Astronomy Final Exam

Front 1

If a radioactive isotope were injected into your bloodstream, how many half-lives would youhave to wait before the amount of this isotope in your body is 1/16 its original amount?

Back 1

4

Front 2

A sunspot is a region on the surface of the sun that is ________ the photosphere of the sun.

Back 2

cooler and dimmer in visible light than

Front 3

What could happen in planetary systems where the nebular gas is quickly disbursed?

Back 3

Large ice-rich planetesimals would not be able to gather hydrogen and helium andbecome gas giants.

Front 4

If Earth had originally formed with less mass, it would likely have have a __________atmosphere and ____________ temperatures compared to now.

Back 4

thinner; cooler

Front 5

The carbon dioxide in Earth’s atmosphere is cycled back down into the mantle by

Back 5

plate tectonics.

Front 6

Which of the following is not a piece of evidence supporting the idea that Europa may havea subsurface ocean?

Back 6

Europa has a magnetic field that appears to respond to Jupiter's magnetic field

Front 7

Approximately what is the core temperature of the Sun that allows hydrogen fusion?

Back 7

10 million K

Front 8

What two physical processes balance each other to create the condition known asgravitational equilibrium in stars?

Back 8

gravitational force and outward pressure

Front 9

Eta Aurigae is a star with an apparent magnitude of m = +3.2, and is located 75 parsecsfrom Earth. The absorption lines in Eta Aurigae's spectrum are slightly redshifted, indicatingthat Eta Aurigae is:

Back 9

moving away from Earth

Front 10

Fusion requires high temperatures in order for nuclei to move quickly enough to:A. overcome gravity

Back 10

overcome electrostatic repulsion

Front 11

Earth has fewer impact craters than the moon because of

Back 11

its atmosphere

Front 12

Compared to the oldest surfaces on Mercury, the more recently developed surfaces have___________ craters

Back 12

fewer

Front 13

Which method could detect a planet in an orbit that is face-on to the Earth?

Back 13

astrometric (or “wobble”) method

Front 14

The planet in our solar system with the highest average surface temperature is _________.

Back 14

Venus

Front 15

5. How do scientists estimate how old the solar system is?

Back 15

They measure the abundances of radioactive elements in meteorites, and use theirhalf-lives to calculate the age.

Front 16

6. Imagine another solar system, with a star of the same mass as the Sun. Suppose a planetwith a mass twice that of Earth (2 MEarth) orbits at a distance of 1 AU from the star. What isthe orbital period of this planet?

Back 16

1 year

Front 17

When we say that jovian planets contain significant amounts of hydrogen compounds, wemean all the following chemicals except _________.

Back 17

carbon dioxide

Front 18

How do we know the mass of Jupiter?

Back 18

by measuring the periods and sizes of the orbits of the moons around Jupiter

Front 19

Which of the following discoveries would cause us to re-evaluate the nebular theory forforming planets?

Back 19

A star's 5 terrestrial planets orbit in the opposite direction of its 3 jovian planets

Front 20

Which of the following statements about the accelerations and gravitational forces betweena planet and a star is true?

Back 20

Forces are equal and opposite; the planet is accelerated more than the star.

Front 21

. If the freezing point of ices of all types were at a much lower temperature, what changewould that imply for the formation of our solar system?

Back 21

The gas giants would have to form at a larger distance.

Front 22

Pluto is different from the Jovian planets in all of the following ways except which one?

Back 22

It formed outside of the frost line in the solar nebula.

Front 23

. Which of the following best explains why many jovian moons have been more geologicallyactive than the Moon or Mercury?

Back 23

Jovian moons are made mostly of ice that can melt or deform at lower temperaturesthan can the rock and metal that make up the Moon and Mercury

Front 24

Which of the following statements does not lend support to the idea that carbon dioxide is acause of global warming?

Back 24

Isotope ratios in atmospheric carbon dioxide show that much of the carbon dioxide inEarth's atmosphere today comes from the burning of fossil fuels.

Front 25

What kind of radiation shines out of the core of the Sun?

Back 25

Gamma rays

Front 26

Why is the sky blue?

Back 26

Air molecules scatter blue light more than red light.

Front 27

Suppose you could float in space just a few meters above Saturn's rings. What would yousee as you looked down on the rings?

Back 27

countless icy particles, ranging in size from dust grains to large boulders

Front 28

9. If Earth passed through the tail of a comet, what would happen?

Back 28

A meteor shower would occur.

Front 29

What is the source of Earth's magnetic field?

Back 29

Molten metal circulating inside of Earth, moving electrons like in a wire