Massive Martian ice discovery opens a window into red planet's history

Massive Martian ice discovery opens a window into red planet's history
A vertically exaggerated view of Mars' north polar cap. Researchers with The University of Texas at Austin and the University of Arizona estimate that if melted, the massive ice deposits discovered in this region would cover the planet in 1.5 meters (5 feet) of water. Credit: SA/DLR/FU Berlin; NASA MGS MOLA Science Team

Newly discovered layers of ice buried a mile beneath Mars' north pole are the remnants of ancient polar ice sheets and could be one of the largest water reservoirs on the planet, according to scientists at The University of Texas at Austin and the University of Arizona.

The team made the discovery using measurements gathered by the Shallow Radar (SHARAD) on NASA's Mars Reconnaissance Orbiter (MRO). SHARAD emits radar waves that can penetrate up to a mile and a half beneath the surface of Mars.

The findings, published May 22 in Geophysical Research Letters, are important because the layers of ice are a record of past climate on Mars in much the same way that tree rings are a record of past climate on Earth. Studying the geometry and composition of these layers could tell scientists whether climate conditions were previously favorable for life, researchers said. The team found layers of sand and ice that were as much as 90% water in some places.

If melted, the newly discovered would be equivalent to a global of water around Mars at least 1.5 meters (5 feet) deep.

"We didn't expect to find this much water ice here," said lead author Stefano Nerozzi, a graduate research assistant at the University of Texas Institute for Geophysics (UTIG) who is completing his Ph.D. at the Jackson School of Geosciences. "That likely makes it the third largest water reservoir on Mars after the polar ice caps."

Massive Martian ice discovery opens a window into red planet's history
A view of Mars showing the planet's northern polar ice cap. A new study led by The University of Texas at Austin has found remnants of ancient ice caps buried in the north polar region. Credit: ISRO/ISSDC/Emily Lakdawalla

The findings were corroborated by an independent study using gravity data instead of radar, led by researchers at Johns Hopkins University. Nerozzi was a co-author. The papers have been published simultaneously in Geophysical Research Letters.

The authors think that the layers formed when ice accumulated at the poles during past ice ages on Mars. Each time the planet warmed, a remnant of the ice caps became covered by sand, which protected the ice from and prevented it from dissipating into the atmosphere.

Scientists have long known about glacial events on Mars, which are driven by variations in the planet's orbit and tilt. Over periods of about 50,000 years, Mars leans toward the sun before gradually returning to an upright position, like a wobbling spinning top. When the planet spins upright, the equator faces the sun, allowing the polar ice caps to grow. As the planet tilts, the ice caps retreat, perhaps vanishing entirely.

Until now, scientists thought that the ancient ice caps were lost. The paper shows that in fact significant ice sheet remnants have survived under the planet's surface, trapped in alternating bands of ice and sand, like layers on a cake.

Co-author Jack Holt, a professor at the Lunar & Planetary Laboratory of the University of Arizona, said that the study provides new, important insights into the exchange of water ice between the poles and the midlatitudes, where his research group previously confirmed the presence of widespread glaciers, also using the SHARAD instrument.

Massive Martian ice discovery opens a window into red planet's history
A composite image showing alternating layers of ice and sand in an area where they are exposed on the surface of Mars. The photograph, taken with the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter, was adjusted to show water ice as light-colored layers and sand as darker layers of blue. The tiny bright white flecks are thin patches of frost. Credit: NASA/JPL/University of Arizona

"Surprisingly, the total volume of water locked up in these buried polar deposits is roughly the same as all the water ice known to exist in glaciers and buried ice layers at lower latitudes on Mars, and they are approximately the same age," he said.

Holt, who was a UTIG scientist and research professor for 19 years before joining the University of Arizona in 2018, has been a co-investigator with SHARAD since the spacecraft arrived at Mars in 2006.

Nerozzi said that studying this record of past polar glaciation could help determine whether Mars was ever habitable.

"Understanding how much water was available globally versus what's trapped in the poles is important if you're going to have liquid water on Mars," Nerozzi said. "You can have all the right conditions for life, but if most of the water is locked up at the poles, then it becomes difficult to have sufficient amounts of liquid near the equator."


Explore further

Image: Radar footprints over buried Mars lake

More information: S. Nerozzi et al. Buried ice and sand caps at the north pole of Mars: revealing a record of climate change in the cavi unit with SHARAD, Geophysical Research Letters (2019). DOI: 10.1029/2019GL082114
Journal information: Geophysical Research Letters

Citation: Massive Martian ice discovery opens a window into red planet's history (2019, May 22) retrieved 21 August 2019 from https://phys.org/news/2019-05-massive-martian-ice-discovery-window.html
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May 22, 2019
"Over periods of about 50,000 years, Mars leans toward the sun before gradually returning to an upright position, like a wobbling spinning top. When the planet spins upright, the equator faces the sun, allowing the polar ice caps to grow. As the planet tilts, the ice caps retreat, perhaps vanishing entirely."

Global Warming, Martian style

May 22, 2019
Well, I for one, am relieved that the writers of this article did not hesitate to obfuscate their conclusions.

Implying that future data may force researcher's to reconsider the meaning of present results.

Or the casual, gullible reader would mistaken the clickbait headline posted here, as confirmed & verified fact.

May 22, 2019
Or the casual, gullible reader would mistaken[sic] the clickbait headline posted here, as confirmed & verified fact.
'Massive': ' "Surprisingly, the total volume of water locked up in these buried polar deposits is roughly the same as all the water ice known to exist in glaciers and buried ice layers at lower latitudes on Mars, and they are approximately the same age," he said.'
Massive √

'confirmed': "The findings were corroborated by an independent study using gravity data instead of radar..."
confirmed ?
corroborated √

Clickbait Nope


May 22, 2019
Mars probably has life somewhere inside it, protected from the outer surface by sealed layers of whatever, and warmed by remnant planetary core heat. Somewhere in those layer cakes, there is room for it to find a way. May not be very impressive, but who knows. In its early years when it could live on a surface warmed by a warmer ancient sun, and maybe nearer to the earth, assuming that the lower elevation area on Mars corresponds to the deeper seas and featureless terrain of our Pacific Ocean and its preedecessor the PanThallasic Ocean. This presents a theory that the impactor of Earth was Mars. It did not go very far away. Prior to that, it may have even shared an orbit with Earth. This was the state of things for maybe 500,000,000 years, so life would have had a perfect chance to not only develope, but advance. Maybe, just maybe ...WE are Martians. The early ones maybe escaped before the collision, colonizing other places.

May 23, 2019
Most of the water of Mars is yet to be discovered deep underground.
There is a simple reason for this.
Any planet that cools down does so from the outside inwards.
First a crust is formed like the shell of an egg.
Then as the planet cools down further it shrinks creating deep crevasses and underground hollows as the surface remains intact.
Eventually the oceans will find a way in and fill these underground hollows.
This process follows an inevitable part of the aging of planets.
The exact same process is going to take place on planet Earth.
This theory of mine can easily be proven.
The amount that the inner layers of a planet would shrink as it cools down far exceeds the volume of the oceans covering it.
A few simple calculations will proof this.

May 23, 2019
This theory of mine can easily be proven.
The amount that the inner layers of a planet would shrink as it cools down far exceeds the volume of the oceans covering it.
A few simple calculations will proof this.
Entry points to the underground water has most likely already been photographed without anyone having zoomed into those locations.
Or maybe they have, just not yet realising the significance thereof.
And this is where we will eventually discover a multitude of life beyond our wildest dreams.
I already published this in a book back in 2008 stating that vast amounts of water and life will still be discovered beneath the Marshian soil still in my lifetime and it is slowly but surely coming true.

May 23, 2019
A few simple calculations will proof this.

Please, show us

May 23, 2019
The amount that the inner layers of a planet would shrink as it cools down far exceeds the volume of the oceans covering it. ... I already published this in a book back in 2008
.

If it is peer published, how come no one mention it or you don't even link it?

Planets have all sorts of water covers, from exoplanets that are mostly water according to density estimates, to dry planets such as Earth. And they have all sorts of temperature histories from hot Jupiters where minerals ash the atmosphere to ice balls like our own Neptune.

I doubt anyone can make head or tails of that in general. We all suspect you can't since you argue about futile pattern recognition of satellite imagery instead of showing us the money (model); in two long, unusually formatted comments to boot, as any mundane crackpot would do. And as the article show we are still finding out how much water Mars ever had or where it is now.

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