Comments on: Two Faces of Mars Explained

By: David S

David S — Tue, 19 Aug 2008 15:02:35 +0000

Perhaps the low land regions of Mars were an ocean once? The southern hemisphere is like the giant continent that used to be on earth.

Also, isn't the moon much older than the Earth? I've also read it's made out of much different material, so it wasn't a part of the Earth.

By: watchful stone guardian

watchful stone guardian — Fri, 27 Jun 2008 19:00:09 +0000

I was under the impression that the Tharsis Bulge (Olympus Mons, et al) was driven up opposite the impact that created the Hellas Basin.

By: Aodhhan

Aodhhan — Thu, 26 Jun 2008 20:56:05 +0000

I don't think the trench would be a product, however it is quite likely such a collision produces a shock wave which bulges and stretches the crust thin enough where a molten interior could get close enough to the surface to break through.

Given the impact, I would have expected to see a volcano more in the southern hemisphere. Although, given the right angle and depending on the make-up of the interior of the planet at the time its possible Olympus Mons is a product of the collision. It will be great to some day get a good geographical study of the interior.

There are typically 2 shock waves which develop from the collision. One along the surface of the planet (which will meet apprx 180 degrees on the other side) and the interior, which could be offset a bit. Speed and power of the internal wave is going to depend on internal resistance.

By: O. Prime

O. Prime — Thu, 26 Jun 2008 15:58:53 +0000

Nexus Says:
June 25th, 2008 at 4:28 pm

Then why don't Venus and Mars have large satellites like Earth does?

They were devoured by Unicron

By: Eric Near Buffalo

Eric Near Buffalo — Thu, 26 Jun 2008 13:40:00 +0000

Aodhhan: Like Valis Marineris? That kind of trench definitely could be caused by something very large hitting the opposite side of Mars. Though popular theory suggests that it was formed by the formations of volcanos in the general area, including Olympus Mons.

By: Aodhhan

Aodhhan — Thu, 26 Jun 2008 13:04:57 +0000

I've seen part of a report from Queen Mary University in London which was working through the original models. Looking a lot at the melting process which would have occured.

I'm particularly interested in the shock wave which would have gone through the planet and made a nice little mark on the other side (not necessarily at the exact opposite point); and to see what explanations can be found with anomolies in the southern hemispheres magnetic field.

By: Al Hall

Al Hall — Thu, 26 Jun 2008 12:39:44 +0000

Yep. It is my understanding that the Earth went pretty much molten when it was struck. Therefore, no impact basin.

By: Paul Eaton-Jones

Paul Eaton-Jones — Thu, 26 Jun 2008 10:31:29 +0000

Since the Earth was impacted and the Moon formed plate tectonics/continental drift have ensured that the original impact site has been obliterated even if it actually existed following the molten state of the Earth afterwards. Therefore the Pacific Ocean as the site is sheer nonesense.
Paul.

By: Yael Dragwyla

Yael Dragwyla — Thu, 26 Jun 2008 05:59:52 +0000

If I remember correctly, the impact that created our Moon happened during the Late Heavy Bombardment, around 3.8-4.1 billion years ago. During that time every body in the Solar System must have sustained significantly large impacts. Some of those impacts would have created moons of various sizes, but subsequent impacts — 300 million years is a long time, and a lot of things can happen during it — might have pulverized most of those moons, or kicked them away from their primaries, out of the system or toward the Sun. Mars and Venus may both have gained moons at that time, then lost them again from later impacts. We may have gained our Moon at a time when those impacts were tapering off, as the Solar System was cleaned out by earlier impacts, and kept our Moon because nothing large enough to destroy or kick away our Moon came our way afterwards. Hmmm . . . wonder if anyone's done a study on those possibilities?

By: Death From The Skies!

Death From The Skies! — Thu, 26 Jun 2008 04:38:01 +0000

It was Nibiru the destroyer! OMFG bbq.

By: Jim Baerg

Jim Baerg — Thu, 26 Jun 2008 04:34:29 +0000

Vanamonde: The idea that the Pacific basin had something to do with the origin of the moon was dropped after plate tectonic theory was established. Any basin left by the formation of the moon would be obliterated by the shuffling of the continents over the last 4 billion years.

BTW is your handle a reference to A.C. Clarke's novel(s) Against the Fall of Night/The City & the Stars ?

By: Ralph Rewes

Ralph Rewes — Thu, 26 Jun 2008 00:47:27 +0000

Funny, funny, funny. Have you thought of IMPROV?

By: Vanamonde

Vanamonde — Thu, 26 Jun 2008 00:46:09 +0000

Nexus, the Large Early Impactor with a glancing blow is the most popular theory of the Moon's creation. We now call that impact basin, the Pacific Ocean.

By: Al Hall

Al Hall — Thu, 26 Jun 2008 00:04:14 +0000

Perhaps neither were hit by anything significant but one's core cooled 'died' (therefore, lost it's magnetic field) and the other has no 'problem'.. it's just too close to the sun.. I don't know.. Just a thought..

By: Nexus

Nexus — Wed, 25 Jun 2008 23:28:26 +0000

Then why don't Venus and Mars have large satellites like Earth does? Perhaps Earth received a glancing blow which stripped off a lot of material that eventually became the Moon, but Mars and Venus copped a direct hit which did not result in a heap of orbiting debris.

By: Stephen

Stephen — Wed, 25 Jun 2008 21:33:58 +0000

10^29 joules, i'm sure.

One of the ideas for the formation of the Moon is that a Mars sized object formed at either the SEL4 or SEL5 point. These points are 60 degrees ahead or behind Earth in it's orbit around the Sun. These points are stable, unless the size of the object gets to be "significant". It gets big enough to become unstable, then slams into the Earth, producing the Moon.

Perhaps Mars had a similar object at it's SML4 point, and did this damage.

Perhaps Venus had one, and it goofed up Venus's spin.

Perhaps Uranus had one, ant it goofed up Uranus's spin.

There. Now get out your computers and start simulating.

By: torsal

torsal — Wed, 25 Jun 2008 21:15:21 +0000

"1029 joules, which is equivalent to 100 billion gigatons of TNT"
hmm…missing SI prefix?