Early Mars: wet, warm, humid & sticky?

[Bad Ronald]

Hurricane Earl makes me wonder how wet, wild & stormy early Mars was. How common were hurricanes, tornadoes, monsoons?

As time went on of course, Mars became Antarctica like, then finally becoming what it is today: arid, dry, thin-aired & deep cold;well below the line.

How wet & humid might early Mars have been? If the 36% of the surface in the north was covered by an immense ocean with rivers flowing into it & scattered lakes, no doubt there was alot of rain & storms.

Mars has 10% of the Earth's mass & 38% of its gravity yes? This is probably why Mars failed to stay Earthlike or Class M as Star Trek calls it.

What would Mars be like today if it had half the Earth's mass? And what would its surface gravity be?

[baric]

How wet & humid might early Mars have been? If the 36% of the surface in the north was covered by an immense ocean with rivers flowing into it & scattered lakes, no doubt there was alot of rain & storms.

It's hard to say. 36% of Mars surface is equal in area to 10% of Earth's surface. That's 1/7th of the total area of water on the Earth. That would seem to constrain the maximum size of ocean-generated storms.

[Lord Jubjub]

The height of the supercells would also be effected. It would be interesting to see what the computer models would do with Mars-like conditions.

[Bad Ronald]

Mars is physically roughly half the size of the Earth yes? But only a 10th as massive with a surface gravity equal to Mercury's. Correct?

Now suppose you leave Mars the same size, but make its mass half the Earth's mass, from the getgo. How does Mars evolve? If Mars had had half Earth's mass in addition to being half Earth's size, what would the surface gravity be?

How Earthlike would Mars be today?

[AndreasJ]

Mars is physically roughly half the size of the Earth yes? But only a 10th as massive with a surface gravity equal to Mercury's. Correct?

Approximately.

Now suppose you leave Mars the same size, but make its mass half the Earth's mass, from the getgo. How does Mars evolve? If Mars had had half Earth's mass in addition to being half Earth's size, what would the surface gravity be?

½ Earth's mass at ½ Earth's radius works out to 2 times Earth's surface gravity. But there's no realistic way so small a planet would end up that dense.

[chornedsnorkack]

½ Earth's mass at ½ Earth's radius works out to 2 times Earth's surface gravity. But there's no realistic way so small a planet would end up that dense.

Indeed - it works out 4 times Earth density. Roughly the density of uncompressed iridium.

[tnjrp]

Hurricane Earl makes me wonder how wet, wild & stormy early Mars was. How common were hurricanes, tornadoes, monsoons?

It certainly is starting to seem more and more like it was fairly wet some time in the past. Without doubt it had it's share of various storm types as it still does. No idea personally how the smaller gravity would affect their behaviour specifically, tho I do believe atmospheric density is a significant factor.

Mars has 10% of the Earth's mass & 38% of its gravity yes? This is probably why Mars failed to stay Earthlike or Class M as Star Trek calls it

One major difference is also the lack of strong magnetic field. Am not sure if it is assumed to have deteriorated over time or if it is thought to have been insignificant to begin with. Combined with smaller gravity, the lack of magnetic field is I believe fairly commonly thought to rather adversely affect planetary atmosphere.

[Jens]

Mars is physically roughly half the size of the Earth yes? But only a 10th as massive with a surface gravity equal to Mercury's. Correct?
?

Others have mentioned that this would be unrealistic. I'm not sure, but it may be that you are assuming that the word "half the size" means "half the size in volume." In fact, it means "half the size in radius," and a body with double the radius will have a much larger volume.

[AndreasJ]

One major difference is also the lack of strong magnetic field. Am not sure if it is assumed to have deteriorated over time or if it is thought to have been insignificant to begin with. Combined with smaller gravity, the lack of magnetic field is I believe fairly commonly thought to rather adversely affect planetary atmosphere.

I don't understand that idea. Venus doesn't have a magnetic field to speak of, yet its atmosphere is far more impressive than Earth's.

[tnjrp]

The very short version is found in Wikipedia (with references for further reading, as well as the estimate I didn't recall earlier on when the magnetosphere "went down"):

Mars lost its magnetosphere 4 billion years ago, so the solar wind interacts directly with the Martian ionosphere, keeping the atmosphere thinner than it would otherwise be by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Express have detected these ionised atmospheric particles trailing off into space behind Mars

In the case of Venus, as I recall, the higher gravity and a different atmospheric composition have created a contrary situation.

[AndreasJ]

That would seem to leave the magnetic field as a factor of secondary importance at most.

[Bad Ronald]

How do you figure out the surface gravity of a planet, moon, other?

It seems Mars went from being hot, humid, muggy, sticky & possibly averaging 80-90 degrees F worldwide with a good magnetic field to being Planet Greenland/Antarctica with weakening magnetic field to what it is now: frigid whisper thin air with "no" magnetic field.

Maybe if Mars had had a quarter of Earth's mass it'd be another Earth today. Greater mass equals denser core yes? Mars spins fast so it probably would have a decent magnetic field.

Seems Mars went, overnight, from being a smaller Earth to what it is now

[AndreasJ]

How do you figure out the surface gravity of a planet, moon, other?

By applying Newton's Law of Gravitation.

If the body's mass (M) and radius (R) are given as multiples of Earth's, it's particularly easy to derive it's surface gravity (g_S) as a multiple of Earth's: it's just g_S=M/R²

Thus, for the example above with ½ Earth's mass and ½ Earth's radius, the surface gravity is 0.5/(0.5)² = 1/(0.5) = 2 times Earth's.

[forrest noble]

According to the links below Mars wet period was thought to be at its height between 3-3 1/2 billion years ago somewhat coinciding with a very active volcanic period at that time. It would seem that volcanic gases could continue to add to the atmosphere that would assist in keeping surface water liquid, allowing for rain and flowing water and probably saline lakes and oceans. Other than CO2, probably not a hospitable atmosphere to many forms of Earth life with probably tiny amounts of oxygen and probably considerable sulfur dioxide and acid rain like the early Earth. Between 1-2 two billion years is the age of most craters on the surface today indicating that the lack of an atmosphere since then allows more small meteor impacts without them burning up first when passing through the atmosphere. Without much of an atmosphere or pressure, water could not be a liquid for long on the surface. To this day there is a small amount of atmospheric water that does condense seasonally, but generally Mars' wet days, storms and Earth-like weather are thought to be billions of years past.

http://volcano.oregonstate.edu/oldro.../Overview.html

http://www.msnbc.msn.com/id/25703726/#slice-2

http://www.sciencedirect.com/science...6&searchtype=a

[John Xenir]

So the last volcanic eruption was not any later than 20 million years?

But going this way, in few million years will Mars become a dead world? (Lunar like (only traces of atmosphere, this is how I call such worlds, I call Mars desert world now)

[forrest noble]

So the last volcanic eruption was not any later than 20 million years?

But going this way, in few million years will Mars become a dead world? (Lunar like (only traces of atmosphere, this is how I call such worlds, I call Mars desert world now)

Many think of Mars as nearly a "dead world" now but others see the seasonal changes and consider the possibility of it having a small hot liquid metallic core. Mars may never be a totally dead world but also not an active world to the extent that the Earth is. When we terraform Mars some day we probably won't have to worry about Mars quakes of any magnitude. Toxic gases escaping from volcanic vents is a possibility but much more likely on Earth. Since Mars sits directly adjacent to the asteroid belt it also has a higher probability of getting hit more often than the Earth does, maybe opening fissures to underground water and relative hot spots that could be explored in the future. When doing mining, mineral, gas and water exploration we will someday send down explosive charges which could also give clues as to the interior character of the planet.

[Bad Ronald]

What if Mars were to suddenly, out of fat air, become volcanically active, very volcanically active. I mean Siberian Traps active. New volcanos, fissure eruptions & the 3 Tharsis Montes & Olympus Mons volcanos all erupting like crazy.

What happens as a result?

[tnjrp]

That would seem to leave the magnetic field as a factor of secondary importance at most.

Not qualified to say personally. The associated NASA site doesn't seem to rank it as fairly important a factor tho:
http://science.nasa.gov/science-news...01/ast31jan_1/

[forrest noble]

What if Mars were to suddenly, out of fat air, become volcanically active, very volcanically active. I mean Siberian Traps active. New volcanos, fissure eruptions & the 3 Tharsis Montes & Olympus Mons volcanos all erupting like crazy.

What happens as a result?

If by some miracle Mars erupted in heavy volcanism all over the planet it would be very difficult for there to be enough resulting atmosphere for water to remain a liquid on the surface. There would most likely be water involved with volcanic explosions like there is on Earth but all would seemingly go into the atmosphere as a gas and most of it would eventually precipitate out at the poles where most of the water can be found now. The volcanic gases, probably mostly CO2 would remain in the atmosphere a long time and so would sulfur dioxide SO2 which is toxic causing acid rain here on Earth. Continuous volcanism for millions of years might do the trick as far as atmospheric pressure would be concerned if there were enough trapped gases and water beneath the surface to re-create an Earth-like atmospheric pressure.

One of the best ways to give Mars a "kick" that I can think of would be to capture several of Jupiter's "small" water laden moons that are in distant orbits around Jupiter and Saturn and drag them off to be in eccentric orbits around Mars. Some could slowly degrade in orbit adding lots of water to the atmosphere if we wanted and others could be bases for our ships providing water, oxygen, and fuel through electrolysis. With a bigger moon we might even create an interior ocean by adding heat (or heat provided by an eccentric orbit) to grow sea farms and fish and maybe even a bit of recreational scuba fun. The same kind of lakes could exist below the surface of Mars today like they do on Earth.

[willstaruss22]

Idk if mars would have been a warm totally wet world. Maybe cool semiwet because 30% of water on a planet wouldnt necessarily drive global storms maybe regional one though.