Martian Overview

With the current missions to Mars, and now with the successful landing of the "Spirit" rover, interest in the red planet is rising by the day, so I thought now would be a good time to make these pages public again, this time updated with the latest information and images.

So starting with this page, which gives a brief overview of Mars, all without using excessive technical information, jargon or even too many rants about Human missions.

Mars is the forth planet out from our sun, it orbits between our Earth and Jupiter, its commonly known as the red planet due to its appearance when viewed from Earth, although we now know that its in fact more tan than red, from various space probes and surface landers. Its coloring is due to the presence of iron oxide in the martian soil, and yes that does mean Mars is rusty...

Before continuing on, just to show that Mars is not just another Earth, here is a direct comparison of the two planets, which shows its a totally different place, nothing at all like the Mars in some of the Hollywood movies which show it as a cold Earth like place, populated by strange alien life forms. Currently we just don't know if there is any life at all on Mars, although the chances of intelligent Martians are slim to non-existent. Whats not beyond hope that life of some form could be found below the martian surface, even though if it does exist its more than likely microbial than any higher forms. Anyway more on the life question later.

As you can see, Mars is not even close to another Earth, just waiting for us to go and take possession. In fact its a very hostile place for humans to goto, the atmosphere is very thin and toxic, its very cold, the surface is subject to high radiation levels, and finally the lower gravity is not good for our bodies.

All this aside Mars is still a fascinating place, there are geologic features which are a different order of magnitude to anything on Earth, the dramatic differences between the ancient southern and the relatively young northern hemispheres, this north south question is only one of the many unanswered questions about Mars we have yet to answer. Is there water there today? with new evidence it looks more and more possible with each new analysis of the data from the orbiters. As for the life question, we know that there was a period in Martian history where it was warmer and wet, but did life get going? and if so does it still exist today? Those are the questions the current missions are trying to answer.

For a little light relief, I also had to include the Mars face, yes Cydonia from "Mission to Mars" movie fame.

Olympus Mons Holds the title as the largest known volcano in the solar system, and is not going to lose that crown anytime soon, if ever. Its one of the four shield volcano's located in the Tharsis region in the northern hemisphere. Of these, Olympus Mons is the largest, being another example of the truly immense features of Mars, it is 624km across at its base, 25km high, is rimmed by cliffs 6km high, has a caldera 80km across.

Now compare that to the largest volcano on Earth, Mauna Loa which is only 120km across, and 10km high. See what I mean its on a different scale. Now for the rock climbers out there, who would like the challenge of the 6km high cliffs at the base? or the wall of the caldera? and these are not even close to the best climb on Mars. Moving onto another example of the awesome geologic features Mars has to offer.

Vallis Mariners is the grand daddy of all geologic features, this canyon truly deserves the title "Grand Canyon", its yet another example of the order of magnitude difference in scale when compared to similar Earth formations. Its so long at 4000km that as you see by the image, it would stretch right across the United States, as for the depth up 7km in places. Impressed, you should be, lets compare that to the "Grand Canyon" in Arizona which is only 800km long and 1.6km deep, no contest. See I told you there would be a better climb on Mars, just imagine standing at the bottom looking up, awe inspiring comes to mind.

Yes Mars has polar caps, just like we do, here on Earth, but unlike Earth the martian poles as far as we know are not make up entirely of water ice, but are composed of carbon dioxide ice (Dry ice), water ice and dust. It is thought that in the summer the CO2 sublimes (goes from a solid directly into a gas) into the atmosphere to leave water ice and dust behind. What is known, is that both poles contract and expand though the martian year and that at the permanent northern polar cap is made up of more water ice than the southern one. Back in 1998 the Mars Polar Lander mission, was to answer some of these questions, but failed after all contact was lost just after it entered the atmosphere.

Moving onto yet another of the unanswered Martian mysteries, the striking difference between the northern and southern hemispheres.

Yes they are different, as for why we do not know for sure why the difference exists, of the many theories that all try to answer this one, most use volcanic eruptions or impacts to try and explain the differences. To finally get to the bottom of this one will take extensive study in which robots are able to do some of the work, but a human presence is also needed.

I digress, so down to the nature of the differences. The north is made up of lightly cratered smooth planes that are thought to be volcanic in origin, and is home to the Tharsis and Elysium bulges. Bulges? yes they are just that, bulges in the crust, Tharsis being the largest at 4000km across, upto 10km high, its so big that it holds Olympus Mons and the other three shield volcano's. Elysium is smaller than Tharsis but is still is 2400km across and 5km high. Now for the south, which is totally different country, its far more like our moon than the north, being ancient judging by the heavy cratering. Some of these impact craters some are truly huge even by martian standards, the largest being Hellis at 1800km across and Argrye which is smaller at a mere 800km. Now compare these to Meteor crater in Arizona which is a little over 1km across. Just imagine, the impacts that created Hellis and Argrye must have been truly immense impacts, and if a rock of similar size was to hit Earth, thats it the end of the human species. Nothing would survive, except maybe the hardest bacteria.

Anyway after the doom and gloom of the end of the world, now seems like as good a place as any to lighten the tone somewhat, so here it is, as promised, the "Mars Face"

This interesting feature first showed up in a viking orbiter image of an area of the northern hemisphere called Cydonia. The original viking shot started all the speculation over whether its artificial, a trick of the light, not there at all, or a government cover-up. To me anythings possible, but not that likely that its artificial, it looks like a trick of the light, which by the way has only been seen on the viking shots not on the MGS images, or is that evidence of a cover-up. The face is not the only oddity, there is another one that's not quite as well known, its called "Happy face" on the MSS site, and for good reason as it looks like a giant smiley. In this case there is little doubt that this is just a fluke of martian geology, its just a crater that looks like a smiling face. With both I leave to you to make up your own mind. Just to stir up the debate even more, Cydonia and the Face was the basis for the movie "Mission to Mars". [more]

OK, now back to reality, and onto talking about some of the robotic space missions.

Over the past 30+ years, Mars has been visited by several space craft, some landing, others orbiting and some just doing a flyby. These missions started way back in 1965 with "Mariner 4" which was the first of many space craft to visit Mars, then in 1976 the Viking mission landed two probes which produced the first images of the surface. Since 1976 nothing else landed, all this changed in 1997 when the Pathfinder mission landed a small rover named "Sojourner" which proved to be a huge success producing the best surface images yet.

Next came the Mars Global Surveyor mission which arrived in Martian orbit back in 1997 and is still functioning even though it completed its primary mission back in January 2001. Following this successful mission came the 2001 Odyssey orbiter which arrived in Martian orbit, late in 2001, and is still operating.

Even more recently, we have the successful landing of the first of NASA's twin rovers "Spirit", soon to be followed by its sister "Opportunity" which is due to land on January 24, 2004. Add to that the recent arrival of the European Mars Express mission, things are starting to get really interesting, giving much to look forward to, and all without the Viking - Pathfinder 20 year delay.

One of the primary objectives of all the current missions, has been to look for signs of water, as its widely believed that Mars was once a warmer and wetter place that it is now.

Images taken by orbital spacecraft show features like; dry river beds, tear drop shape islands and other geologic features that could only have been created by flowing water, in the martian past. Indeed there is still water on Mars, we now know that the permanent northern polar cap is mainly made up of water not carbon dioxide ice, and images from the Viking landers show frost and snow on the surface in the early hours of the martian day. Today unfortunately liquid water cannot exist on the surface as the atmospheric pressure is too low, at these kinds of pressure water would sublime (go from a solid directly to a gas). So there is no liquid water present, this does not mean that it cannot exist underground, indeed in recent times there has been some evidence of the presence of aquifers, and its widely believed that water exists in underground permafrost. The image on the right shows layers of rock on Chandor Chasma taken by the MGS, and showing what look like features, that on Earth would have been made by liquid water. This is but one of many images that show these features, other than this in the past few weeks other images have been released that show layered features that look like sedimentary formations, created by pooled water (sea's and lakes). Yes when comparing to the earth the evidence is compelling, but still cannot be taken as fact until "we go and look", whether robots or human geologists its a question thats critical to future human settlement.

The confirmation of the presence of water on the martian surface away from the poles would make the prospect of human missions more likely sooner than later, as local water could be used to support Human presence on the surface, and all without the need to ship it from Earth or even collect it from the Martian poles.

Finally its time to again touch on the life question

With the mounting evidence for the presence of water on the martian surface in the past, and water being one of the known requirements of life, did life get started on Mars?. What we can be fairly sure about is that life does not exist currently on the surface, due to the extreme environment, such as the soil being super arid (water is needed for life as we know it), and being constantly sterilized by intense ultra violet radiation.

Whats less certain is if life exists or ever existed below the surface, shielded from the UV radiation? The only way to answer this one is the "Go look" which is another of the mission objectives of the current missions. Here on Earth we have found bacteria living in areas that where until recently thought devoid of life, so you never know the same could be true on Mars.

I hope that this page has given you some basic ideas about Mars in general, without boring or blinding with science, now read on to find out about conditions on the surface, the two martian moons and even about the weather.

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