Question | Answer |
____ are small, planetlike bodies. | Planetesimals |
The Big Bang theory states that ____________. | all matter in the Universe was once confined to a single point |
In our current understanding of the Big Bang, ____________. | the Universe is considerably older than Earth |
Heat left over from this planetary formation process along with radioactive decay, drives the Earth's internal heat engine. | differentiation |
The four planets nearest the sun are basically balls of rock and include ____. | Venus |
The Earth's atmosphere is rich in _____, a product of plant photosynthesis. | oxygen |
Mars is named for the Roman god of war, presumably because of its distinct _____ color when seen in the sky. | red |
The gas giant, or Jovian, planets are ____________. | Jupiter, Saturn, Uranus, and Neptune |
Biological processes have removed most of the _______ from the Earth's atmosphere. | carbon dioxide |
The inner planets are sometimes called the terrestrial planets because of their resemblance to ____. | Earth |
When 17th century astronomer _______ first viewed Jupiter with his telescope he saw four satellites orbiting the planet. | Galileo |
In agreement with the Big Bang theory, our Universe is ____________. | expanding |
To the best of our knowledge, the Earth, Sun, and Moon are all the same age, about _______ years old.
To the best of our knowledge, the Earth, Sun, and Moon are all the same age, about _______ years old. | 4.6 billion |
______ is the smallest of the inner four planets and closely resembles our moon. | Mercury |
The stream of charged particles given off by the Sun, which disallowed the accumulation of hydrogen
and helium in terrestrial planet formation, is called ____________. | solar wind |
Aside from Earth, the terrestrial planets are ____________. | Mars, Mercury, and Venus |
Our galaxy is called the ____. | Milky Way |
____ is the largest planet in both radius and mass. | Jupiter |
The Moon's low average density tells us that the interior contains relatively little _______. | iron |
The atmosphere of Venus is dominated by _________. | carbon dioxide |
Atoms that are heavier than iron are generally produced by ____________. | explosion of supernovas |
Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant
galaxies appears to be ____________. | red shifted |
To measure vast distances in the solar system, astronomers use the ____, the Earth's average distance from the Sun. | astronomical unit |
Differentiation of the core from the mantle early in Earth’s history was possible because the planet was
____________ at the time. | very hot |
This star provides the energy that drives Earth's external heat engine. | Sun |
As planetismals struck the growing Earth, their impact energy in combination with ______ melted the planet. | radioactivity |
Venus and Earth have ________ surfaces and atmospheres | very dissimilar |
______ is the planet that is most like the Earth in diameter and mass. | Venus |
Jupiter, Saturn, Uranus, and Neptune are surrounded by atmospheres of _______. | hydrogen and helium |
The four outer (giant) planets are composed largely of _______. | hydrogen |
The sun, its eight planets and their moons, together with smaller objects such as asteroids and comets, form the ____. | solar system |