astronomy: mars

24.6 hours

length of day on mars

erosion

overall, _______ is about 100x slower than on earth, but still faster than on the moon or venus

borealis basin

the giant ________ _____ around the martian north pole could be the result of one of the largest known impacts in the solar system

surface gravity

the height of these volcanoes is a direct consequence of the low _______ _______ on mars

tharsis bulge

the major geological feature of mars is the _______ _____. it lies at the equator and rises about 10 km higher than the rest of the surface

seasons

the most obvious features from earth are the bright polar caps which grow and shrink depending on the _______

valles marineris

the most prominent feature of the tharsis bulge is the great "canyon" known as ______ _________ (the mariner valley)

volcanic plains

the northern hemisphere is made up largely of rolling ________ _____similar to the lunar maria

lava

the northern hemisphere must have been lowered in elevation and then flooded with ____.

southern summer

the only difference is the _________ _______

smaller, brighter

the residual caps are _______ and _________ than the seasonal caps

highlands

the southern hemisphere consists of heavily cratered _________

crustal forces

the valles marineris is believed to have been created by _______ ______, not from erosion due to flowing water. it is 4000 km long and can reach depths of 7 km at its deepest places. it runs nearly a 5th of the way around the planet. it can never be seen from earth.

outflow channels

the volcanism and bombardment by space stuff melted that what frozen water was left causing those ________ ________

ocean

the whole northern lowlands may have been a huge _____

warmer

their temperatures never get ______ thank 150 K (-120 C/ -184 F)

high winds

there are frequent dust storms, with ____ _____

magnetic field

there is no ________ _____, so the core is probably not metallic, not liquid, or neither liquid nor metallic

active

there is no direct evidence that the volcanoes are ______

eruptions

they are much larger than their counterparts on either the moon or earth and a result of __________ that included a lot of material

olympus mons

three volcanoes are located on tharsis bulge, the largest of which is the _______ ____. it measures over 700 km in diameter (about the size of texas)

chryse planitia, isidis planitia

to the east of tharsis is ______ _______ (plains of gold) and to its west a region called ______ ________ (plains of isis)

water

although dry and desolate now, there is a lot of evidence to support that mars may have _____ on its surface in its past

reflective

as water ice froze, mars became more and more ___________ and its atmosphere thinner and thinner, freezing more and more water and eventually carbon dioxide as well

24.0 degrees

axial tilt of mars, very close to earth's 23.5 degrees

conjunction, opposition

because of mars' superior orbit (lying outside of earth's), it can appear to be: closer to the sun - ___________ opposite the sun - __________

composition of atmosphere

95.3% co2 2.7% n2 1.6% ar .13% o2 .07% co .03% h2o

great bombardment

its impact craters suggest that it formed very early in the martian history, probably during the _____ ___________

dry ice

the frozen caps are mostly frozen co2 (___ ___), not water like on earth

mars odyssey, mars express, mro

____ _______, ____ _______, and the ___ have all found direct evidence of large deposits of ice all over the planet

water ice

_____ ___ is permanently frozen. there is some water mixed in with this, but it is not the dominant presence.

runoff channels

______ ________ are extensive systems of interconnecting, twisting channels that seem to merge into larger, wider channels. they are very similar to how the river systems on earth look. generally found in the southern highlands

outflow channels

_______ ________ are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. believed to be a result of a slightly more recent catastrophic flooding events. they are found only in equatorial regions and generally don't form the interconnecting networks of the runoff channels.

impactor

computer simulations show that it could be the result of huge (2000 km across) ________ that grazed the planet

3900 kg/m^3

density of mars, only slightly greater than the moon

hellas basin

diametrically opposite to tharsis, is ______ _____ which contains the lowest point on mars. it is an impact feature and lies over 6km below the average surface

increasing

during martian summer, the exposure to the sun causes co2 to evaporate into the atmosphere there by __________ atmospheric pressure

seasonal cap, residual cap

each cap is composed of two distinct parts: the ________ ___, which grows and shrinks each year the ________ ___, which remains permanently frozen

variation

for most of the year there is little day to day __________: the sun rises, heats up the surface, light winds blow, then the sun sets and it cools again

permafrost

for reasons unknown this water either became frozen as ___________ and in the caps or escaped into the atmosphere and then escaped into space

martian dust

from a distance it appears that ground too changes. we know now that it is just the _______ ____ blowing around making certain areas appear different

100 km

from behavior of the crust, it is estimated to be ____ __ thick

retrograde

from our vantage point, mars appears to travel in a great circle across the sky with period points of __________ motion

permafrost

geologists think that this fluidized ejecta crater indicates that a layer of __________, or water ice, lies just a few meters below that surface.

lake

hellas basin would be another candidate for a giant ____

plate tectonics

if we go with the idea of "continents", tharsis would be the only one however there is no evidence of _____ _________ on mars

viking

in the 70s ______ gave us some of our first images of the martian surface

plate motion

like with venus, none of the volcanoes are associated with _____ ______; they are shield volcanoes sitting atop a hot spot in the underlying mantle

thinner atmosphere

mars also undergoes seasonal change, but it is very different from earth given mars' eccentricity and _______ __________

opposition

mars appears the brightest in the night sky at __________ and especially if this occurs near the martian perihelion

volcanoes

mars contains the largest known ________ is the solar system

deimos, phobos

mars has two tiny moons: ______ (right, 16 x 10 km2) - was probably captured from the asteroid belt ______ (left, 28 x 20km2) - may have formed later, from material ejected from mars by a meteor strike

venus

mars is considerably fainter than _____ due to the fact that: it is twice as far from the sun as _____ it is much less reflective, only about 15% of the sun's light reflects off

fourth

mars is the ______ planet from the sun and is the outermost of the terrestrial planets

.093

mars is the second most eccentrical planet in the solar system with an e of ____

runaway greenhouse effect

mars may be victim of ________ ___________ ______ in the opposite sense of venus'

sunlight

mars' eccentricity results in a large variation of the amount of ________ striking the planet throughout its year

eccentric

mars' orbit is more ________than earths

6.4 x 10^23 kg

mass of mars

demos and phobos

moons of mars

mars global surveryor

more recently, the ____ _____ ________ has mapped out the martian surface to within an accuracy of a few meters

crust

most scientists agree that the southern region is mars' original _____

seismic

no ________ studies have been done

impact craters

on mars, as with venus, there is a lack of small ______ _______. this is most likely due to the thin atmosphere and seasons that move dust and debris around on mars.

3394 km

radius of mars

dust

strong surface winds here carry ____ high into the atmosphere that then get deposited all over the planet

warmer

summers in the south (around perihelion) are much _______ than summers in the north

gullies

surveyor missions since 2000 have reported numerous discoveries of small-scale "_______" in martian cliffs and crater walls that were apparently created by running water in the recent past

youngest

tharsis also appears to be less heavily cratered, suggesting that it is the ________ region on the planet

caldera

the ______ of the olympus mons measures 80 km across.

ejecta

the _______ around impact craters on mars look very different than of those on the moon

northern residual cap

the ________ ________ ___ is much larger and reach slightly warmer temperatures especially during northern winter

younger

the assumption is that the northern surface is _______ than southern (3 billion years old vs 4 billion years old)

co2

the atmosphere of mars is very thin and composed mainly of ___

1/150th

the atmospheric pressure is about _/_____ that of earths

4 billion

the best that scientists can guess is that _ _______ years ago mars had liquid water

carbon dioxide frost

the caps are composed predominantly of ______ _______ _____ - dry ice - and show seasonal variations

.37

the closest mars and earth come to each other is ___ au. the closest approach occurs about every 15 years, the last time being 9/28/03