Mars’ Ancient Mega-Floods Are Still Etched Into the Red Planet

Around 3.5 billion years ago — when basic life was just gaining a foothold on Earth — the Tharsis region on Mars was swamped with vast floods that scar the landscape to this day.

Rendered perspective view of Worcester Crater using Mars Express elevation data. The dramatic crater rim was carved by the flow of ancient floodwater (ESA)

Mars wears its geological history like a badge of honor — ancient craters remain unchanged for hundreds of millions of years and long-extinct volcanoes look as if they were venting only yesterday. This is the nature of Mars’ thin, cold atmosphere; erosional processes that rapidly delete Earth’s geological history are largely absent on the Red Planet, creating a smorgasbord of features that provide planetary scientists with an open book on Mars’ ancient past.

In this latest observation from the European Mars Express mission, a flood of biblical proportions has been captured in all its glory. But this flood didn’t happen recently, this flood engulfed a vast plain to the north of the famous Valles Marineris region billions of years ago.

It is believed that a series of volcanic eruptions and tectonic upheavals in the Tharsis region caused several massive groundwater releases from Echus Chasma, a collection of valleys some 100 kilometers (62 miles) long and up to 4 kilometers (2.5 miles) deep. These powerful bursts of water carved vast outflow channels into the adjacent Lunae Planum, contributing to the formation of the Kasei Valles outflow channels, releasing water into the vast Chryse Planitia plains which acted as a “sink.” Smaller “dendritic” channels can be seen throughout the plain, indicating that there were likely many episodic bursts of water flooding the region.

This context image shows a region of Mars where Kasei Vallis empties into the vast Chryse Planitia (NASA MGS MOLA Science Team)
This context image shows a region of Mars where Kasei Vallis empties into the vast Chryse Planitia (NASA MGS MOLA Science Team)

These floods happened between 3.4 to 3.6 billion years ago, less than a billion years after the most basic lifeforms started to appear on Earth (a period of time known as the Paleoarchean era).

In the middle of what was likely a powerful, vast and turbulent flows of water is Worcester Crater that was created before the Tharsis floods and, though its crater rim stands to this day and retains its shape, it was obviously affected by the flow of water, with a “tail” of sediment downstream.

ESA Mars Express observation of the mouth of Kasei Valles, as it transitions into Chryse Planitia. The large crater in the lower left is Worcester Crater. (ESA/DLR/FU Berlin)
ESA Mars Express observation of the mouth of Kasei Valles, as it transitions into Chryse Planitia. The large crater in the lower left is Worcester Crater (ESA/DLR/FU Berlin)

Also of note are smaller “fresh” craters that would have appeared long after the flooding took place, excavating the otherwise smooth outflow channels. These younger craters have tails that seem to be pointed in the opposite direction of the flow of water. These tails weren’t caused by the flow of water, but by the prevailing wind direction.

From orbital observations by our armada of Mars missions, it is well known that these channels contain clays and other minerals associated with the long-term presence of water. Although the Red Planet is now a very dry place, as these beautiful Mars Express images show, this certainly hasn’t always been the case.

No Matter How You Spin It, A Hole is Still a Hole

Mars Express to Beagle 2: But you forgot your... ah, never mind.
Mars Express to Beagle 2: "But you forgot your... ah, never mind." (ESA)

Over Christmas in 2003, I was watching the BBC news with my grandfather, hoping to hear that ESA or NASA had picked up a signal from the Martian surface. We waited.

We waited a bit more. However, it wasn’t until some weeks later (if I remember correctly) that the UK’s Beagle 2 Mars lander was officially declared dead (although I suspected as much in the 30 minutes of silence after the time it was supposed to touch down). The little lander’s taxi ride across millions of miles of space, the Mars Express, was working just fine, but Beagle 2? Not so much.

This was incredibly sad on so many levels. From a patriotic viewpoint, I was shattered. The chance to have a British presence on the Red Planet would not only have been inspiring, it may have given funding a small boost for the UK science community. Also, personally, only the week before, I’d been defending the mission to some friends who were convinced that the crazy idea of sending a British probe to Mars was pointless, as it was never going to make it.

What ever came before that December in 2003, it was all academic. Beagle 2, for whatever reason, didn’t phone home. Game over.

Of course, that wouldn’t be it. For months after, Martian satellites hunted for any evidence for a mini Beagle-shaped divot in the red dirt. Eventually, they found it, two years later.

So what happened to the little robot? Why did it turn into a meteorite and not a lander? Well, back in 2008, Madhat Abdel-Jawad and his engineer team at the University of Queensland thought they’d worked it all out. Apparently, Beagle 2’s gyroscopic spin was too fast, causing it to become unstable during re-entry. This may have caused it to tumble as it entered the Mars atmosphere. Obviously, tumbling isn’t good, so it hit the ground like scrap metal.

As it turns out, the Beagle 2 team are far from convinced this happened at all. Arthur Smith of Fluid Gravity Engineering in Emsworth, Hampshire, points out that Abdel-Jawad’s team did not simulate re-entry in a gravity field, and they failed to realize the lander had an offset centre of gravity. This means the simulation wasn’t complete, indicating the “tumbling Beagle” may not be the final explanation.

Now, Smith and his team will be publishing a paper with their findings

All our assumptions were valid over the time of flight we analysed,” Abdel-Jawad said in response to this news. “We would be delighted to accept the findings of the Beagle team’s new study if it were found to be valid after we review their analysis.”

Whether the Australian team is correct or not seems rather academic. Something went terribly wrong during re-entry, this is true, but there are so many variables that I’m not sure if we’ll ever hit on the real reason why Beagle 2 dropped from the sky that 2003 winter. Sure, it might aid future development of future landers, but unless they find a gaping design flaw or construction mistake (like the NASA Genesis “woops, I installed the accelerometer backwards” mission mishap), Beagle 2 made a crater in the Martian surface, and there won’t be a crash recovery team to pick up the bits for a long while yet…

Source: New Scientist

Mars Chaos

Of all the places I’d want to visit on Mars, this would be high on my list. After travelling to the bottom of Hellas Planitia (for the thick atmosphere and possibly finding liquid water) and the summit of Olympus Mons (for the view), I’d be sure to have a scout around Ariadnes Colles, in the southern hemisphere (pictured above).

The Ariadnes Colles region may not be a household name, but looking at these new high resolution images coming from the Mars Express orbiter, I can’t help but be impressed…
Continue reading “Mars Chaos”