Celestia Forums

If Mars had a magnetic field like Earth, I think it would be hospitable to life. Our magnetic field protect us from radiation and avoid atmospheric erosion by the solar wind. So with that, Mars should keep a thicker atmosphere, even at it's lower gravity and also most deadly radiation would not reach the surface. The magnetic field should protect Mars from solar wind and so avoiding erosion of the atmosphere over time. Avoiding erosion of air, and having a thick air the planet would be hotter, maybe allowing lots of liquid water on it's surface.
I think the secret is if Mars was as dense as Earth or even more dense. If the core was denser, it would have such magnetic field. Not only this but the gravity would be higher, keeping more volatiles, keeping that planet hotter.
Another possibility if if Mars orbited a gas giant. A not so massive gas giant like Uranus or Neptune should cause enough stress on Mars core to make it hotter and maybe the magnetic field of the gas giant should protect Mars, or activate the field of Mars.
One more possibility is if Mars had a big moon orbiting it. The moon would cause a constant tidal stress on Mars interior, as in the case of a gas giant, keeping it hotter for a much longer time.

Hot and protected Mars= A green/blue Mars!!!

Someone have another opinion? I want to discuss such possibilities.

I am not sure that this actually belongs in this section, but here goes.

Most of what you state could be true. Mars being almost half the size of Earth one would think it would have at least has its density ergo nearly half its gravity. But in the real world Mars is made up of lighter materials. Its like saying that if Earth is made of wood, Mars is made of balsa. Both are wood, but balsa is is not very dense at all. Why Mars got to be so light is anyones guess. Most likely being to close to Jupiter had allot to do with it.

Now as for the magnetic field. New information gleaned by magnetic surface scans of Mars suggest that in it youth it very possibly had a magnetic field even stronger than the one Earth has now. It had a very strong spinning core and it created a very strong dynamo effect. So Mars did have a good protective barrier early on. But Mars was also struck by many very large impacts. When something is impacted like that it creates strong shock waves. Possibly even strong enough to have an effect on the dynamo effect. At least the shock waves may have been enough to slow it down. Once it started to slow down, it was all down hill from there.

Another thing are the new findings are starting to point that Mars is actually over time been getting more volcanically active over the eons, totally backward to how most have thought it should be. Volcanic activity is a strong way for a planet to move heat from its interior to its surface. Its also pointing that Mars is actually trying to kick start plate tectonics, but there being no oceans there, there is no water to lubricate the rocks. Or at least water in liquid form enough to help this process along but maybe in small regional areas.

We really hardly no very much about are own little neighbor planet. The rest of your ideas are well and fine, but Mars doesn't orbit a gas giant and if it did, it would be made of allot of ice and it would be a totally different place. It would be Ganymede, Titan, or Triton and your ideas would simply not apply. Even if the gas giant orbited in the habitable zone of a star, it would have migrated there from farther out in the system and again the moon would have originally been made of allot of ice. This could be debated all day and night.

The one really good point you made was what it would like if Mars had a large moon. Far in the future we might be able to move large objects like dwarf planets around the solar system. There is a very good candidate that id very close to Mars. Its Called Ceres and one day we might have the ability to move that little world into a Martian orbit and see what the gravitation effects would be. I have taken this into account in a project I am working on. Oh and interestingly enough Ceres was the goddess of agriculture, fertility and harvest. Kind of makes you wonder what I did with it.

Don. Edwards

Don. Edwards wrote:Most of what you state could be true. Mars being almost half the size of Earth one would think it would have at least has its density ergo nearly half its gravity. But in the real world Mars is made up of lighter materials. Its like saying that if Earth is made of wood, Mars is made of balsa. Both are wood, but balsa is is not very dense at all. Why Mars got to be so light is anyones guess. Most likely being to close to Jupiter had allot to do with it.

At least some of the density contrast is due to greater gravitational compression in the more massive Earth, but the uncompressed density of Mars is still estimated to be smaller than that of the Earth: Mars apparently contains a smaller proportion of iron and more oxygen than the Earth does. I'd guess this is down to the planet being located closer to the snowline and hence incorporating more volatile-rich material rather than the influence of Jupiter.

Don. Edwards wrote:Another thing are the new findings are starting to point that Mars is actually over time been getting more volcanically active over the eons, totally backward to how most have thought it should be. Volcanic activity is a strong way for a planet to move heat from its interior to its surface. Its also pointing that Mars is actually trying to kick start plate tectonics, but there being no oceans there, there is no water to lubricate the rocks. Or at least water in liquid form enough to help this process along but maybe in small regional areas.

Really? Latest I've heard is that the Martian activity is episodic, with a general decrease over time (however there seems to be a long gap between 2-3 Gyr in which data seems to be lacking). See here and here.

Don. Edwards wrote:The rest of your ideas are well and fine, but Mars doesn't orbit a gas giant and if it did, it would be made of allot of ice and it would be a totally different place. It would be Ganymede, Titan, or Triton and your ideas would simply not apply. Even if the gas giant orbited in the habitable zone of a star, it would have migrated there from farther out in the system and again the moon would have originally been made of allot of ice.

Terrestrial planets can form in orbit around gas giants: we have an example of such a world in our solar system, which is Jupiter's moon Io. This may have been because of hot conditions in the inner circumjovian disc where Io formed. Similarly Europa is basically a terrestrial planet (in that it is mainly rocky), albeit one with a global ocean, in contrast to the ice-dominated Ganymede and Callisto. Whether it would be possible to build up Mars-size terrestrials in a circumjovian disc (perhaps around a more massive jovian or in a more metal-rich system), I don't know. The case for migrating planets isn't entirely clear either: it also depends on the timescale for moon formation. If the moons begin forming post-migration, the circumjovian disc would then be supplied with material from the inner disc, which would be less volatile-rich, leading to the possibility of terrestrial-type moons.

ajtribick,

I went took a look to find the article I spoke of. Its titled "Violent Volcanic Mars"

Here is the article.

Violent Volcanic Mars
Based on an ESA news release

Mars Express reveals the Red Planet's volcanic past

A new analysis of impact cratering data from Mars reveals that the planet has undergone a series of global volcanic upheavals. These violent episodes spewed lava and water onto the surface, sculpting the landscape that ESA's Mars Express looks down on today.

Using images from the High Resolution Stereo Camera (HRSC) on Mars Express, Gerhard Neukum, Freie Universit?t Berlin, Germany, and colleagues are discovering the history of the Red Planet's geological activity. "We can now determine the ages of large regions and resurfacing events on the planet," says Neukum. Resurfacing occurs when volcanic eruptions spread lava across the planet's surface.

This graph illustrates volcanic episodes in martian history, as inferred by G. Neukum et al. using pictures from the High Resolution Stereo Camera on board Mars Express.
Credit: Neukum and HRSC Team, 2008, chronology: Neukum & Hartmann, 2001
This work has suggested that the sculpting of the Martian surface has not proceeded in a steady fashion, as it does on Earth. Rather, the team have discovered that Mars has been wracked by violent volcanic activity five times in the past, after the early supposedly warmer and wetter phase, more than 3.8 thousand million years ago. In between these episodes, the planet has been relatively calm.

Mars Express image of Daedalia Planum.
Credit: ESA/ DLR/ FU Berlin (G. Neukum)
The five volcanic episodes stretch throughout Martian history, occurring around 3.5 thousand million years ago, 1.5 thousand million years ago, 400-800 million years ago, 200 million years ago and 100 million years ago. Neukum estimates that the dates of the earlier episodes are correct to within 100-200 million years and that the later dates are correct to within 20-30 million years.

The ages have been estimated by counting the number of small craters that appear on the landscape. The idea is simple: the older the surface, the more craters it will have accumulated as meteorites of all sizes have struck over the ages.

There has been a debate recently about the validity of this method. Some researchers believe that the small craters are not produced by incoming meteorites but by chunks of Martian rock blasted over the surface after a single large impact. However American researchers, analysing seven years' worth of images from the Mars Orbiter Camera (MOC) on NASA's Mars Global Surveyor, have found new craters appearing on the surface during that time.

Mars Express above the thin Martian upper atmosphere successfully achieved orbital insertion on Christmas 2003. The satellite recently completed its first 'extended' mission, and has been in orbit around Mars for a total of almost four years.
Credit: ESA
"The present day cratering rate can be calculated from their observations," says Neukum. It fits very closely with the cratering rate he established from the Mars Express data with Bill Hartmann, Planetary Science Institute, Tucson, Arizona, giving him confidence in the estimates.

During these volcanic episodes, eruptions of lava flowed across Mars. The internal heat generated by the volcanic activity also caused water to erupt from the interior, causing wide-scale flash flooding. The data provides insight into the history of water on Mars, and can help astrobiologists understand if and when Mars may have been a suitable habitat for life.

As for why Mars behaves like this, geophysical computer-based models suggest that the planet has been trying to establish a system of plate tectonics, as there is on Earth where the crust is broken into slowly moving plates. On Mars, the volcanic episodes represent the planet almost achieving, but not actually attaining, plate tectonics - and these volcanic episodes might not be over.

"The interior of the planet is not cold yet, so this could happen again," says Neukum.

Far from revealing a geologically dead world, Mars Express is exposing a place of subtle activity that could still erupt into something more spectacular.

The article its self can be found here http://www.astrobio.net/news/modules.ph ... =0&thold=0

Even with the debate about how the cratering is occurring it plainly shows that the activity has been increasing not decreasing.

Don. Edwards

Actually it is not clear at all from that diagram that the activity is increasing. Without values on the volume of erupted material it is pretty much impossibe to make that call: on the diagram the last two episodes are depicted using smaller icons but it is not clear whether that is merely a means to put all the episodes on the diagram or if they were genuinely smaller events.

There is also bias to consider: in general, events further back in time are harder to detect: thus, assuming smaller volcanic episodes are more common than large ones, we would expect to find more evidence for volcanic episodes in the recent past, since only the rare large ones can be detected that far back in time.

From the first reference I gave (which actually corresponds to the information in the news release - I prefer to get information from the source rather than news releases)

There is a remarkable paucity of age occurrences in the 2-3 Ga age range in the cratering data. This corresponds to a paucity of meteorite ages in the same, even somewhat more extended age range. This appears to be a hint to either lower geologic activity in this time frame, or the covering up of more ancient activity by subsequent events <2 Ga ago, with the exception of the residues from the time >3 Ga ago (the peak at approx. 3.5 Ga) when the martian surface was thoroughly shaped at a very high level of activity by gigantic volcanic, fluvial, and glacial events which could not be completely erased by later events.

So it would seem that the 3.5 Ga event was indeed a very large one, which would fit in with the bias idea.

In my add-on, Cydo'Nia and Cythe'Rea orbit each other. Cydo'Nia is like Mars, but geologically active and with life. The same for Cythe'Rea. The fact of they are orbiting near each other makes intense vulcanism. One is tidal heating the core of the other, so they'll be active for many and many billions of years. Each one have a small moon, like Phobos and Deimos, orbiting them. I called them Folbina and Daimona. Cythe'Rea don't have a so thick air as Venus and the air pressure is about 5atm. Cydo'Nia air pressure is about the same as Earth. Cythe'Rea is much hotter than Cydo'Nia, while Cydo'Nia is a bit colder than Earth but both are still good for the development of complex and intelligent life. Both worlds are toxic to humans, because of the higher concentration of CO2 in the air.

Cere'Sia is even more poisonous, because the air has much N2, CH4, hydrocarbons and CO2. Complex life here didn't needed oxygen, maybe because of the lower reactions caused by the low temperature of the planet, that have oceans of water/ammonia at surface temperature of about -50°C. Maybe complex life, in some worlds, don't need oxygen because there are other biosignal gases for them to use, like methane, N2O...