All the recent attention being placed on Mars is revealing an interesting planet with a history that I personally think would be hard to explain in a 6000 year old universe. There are details being revealed about possible past plate techtonics, magnetic fields, and surface water. Let's take a look, shall we. On earth, there is a record of crustal spreading that continues up to this very day. Perhaps the most famous example is in the middle of the Atlantic Ocean. Here new crust is being formed as the ocean spreads the Americas further and further away from Africa and Europe. Recorded in the new crust being formed are alternating magnetic field lines. As it turns out, a very similar situation has been found to have occurred on Mars in the distant past. "Magnetic lineations in the ancient crust of mars," Connerney JE, Acuna MH, Wasilewski PJ, Ness NF, Reme H, Mazelle C, Vignes D, Lin RP, Mitchell DL, Cloutier PA, Science. 1999 Apr 30;284(5415):794-8. On some of the oldest, most heavily cratered terrain on Mars, the Mars Global Surveyor has found evidence of banded magnetic lines. See http://www.solarviews.com/browse/mgs/magmap.jpg for an image of the data. The data is circumstantial in revealing the possiblity of past tectonic activity on Mars. While this seems to be the most likely possibility, others are possible. But what it does show with even more certainty is the Mars once possessed a relatively powerful global magnetic field. This field faded over time as younger, less heavily cratered areas do not show the banding. The loss of the magnetic field had other consequences. Both orbiting and surface exploration of Mars is revealing a history in which liquid water once existed on the surface of Mars. Currently, almost all of Mars exists at a set of surface conditions cooler and at lower pressure than the triple point of water. This means that for most of Mars, liquid water on the surface is not possible. Even where possible, it is only in an extremely narrow range of temperatures and at points much below the mean elevation where there is sufficient (just) pressure for water to exist as a liquid. But this was not so in the past. For instance if you follow this link http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20041007a.html you will see evidence for water action from the two Mars rovers. The article talks about a number of items, including layered rocks such as this http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20041007a/04-SS1-04-Color_Rock-A268R1_br.jpg that seem to have been deposited by water. There are also the "blueberries" that show evidence of formation in water. http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040318a.html . There are numerous bits of evidence for large scale water action on Mars. There are large canyons such as Valles Marineris which is the largest and most famous. But there is also evidence for lakes and meandering rivers and river deltas and even an ocean. For examples see "Evidence for persistent flow and aqueous sedimentation on early Mars," Malin MC, Edgett KS, Science. 2003 Dec 12;302(5652):1931-4. So what we have is a picture of Mars where the persistence of water indicates that it once held a much thicker atmosphere. This thicker atmosphere would have neccesitated a global magnetic field to prevent the atmosphere from being stripped away. We have evidence of just such a magnetic field in the bands of magnetic field lines on the surface of parts of Mars. That there are many bands indicates that the field persisted long enough for growth of new crust to occur through plate tectonics. Since we constantly disagree over how long it takes to form geologic features on earth, we will neglect for now even considering the time involved for them to form. Results from the Mars Express orbitor have measured the current loss of atmosphere from Mars at about 1 kg / sec and estimate that the loss at its maximum was about 100 kg / sec. Making an assumption that the atmosphere on Mars started at about 1 atm pressure (I have seen estimate that the atmosphere would have actually needed to be thicker than this to provide enough CO2 partial pressure to have sufficient surface temperatures.) and going through a very crude back of the envelope calculation, if that maximum rate had been maintained, it would take about 400 million years for Mars to lose its atmosphere. Even if the crude analysis is off by two orders of magnitude, you are still talking about millions of years for Mars to lose its atmosphere. (The process could be speed along a bit. Large impacts could remove some of the atmosphere quickly. But I do not think you will be able to lose the atmosphere in a couple thousand years that way. No impacts quite that big on Mars.) But before it can lose its atmosphere, it has to lose its magnetic field. That it had a magnetic field to begin with implies that it had a molten core capable of powering a dynamo producing a global magnetic field. To lose this dynamo, all that heat must be lost. Over 100 years ago, Kelvin estimated the cooling time of the earth to be 20 to 400 million years. His estimate were found to be very low because he did not know to include the effects of radioactivity. Even if we, too, ignore the effects of radioactivity, you should be able to see that it would take millions of years for the heat of Mars to escape to a point at which the dynamo would be lost. Unsteady state heat transfer is not that hard of a subject to get a grasp on. There just is not a way to remove all of that heat quickly. So, in summary, Mars shows evidence of an age much greater than a few thousand years. It surface shows the effects of a previous denser atmosphere that was capable of sustaining liquid water at the surface long enough for various features to form. The thicker atmosphere implies the need for a global magnetic field to keep the solar wind from removing the atmosphere. The magnetic bands found on the surface give evidence both for the magnetic field and that the planet was once geologically active and had a warmer interior. These both support that Mars once had an internal dynamo powered by a molten core. The rate of heat loss needed to lose the magnetic field and the subsequent rate of atmospheric loss after that both show that the process from where Mars started to where it is today would have taken orders of magnitude longer than a few thousand years.