Astronomy Exam 3 Cooney

How much larger is the diameter of Jupiter than the earth?

11 times larger

Why must the core of Jupiter be able to conduct electricity?

Because it has magnetic fields

What supplies the heat to drive the volcanoes on Jupiter's moon Io?

Tidal effect from Jupiter creates tidal heat energy

Given 4 moons with the same diameter would a moon with a 1 g/cc or 2 g/cc density have the lowest escape velocity?

1 g/cc

What did the Galileo/ Cassini mission to Jupiter/Saturn do?

Studied the planets, moons, magnetospheres, etc.

What element are both the Sun and Jupiter mostly made of?

Hydrogen

In which planet(s) may liquid hydrogen give a magnetic field?

Jupiter and Saturn

What is the density of Jupiter?

1.33 g/cm^3

Which planet has the largest mass?

Jupiter

What is the density of water?

1 g/cm^3

What is the density of iron?

7.874 g/cm^3

What is the shape of Jupiter's orbit around the sun?

Ellipse

Can liquid metallic hydrogen conduct an electric current?

Yes

Why are fewer craters on Io or Europa than Callisto or Ganymede?

Because Io has lots of active volcanoes and Europa is covered by ice

Why does the apparent angular diameter of Jupiter change with time?

Because our distance from Jupiter changes and when you are farther away from an object it appears smaller and vice versa

Does an electric current generate a magnetic field?

Yes

Which planets have rings that have been observed?

Jupiter, Saturn, Uranus, and Neptune

What did Galileo observe about Jupiter that suggested that all objects in the solar system didn't revolve around the earth?

He observed moons orbiting Jupiter

Is it possible to stand on the surface of Jupiter?

No

What is the size of Jupiter's magnetosphere?

150-200 Jupiter radii

Why is Io denser than Callisto?

Io is warmer and therefore more dense than icy Callisto

How many moons does Jupiter have?

63

Does Jupiter have a ring?

Yes

What is the Great Red Spot?

An atmospheric storm in Jupiter's southern hemisphere

What is Jupiter's rotation period?

9.8 Earth hours

Why has Jupiter retained most of its original atmosphere?

Because its large mass and cold temperatures prohibit atoms and molecules from attaining escape velocity

What is responsible for Jupiter's enormous magnetic field?

Metallic hydrogen created Jupiter's electric current

On which of Jupiter's moons might there be liquid water?

Europa

What could keep the water from freezing on Europa?

Heat energy from tidal flexing

Why does Callisto have more craters than Europa?

Callisto is not volcanically active and cannot cover craters with lava

What comes out of Io's volcanoes?

Sulfur

Is water ice common on the moons of Jupiter?

Yes

How long does it take Jupiter to go past a zodiac constellation?

1 year

Can Saturn's brightest moon, Titan, be seen with an 8" telescope?

Yes

What would happen to Titan if it came inside Saturn's rings?

It would be torn apart by tidal forces

Where does Saturn's moon Titan orbit Saturn?

Beyond the rings

Which planet has the most obvious rings as viewed from the earth?

Saturn

How can we tell from naked-eye observations that Saturn is the most distant of the 5 inner planets?

It's motion relative to other stars is much slower than the closer planets

A one cubic centimeter piece of Saturn's moon Enceladus is taken to earth and found to have a mass of one gram. What is it made of?

Water ice

What happens to a moon if it gets inside the Roche limit?

It is torn apart by tidal forces

Are Saturn's rings solid bands?

No

Which is denser? Saturn or water?

Water

Which moon in the solar system has a substantial atmosphere?

Titan

How many moons does Saturn have?

62

Name four planets that Voyager 2 photographed

Jupiter, Saturn, Uranus, and Neptune

What happens to the volume of water when it freezes?

It increases

Why can Titan have an atmosphere while no other moons in the solar system do?

It is large and cold enough so atoms and molecules can't attain escape velocity. Also some say it was a captured planed and was not created by Jupiter.

What are the clouds in Titan made of?

Methane and ethane

What is Titan's surface temperature?

-290 degrees F

How big is Titan versus our moon?

30 billion times larger

How long is Saturn's day?

10-11 Earth hours

Which is denser? 34 degrees F water or 30 degrees F ice?

Water

What sets a limit in the size crater that can occur on a moon?

If the crater is too big it will blow the moon apart

What allows Saturn to emit more heat than it receives from the sun?

Helium precipitation

What is the Roche limit?

The closest an object can get before a planet's tidal forces tear it apart

What causes the gaps in Saturn's rings?

The rings are made of particles of ice which orbit Saturn individually. The particles closer to Saturn orbit faster and cannot connect to particles farther away, creating gaps

Which is larger on Saturn, equatorial or polar diameter?

Equatorial diameter

How does the surface gravity on Titan compare to the Earth's?

Titan: 1.352 m/s^2|Earth: 9.78 m/s^2

What is helium precipitation?

When the helium on Saturn dissolves from the surrounding hydrogen and then turns into liquid helium much like water turns to mist on earth

What generates heat inside Saturn?

Slow gravitational compression and when droplets of helium descend through the lower density hydrogen and creates friction which creates heat

At what temperature does helium become a liquid?

4.2 k

What is the Cassini division?

The apparent gap in Saturn's rings created by the moon Mimus which periodically nudges particles out what try to enter the gap

When did the Cassini spacecraft arrive at Saturn?

2004

What technique has been used to boost spaceships into the outer solar system?

Planetary slingshots

The axis of rotation of what planet is almost in the same plane as the orbit of the planet?

Uranus

Neptune's moon, Triton, had a retrograde orbit which is slowly spiraling in, due to tides. If no one intervenes, what will eventually happen to Triton?

It will be torn apart by tidal forces

How was the location of Neptune predicted in 1846?

Astronomers were trying to explain why Uranus's orbit differed from the one predicted by Newton's laws of gravity

Which planet was found using Newton's theory of gravity?

Neptune

Where in the solar system have active volcanoes been seen?

Earth, Jupiter's moon Io, Neptune's moon Triton, and Saturn's moon Enceladus

Will seasonal changes on Uranus be more or less extreme than on earth? Why?

More extreme because Uranus's tilt makes each season last 20 years and the sun only shines on one pole, making the other side frigid and dark

The sun appears to be 30 minutes of arc across from earth. How big does it appear to be from Neptune?

One minute of arc

Why did Voyager cameras use longer exposures for Neptune than Jupiter?

Because the light from the sun is barely one thousandth the brightness at earth

How were the rings of Neptune an Uranus first seen?

Stellar occultation

Does Triton orbit around Neptune in the same direction of Neptune's rotation?

No

What might have caused the frozen lake on Triton?

Liquid nitrogen geysers make a pool and it freezes

Which planet has more distinctive cloud patterns, Uranus or Neptune?

Neptune

Which planet is closest in size to Neptune?

Uranus

Where are liquid nitrogen geysers found?

Neptune's moon Triton

Are planetary magnetic fields lined up with the rotation axis?

no

What are Neptune's moon Triton's geysers made of?

heated nitrogen and methane

What is unusual about the rotation of Uranus?

its axis is almost on the same plane as its orbit plane

Does Neptune's moon Triton cause tides on Neptune?

yes

What is responsible for the colors of Uranus and Neptune?

the methane gas in their atmospheres

Do Uranus and Neptune have magnetic fields?

yes

Is Neptune frozen solid or does it have weather?

it has weather

What is unique about Miranda?

it has very diverse terrain

Between which 2 planetary orbits are most asteroids found?

Mars and Jupiter

Giuseppe Piazzi discovered the asteroid Ceres in 1801. What is its diameter?

974 km

Which planet has the most effect on comet and asteroid orbits?

Jupiter

The semi-major axis of Halley's comet is 18 AU. Calculate its orbital period.

T^2=18^3

76.368 years

A comet with a semi-major axis of 10 AU is seen in 1996. When will it return?

T^2=10^3

31.623 years

What are comets mostly made of?

ice

What is a meteor shower radiant?

the point in the sky from which meteors appear to originate

On the night of December 13, 50 meteors per hour should be visible from the Geminid meteor shower. All meteors will appear to come from the constellation Gemini. Why?

because the asteroid the meteors came from used to orbit there

What will the Geminid meteors be composed of?

comet dust

What has been found in 63 million year old layers of clay at several places on the earth that suggests that the impact of an asteroid may have caused the extinction of dinosaurs?

Iridium

If comets are made of iron and not ices, would they grow tails as they pass the sun?

no

What is unusual about meteorite surfaces?

their surfaces look melted

How can you tell an asteroid from a star using a telescope?

by measuring the distances between the stars, if the distances change then one is an asteroid

What may have caused the extinction of the dinosaurs?

impact from a giant asteroid