the greatest of life as we know it?

Mars

Which of the following planets has a surface with inactive volcanic regions, huge systems of canyons, flat regions pitted with craters, and channels that appear to be riverbeds?

Mars

Which planets, if any, have no satellites?

Mercury and Venus

What has been the chief influence that shaped the lunar landscape during the past 3 billion years?

Meteorite Impacts

Why are few asteroids spherical, as planets are?

Most asteroids are too small for gravity to have pulled them into spheres.

What is the moon phase that is observed when the Moon is located between the Earth and the Sun, but not directly between?

New Moon

Are rock fragments that strike the Moon correctly called meteorites?

No, according to the definition a rock must strike Earth to be called a meteorite.

Do galaxies become larger as the universe expands?

No, it is space between the galaxies that is expanding, not galaxies.

Which planets have ring structures?

Saturn, Jupiter, Uranus, and Neptune

Which of the following does not support a big bang theory of the universe?

Some people have calculated that Earth is about 6,000 years old

What are two massive bodies in the solar system that radiate more heat than they absorb?

Sun and Jupiter

Why do these tails usually point away from the sun, even when the comet is receding from it?

The direction of the solar wind is always radially outward from the sun.

How does Pluto compare in size with our moon? With the satellites of the other seven planets?

The moon and six other satellites are larger than Pluto.

We always see the same hemisphere of the moon. Why?

The moon rotates on its axis with the same period as that of its revolution with respect to the earth.

What, if anything, is the meaning of the Hubble classification scheme of galaxies?

The shapes are a result of the conditions under which the galaxy formed.

Why do comets have tails only in the vicinity of the sun?

The tail of a comet is formed by the pressure of the solar wind; its effect is too small to produce a tail far from the sun.

Which planet resembles the earth most in size and mass? In surface conditions?

Venus ; Mars

Give two reason why the surface of Venus is so much hotter than the earth's surface.

Venus is closer to the sun and its carbon dioxide atmosphere promotes a very effective greenhouse effect.

What is a red giant star?

a bright, low-temperature star that is very large

The most probable source of particles making a meteor shower is

a comet

What is the main sequence on the Hertzsprung-Russell diagram?

a narrow band of stars from bright blue to dimmer red stars

What is a meteorite?

a rock that fell to the surface of Earth

The brightness of a star at a define, standard distance is the

absolute magnitude

If the edge of the Sun forms a bright ring around the Moon it is called an

annular solar eclipse

A classification scheme for different levels of brightness observed from a star is

apparent magnitude

Giant Planets

are mostly composed of hydrogen, helium, and methane

A star with a mass of at least 3 solar masses uses all the fuel at its core, which undergoes a gravitational collapse and the force of gravity overwhelms all other forces. This has formed a

black hole

The variations in the number of daylight hours throughout a year is caused by:

constant tilt of Earth's axis relative to plane of the ecliptic

What is not true about the structure of an average sized star? The star has a

convection zone with density of molten iron.

Nuclear fusion reactions take place in what part of a star?

core

What evidence exists today that the number of rocks and rock particles floating around in the solar system was much greater in the past?q

craters on terrestrial planets and moons

What evidence exists that Mars at one time had abundant liquid water?

dry river beds and channels

When are daylight and night of equal length? On the:

equinox

From where do comets originate?

from the surrounding outer regions of the solar system

What is the source of all the elements in the universe that are more massive than helium, but less massive than iron?

fusion in a massive star

What is the one thing that determines where a star is located on the main sequence?

mass

What does the position of a star on the Hertzsprung-Russell diagram suggest about a star?

mass and age

A streak of light and smoke from a rock falling through the atmosphere is known as a

meteor

Which of the following is evidence that Earth moves?

movement of a Foucault pendulum

A massive star uses all of its energy sources, and then collapses in a supernova. If the remains after the supernova are between about 1.4 and 3 solar masses, the remaining matter is compressed so much that the nuclei of all atoms collapse , forming a core of pure neutrons. This forms a

neutron star

Spring Tides:

occur during a full or a new moon

What are the rings of Saturn?

particles ranging in size from dust to boulders

Which of the following describes the correct order of events in the life of a star?

protostar, main sequence, red giant, supernova, black hole

What is the sequence of stages in the life history of a star with an average mass like the Sun?

protostar-main sequence-red giant-white dwarf-lump of carbon

What is the part of an average star composed of plasma with approximately the same density as water ,where energy from gamma and X-ray radiation is absorbed, then moves from particle to particle?

radiation zone

This low-temperature star forms as hydrogen in the core runs out and the star begins to collapse. Hydrogen in the outer layers becomes hot enough to fuse, so the star expands. This forms a

red giant

Why does a comet appear bright in the night sky?

reflected sunlight from dust and fluorescent light from ionized gases

What is the most likely source of meteorites?

rocks from the collisions of asteroids

What are asteroids?

rocky or iron bodies in a belt between Jupiter and Mars

When the Sun stops increasing or decreasing its altitude the event is known as:

solstice

The planet Venus

spins backwards to its direction of movement in its orbit

What is the Hertzsprung-Russell diagram?

star spectral type versus the brightness

A rebound explosion from the catastrophic collapse of a massive star that has run out of fuel is a

supernova

A violent flare-up of a star for a short time is called a

supernova

What is the source of all the elements in the universe that are more massive than iron?

supernova

The different colors of stars are a result of differences in

surface temperature

What is a light-year? A light-year is

the distance that light travels during one year.

Why doesn't an eclipse of the Sun occur at each new moon when the Moon is between the Earth and the Sun?

the plane of the Moon's orbit is tilted to the plane of the Earth's orbit

Why are astronomers so interested in studying the physical and chemical structures of comets?

they are believed to be leftover materials from the formation of the solar system

What identifies the limit toward the North Pole of where the Sun appears directly overhead sometime during the course of a year?

tropic of Cancer

What identifies the limit toward the North Pole of where the Sun appears directly overhead sometime during the course of the year?

tropic of Cancer

A red giant the mass of the sun or less loses heat from its core, and then undergoes expansion cooling and expansion heating until the matter surrounding the core is blown away in a violent explosion. This leaves a

white dwarf

A solstice marks the beginning of the:

winter or summer season

Which size of start has the longest life span? A star

with a mass of one twenty-fifth of the sun