Traces of salty water on Mars … and more mysteries!

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[Credit: Randall Munroe]

Water Found on Mars Could Be First Signs of Martian Life

NASA’s Mars Reconnaissance Orbiter found traces of water that comes and goes on Mars—aka flowing water

For The Daily Beast:

We seem to discover water on Mars about once a year. Well, that’s not quite true: we’ve known Mars has water for quite a while. However, there are a lot of mysteries still to solve about how that water behaves and where it’s located. In particular, we’d like to know if water sometimes flows on the surface of the planet, which would tell us a lot about the cycles both above and below ground. And of course water is essential for life as we know it—finding flowing water, even transient flows, would make Mars seem a little more Earth-like.

The problem is that any liquid water evaporates quickly in the bone-dry Martian desert, and other processes can leave traces that mimic dried-up flows. When so little water is involved in the first place, it leaves us looking for the Martian equivalent of water spots on a long-dry drinking glass. And those spots are chemical traces—salt and other minerals once dissolved in the water—which must be identified by robotic spacecraft from orbit.

Today, scientists using NASA’s Mars Reconnaissance Orbiter (MRO) have identified some of those traces: a little bit of water comes and goes on Mars’ surface. [Read the rest at The Daily Beast…]


A possible ocean like ours on the moon Europa

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Europa’s Salty Sea

My first contribution to the brand-new magazine Hakai:

You can find bits and pieces of Earth seemingly scattered around the solar system. The surface of Mars looks a lot like Earth’s deserts; Titan’s atmosphere isn’t far off (minus a lack of oxygen); and the moon shares Earth’s basic geology. If you want to see oceans like ours, new research suggests your best bet is Jupiter’s moon Europa.

“Oceans like ours” in a chemical sense, that is. There are no fish or whales or coral on Europa. But Europa’s massive ocean is a salty one—and according to planetary geologist Kevin P. Hand and geochemist Richard W. Carlson, the specific salt that fills its sea, sodium chloride (or table salt), is the same salt that is crucial to life on Earth. [Read the read at Hakai…]

Hakai is focused on coastal ecosystems, which is a little off the beaten path for me, but they indulged me in writing about oceans on another world. And of course there’s physics hiding in a lot of areas, so I’ll hopefully be writing more for them in the future. In the meantime, check out the magazine: it looks really great!

Are comets the origin of Earth’s oceans?

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Are comets the origin of Earth’s oceans?

From The Daily Beast:

Water, water everywhere, but where did it come from? One common explanation is that the water in Earth’s oceans was brought by comets, which bombarded the planet during its earliest period. It’s a simple, logical, and testable story.

But that doesn’t mean it’s right. A new study published last week in Science revealed that the water on Comet 67P/Churyumov-Gerasimenko doesn’t match that found on Earth. Specifically, instruments aboard the Rosetta probe measured the relative amount of deuterium in the comet’s water and found it was roughly three times higher than the amount in Earth’s oceans. Comets are chemically pristine, mostly unchanged over the Solar System’s 4.5 billion year history, so a mismatch in the deuterium content complicates the story of Earth’s water. [Read more at The Daily Beast….]

The MESSENGER (MErcury Surface Space ENvironment, GEochemistry, and Ranging) spacecraft has found strong evidence both for water ice and organic molecules in shadowed craters near Mercury’s poles. Unlike Earth, Mercury has no seasons: its axis stands perpendicular to its plane of orbit, so deep craters near the north and south pole will have bottoms in permanent shade. Any place else on the surface will eventually be exposed to the Sun’s punishing glare, not only melting ice but boiling away any residual water. However, during the early Solar System, meteorites and comets brought water and organic compounds to the planet’s surface—at least according to planet formation models. This new discovery lends strong support to that theory.

The results from both the reflection and neutron analyses were consistent: several craters in Mercury’s polar regions provide sufficient shadow for stable water ice. The large craters named Prokofiev and Kandinsky were both found to contain significant radar-bright (RB) patches, indicating highly reflective materials. (Craters on Mercury are commonly named for famous artists, authors, composers, and the like. As a fan of both Prokofiev and Kandinsky, I approve.)

The size of the reflective patches matched the total proportion of each crater that lies in permanent shadow. [Read more…]

MESSENGER: Mercury’s craters have ice and organic molecules