Greenhouse Effect
trapping of infrared radiation from the Earth's surface by greenhouse gases like carbon dioxide, methane, and water
Terrestrial (4 inner) planets
The following are charateristics of which type of planets...
1) They are relatively smaller than the outer planets.
2) They all have solid, rocky surfaces.
3) Their orbits are relatively closely spaced when compared with the outer planets.
4) They have ve
Solar Nebula
As the cloud shrank, its gravitational potential energy was converted to kinetic energy of the gas composing the nebula causing it to heat up and collapse
Difference between Terrestrial and Jovian planets
the protoplanetary disk was much hotter in the inner regions where the terrestrials formed, so hydrogen compounds and ices could not condense
The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk
How do astronomers account for the fact that all the planets orbit the Sun in the same direction and in nearly the same plane?
increases
Since angular momentum is conserved, the rotational speed of a gas cloud does what as it is collapsing
2
What percentage of the mass of the solar nebula consisted of elements other than hydrogen and helium?
outgassing by volcanoes
what do we believe is the main source of Terrestrial Atmospheres?
global magnetism
Which component of Earth's geology has helped to shield the Earth's atmosphere from energetic particles of solar wind from the Sun which would have gradually stripped it away into space?
hydrogen (h2)
The composition of the EARLY (primary) atmosphere was dominated by
Carbon Dioxide (CO2)
the composition of the SECONDARY atmosphere was dominated by
internal heat
Geological processes on the Earth's surface are directly related to
convection
Transfer of heat in the Earth's mantle is dominated by
Lithosphere
Which one of the Earth's layers has broken up into plates because of stresses arising from mantle convection
Moon Mercury Mars
These 3 planets have cooled so rapidly that they do not have enough internal convection to break up their thick crusts, causing plate tectonics to be absent
Differentiation
process by which denser materials like iron sank to the center of the Earth while less dense materials like rock rose to the surface
solar wind stripping
The sweeping of atmospheric gas particles into space by the Sun is referred to as
weaker gravity
Smaller worlds are more prone than are large worlds to losing their atmosphere because they have
Moon
In theory, which body had giant impact model in which material was blasted from the Earth after an impact with a body the size of the planet Mars
global magnetic field
a planet must have an electrically conducting fluid in its interior which is undergoing convection and a reasonably rapid rotation in order to have what type of magnetic field
infrared
At the temperature of the Earth's surface, most thermal emissions are in which portion of the electromagnetic spectrum
solid iron and nickel
The center of the Earth is made of what
Late Heavy Bombardment
which theory explains the following
1) the presence of significant amounts of water on the Earth
2) the fact that craters in the heavily cratered lunar highlands appear to be younger than the Moon itself
3) the current locations of Uranus and Neptune
Carbon Dioxide
Most of the Earth's _____ has dissolved in the oceans and is locked up in sedimentary carbonate rocks like limestone
4.6 billion
How old is the Earth
200
The geological record suggests that life on Earth appeared very soon after the heavy bombardment in a short time period of perhaps only ____ million years or less
2.4 billion
Oxygen first started to be placed in the Earth's atmosphere by aerobic organisms around how many years ago
UV rays
A major reason why life on Earth is unlikely to have originated on land is that there was no ozone layer to shield out what?
Oxygen
When what gas is present are prebiotic molecules are NOT produced in Earth's early atmosphere
Frozen
Without the greenhouse effect, the oceans on the Earth's surface would be?
single celled prokaryotes
The first living organisms on Earth probably resembled
Eukarya
All multicellular organisms on Earth are
ozone layer
The origin of land-based life was closely tied to the development of what?
100,000
Homo Sapiens appeared how many years ago
panspermia
refers to the theory that the first life on Earth was transported here by meteorites.
extinction of older anaerobic life
In the context of the evolution of life on Earth, the "Oxygen Crisis" refers to the ___________________ as oxygen builds up in the atmosphere.
prebiotic molecules
The following are an important source of ______ on early Earth?
1) molecules prouced in the atmosphere by the action of lightning
2) molecules produced by chemical reactions near deep-sea ocean vents
3) molecules transported to the surface by impacts
its size and distance from the sun
The Earth owes it's habitabilty primarily to what 2 features?
extremophiles
The discovery of _______ on Earth suggests that life elsewhere may be possible over a much wider range of conditions than initially thought
liquid water
The search for extraterrestrial Earth-like life is essentially a search for
clay or other minerals
Biologists suspect that the first molecules of RNA probably formed on the surfaces of
545 million
At the start of the Cambrian Period an explosion of genetic diversity appeared, leading to the appearance of the first animals, how many years ago
deep sea volcanic vents
By studying the "Tree of Life" scientists have been able to deduce that life on Earth most likely originated close to
anaerobic
If life is discovered on Mars, it is most likely to be
biological and volcanic activity
What is/are the most likely source(s) of the methane gas detected in the Martian atmosphere by the Mars Express orbiter?
shares a common ancestor
It is an observed fact that all cells found in life forms on Earth are based on the same biochemistry, this suggests that all life on Earth
inorganic
Molecules that lack carbon atoms are referred to as
thinning of the Martian atmosphere
The following are contributing factors to what celestial body during its early history?
1) the photodissociation of water molecules by ultraviolet light in the atmosphere
2) the stripping of the atmosphere by solar wind particles from the Sun
3) atmospher
relation to Jupiter and lack of moon
Compared to the Earth, Mars has experienced wild swings in its axis tilt over relatively short time periods. This is because of what?
DNA
On Earth, evolutionary adaptations in organisms are related to changes in ________________ that occur through time.
liquids
Mercury and the Moon are among the least-habitable bodies in the solar system because they are unlikely to have what
Northern Hemisphere of Mars
has a lower than average elevation and is relatively smooth
Warm and Thick
The ancient water erosion features on the surface of Mars suggest that what type of atmosphere?
gullies
Evidence for very recent water erosion on Mars comes from the observations of what in the rims of craters?
terraforming
The process of making an uninhabitable planet like Mars habitable and suitable for humans is referred to as
atmosphere is too thin
Liquid water cannot exist for very long on the surface of Mars today because of what?
Carbon Dioxide ice over water ice
During winter, the northern polar cap of Mars is made of what
summer
An image of Mars taken with the Hubble Space Telescope shows a small Northern polar cap and a large Southern Polar cap. What season was it in the Northern hemisphere when this image was obtained?
south to north
During summer in the Southern hemisphere of Mars, winds travel from which pole