![Mars-Earth comparison [image credit: Wikipedia]](https://tallbloke.files.wordpress.com/2014/08/mars_earth1.jpg)
Mars-Earth comparison
[image credit: Wikipedia]
It’s an old question, and investigations are hotting up.
Phys.org reports: ‘On October 19, 2014, Comet Siding Spring will pass by Mars only 132,000 km away—which would be like a comet passing about 1/3 of the distance between Earth and the Moon.’
In other words, very close. And NASA’s MAVEN probe will arrive at Mars just in time to see the show.
‘MAVEN is on a mission to solve a longstanding mystery: What happened to the atmosphere of Mars? Billions of years ago, Mars had a substantial atmosphere that blanketed the planet, keeping Mars warm and sustaining liquid water on its surface.’
‘Today, only a wispy shroud of CO2 remains, and the planet below is colder and dryer than any desert on Earth. Theories for this planetary catastrophe center on erosion of the atmosphere by solar wind.’
Read more at: Colliding atmospheres: Mars vs Comet Siding Spring
Let’s see if something interesting happens in October.
Tallbloke's Talkshop 
I would be very interested in the views of your readers. The eroding atmosphere by solar wind applies I guess if you believe the planets have not changed much in 4 billion years. But for me I find the expanding earth theories to hold many of the answers to questions like this one you pose. And this ties in with understanding what gravity actually is, because it’s looking as if the Newtonian version may be off the mark.
Maybe we look at Mars today and see the earth as it was 2 billion? years ago, unable to sustain an atmosphere and cold. Perhaps only 250 million years ago the earth was similar. Water and atmosphere come from within the planet and ultra violet light and other ironizing radiation has a major influence on the final composition. Maybe the planets require a big impact from time to time to trigger activity that leads to expansion.
Whatever the answer turns out to be the only sure thing is we will only find that answer with a greater degree of open mindedness from the established scientific community.
PeterMG says:
August 13, 2014 at 1:14 pm
But for me I find the expanding earth theories to hold many of the answers to questions like this one you pose
The earth is cooling and therefore shrinking. Hence the tetrahedral arrangement of the continents.
http://en.wikipedia.org/wiki/Tetrahedral_hypothesis
What happened to the atmosphere of Mars [proposed using methodology of climastrology truth]: after Jupiter’s apocalyptic tug tied apart the Carbon Planet between him and Mars, all the carbon was detached from the asteroid debris and rigorously attracted by the tug of Mars. But on arrival in the Martian atmosphere the carbon chunks burned up and so only CO2 remained; unfortunately we can no longer find the carbon chunks on Mars (like we can no longer find the inconceivable huge gold treasures in pyramids).
Proof A: many of the carbon chunks hammered down deep on Earth which by that time was in pre-paradise condition, meaning that waters and heaven were not separated yet.
Proof B: a similar CO2 catastrophe, like that on Mars, happened to the atmosphere on Venus.
Proof C [derived from 200 years old scientific consensus]: the carbon chunks could not hit Mercury because the Sun’s tug was too strong, and therefore the fresh carbon supply extended the Sun’s lifetime by more than 5000 years (being the estimate ~200 years ago).
True scientific consensus about Mars catastrophes: https://en.wikipedia.org/wiki/Mars_meteorite
There you have it, all based on as much impartial consensus as available without suppression of facts.
/sarc
Duh. 5000/5,000,000,000 = 1/1,000,000 = 0.000001. Accuracy does not equal precision. That’s a Wild-Assed-Guess composed of utter nonsense.
The nuclear heat of Mars ran down. Planet solidified and outgassing ended, as did water and CO2 recycle. Gasses and water bound into rocks as things halted. We do the same thing as our nuclear heat runs down and tectonics halts. We have water because subduction cooks it out of the rocks. Ditto air. But nothing runs forever…
If we look at the question of atmosphere in isolation you get drawn to one conclusion. However if you look at all events from the past then your initial conclusions may not fit.
As an example 200 million years ago we had 50 to 100 ton plant eating dinosaurs that if you believe in plate tectonics and Newtonian gravity defied the law of gravity and could not have lived as we imagine them to have lived. Galileo’s Square-Cube Law helps us understand that size matters and small dimensional changes require enormous changes in strength. So either earth hand an atmosphere as thick as water or gravity was less.
I once thought the thick atmosphere may hold the key, would account for a lot of the answers except how has it disappeared so quickly and why is it not disappearing that fast now. Why do we see no evidence of this recent thick atmosphere? Could we have more gravity that has halted that process? But how would that happen? It couldn’t according to Newton. But look at the dinosaurs, once they reached their peak they got smaller and smaller until 65 million years or so ago they were but a shadow of their former glory. How is this? And it’s not just the dinosaurs. Watch the BBC dinosaur animations and marvel at all the trees they wander through. Aren’t trees a recent plant phenomenon, perhaps they are a response to increasing gravity because water could no longer provide all the strength the plants need in a world of increasing gravity.
Look at google earth and note the large trench below South America. Looks suspiciously like an impact to me, and there is another in the South Caribbean, both west to east, and both reputedly only 100 million years or so old, both big enough to accelerate expansion of the earth? The southern impact looks as if it bent the tips of two continents.
How true is any of this? Who knows, but some of the observational evidence we have today, if we look at as a whole rather than as individual pieces, something science seldom dose these days, then I think we can only be drawn to the conclusion that whatever we think we know today is likely to be completely wrong. This is what I once loved about science, all the discovery; that is until settled science spoilt it all, or perhaps it was spoilt long ago by mathematicians that have managed to convince many that maths is the only way to truly understand science.
‘Billions of years ago, Mars had a substantial atmosphere that blanketed the planet, keeping Mars warm and sustaining liquid water on its surface.’
‘Keeping Mars warm’? Depends on how ‘warm’ is defined.
If Earth today was where Mars is, it would not be warm – too far from the Sun.
Climatology of Mars? I saw a National Public Radio TV program devoted to the atmosphere of Mars. They concluded that the atmosphere unprotected by a magnetosphere was blown away by strong solar winds, and how lucky the Earth was to have a magnetic field. They never mentioned Venus (very thick atmosphere, no magnetic field, much closer to the Sun).
There is no difference between Martian climatologists and Earth climatologists.
Mars does not have a magnetic core.
‘Red Planet’s Climate History uncovered in Unique Meteorite’
http://www.sciencedaily.com/releases/2014/08/140827131553.htm
“First we learned that, about 4.5 billion years ago, water was more abundant on Mars, and now we’ve learned that something dramatically changed that,” said Humayun, a professor of geochemistry. “Now we can conclude that the conditions that we see today on Mars, this dry Martian desert, must have persisted for at least the past 1.7 billion years. We know now that Mars has been dry for a very long time.”