New research suggests Mercury’s poles are icier than scientists thought

Posted: September 20, 2017 by oldbrew in Astronomy, research, solar system dynamics
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Mercury [image credit: NASA]


The first photos of ice at Mercury’s poles were released in 2014 but this research goes a step further, as Phys.org reports. It finds that ‘the total area of the three sheets [is] about 3,400 square kilometers—slightly larger than the state of Rhode Island’.

The scorching hot surface of Mercury seems like an unlikely place to find ice, but research over the past three decades has suggested that water is frozen on the first rock from the sun, hidden away on crater floors that are permanently shadowed from the sun’s blistering rays.

Now, a new study led by Brown University researchers suggests that there could be much more ice on Mercury’s surface than previously thought.

The study, published in Geophysical Research Letters, adds three new members to the list of craters near Mercury’s north pole that appear to harbor large surface ice deposits.


But in addition to those large deposits, the research also shows evidence that smaller-scale deposits scattered around Mercury’s north pole, both inside craters and in shadowed terrain between craters. Those deposits may be small, but they could add up to a lot more previously unaccounted-for ice.

“The assumption has been that surface ice on Mercury exists predominantly in large craters, but we show evidence for these smaller-scale deposits as well,” said Ariel Deutsch, the study’s lead author and a Ph.D. candidate at Brown. “Adding these small-scale deposits to the large deposits within craters adds significantly to the surface ice inventory on Mercury.”

The idea that Mercury might have frozen water emerged in the 1990s, when Earth-based radar telescopes detected highly reflective regions inside several craters near Mercury’s poles. The planet’s axis doesn’t have much tilt, so its poles get little direct sunlight, and the floors of some craters get no direct sunlight at all.

Without an atmosphere to hold in any heat from surrounding surfaces, temperatures in those eternal shadows have been calculated to be low enough for water ice to be stable. That raised the possibility these “radar-bright” regions could be ice.

That idea got a boost after NASA’s MESSENGER probe entered Mercury’s orbit in 2011. The spacecraft detected neutron signals from the planet’s north pole that were consistent with water ice.

Continued here.

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