Possible Ocean in the Nothern Hemisphere of Mars?

• by mschwamb scientist, translator

  Hi,

  I saw the recent discussions of a new Nature paper about the possibility of much more water on Mars, enough water to theoretically cover a large portion of the Northern Hemisphere on Mars. I thought I'd post for anyone interested. You can read a really nice summary in the Guardian here.

  Cheers,

  ~Meg

  Posted March 8, 2015 2:14 AM

• by Kitharode moderator

  Thanks for that Meg. Interesting indeed. Seems to me that an ocean so deep, and so wide, and so long-lived, would have a significant effect in shaping the ocean floor which we now see as martian surface. Something for us to bear in mind when we eventually move 'up north'?

  Posted March 9, 2015 4:19 PM

• by pete-j

  Thanks from me as well! More evidence for the Oceanus Borealis... I have the standard Mars globe with the topographic globe as well in my room; this is probably as near to Mars as any of us shall ever get!

  Cheers

  Posted March 9, 2015 8:13 PM

• by pete-j

  There is a book, which I have noticed: Alien Seas: Oceans in Space. Michael Carroll, Hardcover – 30 Jul 2013.

  There are interesting chapters on the 'Lost Oceans of Venus' and, of course 'Oceans on Mars'. Here are a few lines reproduced directly from the Amazon site.

  'Oceans were long thought to exist in all corners of the Solar System, from carbonated seas percolating beneath the clouds of Venus to features on the Moon's surface given names such as "the Bay of Rainbows” and the "Ocean of Storms." With the advent of modern telescopes and spacecraft exploration these ancient concepts of planetary seas have, for the most part, evaporated. But they have been replaced by the reality of something even more exotic. For example, although it is still uncertain whether Mars ever had actual oceans, it now seems that a web of waterways did indeed at one time spread across its surface'.

  I have often wondered if Mars had been slightly more massive, then we would have had a 'more interesting' scenario today. There was a model of the Solar System with discussions of the results if Mars was more massive [internet]. I am struggling to find where I read this, however, the result was instability, Mercury particularly developed wild irregularities in its orbital eccentricity. The conclusion was that the present set-up is stable as it is a result of billions of years of orbital evolution.

  Just blame Jupiter for Mars' poor mass at ~11% Earth's. It is a wonder it could hold on to an ocean for such a long time.

  Posted March 9, 2015 8:48 PM

• by HMB6EQUJ5 in response to pete-j's comment.

  agreed....there is a guy though, just up the coast from me in Moss Beach, Ca who was recently selected as one of the candidates in training for the 2024 Mars One proposed expedition

  Posted March 10, 2015 1:44 PM

• by pete-j

  It is going to be very interesting how that [the proposed expedition] plays out: watch this space!

  No pun intended!

  Posted March 10, 2015 4:11 PM

• by mschwamb scientist, translator in response to pete-j's comment.

  Hi,

  Well actually that's the current theory that Jupiter is the reason why Mars is small, but probably not for the reason you're thinking of. It's a problem because dynamical accretion models in computers don't make Mars at the right mass if you assume a planetesimal disk with gas. The models tend to form bigger bodies. So making a smaller Mars than Earth is something planet formation scenarios for our Solar System have to explain.. It looks like if you truncate the planetesimals you can get a smaller Mars and that can Jupiter can do this if it migrated inward and then back outward. This model is known at the Grand Tack. You can read more about the Grand Tack here and here. I spent part of last week with one of the creators of this theory. We were both visiting a collaborator in Japan.

  Cheers,

  ~Meg

  Posted March 10, 2015 9:46 PM

• by Kitharode moderator

  There was a tv program recently (Secrets of the Solar System) that talked about the 'Grand Tack' and the migration of the gas giants. An interesting idea.

  Posted March 11, 2015 4:27 PM

• by pete-j

  Hi Meg

  Thanks for the explanation. I understand what you are saying, I shall scrutinise the links.

  My second comment 'blaming Jupiter' was separate from the earlier paragraphs and was derived from the same BBC program that Kitharode watched: BBC Horizon: Secrets of the Solar System

  On an ending note, one of the researchers gave his view that he couldn't have arrived at the present set up of the solar system [in his planetary models] without an extra ice-dwarf between the orbits of Uranus and Saturn. This body was subsequently ejected early on in the Solar System's history and we arrive at the present set-up.

  Cheers and thanks,

  Pete

  Posted March 11, 2015 8:18 PM

• by wassock moderator in response to mschwamb's comment.

  I watched the Horizon thing last night on i-player. It was giving the message pretty much as "This is the way it happened - Gospel" is this where we are at - that this idea is now accepted pretty much as how it all came to be, or is it one of a number of competing theories?

  Posted March 12, 2015 11:48 AM

• by mschwamb scientist, translator in response to wassock's comment.

  there's a large amount of properties about the asteroid belt and Kuiper belt as well as the Jupiter trojans and irregular satellites that the planetesimal driven giant planet migration model gets correct. The extra ice giant bit seems to be needed to explain other parameters about the obits of the giant planets (so it is a possibilty) for a recent paper I'm a co-author on we test a 4 giant planet and a 5 giant planet model when we were looking at the evolution of the outer solar system.

  The Grant Tack, gets distributions of asteroids mostly right compared to what we see, but again it's still being test. If there's evidence that disproves these models, we'd find a new model that would fit the new evidence. More sophisticated number simulations are being run to test all these models. So I would say these are our leading favored theories for our Solar System's evolution.

  Cheers,
  ~Meg

  Posted March 12, 2015 11:54 AM

• by wassock moderator

  The bit I didn't really understand was the time function - the gas giants need to form a lot quicker than the rocky planets. I can see why the gas ones need to form quick but don't really see why they should. As I understand it the gas giants form a long way out and thus from bits spread out around a large disc and the components are mainly Hydrogen (not very heavy). The rocky ones are closer in have bits with more mass which are spread around a smaller orbit. So it would seem that it should take longer to gather up the gassy bits than the rocky ones? Horizon explained why the gas giants need to form rapidly but was a bit scant on the how.

  Posted March 12, 2015 12:12 PM

• by pete-j

  The boundary of the Solar System as we know it probably does not end at the outer edge of the Kuiper belt (I am not referring to the Oort cloud) but the possibility of extra planets far beyond Neptune: New Scientist Article, 2014 with the respective paper: arxiv.

  If these really do exist, then presumably another mechanism for their formation (other than accretion) would have to be put forward (migration outwards??).

  Cheers,
  PJ

  Posted March 12, 2015 6:49 PM

• by mschwamb scientist, translator in response to pete-j's comment.

  Hi Pete,

  Yes, that's part of the other half of my life. I work on Kuiper belt objects and the inner Oort cloud. I was in just in Japan talking about that with a collaborator. I'm running numerical simulations to probe the parameters space for the potential planet out at ~200 AU, though it's not a definite that it's there. Still lots more observations of the planetesimals in the Kuiper belt and Inner Oort cloud needed to confirm its existence.

  Cheers,

  ~Meg

  Posted March 14, 2015 9:00 AM