Monday, December 30, 2013

ASTRO 101 FINAL FLASH CARDS

Which two properties are most important in determining the surface temperature of a planet?

distance from the Sun and atmosphere

Rank the five terrestrial worlds in order of size from smallest to largest:

Moon, Mercury, Mars, Venus, Earth.

Which of the following most likely explains why Venus does not have a strong magnetic field?

Its rotation is too slow.

Which of the following does not have a major effect in shaping planetary surfaces?

magnetism

The relatively few craters that we see within the lunar maria

were formed by impacts that occurred after those that formed most of the craters in the lunar highlands.

The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that

he Caloris Basin formed toward the end of the solar system's period of heavy bombardment.

Olympus Mons is a

shield volcano on Mars.

Why does Venus have such a great difference in temperature between its "no atmosphere" temperature and its actual temperature?

It has a large amount of greenhouse gases in its atmosphere.

What are greenhouse gases?

gases that absorb infrared light

There are no aurora on Venus because it

lacks a strong magnetic field.

Where is most of the water on Mars?

in its polar caps and subsurface ground ice

Why is Mars red?

Its surface rocks were rusted by oxygen.

How does Jupiter's core compare to Earth's?

It is about the same size but is 10 times more massive.

The fact that most moons always show the same face to their planet is

a natural consequence of tidal forces acting on the moons.

What is the most important reason why an icy moon is more likely to be geologically active than a rocky moon of the same size?

Ice has a lower melting point than rock.

Why is Jupiter denser than Saturn?

The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn.

What is Jupiter's Great Red Spot?

a long-lived, high-pressure storm

The four Galilean moons around Jupiter are

a mixture of rock and ice, with the ice fraction increasing with distance from Jupiter.

Why are there no impact craters on the surface of Io?

Io did have impact craters but they have all been buried in lava flows.

Which moon has the most substantial atmosphere?

Titan

How thick are Saturn's rings from top to bottom?

a few tens of meters

Which is closest to the average distance between asteroids in the asteroid belt?

1 million km

Why isn't there a planet where the asteroid belt is located?

Gravitational tugs from Jupiter prevented material from collecting together to form a planet.

What do we call a small piece of solar system debris found on Earth?

meteorite

Halley's comet is named after the English scientist Edmund Halley because he

calculated its orbit and predicted that it would return in 1758.

What part of a comet points most directly away from the Sun?

The plasma tail

Most of the planets discovered around other stars

are more massive than Earth and orbit very close to the star.

What is astrometry?

measuring the positions of stars on the sky

Current techniques can measure stellar motion to less than

walking speed.

Why are many of the newly detected extrasolar planets called "hot Jupiters"

Their masses are similar to Jupiter but they are very close to the central star and therefore hot.

The core of the Sun is

hotter and denser than the surface.

What two forces are balanced in what we call gravitational equilibrium?

outward pressure and gravity

What is the average temperature of the surface of the Sun?

6,000 K

Which layer of the Sun do we normally see?

photosphere

At the center of the Sun, fusion converts hydrogen into

helium, energy and neutrinos.

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