Mars Research Flashcards
What is the diameter of the Milky Way? (In light years)
100,000 light years
Astronomical Unit (AU)
The distance between the Earth and the sun (150 mil km)
How long does it take for Mars to orbit around the sun?
687 earth days, 1.88 earth years, 669 Martian sols
Mars surface area is what percent of earth’s?
38%
Mar’s diameter is what percent of earth’s
53%
What are Mars and earth’s average orbit speed around sun?
Earth: 18.5 miles per second
Mars: 14.5 miles per second
What is Mars and earths length of day?
Earth: 23 hr 56 min
Mars: 24 hr 37 min
What is mars is gravity in comparison to earth?
0.375
Mars average temperature
-81 F
Mar’s Moons
Phobos/ Deimos
Mar’s atmosphere
Mostly carbon dioxide
Mars habitable timeframe
4.1 to 3 billion years ago
Perhelion
The point in the orbit of a planet, asteroid, or comet at which it is closest to the sun.
Arsecond
A unit of angular measurement (1 degree= 3600 arcseconds)
Arcminute
A unit of angular measurement (1degree= 60 arcminutes)
Planetary Opposition
When the Earth is directly between the planet at opposition and the sun, forming a straight line. The planet is brighter and visible in the night sky, and is closer in proximity to Earth (Saturn, Jupiter, Mars)
How far apart are Earth-Mars opposition? (In days)
Approx. 780 days apart
Eccentric Orbit
- The planet’s distance from the sun varies throughout it’s orbit.
- Varying orbit speed: the planet moves faster at perihelion and slower at aphelion.
Albedo
The reflection of a celestial body’s surface. It’s the fraction of solar radiation reflected back into space often expressed as a percentage. High albedo means more reflection and low albedo indicates more absorption of incoming sunlight.
Opacity
The degree to which the atmosphere obstructs the passage of light through how much it scatters or absorbs incoming radiation, affecting visibility and the transmission of sun through the atmosphere.
High Opacity means less transparency often due to factors like particles or gases in the atmosphere.
Two Types of Martian Clouds
- Yellow clouds: dust storms
- White clouds: condensate
What hemisphere and when do yellow dust clouds often occur?
- Region: Southern Hemisphere
- Timing: Southern Hemishere’s spring and summer at perihelion.
What is the degree of Earth’s axial tilt?
Approx. 23.5 degrees
Obliquity
The tilt of a planet’s axis in relation to it’s orbital plane around the sun.
How does obliquity impact the potential habitability of a planet?
- Seasonal Variations: variations in the duration and intensity of sunlight at different latitudes throughout the year= distinct seasons.
- Temperature Extremes: a planet with a very high or low obliquity might experience significant temperature extremes, making it potentially challenging for life.
- Climate Stability: moderate obliquity can contribute to climate stability. Too much variation in climate over time could be detrimental to the development and sustainability of life.
- Ice cap dynamics: significant obliquity= polar ice caps might expand and contract dramatically, effecting sea levels and regional climates.
Mars Obliquity (present day)
Approx. 25.1 degrees
Maximum possible variation for Mars obliquity
14.9 to 35.5 degrees
Sol (sols)
Martian days
Martian year
- Areocentric solar day
- Areosynchratic year
How is Areocentric Longitude of the Sun abbreviated?
Ls
Areocentric Longitude
A way of describing Mar’s orbit around the sun using an angle measured to where in the Martian year the planet is.
What is the eccentricity value of Mars?
0.093
What is the eccentricity value of Earth?
0.017
How far is Mars for the sun during perhelion? (Au)
1.381 Au
How far is Mars from the sun at aphelion? (Au)
1.666 Au
Solar Flux
The amount of solar energy and radiation received per unit of time, per unit of area, and per unit of frequency.
Often expressed in watts per square meter (w/m^2)
What is the difference in percentage of solar flux on Mars between perhelion and aphelion?
Mars receives 45% more sunlight at perhelion than aphelion.