ISP 205 Exam 2

Visions of the Universe Exam 2

What will happen to the temperature of an opaque gas cloud when it shrinks?

Increase

Transit Method

Why is the sky blue?

Earth's atmosphere scatters shorter, high-frequency wavelengths of sunlight, like blue and violet, more than longer wavelengths, like red and orange

Gravitational potential energy

energy an object possesses because of its position in a gravitational field.

The nebular theory

Explains planet composition differences by temperature gradients in the early solar nebula: hot inner regions condensed only metals and rock, while cooler outer regions allowed volatile ices.

Thermal energy.

Energy contained within a system that is responsible for its temperature.

Planetary orbits in our solar system are

fairly circular and in the same plane.

The composition of the solar nebula was 98%

hydrogen and helium.

Solar Nebula

A rotating disk of gas and dust that is the origin of our solar system.

Comet

Leftover ice-rich planetesimals

Asteroid

a small rocky body orbiting the sun made of rock and metal

Meteorite

A meteor that survives the Earth’s atmosphere and strikes the ground.

Which of the following did NOT occur during the collapse of the solar nebula?

Concentrating denser materials nearer the Sun

Which lists the major steps of solar system formation in the correct order?

collapse, condensation, accretion

How old is the Solar System?

4.5 Billion years

How many of the planets orbit the Sun in the same direction as Earth does?

All

What is Jupiter's main ingredient?

hydrogen and helium

Are there any exceptions to the rule that planets rotate with small axis tilts and in the same direction as they orbit the Sun?

Venus and Uranus are exceptions.

On average, Venus has the hottest surface temperature of any planet in the solar system.

True

Our Moon is about the same size as moons of the other terrestrial planets.

False

The weather conditions on Mars today are much different than they were in the distant past.

True

When scientists say that our solar system is about 4 billion years old, they are making a rough estimate based on guesswork about how long it should have taken planets to form.

False

Compare the graph in (Figure 1) to (Figure 2), which shows the decay of potassium-40. Which element is more radioactive (undergoes radioactive decay more quickly)?

uranium-235

What fraction of the original uranium-235 should be left after 3.5 billion years?

1/32

You find a mysterious rock on the ground and determine that 60% of its uranium-235 has been converted into lead-207. What is the most likely origin of the rock, based on its radiometric age?

It's a volcanic rock nearly a billion years old.

Doppler Effect

Change in the frequency of a wave as a result of relative motion between the wave's source and an observer

What can the transit method tell us about a planet?

its size

Based on the model types shown in the figure above, a planet made almost entirely of hydrogen compounds would be considered a

Water world

Planetary systems appear to be present around what percentage of stars?

Very common, 99%

What's the best explanation for the location of hot Jupiters?

They formed farther out like Jupiter but then migrated inward.

How long does it take the star and planet to complete one orbit around their center of mass?

4 days

What maximum velocity does the star attain?

50 m/s

How would the plot change if the planet were more massive (but remained at the same orbital distance)?

The peaks and valleys would get significantly larger (greater positive and negative velocities) because of larger gravitational tugs.

The larger the decrease in the star's brightness as the planet transits in front of a star, _______.

The larger the size of the planet