Mystery White Substance, But No Water Yet at Martian Pole

Illustration for article titled Mystery White Substance, But No Water Yet at Martian Pole

The Phoenix Lander, our favorite robot chemistry lab on Mars, has successfully cooked up some soil in its oven to see if water evaporates from it when heated. So far, no dice. Though the Martian rovers Opportunity and Spirit have found evidence of evaporated water at the equator of the planet, Phoenix hasn't yet found similar evidence at the pole. What it has found, however, is fascinating. There is an unknown white substance right beneath the surface of the soil next to it (pictured), which could be ice or salt. And the Martian soil has turned out to be chunky, rather than sandy, which surprised scientists. reports on the ongoing water search:

[TEGA team leader William] Boynton says the team wasn't surprised that they found no indication of water ice because the sample sat out in the Martian sun for several days while it was stuck at the entrance to one of TEGA's ovens, which heat up the soil so that the instrument's mass spectrometer can analyze the composition of the vapors the soil gives off.

In the next few days, scientists will further heat the sample up, to a maximum of 1,800 F (1,000 C), to vaporize out minerals that might have chemically-bound water, carbon dioxide or sulfur dioxide.

"We expect there's a high probability that we would find minerals with chemically-bound water, which would release their water at higher temperatures," Boynton said. Signs of water in the minerals would indicate that rocks on the surface once interacted with liquid water.


And here's what's going on with that mystery white substance:

Mission scientists are still debating whether this bright, white material is exposed subsurface water ice or salt minerals. "It could be ice; it could be salt. We have to sample it to be able to tell," said Phoenix robotic arm team leader and mission digging czar Peter Arvidson of Washington University in St. Louis.

A small chunk of the material was knocked loose by the robotic arm scoop as it performed one of its backhoe-like maneuvers in the trench. Scientists will be monitoring this chunk and expect to see it change if it actually is ice.

"If it really is ice, we expect it to sublimate, or go into the vapor phase," Arvidson said.

Here's hoping it's the top of a secret underground laboratory put there by an alien race to study humanity from a distance.

Robot Finds Mars Dry So Far [via]

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@corpore-metal: For any individual missions, yes, robotics are usually cheaper. In order to do a large number of things, and assuming it's technically feasible, people sometimes have the advantage. For instance, I don't have a special door-opening robot, and getting one would certainly cost more than the time it takes for me to get up and open the door.

@diverguy: Clay is partially liquid water, so I don't think that's too likely. For the same reason you mentioned though (permafrost depth) and the fact that they found the stuff under the lander's engines, I like the salt theory. Or perhaps just some white mineral. No idea it it would be related to why the soil is also clumping.