Mars North Polar Basin, A really big impact basin? Options

[Juramike]

Recent articles coming out in Nature, reported in space.com:

"Huge Impact Created Mars Split Personality"

So, technically (and theoretically), all three operating landers are currently sitting in impact basins.

Spirit - Gusev
Oppy - Victoria
Phoenix - North Polar (putative) impact basin

-Mike

[DDAVIS]

Recent articles coming out in Nature, reported in space.com:

The related article by Jay Melosh coming out in 'Nature Geosciences' has a painting I did based on feedback from Jay. Unfortunately the image they chose for the web articles was of a rather dryly rendered CGI 'splat' over a present day Mars! Those of you who get the magazine 'Nature Geosciences' will see what I came up with.

Don

[tasp]

Just musing here;

With such a big impactor (~Pluto sized!!) and therefore a significant % of the mass of the then Mars, and the crater ~ centered on Martian north pole area, could we extrapolate a plausible impact speed, do the math, and tease out a 'more probable than not ' pre-impact orbit about the sun for Mars ?

Might be a unique opportunity to have a little better idea of the primordial Mars solar orbit, and see if there is anything interesting about it.

(I realize this is not a high precision exercise, but such a gross wallop to Mars might be able to probe something interesting from the solar system's early days)

[tasp]

If no one else has yet done so, may I propose a name for the impacting body?

How about:

Redimio



If I have my tenses correct, it is Latin for 'to crown'. And if you imagine the crater wall on Mars shortly after impact, it might strongly suggest Mars has been 'crowned'.


AFAIK, name is not used for an asteroid or moon at this point.

[nprev]

Hmm. Okay, if this hypothesis is accepted, can any of the southern highlands be explained as fossil collision shock features, such as the chaotic terrain on Mercury on the opposite side of the Caloris basin?

The random orientation of the fossil magnetic field remnants in the south seems to imply that the crust was not extensively transformed after the putative event, and therefore I am a bit skeptical. An impact this energetic at first glance should have been enough to re-melt most of the crust, unless its thermal properties are much different then those of Earth (paucity of water? Sheer crustal thickness? Effective cessation of internal activity by 3.8 By BPE, which contradicts the estimated age of Tharsis and other volcanic features?) Imbrium did not re-melt the Moon's crust, so maybe this is an analogous situation.

Bottom line: Can't call this a done deal yet, IMHO.

[Juramike]

An impact this energetic at first glance should have been enough to re-melt most of the crust, unless its thermal properties are much different then those of Earth (paucity of water? Sheer crustal thickness?

Bottom line: Can't call this a done deal yet, IMHO.

Looking only at the space.com article. the article states:
"The results help address one of the other main objections to the impact hypothesis — the suggestion that any space rock massive enough to form such a large basin would have melted so much of the planet's surface that all evidence of it would be erased.

'They found, contrary to what was previously thought, that you don't produce that much melt," Andrews-Hanna said. "Most of the melt gets contained in the basin.'"

I wouldn't call it a done deal either, but it's certainly an interesting hypothesis.

-Mike

[David]

Redimio

If I have my tenses correct, it is Latin for 'to crown'. And if you imagine the crater wall on Mars shortly after impact, it might strongly suggest Mars has been 'crowned'.

Redimio is "I crown" -- "crown" in the Roman sense of "encircling the head with a wreath". "One who crowns" would be a redimitor -- stress on the second i.

[tasp]

"I crown" seems even more appropo.

Wow, to have a video of the impact! Kerblewie !!!

[Juramike]

"I crown" seems even more appropo.

Wow, to have a video of the impact! Kerblewie !!!

Giga-splat!

[Juramike]

New scientist article here.

And a YouTube video of the simulated impact (5 sec. video): http://www.youtube.com/watch?v=0iobBQWNTqA

-Mike

(And it does look like the milk drop image posted above!)

[stevesliva]

With such a big impactor (~Pluto sized!!) and therefore a significant % of the mass of the then Mars, and the crater ~ centered on Martian north pole area, could we extrapolate a plausible impact speed, do the math, and tease out a 'more probable than not ' pre-impact orbit about the sun for Mars ?

There is a recent hypothesis (or at least new evidence) that the northern hemisphere wasn't always northern:
http://www.astrobio.net/news/modules.php?o...le&sid=2364

[tasp]

There is a recent hypothesis (or at least new evidence) that the northern hemisphere wasn't always northern:
http://www.astrobio.net/news/modules.php?o...le&sid=2364

LOL!

That darn reality always messing up what I want to do. The pre impact Mars orbit might be pretty interesting, but I concur now, it is profoundly unlikely we will ever know.

Piffle.

[tasp]

Pondering the circumstances of this impact some more . . .

* A Pluto sized object in the Mars part of the solar system in that epoch would probably have been a rocky object rather than an icy object. Assuming the solar luminosity was lower then, the object might have had an atmosphere and weather prior to impact. Perhaps even more interesting to watch the impact than I had earlier thought as the atmospheres of Mars and the Impactor would be interacting during the collision.

* The impactor might have been binary or enmooned too. We will never know, but seems plausible for such a big object to have attendants. Further heightening our interest of the impact.

* could impactor still have been accreting? Wild if it had a significant debris disk during impact phase with Mars (this might apply to Mars too)

*Seems like possible orbits for the impactor might have been;
a] co-orbital with Mars, but was 'upset' somehow
b] hit Mars at aphelion so on average, a warmer world than Mars. Maybe had its' orbit 'pumped by earth?
c] hit Mars at perihelion, more of an asteroidally gestated object. Note this body is larger than Ceres!!
d] Mars crossing orbit, ho hum, boring
e] orbit as one of the above, but significantly inclined to ecliptic, very interesting, and possibly one of the largest objects of that epoch to have an orbit like that ?

[edstrick]

One explanation for why oxygen isotopes of earth and moon samples are from the same original "mix" is that the pre-moon giant impactor formed in an earth-sun Lagrange point <L3 or L4>, and when it grew big enough, became unstable and wandered out of the L-point, to eventually impact earth. Having grown from the same sources of material as the proto-earth, it would have been isotopically very similar. Martian and asteroidal samples are from very different original batches of oxygen isotopes, with many populations present among non-martian meteorite samples.

[jasedm]

enmooned

Love that word!! There's always more than one way of saying something in English