Starts With A Bang!

Mars: Possibly the Awesomest Planet Ever

Watch. Seriously, just watch this video first. It’s a video of the surface of Mars, and all the information on why it’s important is below.

Wow. So it looks like sand dunes, or perhaps eroded sedimentary rock. Since we have those on Earth, I can show you what I’m talking about (dunes to the left and sedimentary rock to the right).

So let’s tell you where we are on Mars, and try to figure out what’s going on. First off, this is the Mars HiRISE orbiter that snapped the photos that were spliced together to make this video. The crater imaged here is Becquerel crater. (Still-shot below.)

Did you notice, at the end of the video, a series of “staircase” patterns that repeated themselves? The flights of stairs are shown in the image above. It turns out that there are 10 “steps” (or 10 layers of sedimentary rock) in each “flight” of stairs. The faulting seen here shows that these are layers of hardened rock, not softer material like sand dunes. Take a look at the face-on view of these rock layers:

And check out the oblique view as well:

So yes, there are periodic shelves of sedimentary rock on Mars. But do you know what this means?

Layers of similar thickness repeat dozens to hundreds of times in rocks
exposed inside four craters in the Arabia Terra region of Mars. In one of
the craters, Becquerel, bundles of a 10-layer pattern repeat at least 10
times, which could correspond to a known 10-to-one pattern of changes in
the tilt of the planet’s rotation axis.

We are seeing evidence of Mars’ rotation axis changing in the rocks on Mars. Millions of years of history are right there on the Martian surface, just like in sedimentary rocks on Earth. More details? You got it. From the Jet Propulsion Laboratory:

Geologists commonly find “rhythms,” or repeating patterns, in sedimentary layers on Earth. Determining the source of the rhythms can be difficult. Some result from annual or tidal cycles, or from episodic flooding that may not be periodic at all, but the role of longer-term astronomical cycles has been debated. One step in showing that astronomical cycles can leave their mark in sediments came from finding repeating five-layer sets in some terrestrial bedrock, matching a known five-to-one ratio of two cyclical variations in Earth’s orbit.

Lewis and colleagues found something similar on Mars: “Our findings suggest that cycles of climate change led to the patterns we see recorded in the Mars rock layers today, possibly as a result of similar variations in Mars’ orbit,” he said. “Mars has a 10-to-one ratio in cycles of how its tilt changes — smaller wobbles within larger packages. Sure enough, we see a 10-to-one ratio in one of these layered deposits. It’s like trying to identify a song — it’s easier if there are multiple instruments playing different parts, rather than just a single rhythm.”

Amazing. Seriously, amazing! We are doing geology that allows us to date different areas of rock and determine when they were deposited on another planet. I wonder what the next incredible news about Mars will be?

And for those of you looking for a great television event, this Sunday at 8PM, the National Geographic Channel is premiering a program called Journey to the Edge of the Universe. I’ve gotten access to a preview, and it looks really good. Check it out if you’ve got some time this weekend!