Universe Today

Of all the features of Mars, its axial tilt is most similar to Earth. Mars’ tilt is 25 degrees, just a fraction away from the Earth’s 23.5 degrees. And because of this tilt, Mars has seasons, just like the Earth. Of course, since Mars takes twice as long as Earth to orbit the Sun, the seasons are twice as long.

Mars also has a very elliptical orbit. Because of this, the difference between its closest and most distant point along its orbit vary by 19%. This extreme difference makes the planet’s southern winters long and extreme. The northern winters aren’t as long or cold.

Astronomers know that the current tilt of Mars’ axis is just a fluke. Unlike Earth, the planet’s tilt has changed dramatically over long periods of time. In fact, astronomers think that the wobble in the tilt might help explain why vast underground reservoirs of water ice have been found at mid-latitudes, and not just around the planet’s poles. It’s possible that in the distant past, Mars was tilted at a much more extreme angle, and the ice caps were able to grow across the planet. When the tilt was less extreme, the ice remained, and was covered by a layer of dust.

Researchers have developed a model that accounts for the advance and retreat of the subsurface Martian ice sheets over 40 ice ages and 5 million years.

Here’s an article that explains how scientists track the Martian equator in the past. And the lopsided ancient oceans on Mars are explained by its tilt in the past.

Here’s some information about the tilt and seasons on Mars from MSSS. And the Wikipedia article about timekeeping on Mars.

Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Mars dust storms are much different than the dust devils that many people have seen in images sent back from the planet. On Mars a dust storm can develop in a matter of hours and envelope the entire planet within a few days. After developing, it can take weeks for a dust storm on Mars to completely expend itself. Scientists are still trying to determine why the storms become so large and last so long.

All Mars dust storms are powered by sunshine. Solar heating warms the Martian atmosphere and causes the air to move, lifting dust off the ground. The chance for storms is increased when there are great temperature variations like those seen at the equator during the Martian summer. Because the planet’s atmosphere is only about 1% as dense as Earth’s only the smallest dust grains hang in the air.

Surprisingly, many of the dust storms on the planet originate from one impact basin. Hellas Basin is the deepest impact crater in the Solar System. It was formed more than three billion years ago during the Late Bombardment Period when a very large asteroid hit the surface of Mars. The temperatures at the bottom of the crater can be 10 degrees warmer than on the surface and the crater is deeply filled with dust. The difference in temperature fuels wind action that picks up the dust, then storm emerge from the basin.

The dust storms were of great concern when probes were first sent to Mars. Early probes happened to arrive in orbit during large events. The Viking missions of 1976 easily withstood two big dust storms without being damaged. They were not the first missions to survive Martian dust storms. In 1971, Mariner 9 arrived at Mars during the biggest dust storm ever recorded. Mission controllers simply waited a few weeks for the storm to subside, then carried on with the mission. The biggest issue that rovers face during a dust storm is the lack of sunlight. Without the light, the rovers have trouble generating enough power to keep their electronic warm enough to function.

Mars dust storms are of great interest to scientists. Even though several spacecraft have observed the storms first hand, scientists are no closer to a definitive answer. For now, the storms on Mars are going to continue to present challenges to planning a human mission to the planet.

Here’s an article describing how the dust storms threatened the Mars rovers, and another discussing how electrical dust storms could make life on Mars impossible.

Here’s one of the best articles from NASA about the dust storms, and another gallery from NASA/JPL.

Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Sources:
http://science.nasa.gov/science-news/science-at-nasa/2003/09jul_marsdust/
http://www.jpl.nasa.gov/news/news.cfm?release=2007-080
http://science.nasa.gov/science-news/science-at-nasa/2001/ast16jul_1/

Mars rotation is 24 hours, 39 minutes, and 35 seconds if you are interested in the solar day or 24 hours, 37 minutes and 22 seconds for the sidereal day. Since the planet only rotates about 40 minutes slower than Earth, this is one category where the two planets are not very different. Mars, like all of the planets except Venus, rotates in prograde(counter clockwise). The planet has a rotational speed of 868.22 km/h at the equator. The similarity if the length of the day allows the engineers as NASA to switch their day to a ”Mars day” when they are working with rovers on the planet. This maximizes their time with the equipment, but drastically changes their actual Earth schedule. They end up working an ever changing day as the Martian/Earth day difference accumulates.

Mars is a well studied planet. As a matter of fact, it is the best understood planet in our Solar System other than our own. There are currently(July 2011) 6 missions either in orbit or on the planet’s surface. With all of the data accumulated, Mars rotation is only one of thousands of facts known about the planet. Here are a few more.

Multiple missions to Mars have found evidence of water ice and carbon dioxide ice under the planet’s surface. How do scientists know the difference? When the ice is exposed to the Martian atmosphere, carbon dioxide ice(dry ice) will melt and vaporize quickly, in one day or less. Water ice will take up to four days. The other way is to heat a sample in one of the tiny ovens aboard a rover. The spectrometer on the rover will then be able to detect H₂O in the gases that the sample releases.

Mars has a reddish appearance because it is covered in rust. Well, iron oxide dust. That dust is every where. Mars has large dust storms that can sometimes cover the entire planet, so that dust is in the air as well. During global dust storms it is impossible to optical observe the surface.

Mars has not had plate tectonics for billions of years, if ever. The lack of plate movement allowed volcanic hotspots to spew magma onto the surface for millions of consecutive years. Because of these uninterrupted eruptions, there are many large volcanic mountains on Mars. Olympus Mons, on Mars, is the largest mountain in the Solar System.

Those are just a few teaser facts. I wish I had more space to keep going, but we have hundreds of more articles about Mars here on Universe Today and do not forget to check out NASA’s website. Good luck with your research.

Here’s an article about how crater impacts measure the ancient equator of Mars. How long is a day on Mars?

Enjoy some Mars facts from NASA, and Hubblesite’s News Releases about Mars.

Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Source: NASA

Mars mass is 6.4169 x 10²³ kg. That is slightly more than 10% of the Earth’s mass. Mars is a tiny world in every way when compared to Earth. In our Solar System, Mars is the second smallest planet by mass. Only Mercury is smaller. While Mars is a tiny planet, it is the most explored outside of our own. Here are a few Mars missions and some of the discoveries that each made.

Mariner 3 and 4 were meant to be sister missions to Mars. Mariner 3 failed shortly after launch, but Mariner 4 arrived in Martian orbit after an 8 month journey. It is credited with returning the first images from another planet. It was able to show large impact craters that appeared to have frost on them. The spacecraft and its equipment were crude by modern standards.

We will skip a few missions and move to the Phoenix Lander. This mission’s objective was to confirm the presence of water ice underneath the Martian surface. This water ice had been theorized for quite some time, but lacked confirmation. On June 19, 2008, NASA announced that bits of bright material in a trench dug by the lander’s robotic arm had disappeared over the course of four days. This implied that they were composed of water ice. Initially, they were thought to be water ice or carbon dioxide ice(dry ice) In the conditions on Mars dry ice would have disappeared much faster. Phoenix later confirmed the presence of water ice on Mars using a mass spectrometer. When a soil sample was heated, water vapor appeared as the sample heated to 0 degrees Celsius.

The Mars Express is one of several spacecraft currently exploring Mars. It has sent back images and data the strongly suggest that the Martian environment is much different today than it was a few billion years ago. Interpretation of the data shows that Mars was once a warm and wet world with rivers and oceans dotting its surface. No evidence of past vegetation or life has been found, but proof of liquid water in the planet’s past is intriguing enough.

Knowing Mars mass is enough to answer one question on a test or in a paper, but, to understand the planet, you will have to do quite a bit more research. You will not be alone. NASA scientists are planning at least four more missions by 2020 including a mission to return samples of the Martian soil. The goal is to understand Mars well enough to send a manned flight to the Red Planet.

Here’s a great article about how difficult it will be to land large loads on Mars.

This site lets you calculate your weight on other worlds. And here’s NASA’s fact sheet on Mars.

Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Sources:
NASA: Mars Facts
NASA: Mars Missions

Mar’s surface is a dry, barren wasteland marked by old volcanoes and impact craters. The entire surface can be scoured by a single sand storm that hides it from observation for days at a time. Despite the formidable conditions, Mar’s surface is better understood by scientists than any other part of the Solar System, except our own planet, of course.

Mars is a small world. Its radius is half of the Earth’s and it has a mass that is less than one tenth. The Red Planet’s total surface area is about 28% of Earth. While that does not sound like a large world at all, it is nearly equivalent to all of the dry land on Earth. The surface is thought to be mostly basalt, covered by a fine layer of iron oxide dust that has the consistency of talcum powder. Iron oxide(rust as it is commonly called) gives the planet its characteristic red hue.

In the ancient past of the planet volcanoes were able to erupt for millions of years unabated. A single hotspot could dump molten rock on the surface for millenia because Mars lacks plate tectonics. The lack of tectonics means that the same rupture in the surface stayed open until there was no more pressure to force magma to the surface. Olympus Mons formed in this manner and is the largest mountain in the Solar System. It is three time taller than Mt. Everest. These runaway volcanic actions could also partially explain the deepest valley in the Solar System. Valles Marineris is thought to be the result of a collapse of the material between two hotspots and is also on Mars.

The Martian surface is dotted with impact craters. Most of these craters are still intact because there are no environmental forces to erode them. The planet lacks the wind, rain, and plate tectonics that cause erosion here on Earth. The atmosphere is much thinner than Earth’s so smaller meteorites are able to impact the planet.

Mar’s surface is believed to be much different than it was billions of years ago. Data returned by rovers and orbiters has shown that there are many minerals and erosion patterns on the planet that indicate liquid water in the past. It is possible that small oceans and long rivers once dominated the landscape. The last vestiges of that water are trapped as water ice below the surface. Scientists hope to analyze some of that ice and discover hidden Martian treasures.

How seasonal jets darken the surface of Mars, and how ice depth varies across Mars.

Want to explore the surface of Mars, check it out with Google Mars. Here is some more information about surface features on Mars.

Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Mars
http://search.nasa.gov/search/search.jsp?nasaInclude=mars+planet