Class Notes (807,075)
Canada (492,584)
York University (33,494)
Natural Science (2,766)
NATS 1880 (104)

Life Beyond Earth Lecture Notes.docx

7 Pages
Unlock Document

York University
Natural Science
NATS 1880
Paul Delaney

Life Beyond Earth Notes MARS - 70% of earth is ocean but mars has no oceans - there is a striking difference in north and south on mars - south is old looking - north is much smoother - the average age of the two hemispheres is quite different - Olympus Mons is the largest volcano in the solar system - Valles Marineris - A huge canyon adorns the equator of mars - 3 eras of mars surface - Noachian Era (oldest) - Hesperian Era (intermediate) - Amazonian (most recent) - Water was once was evident on mars - What can cause water to appear and disappear? - Permafrost must be heated to turn into liquid water - what is the source of the heat? - Imacts- Metorites strikes which brings enegery which causes materialte to vaporize and generates heat and melts and evaporates the perma frost cause the mad gushes of water to run down the river beds - Minerals are found on Mars that can only be found in the presence of water - Clay Minerals - Hydrated Sulphates - Hydrated Silica (opal) - Opal deposits form in hot springs - Theres alot of sedimentary rock - which is formed when rocks blend layer upon layer upon layer with water - All the circumstantial evidence points heavily that there was once liquid water on MArs - Its unknown how long the water lasted on Mars - What can happen to water to allow it to escape? - About 3 billion years ago Mars lost its atmosphere -3 Main reason this occurred - The gravity - the magnetic field weakened and eventually disappeared thus the solar wind is able to penetrate to the surface of mars thereby expelling harmful gasses - No ozone layer = the harmful radiation gets to the surface of the planet - Other processes that affect Mars’ climate: - Mars has two small moons, which means its axial tilt varies form 0-80 degrees - radical seasonal changes - Is Mars habitable? - We think Mars has been habitable in the past - In the first billion years mars was in the habitable zone - Mars is no longer in the habitable zone - The organic molecules had no strong evidence for life on mars - the detection of methane ch4 is promising for life on Mars - Mars and Earth swap meteors - a typical speed of something that hits mars is traveling 30km a second thus heating the surface CHAPTER 9 LIFE ON JOVIAN MOONS - The largest moons are Ganymede and Titan - Prograde = counter clockwise direction - retrograde = against the normal direction - Why are the moons all orbiting in the same direction? - they formed from many solar systems - a cloud that collapsed into a disk the swirled around the solar sun - Where we find jupiter and mars now is not actually where it was formed - The gas giants can move quite a distance from where they are formed to where they end up - Most of the moons are made of rock and ice - not super dense - Order of Galilean satellites - Io - 4 rotations - Europa - 2 rotation - Ganymede - 1 rotation - Callisto - Tides - energy source - always come in pairs - differential gravitational force - Io - volcanic activity arises for 2 reasons: - Tidal heating is very strong Io’s orbit is elliptica Chapter 9 continued… Europa - Has a very young surface - The craters help decipher the age of the surface - The surface is recent - There are surface cracks - Rocky interior and water ice around the surface - What evidence is there that there really is liquid water? - Salt water is important - Europa is in sync with the orbit as Jupiter thus keeps the same face towards Jupiter - Surface temp. is really cold (-150) - Life on Europa - Liquid water (engery) - The things are there for life - Lake Vostok (Earth) - Largest sub-glacial lake (under 4km of ice in Antarctica) Ganymede - Older surface - Very strange terrain looks like whole areas have been “flooded” from the eruptions of the water ice - Less likely to be habitable that Europa Callisto - Ancient surface - Filled with craters - Weak tidal heating - Something hit callisto with such impact that it melted everything for several km on the surface - The least likely habitable world of the Galilean satellites Saturn & Company - Has the only moon in the solar system with a atmosphere (Titan) - The Cassini air craft is going to smash into the rings of Saturn when it is no longer functioning or useful to us - Titan – largely nitrogen (-180c) no oxygen - Huygens – craft that landed on Titan on a dry river bed - determined that there was one water-ice present in the river beds - Why is Titan the only moon with atmosphere? - The temp. is so cool so it holds the atmosphere longer - Nitrogen - All amino acids are left handed - Earth melted very soon after if formed - A result of radioactive heating Chapter 10 Habitable Zone: Volume within which a planets (similar to earth) could have surface temperature that permit liquid water on its surface - Temp on a planet depends on: a) Distance of the planet from its host start b) Albedo (proportion of radiation it reflects) c) Atmosphere (greenhouse effect) d) Internal heat (primordial, tidal, or radioactive) e) Tilt of rotation axis and rotation rate - As soon as you put an atmosphere around a planet it’s like putting a sweater on thus making it warmer - Greenhouse Effect: Radiation from the sun reaches down to the planet then is absorbed by the planet then radiated by the planet - Were grateful for the greenhouse effect - Helps keep the average temp of earth around 14-15 degrees a year C: The habitable zone is? - Any planet on which liquid water could exist C: The habitable zone in the solar system now contains? - Only Earth Venus:
More Less

Related notes for NATS 1880

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.