Possilbity of past life on Mars?

[Ophiolite]

Anyway, back to Mars: Would you say dust storms or water are more likely the cause of its appearance of oceans between continents?

Water. 97% probability.

I notice RDKirk never came back to justify his claim that wind was responsible. Did I scare him off when I corrected his multiple errors?

 

[GodLovesCats]

Water. 97% probability.

I notice RDKirk never came back to justify his claim that wind was responsible. Did I scare him off when I corrected his multiple errors?

RDK is one of the creationists who refuses to accept the obvious, scientifically proven fact that evolution - both geological and biological - is evidenced in millions of pieces around the world. Every time I told him this, he gave me the same old crap that it is impossible for any evidence to be proven and the Bible itself is proof that the world was created in 144 hours. Total baloney.

So I am not surprised Kirk has never returned to even try to understand why it is probable Mars used to be like Earth is almost every way.

Reading that great post again, it is obvious to me Kirk just does not want to accept facts which have been proven by every kind of astronomer and geologist. People who do this are full of pride and want to believe they are right about everything.

 

[Ophiolite]

RDK is one of the creationists who refuses to accept the obvious, scientifically proven fact that evolution - both geological and biological - is evidenced in millions of pieces around the world. Every time I told him this, he gave me the same old crap that it is impossible for any evidence to be proven and the Bible itself is proof that the world was created in 144 hours. Total baloney.

So I am not surprised Kirk has never returned to even try to understand why it is probable Mars used to be like Earth is almost every way.

Reading that great post again, it is obvious to me Kirk just does not want to accept facts which have been proven by every kind of astronomer and geologist. People who do this are full of pride and want to believe they are right about everything.

Thank you for that background. One of the reasons I participate in forums is to increase my knowledge. My corrections of what seemed to me errors on the part of RD had a dual function. Primarily, they were corrections. However, if I am mistaken, I want to know. My request for citations was an opportunity for RD to correct me and for me, thereby. to learn something and to correct a misunderstanding. I had forgotten the absence of a reply until your recent post reminded me.

@RDKirk I hope you will respond to at least some of my earlier points with relevant citations. In that way we both can learn.

 

[FrumiousBandersnatch]

So continents just broke apart without the kind of movement that causes earthquakes?

The kind of movement that causes earthquakes and breaks continents apart (or brings them together) is plate tectonics. It also raises mountain ranges and triggers volcanoes.

 

[GodLovesCats]

Not all mountain ranges are made the same way. You are describing the Grand Tetons rising straight up - which is what makes them famous. Other mountains, such as those in the Badlands, are sedimentary and made by the piling up of rock on top of land.

 

[Ophiolite]

Not all mountain ranges are made the same way. You are describing the Grand Tetons rising straight up - which is what makes them famous. Other mountains, such as those in the Badlands, are sedimentary and made by the piling up of rock on top of land.

I think you are a little confused. Mountains are generated either through tectonic uplift generated by subducting plates, or by volcanic activity, also generated by subducting plates. (There are some minor variations that we can ignore in this simple summary.) The Badlands do include some terrestrial deposits (along with marine sediments and lavas), but they are exposed today because of uplift caused by plate tectonic activity.

 

[GodLovesCats]

Do you know anything about the volcanic activity on Mars?

 

[ViaCrucis]

Do you know anything about the volcanic activity on Mars?

Used to be active, isn't any longer. Olympus Mons, were it still an active volcano, would be an amazing sight to behold no doubt. If on earth the mountain would nearly cover the entire US state of Arizona.

-CryptoLutheran

 

[Ophiolite]

Do you know anything about the volcanic activity on Mars?

A fair bit. Principal centres are the Tharsis Bulge where we have Olympus Mons and three smaller, but still substantial neighbours Arsia Mons, Pavonis Mons, and Ascraeus Mons, then the much smaller Elysium region with three or four volcanoes.

The exceptional size of the volcanoes is a consequence of no (significant) plate tectonics and relatively fixed mantle plumes feeding them. Lavas for the most part are basalts. Eruptions continued periodically for many millions of years. Emptying magma chambers led to caldera collapse, most notably on Olympus Mons.

While the bulk of the eruptions occurred early in Martian history there is some suggestion that some activity could have taken place quite recently, geologically speaking, perhaps even in the last ten million years. This, however, is a matter of much debate.

What specifically did you want to know?

 

[FrumiousBandersnatch]

Not all mountain ranges are made the same way. You are describing the Grand Tetons rising straight up - which is what makes them famous. Other mountains, such as those in the Badlands, are sedimentary and made by the piling up of rock on top of land.

I was thinking of the Himalayas; but yes, not all mountain ranges are solely the product of plate tectonics.

 

[Ophiolite]

I was thinking of the Himalayas; but yes, not all mountain ranges are solely the product of plate tectonics.

However, there are very few that do not owe their existence primarily to plate tectonics. Mid-plate volcanism, perhaps. CforC's examples are plate tectonic in origin. Can you suggest any?

 

[Shemjaza]

Used to be active, isn't any longer. Olympus Mons, were it still an active volcano, would be an amazing sight to behold no doubt. If on earth the mountain would nearly cover the entire US state of Arizona.

-CryptoLutheran

It's huge... but it has such a gentle slope that it sort of reduces the majesty.

 

[Astrophile]

Anyway, back to Mars: Would you say dust storms or water are more likely the cause of its appearance of oceans between continents?

In simple terms, according to W.K. Hartmann, in A Traveller's Guide to Mars (pp. 34-35), during the Noachian era (about 4570 to 3500 million years ago) Mars was dominated by hydrological processes, with rivers and lakes, and perhaps even oceans. During the Hesperian era (about 3500 to 2500 million years ago), there was a transition from a planet dominated by water to the present dry and dusty world; rivers were still active and there were massive local floods, but much of the water was freezing to form underground ice deposits. During the Amazonian era (about 2500 million years ago to the present), Mars has had very little surface water, and its surface processes have been dominated by the transport of dust by seasonal winds, and in particular by dust storms.

The simple answer to your question is therefore that both water and dust storms have contributed to the shaping of the Martian surface, but at different times.

 

[GodLovesCats]

It's huge... but it has such a gentle slope that it sort of reduces the majesty.

Try telling that to Japanese people about Mount Fuji.

 

[GodLovesCats]

What specifically did you want to know?

Anything! Nothing specific, except for how volcanic activity could be related to the atmosphere and water losses on Mars.

 

[Ophiolite]

Anything! Nothing specific, except for how volcanic activity could be related to the atmosphere and water losses on Mars.

The atmosphere was largely generated by volcanic activity. The strong consensus view, replacing the original thinking, is that the terrestrial planets formed by hot accretion rather than cold accretion. This meant that any primeval atmosphere was lost, either by thermal escape, or impact erosion from ongoing accretion impacts.

The current atmosphere was produced by degassing of the Martian mantle through volcanic eruptions. This 'replacement' atmosphere then suffered significant loss through a variety of mechanisms, leaving Mars with its present thin, carbon dioxide rich version.

Could your repeat/rephrase the heart of what you asking in this thread and I'll seek to put together a comprehensive answer for you?

 

[GodLovesCats]

Sure. NASA and its robotic rovers have been discovering water (both solid and liquid) on and below Mars' surface,; along with dried-up rivers, lakes, and oceans. As more and more images are being looked at the astronomers and geologists observing them keep moving up the date range that the atomsphere was lost and surface water disappeared. Do these more recent conclusions mean it is conceivable life existed there when Mars was like Earth?

 

[Ophiolite]

Sure. NASA and its robotic rovers have been discovering water (both solid and liquid) on and below Mars' surface,; along with dried-up rivers, lakes, and oceans. As more and more images are being looked at the astronomers and geologists observing them keep moving up the date range that the atomsphere was lost and surface water disappeared. Do these more recent conclusions mean it is conceivable life existed there when Mars was like Earth?

Please keep in mind that when we talk of Mars being like the Earth, we are talking about it being like the Earth of three and a half or four billion years ago. That would be a wholly different planet from the one we are familiar with.

The amount of water originally present, the extent of water loss, the timing of that loss, and the effect of such things as CO2 release through impact events, or major changes in axial tilt, continue to be hotly debated topics. There have almost always been those who argued for a warm, wet early Mars. What has shifted is the number of people in that camp.

We do not know exactly how life arose on Earth. We do not know exactly what conditions were necessary. We do not know how much time was required for that life to develop. We have several plausible hypotheses, but are still some distance from being able to give a confident answer. This makes any estimate of the probability of life on Mars highly speculative. I won't make any prediction based on a sample size of one - the Earth.

Even without the more recent conclusions it has, I think, always been plausible that life arose on Mars, but as I said above I would not assign a % probability. My own view is that if it did arise, then it almost certainly is still present as chemotrophs at some depth in the Martian crust.

Aside: I am one of that small band (of gullible fools?) who believe NASA was too quick to abandon the positive indications of life delivered by multiple experiments on both Viking landers. In my view we have wasted almost half a century of footering around looking for the prerequisites for life, rather than directly for life itself.

 

[Ophiolite]

This recent (2016) review paper is excellent. Technical terms are kept to a minimum.

Wordsworth, R.D. The Climate of Early Mars www.annualreviews.org

 

[GodLovesCats]

I am one of that small band (of gullible fools?) who believe NASA was too quick to abandon the positive indications of life delivered by multiple experiments on both Viking landers. In my view we have wasted almost half a century of footering around looking for the prerequisites for life, rather than directly for life itself.

I am too young to remember the Viking explorations, but my understanding is they looked for life without first trying to figure out if the requirements for life to exist were present. If this is the case, NASA made a good decision by reversing the order of operations. The problem was NASA later got the idea that life can exist without water and there may even be species that cannot exist on Earth but did live on Mars.