The Sun, Moons, & Mars

Let's meet the aliens!

By Julianna Milidantri

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Day & Night on Mars

Mars will have day and night because it revolves a sun and rotates on an axis. A full day and night is how long it takes a planet to make one full rotation on its axis. Mars' period of rotation is 24 hours and 37 minutes. For the 12 hours (approximately) one side of the planet faces the Sun, and it is day there. It is dark (night) on the other side of the planet, because the sunlight can't reach it yet. As the planet rotates, the other side of the planet then gets its 12 hours of sun. However, we say on Earth it has been "one day." One Mars, one day would be called "one sol," pronounced like the word "soul."

(picture courtesy of buzzle.com)

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Years on Mars

Mars will have years because it revolves, or orbits, around the sun. Mars orbits the Sun, because the Sun has more mass and therefore more gravity. By "revolving the Sun," it means that Mars makes an elliptical (slightly oval) path around the sun continuously. Mars makes 1 complete revolution around the Sun every 687 Earth days. One revolution around the sun is equal to one year.

(picture courtesy of www.space.com)

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Seasons on Mars

Mars will have seasons because it revolves around the Sun and is tilted on its axis. To have a "tilted axis" means that Mars doesn't revolve around the Sun in a completely upright position. It is tilted a little. As it revolves around the sun at a 23.5 degree tilt, areas tilted towards the sun at one point receive more direct sunlight than areas that aren't. The more direct light received, the hotter the area becomes, and it will most likely be summer. When an area of the planet receives indirect light, it is colder, mostly likely winter. Then, as the planet continues to revolve, other areas will be tilted towards the sun and receive more direct sunlight than previously.

(picture courtesy of blogs.discovermagazine.com)

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Phases of the Moon(s) on Mars

Mars will have phases of the moon, because it has a Sun to revolve around and two moons (Deimos and Phobos) that orbit it. Phobos and Deimos orbit Mars, because Mars has more mass and therefore more gravity than its moons. The Sun's light will create lighter and darker parts on the moons at different positions around Mars. This causes different areas to be lit or appear "fuller." When a moon is "waxing," the light appears to increase. When a moon is "waning," the light appears to decrease.

Tides on Mars

Mars will not have tides because it does not have a large amount of running water. Tides, though, are the rise and fall of the ocean along a shoreline. Tides are caused by the pull of the Sun, Mars, and its moons' gravity. The moon will pull the ocean water toward it a little, and the Sun will also cause a gravitational influence, causing high and low tides at various points of the day. Mars won't have tides because cold temperatures cause frozen water to go straight from solid to gas form! The liquid form is completely skipped. For a long time, scientists even believed that Mars had no running water!

(picture courtesy of en.wikipedia.org)

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Eclipses on Mars

Mars will have lunar eclipses because it has a Sun that it revolves around, and the moon(s) have enough of a tilt to sometimes reach the ecliptic plane. An eclipse is when an something comes between another object and the Sun. The tilt of Deimos is about 0.93 degrees, and Phobos' tilt is about 1.093 degrees. (Remember, Phobos and Deimos are Mars' two moons.) The 'ecliptic plane' is the level in which a moon, the Sun, and Mars are lined up exactly. This causes the moon to be in a shadow, which is a lunar eclipse. In a solar eclipse, the moon is between the Sun and Mars and casts a shadow on Mars. The moon may even appear red, because light from the atmosphere refracts onto the moon. Eclipses will happen more often on Mars than on Earth, about twice a month to be exact, because there are two moons that could eclipse. However, only one moon would eclipse at a given time.

(picture courtesy of www.spaceacademy.net.au)


Note: although the image below shows Earth, the same concept of eclipses applies to Mars. The picture below specifically shows a lunar eclipse.

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Comparison of Earth & Mars

Mars will have years because it revolves around the Sun. It revolves specifically around the Sun, because the Sun has more mass and therefore more gravity than Mars. This is the same with Mars' moons revolving Mars, they have less mass than Mars, so they revolve it. It will be different from Earth because:

** Its revolution time is much longer than Earth’s. Earth's revolution time, or the time it takes to make one full orbit around the sun, is 365.25 days (which is why we have a leap year every 4 years, because .25 * 4 is 1.0 year).

** Mars' period of revolution, however, is 687 Earth days. Why is Mars' period of revolution so much longer? It is longer because, as pictured below, Mars is farther from the Sun. This will affect its period of revolution because it will have to make a larger orbit in order to complete a full revolution, and that takes longer.

** Mars has 2 moons and Earth has only 1.

Mars and Earth are also similar because:

** They both make elliptical orbits (oval-shaped orbits). In addition, they each revolve in the same direction around the Sun.

** A final similarity is they revolve around the sun at similar speeds, Earth revolving at 30 km/sec (according to link A below) and Mars revolves at 24 km/sec (according to link B below).


A: coolcosmos.ipac.caltech.edu

B: www.enchantedlearning.com/subjects/astronomy/planets/earth/Speeds.shtml


(picture below courtesy of http://illuminations.nctm.org/)

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