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137 Cards in this Set
- Front
- Back
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What is Mars in regards to life? |
Mars is the second most hospitable planet. |
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Does Mars have water? |
There may have been flowing water, and there is a chance there may still be significant water there still. |
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What kind of ice is Mars bottom? |
Carbon dioxide ice. |
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Tell me about the Mariner 4 (1964). |
It was the first successful flyby, first pictures of another planet taken from deep space. |
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What did the Mariner 9 do? |
Took pictures that showed the first evidence of water structures. |
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What is significant about Mars regolith? |
It has a high iron content, gives it a rusty look. |
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What was significant about the Sojourner (1997)? |
It was the first rover on another planet. |
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What did the Sojourner and Pathfinder do? |
They were rovers sent to look for evidence of water. They carried atmospheric equipment and studied regolith in different location to Viking lander. They found numerous little round pebbles, indicative of water flow. |
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What did Spirit and Opportunity do? |
They were twin landers sent with high precision chemical analysis tools. Found distinctlayering in rocks,indicative of cyclicwater behaviour. |
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Tell me about Opportunity (2004). |
It was originally supposed to be a 90 day mission, but it is still an active rover! |
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Tell me about Phoenix. |
Just a lander, confirmed presence of subsurface ice. Found clay & carbonitein soil (indicates water). |
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Tell me about Curiousity. |
Studied potential for past/future life, landed in an ancient streambed. Found water, sulfurand chlorinecompounds. These compounds are significant because according to Earth, these are the basic building blocks of life. Drilled holes in surface to study rock that had never seen the surface/atmosphere before.
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T/F: Mars is the closest planet that can align in opposition. |
True, closest superior planet to Earth. |
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What's Mars' eccentricity like? |
Eccentricity about 0.093, larger than all others exceptMercury.
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What is significant about Mars's perihelion? |
Mars's perihelion closeto Earth aphelion. Much better viewing when they line up at this point.
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How close is the distance between Mars and Earth at closest opposition and furtherest opposition? |
Closest opposition, 0.37 AU, farthest opposition 0.67AU
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What can we see of Mars form Earth at closest approach? |
25” size at closestapproach, 100 kmfeatures visiblefrom Earth scopes.
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How often does Mars and the Earth line up in opposition? |
Approx. every 2 years (~780 days) |
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How often is the approximate closest approach? |
Every 15 years. |
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Why is Mars fainter than Venus? |
It's smaller than Venus, it's 2x further away from the Sun, and it's much less reflective (only about 15%). |
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How much more sun is there in different places in Mars's orbit? |
45% more sunlight at perihelion than aphelion.
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How much of an offset of the rotation axis is Mars in comparison to Earth? |
24 degrees offset of rotation axis (Earth has 23.5 degrees)
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How long is Mars's solar day? |
24.6 hours. |
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What are Mars's seasons affected by? |
Distance AND spin axis. |
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How big is Mars's radius? |
53% of Earth's. |
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What are Mars's moons? |
Phobos (Fear) and Deimos (Panic). Very small moons. Not enough gravity to be spherical. |
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What is Mars's mass and how can we measure it? |
We use its moons to tell the mass, and it is 11% of Earth's mass. |
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What is Mars's density? |
71% of Earth's. |
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Is there any seismic activity on Mars? |
None that we have seen. |
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What's Mars's magnetic field like? |
It's a very weak, localized magnetic field. |
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What is Mars's core like? |
It is mainly solid and full of iron sulphide. |
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Does Mars have radioactive heating? |
No, planet is too small. |
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Does Mars have plate tectonics? |
Topography suggestsplate tectonics werein process of formingwhen planet cooled,but never actuallyseparated |
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What does Mars's Volcanic activity suggest?
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Volcanic activity suggests some magma/melting,could be influenced by collision heating.
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What is one of Mars's most distinguishing features? |
Most distinguishing feature are distinct polar capsthat change size with seasons. |
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What are Mars's polar ice caps all about? What is the residual cap and seasonal cap? |
Ice caps mainly C02. Residual cap never melts, seasonal cap changes with the seasons. |
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How big are the Southern and Northern ice caps? Why is it colder at the South Pole during the winter? |
Southern ice cap 4000 km diameter max (seasonal). Northern ice cap 3000 km diameter max (seasonal). Colder at that South pole during the winter. Distance from sun, eccentricity means southern icecap tilted away from sun at aphelion.
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How thick is the seasonal ice cap and why does it retreat? |
Only 1m thick on average. Retreats in summer due to sublimation. |
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What does sublimation mean? |
When something solid turns into a gas before it goes through the process of melting into a liquid. So when snow becomes fog or steam before it is able to melt. |
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How much does the atmospheric density change over the seasons? |
Changes by 30% over seasons. |
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What affects Mars's colouration? |
Dust storms affect it, changing visible distinctiveness. |
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What happens to the dark regions on Mars? |
They change over the seasons, too. |
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What are the main surface features of Mars? |
Huge volcanoes, deep canyons, vast dune fields. |
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Has the surface been mapped? |
Surface mapped to accuracy of 1m (even boulders~1m in size mapped in 3D).
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What is characteristic of Mars's Northern hemisphere? |
large, rolling, volcanic plainslike lunar maria
Mostly ~5 km belowplanet average radius, incredibly deep. Many boulders, somemeteor craters |
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What is characteristic of the Southern hemisphere? |
Rocky highlands, More cratering in South than in North, indicating age difference |
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What is the reason for the N/S HUGE elevation difference? |
Likely South hemi was original crust while North hemi underwent catastrophic change,lowering, lava flooding.
Believe southern hemisphere is what the planet generally looks like when it was first formed.Then a giant impact occurred that flattened and melted the entire northern hemisphere.
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What is the tharsis bulge? |
Size of Noth America, Rises 10 km higherthan planet avg (Taller than Mt. Everest!) Contains youngest rock on planet (fewest craters).The white peaks are the primary volcanoes on the planet. At one point they were very active. Lots more craters in other areas of southern hemisphere. |
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What is the Hellas Basin? |
Opposite side of Tharsis, Deepest place on Mars,6 km deep, 3000 km across, Clearly impact feature,based on shape/structure, Sent shockwaves to other side of planet, that’s why volcanoes were able to spew out because rock was weakened. Such a large collision would cause catastrophy. |
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What is the borealis basin? |
Centre of N hemisphere, May be largest impact crater insolar system, Simulation & observation suggest impact object of2000 km diameter, Twice size of current largest asteroid in solar system, Responsible for majority of flattening. So large that it would’ve melted all the northern hemisphere. This was created first. |
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What is Utopia Planetia? |
Adjacent to Borealis Basin Second largest impact craterin the solar system.
Small enough that they don’t melt, but large enough to make an impact. |
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Why does Mars have lots of impact craters? |
Closer to Asteroid belt, lots more impacts. |
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What is the Valles Marineris? |
Martian “Grand Canyon” (not caused by water) Crack formed asTharsis bulged out, Many similarstructures aroundTharsis, though thisis biggest , Largest canyon in the solar system, As hellas basin was formed, it pulled apart surface of planet. Not the only crack on Mars that was likely created in this way, but it is the largest and most distinctive.
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How old is Valles Marineris and Tharsis? |
Cratering suggests older than 2B years, Tharsis 3Byears
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What is the olympus mons? |
Olympus Mons, west side of Tharsis700 km diameter (Texas)25 km high
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What are Mars's volcanoes like? |
All volcanoes are shield volcanoes (no tectonics)All show lava flow features (lava flow channels) Hundreds of others, acrossTharsis and Northern plains
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Are there active volcanoes on Mars? |
No evidence of recent activity Volcanoes active ~100M yearsago, and intermittently
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Explain low gravity volcanism. |
Shield volcanoes have a maximum height that they can reach before spreading out. Olympus mons had lesseffect of pulling that lava back down the slopes, so it just kept building upwards. Height of volcanoes due in part to low gravity |
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Why does Mars have few small craters (same as Venus) but not as much of an atmosphere? |
Not enough atmosphere to stop small craters, the reason there are so few small craters are because of the dust covers. Atmosphere will also erode the cliff faces of the craters, smoothing them and flattening them. |
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What's the idea about water on Mars? |
Dry and desolate now, evidence suggests not always. Some surface features remain from billions of yearsago, despite erosion Surface features that we are seeing now looks like water flows. Small streamsleading to larger streams. |
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What are runoff channels? |
Runoff channels, interconnected, twisted, merge intowider channel Resemble riversystems Thought to bedried up river beds from mountainous regions Could be due to water cycle, or due to periodic icemelting (currently, water cycle more supported)
Does not have to be caused by an ongoing weather cyclical system (like rain on Earth). It’s possible this could have been caused by melting ice. Periodic deluge of water. |
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What does the volcanic ejecta evidence tell us about Mars? |
Volcanic ejecta from old volcanoes didn’t travel farenough for current atmosphere (suggest 20x thickeratmosphere
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How old are the runoff valley networks? |
~4B years old, age determined by craters.
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What are outflow channels? |
Slightly different, they are shorter. Run off are longer. Appear only in equatorial regions (warmest)Paths taken by large volumes of water Rushing waterformed teardropislands Carried 100x morewater thanAmazon, 3B years ago |
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What do we assume about Mars's periods of water? |
4B years ago, water created runoff Then planet froze. Then impact created heat. 3B years ago, large outflow occurred |
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What is terracing? |
Occurs when you have some sort of seasonal rising water levels. Suggests waterfills to some level, collapses walls (erosion) Causes LEVELS. Critics claim terracing could be caused by geologicalactivity |
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What evidence is there for subsurface ice on Mars? |
No surface water now Ejecta from craters showsdifferent pattern from ejecta on Mars vs Mercury Ejecta from meteor impacts should eject like a cloud, with a bunch of boulders in places. On Mars, Collision melts surface, melts ice,becomes liquid water that flows and carries the dust. Suggest permafrost belowsurface, melted on impact Massive outrush of water |
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What was found on Mars in regards to subsurface ice? |
Mars Odyssey found extensive subsurface water ice,up to 50% of volume in some regions. Mars Express confirmed results using alternatetechnique (replicability!)
Mars Reconnaissancefound glacial melts less than100M years old. Ice on Mars widely agreed upon. |
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What do observations of small gullies that exist on Mars that should have eroded away tell us? |
Suggest carvingdue to fluid flow
The fact that it has changed over timeindicates there is some kind of flow. Some argue liquid water may be 500m below surface because the planet is deep enough that planet could keep it in liquid state. Pressure could build up and push it up through cracks here and there. Others argue solid CO2 expelled due to pressure This white substance could also be considered as Carbon dioxide. |
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What do the craters on Mars tell us about recent water? |
Craters show evidenceof change betweenyears Surveyor’s camera found white streak on crater wall ....Indicates water that flowed, then froze (or CO2?)
No shadows here… harderto make argument for C02 Some features change over course of years, ratherthan 100M years, indicating something is occurringon the surface |
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What about water on the surface? |
No direct evidence for current surface liquid water,water vapour small portion of atmosphere
If liquid water was coming to surface in large amounts, it would sublimate because of cold temperatures. But we don’t have very much water vapour in the atmosphere. So, we only have circumstantial evidence for water on the surface. |
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What is the pressure of Mars's atmosphere? |
There is such a thin atmosphere that the pressure is 1/50th of Earth's. |
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Where is the troposphere and what does it got? |
Troposphere up to 30 km,water-ice clouds. |
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Where are mars's carbon dioxide clouds and why does it have co2 clouds? |
Carbon dioxide ice clouds at 50 km up.
On earth we have clouds that are made up of water. mars c02 is so light that they freeze together and form snow buyont enoughthat it stays up as a cloud.
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What should you know about the weather on Mars? |
Temperature at noon, summertime can reach 30oC, but It would not feel like 30 degrees because atmosphere is so thin. Surface winds in South create temperature andweather variations Dust storms coversignificant part ofplanet, last formonths at a time |
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Does Mars have low gravity? |
Yes! |
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Tell me about Mars's atmospheric evolution? |
Secondary outgassed atmosphere formed, like Earth. Greenhouse effect initially kept planet warm. Significant enough the atmosphere was thick enough at one point. It could have been tropical temperatures or even warmer.
Atmosphere vanished 3-4B years ago, at least in partdue to collisions, and slow release to space (lowgravity) Experienced reversegreenhouse effect
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What is the climate change story of Mars? |
Early Mars was warmer,liquid water widespread 4B years ago, majorclimate change caused water to freeze (run off channels)
3B years ago, volcanic activity and/or meteoricimpact(s) melted ice, causing flash floods (outflow channels, catastrophic event) |
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What were the oceans on Mars like? |
Oceans may have onlyexisted for very shortperiod of time (few hundred million years) Estimates of total watercontent on Mars, around10 m depth for entire planet
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What happens in the reverse greenhouse effect? |
Something happened to freeze planet, atmosphere changes and removal of greenhouse gases. If co2 is primary greenhouse gas,that co2 would be slowly absorbed into oceans, which acidifies, then is deposited into rocks. Water absorbs CO2 into rocks (e.g. carbonite)Less CO2 in atmosphere = less greenhouse gas = planet cools Water freezes out of air, reduces greenhouse gasesfurther (When water is frozen, it reflects more light which eliminates more gases.) |
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What did the Pioneer 11 find out about Jupiter? |
Closest approach of 34 000 km from cloud top ofJupiter.
Obtained Dramatic images of Great Red SpotObserved poles & measured mass of one moon |
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What did Voyager 1 & 2 do for Jupiter? |
Only months apart
Observed rings & moons Studied Jupiter’s atmosphere |
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What did Galileo do for Jupiter? |
Made 35 orbits before controlled collision withJupiter - needed to avoid contaminating Europa
Studied all of the major moons Sent an atmospheric probe 150 km deep into atmo. |
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What's Jupiter's visibility like? |
5th planet, 4th brightest object
Superior planet (i.e. brightest at opposition)Jupiter as large as 50” angular size! |
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What are the Galilean Moons? |
The 4 largest moons of Jupiter. |
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What do we know about Jupiter's mass? |
Mass first determined from moons: 318 Earth masses
Twice mass of ALL other planets combined Large mass has significant impact on orbits |
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What's the radius, volume, and density of Jupiter? |
Angular size gives radius of 11.2 Earth radii
1400x Earth’s volume Avg density of 1300 kg/m3, slightly more than water |
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What is Jupiter mostly made up of? |
Hydrogen and Helium, like the sun. |
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What is significant about Jupiter's gravity and gasses? |
Massive gravity ofJupiter compressesH & He to16000x higher density |
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What is weird about Jupiter's heat? What is the best theory for the heat? |
Jupiter radiates more heat energy than it receivesfrom the Sun. Heat can’t be radioactivity (like Earth),can’t be fusion power (like the Sun) Best theory: very slow escape of heat generated from planet formation. Jupiter is STILLcooling down |
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Can Jupiter ignite? |
While Jupiter has the same composition as stars, itneeds at least 80x more mass to ignite |
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Why is Jupiter important for life?
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If Jupiter were large enough to become a star, Earth would have been too hot for life. If Jupiter were smaller, inner planets would have received more asteroid collisions and harmed potential for life. Jupiter is pretty important!
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What is Jupiter's rotation like? |
“Surface features” indeterminable (i.e. no visiblesurface)
Differential rotation of atmosphere, similar to theSun Use doppler technique tomeasure atmosphericrotation |
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What is the magnetosphere all about? |
Magnetosphere produces radio pulse with period of9h 55m (sidereal day) Assumed to be rotation below atmosphere This is same rotation rate as the polar atmosphere |
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How is Jupiter fat? What is the equatorial and polar radius? |
Centripetal effect 65x largerthan Earth’s Equatorial radius: 71 500 km Polar radius: 66 900 km |
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What does the centripedal effect do? |
Causes bulging at equator. |
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Why is it thought that Jupiter may have a rocky core? |
Oddly, pure H and Hewould result in even greaterbulge than observed! Thus, it must have somekind of solid, rocky core of5-10 Earth masses
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What are the 2 distinct features of Jupiter's atmosphere? |
Alternating bands, and the GREAT RED SPOT! |
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What is the Great Red Spot? |
Hurricane the size of Earth, >300 years old. |
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What is Jupiter's atmospheric composition? |
86% molecular hydrogen 13.8% helium Gravity too strong forloss of atmosphere... These don’t create colouredbands - 0.2% remaining does 0.2%: methane, ammonia, water vapour |
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What are the atmospheric "belts" and "zones"? |
Alternating convection |
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How does Jupiter's weather spread? |
Fast rotation of Jupiter spreads weather across entire circumference, into strips |
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What do the atmospheric colours depend on? |
The colour of the band depends on which gasesdominate - rising atmosphere pushes lower layers up
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What is the normal colour? Ammonia ice? Ammonia HS? Water ice? Lower levels? |
Normal colour: tan/yellow
Ammonia ice: white/grey Ammonia HS: red/orange Water ice: blue Lower levels: deeper red |
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What is the Great Red Spot? |
Friction between the bands causes large scale storms
Circumnavigates the planet at same speed as interior. If this was purelyan atmosphericphenomenon, then itshould rotate with atmo,not with interior! Example of a Jovian storm. |
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Do Jovian storms get lightning? |
Like on Earth, the friction of the cloud layers movingbuilds up static charge, which is visible as lightningwhen viewed by a satellite on dark side of Jupiter
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Storms on Earth break up when they hit land... so why do Jupiter's storms last for so long? |
The fact that the storms on Jupiter last so long (GreatRed Spot > 300 years old) suggests that there is verylittle structure within Jupiter |
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What is the inside of Jupiter like? |
Pressure increases too much to maintain gas (1MxEarth’s atmosphere by 20 000 km in) Transitions to liquid state
Hydrogen becomes metallic Becomes a solid. This is really important because hydrogen becomes a very good conductor. Deeper down, inner core rocky (5-20 Earth masses) |
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How is Jupiter's magnetic field created? |
Hydrogen Conducts electricity so well that it creates dynamo effect that creates magnetic field. |
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How big is Jupiter's magnetosphere? How strong? |
100x larger thanEarth’s 20 000x stronger thanEarth’s field |
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What makes a stronger field? |
A better conductor. |
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Does Jupiter have a "van allen belt"? |
Jupiter has its own “Van Allen Belt” equivalent>1000x more radiation
Very hazardous to all missions Producesspectacularaurorae |
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How many moons does Jupiter have? What are their orbits? |
Total: 67 (4 of which are Galilean) Nearly circular orbits (very low eccentricity) |
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Why are Jupiter's moons like a " Mini Galilean Model of Solar System"? |
It's an analogy that fits because: they all have prograde orbits, all have low eccentricity, density decreases with distance, largest of them is furthest out. Ganymede would be equivalent to “Jupiter” Inner 2 have rocky mantles, terrestrialcrusts, iron/iron-sulfide cores (Io and Europa) Water-ice and other light materials furtherout (gannymede and callisto) |
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What is the Jupiter and inner 3 moons resonance? |
Inner 3 moon orbital radius lies in 4:2:1 ratio All are very close to tidal lock |
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What about Callisto's resonance? |
Callisto close to 10:1 ratio, Resonance in the works, its orbit is likely changing just very very slowly. |
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What's Io like? |
Most active surface in solar systemVery active volcanoes
The entire surface of the moon changed in 16 years, observations by Galileo Orbiter found. 80 periodically activevolcanoes observed |
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What is Loki? |
Loki is a volcano on Io larger than Maryland, emits more than all Earth volcanos |
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What is the yellow/orange colour you can see on Io? |
Sulfur released from volcanoescauses yellow/orange colour
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What do we need to know about Io's tidal bulges and gravitational pull? |
Source of energy/heat: gravitational heating Io is not in rotational tidal lock Jupiter creates large tidal bulge Europa creates second bulge Creates a bunch of jumbling, creates primary source of heat on Io.Whenever you have a system that produces heat from orbits, that will not lastforever since it draining energy from tidal lock, means Io is slowly going to movecloser to Jupiter. Will be in tidal lock. Orbit of Europa causes friction as bulges oscillatearound moon - friction heats up the moon |
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What is Europa like? |
Voyager observed few craters, indicates activity Dark region: rock white region: water ice
Network of cracks acrosssurface - extend half way across planet It is assumed the rock is sitting on top of ice crust.... material that has been swept up. |
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What is significant about Europa? |
Galileo data supports liquid interior --> Life?
Potentially 1 km crust, 100 km ocean Surface pulled apart,liquid filled in cracks |
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Why are there not many craters on Europa? |
Hydrovolcanism: the reason there are not very many craters. When ice builds up pressure, it spews up water and fills in any of those craters. |
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Explain more about hydrovolcanism. |
To the best of our knowledge, there is volcanoes on Europa keepingthe main layer liquid. Big giant ocean underneath ice. |
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What is Ganymede like? |
Ganymede largest moon in solar systemDark regions oldest, most craters
Light regions youngest, least cratersEvidence of tectonic movement |
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What is callisto like? |
Similar to Ganymede
More craters, fewer faults (suggests surface is older. Didn’t undergo tectonic or volcanic activity.That’s because it is further away from Jupiter.) Two large basins Valhalla 3000 km across Collision melted surface,created ripples, froze |
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What did Pioneer 11 do for Saturn? |
Data transmission was so far away, was really bad transmission. but! Closest approach of 20 000 km |
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What was Voyager 1 and 2 all about for Saturn? |
Path of Voyager 1 adjusted to perform close flyby of Titan Voyager 1 Significantly disrupted its original path, gravitationally slingshot up and out of disc. Caused Voyager 1 to fly out of ecliptic and missUranus, Neptune and Pluto |
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What did Cassini do for Saturn? |
Close flybys of Phoebe and Titan
Carried Huygens probe to study Titan Discovered new moons, new rings Discovered hydrocarbon seas on Titan |
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What is Saturn's visbility like? How far away is it? |
Furthest planet observable by naked eye astronomy ....Very far out, the reason it’s visible is that it is so much bigger than uranus and neptune. Almost 2x distance to Sun as Jupiter is |
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What is Saturn's orbital period and orbital distance? |
Orbital period: 29.4 Earth Years
Orbital distance: 8 AU |
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Is Saturn a noticeable object in the sky? |
Saturn dimmer than many faint stars.... Saturn looks like an average star. If you weren’t tracking its movements through the sky, you’d have no ideathat it is not a star.
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What is Saturn's mass, equatorial radius, and density? |
95 Earth Masses (1/3 of Jupiter’s)
Equatorial Radius 9.5x Earth’s Density: 700 kg/m3 (1/3 Jupiter, 1/8 Earth) |
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What is Saturn mostly made out of ? |
Made of mostly H and He, but lower gravity than J. (Because of smaller mass) |
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What does Saturn's shape look like? Is the radius the same all around? |
Like Jupiter, flatter due to high rotation speedPolar radius 90%equatorial radius
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Saturn is less flattened than a planet of pure H and He, what does this suggest? |
Less flattened than a planet of pure H/He Suggests solid inner core
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During the seasons, what are Saturn's rings looking like? |
Saturn spring/fall (equinoxes),rings edge-on
Saturn summer/winter (solstices), rings at max tilt |
