The largest planets also have the largest densities
The total mass of all the planets is much less than the mass of the Sun.
Asteroids, meteoroids, and comets are remnants of the early solar system
If we were to construct an accurate scale model of the solar system on a football field with the Sun at one end and Neptune at the other, the planet closest to the center of the field would be
In the leading theory of solar system formation, the planets
formed from the same flattened, swirling gas cloud that formed the Sun.
The solar system is differentiated because
only rocky and metallic particles could form close to the Sun
According to the chart in Discovery 4-1 in the textbook, an impact resulting in global catastrophe is expected to occur roughly once per
Which of the following are the Jovian planets?
Jupiter, Saturn, Uranus, and Neptune only
Which planet by itself contains the majority of mass of all the planets?
are almost circular, with low eccentricities
Which of the following is not icy in composition?
In terms of ________, all the terrestrials are greater than any of the jovians
The jovian planets
all have rings around their equators.
All the planets orbit the Sun in the ________ plane
The Kuiper Belt is found where in the solar system?
beyond the orbit of Neptune
The tail of a comet always points
away from the Sun and becomes longest and brightest at perihelion
The Oort Cloud is believed to be
a spherical cloud of cometary nuclei far beyond the Kuiper Belt
Which of the following have an icy composition?
The most distant objects in our solar system are
in the Oort Cloud.
The most detailed look we've had of an asteroid comes from
spacecraft sent to an asteroid
A meteorite is
a chunk of space debris that has struck the ground
The orbits of most comets
lie almost entirely beyond the orbit of Neptune.
Objects in the Kuiper belt
lie beyond the orbit of Neptune, and close to the ecliptic.
In terms of composition
the jovian planets are more like the Sun than are the terrestrials
As the solar nebula contracts it
spins faster due to conservation of angular momentum
According to the Solar Nebula theory, planets
should be a common result of star formation
As a rotating gas cloud contracts, it spins
faster due to conservation of angular momentum
So far, beyond the solar system the extrasolar planets found have been mostly
large jovians with terrestrial-type orbits.
Most of the extrasolar planets found so far were detected by
noting the Doppler shifts of the star as the planet orbits it from side to side
Which statement about extrasolar planets found to date is true?
Some are so close to their stars that their periods are just a few days
All the terrestrial planets lie inside the asteroid belt.
One characteristic of the Terrestrial planets is their extensive moon systems
Earth is nearly twice as large as Venus
All Jovian planets have rings around their equators and at least eight moons
Due to their great masses, all four Jovian worlds are much denser than the earth.
Comets are not actually members of the solar system, but captured by the Sun
In addition to revolving around the Sun counter clockwise, most planets also rotate on their axis counter clockwise
Astronomers have not yet been able to detect planets outside our solar system
Relative to the comet, the direction of the ion tail tells us
the direction of the Sun
Meteor showers are
caused by the Earth passing near the orbit of an old short-period comet and usually annual events, as the orbits again intersect
A meteor is
a streak of light in the atmosphere.
Long-period comets are believed to originally come from
the Oort cloud.
All the planets revolve around the Sun counter clockwise, except for Venus and Uranus.
All the planets' orbits are even spaced.
Pluto is more similar to the jovian planet's icy moons than to any of the other planets
A Kuiper Belt object was recently discovered that may be larger than Pluto
Barringer Crater in Arizona is an example of a meteorite impact
The Oort Cloud lies closer to the Sun than the Kuiper Belt
Some meteorites are believed to have come from Mars and the Moon.
As a rotating gas cloud contracts, it spins faster
We would expect other planets beyond our own solar system to orbit the equators of their home stars, as our own planets orbit the Sun.
The nucleus of a comet is typically
a few kilometers in size, and very low in density
The Manicouagan reservoir near Quebec is an example of
a large meteorite impact.
Characteristics of terresterial planets
small size, solid rocky surface, located within the inner solar system
Characteristics of jovian planets
low average density, extensive ring system, numerous orbiting moons, primarily composed of hydrogen, helium, and hydrogen compounds
The length of the tail of a comet depends primarily on
the distance of the comet from the Sun
Comet tails are _________when the comet is closer to the Sun
Comet tails are ______________ when farther from the sun
shorter (or nonexistent)
About a trillion comets are thought to be located far, far beyond Pluto in the______
The bright spherical part of a comet observed when it is close to the sun is
A comets ________stretches directly away from the sun
A comet's ______if the frozen part of the comet.
Particles ejected from a comet can cause a ___________on Earth
________extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the sun.
The Kuiper Belt