Author Topic: New theory on the origin of Phobos & Deimos  (Read 2474 times)

Offline Star One

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New theory on the origin of Phobos & Deimos
« on: 07/04/2016 05:12 PM »
Phobos and Deimos in an extended debris disc stirred by transient moons

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Phobos and Deimos, the two small satellites of Mars, are thought either to be asteroids captured by the planet or to have formed in a disc of debris surrounding Mars following a giant impact1, 2, 3, 4. Both scenarios, however, have been unable to account for the current Mars system1, 2, 3, 5, 6, 7. Here we use numerical simulations to suggest that Phobos and Deimos accreted from the outer portion of a debris disc formed after a giant impact on Mars. In our simulations, larger moons form from material in the denser inner disc and migrate outwards due to gravitational interactions with the disc. The resulting orbital resonances spread outwards and gather dispersed outer disc debris, facilitating accretion into two satellites of sizes similar to Phobos and Deimos. The larger inner moons fall back to Mars after about 5 million years due to the tidal pull of the planet, after which the two outer satellites evolve into Phobos- and Deimos-like orbits. The proposed scenario can explain why Mars has two small satellites instead of one large moon. Our model predicts that Phobos and Deimos are composed of a mixture of material from Mars and the impactor.

Paper on link.

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2742.html

Offline llanitedave

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Re: New theory on the origin of Phobos & Deimos
« Reply #1 on: 07/05/2016 05:56 AM »
Would this also explain the Hellas basin?
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Offline Ben the Space Brit

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Re: New theory on the origin of Phobos & Deimos
« Reply #2 on: 07/05/2016 07:32 AM »
It makes sense for both moons to be 'rock-pile' rubble accumulations; their density is quite low, even for their size.

IIRC correctly, there's a similar theory about Earth's co-orbital asteroids originating from the debris field of the lunar formation impact.
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Offline catdlr

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Re: New theory on the origin of Phobos & Deimos
« Reply #3 on: 11/04/2016 02:44 AM »
Creation of Stickney crater on Phobos

 
Lawrence Livermore National Laboratory

Published on Nov 3, 2016
This animation shows one scenario for how the massive crater Stickney could have formed, with a 200-meter object impacting at 8 kps into the 20-km-wide moon. The colored material is moving fast enough to evacuate the forming crater, and the red is moving quickly enough to entirely escape Phobos

https://www.youtube.com/watch?v=bf9_3uOgi_I/t=001

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Offline Blackstar

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Re: New theory on the origin of Phobos & Deimos
« Reply #4 on: 04/25/2017 10:16 PM »

Offline redliox

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Re: New theory on the origin of Phobos & Deimos
« Reply #5 on: 04/25/2017 11:05 PM »
Dear lord I need that book...  :o
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Online MATTBLAK

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Re: New theory on the origin of Phobos & Deimos
« Reply #6 on: 04/25/2017 11:10 PM »
Dear lord I need that book...  :o
I've just ordered it this very minute! According to Amazon; there's quite a wait, though :(
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Offline redliox

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Re: New theory on the origin of Phobos & Deimos
« Reply #7 on: 04/26/2017 01:10 AM »
Dear lord I need that book...  :o
I've just ordered it this very minute! According to Amazon; there's quite a wait, though :(

Ditto.  I definitely support exploring the moons.

Not to totally ruin this thread best to get back to topic....

I suspect Deimos and Phobos may be more different than expected.  Part of the latest theory on their formation states that the 2 moons basically formed in separate waves of impacts with Deimos being the older of the 2.
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Offline Blackstar

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Offline Zed_Noir

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Re: New theory on the origin of Phobos & Deimos
« Reply #9 on: 05/09/2017 12:16 AM »
Dear lord I need that book...  :o

You could get instant gratification with the eBook edition from the publisher.  Springer Publ link for the book  ;)

Offline eric z

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Re: New theory on the origin of Phobos & Deimos
« Reply #10 on: 05/09/2017 12:46 AM »
 I just ordered that book; Amazon said it will be here in two days. Let's see if that really happens. Sounds like a great read-Springer Books are almost always really nice!

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Re: New theory on the origin of Phobos & Deimos
« Reply #11 on: 05/15/2017 11:57 AM »
I've been reading the book and it's very good - though it's a bit SLS-centric... If that booster gets canned then this book is going to become somewhat obsolete; just like the many Constellation also-ran books are now :(

A second edition could have the author adjusting the Design Reference Missions to go with the veritable fleet of Commercial launchers coming down the pipeline.
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Offline Star One

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Re: New theory on the origin of Phobos & Deimos
« Reply #12 on: 05/15/2017 04:02 PM »
This might as well go here as anywhere.

Mars May Have Been Born in the Asteroid Belt

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Research suggests that gravitational interactions forced Mars out of the asteroid belt and toward the sun about 120 million years after the birth of the solar system.

https://www.seeker.com/space/planets/mars-may-have-been-born-in-the-asteroid-belt#

Offline Ben the Space Brit

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Re: New theory on the origin of Phobos & Deimos
« Reply #13 on: 05/16/2017 09:49 AM »
Regarding the above post about Mars originally starting in the Main Belt and given the theory about the migration of Neptune and the known long-term instability of all orbits outside of Jupiter, I'm thinking that one of the big recent paradigm shifts in theories about the origin of the solar system is being willing to drop the assumption that the current orbits of the major bodies have always been as we see them now.

It is quite possible that, skipping back 4Gy, the arrangement of the solar system might have been very different. If it is extant, Sol-IX might have been a lot closer in too.
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Offline Blackstar

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Offline redliox

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Re: New theory on the origin of Phobos & Deimos
« Reply #15 on: 05/20/2017 11:30 PM »
http://www.businessinsider.com/spidersuit-mars-astronauts-lockheed-nasa-2017-5

Love the suit design...but I am honestly split about whether developing a suit like that is better as opposed to an SEV equipped with arms that'd be safer for the astronauts?

Also shouldn't this be put in one of the HSF threads instead of here?
« Last Edit: 05/20/2017 11:34 PM by redliox »
"Let the trails lead where they may, I will follow."
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Offline Blackstar

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Re: New theory on the origin of Phobos & Deimos
« Reply #16 on: 05/21/2017 01:18 AM »
http://www.businessinsider.com/spidersuit-mars-astronauts-lockheed-nasa-2017-5

Love the suit design...but I am honestly split about whether developing a suit like that is better as opposed to an SEV equipped with arms that'd be safer for the astronauts?

Also shouldn't this be put in one of the HSF threads instead of here?

I did put it into one of the human spaceflight threads. But because we are not paying by the electron, I thought it was also appropriate here.

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