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CA (650,000)
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ASTA01H3 (100)
Lecture 1

ASTA01H3 Lecture Notes - Lecture 1: Hematite, Long Path, Photon


Department
Astronomy
Course Code
ASTA01H3
Professor
Parandis Tajbakhsh
Lecture
1

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Mars
Distance from the Sun: 1.52 AU
Orbital period: 1.881 Earth year
Length of the Day: 24h 37m 22s
Radius: 0.53 RE
Mass: 0.1 ME
Atmospheric Composition: 95% CO2, 2.7% N2, 1.6% Argon
Surface Gravity: 0.38 Earth
Average Surface Pressure: 0.007 bar
Average Surface Temperature: -50 C
Water, in liquid form, is unstable on Mars due to low atmospheric pressure.
The freezing and boiling points of a liquid depends on the pressure. The lower the
pressure, the lower the boil and evaporation temperature.
Water On Mars
Radar studies have revealed the presence of a thick layer of water ice in the Martian
Poles (at least 1 km below polar cap).
During winter, this water ice is covered with a layer of dry ice.
Ancient Water on Mars
Outflow channels, geological features carved by sudden flow of massive amounts of water,
strongly suggest that Mars has suffered catastrophic floods.
Valley networks, a system of dry drainage channels, resemble riverbeds on Earth.
The number of craters in the vicinity of theses features reveals that they are quite old.
Evidence for Past Liquid Water
Opportunity has found strong evidence which indicates the hematite on Mars was formed
in the presence of water.
The rocks examined by Opportunity have a layered structure and contain tiny hematite
spheres called “Blueberries”!
Blueberries on Earth are formed in the presence of water and it is believed that this is
also true in the case of Martian Blueberries.
Recent Water Flow
Most of the evidence points to the fact that liquid water existed on Mars prior to 2-3 billion
years ago.
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