MarsNews.com
May 28th, 2019

Curiosity Gazes Upon Noctilucent Clouds Over Gale Crater

Just imagine this scene. You’re on Mars, in Gale crater, with Curiosity. The sun has just set, and the temperature is falling rapidly. You look up. You see brilliant, wispy clouds, still sunlit even though night has fallen where you’re standing. They’re high in elevation, so the Sun can still reach them. As you stand there, skygazing, feeling increasingly chilled, the noctilucent clouds waft along in the Martian air, dimming from east to west as the Sun sets on them.

Curiosity has, in fact, been looking up after sunset recently. It’s been taking Navcam photos, and the camera’s reasonably broad field of view (45 degrees) lets it take in a lot of clouds, giving all of us back on Earth a chance to see them, too.

May 9th, 2019

New water cycle on Mars discovered

Billions of years ago, Mars could have looked like this with an ocean covering part of its surface.
© NASA/GSFC

Approximately every two Earth years, when it is summer on the southern hemisphere of Mars, a window opens: only there and only in this season can water vapor efficiently rise from the lower into the upper atmosphere. There, winds carry the rare gas to the North Pole. While part of the water vapor decays and escapes into space, the rest sinks back down near the poles. Researchers from the Moscow Institute of Physics and Technology and the Max Planck Institute for Solar System Research (MPS) in Germany describe this unusual Martian water cycle in a current issue of the Geophysical Research Letters. Their computer simulations show how water vapor overcomes the barrier of cold air in the middle atmosphere of Mars and reaches higher air layers. This could help to understand why Mars – unlike Earth – has lost most of its water.

Billions of years ago, Mars was a planet rich in water with rivers and even an ocean. Since then, our neighboring planet has changed dramatically: today, only small amounts of frozen water exist in the ground; in the atmosphere, water vapor occurs only in traces. All in all, the planet may have lost at least 80 percent of its original water. In the upper atmosphere of Mars, ultraviolet radiation from the Sun split water molecules into hydrogen (H) and hydroxyl radicals (OH). The hydrogen escaped from there irretrievably into space. Measurements by space probes and space telescopes show that even today water is still lost in this way. But how is this possible? The middle atmosphere layer of Mars, like Earth’s tropopause, should actually stop the rising gas. After all, this region is usually so cold that water vapor would turn to ice. How does the Martian water vapor reach the upper air layers?

In their current simulations, the Russian and German researchers find a previously unknown mechanism reminiscent of a kind of pump. Their model comprehensively describes the flows in the entire gas envelope surrounding Mars: from the surface to an altitude of 160 kilometers. The calculations show that the normally ice-cold middle atmosphere becomes permeable to water vapor twice a day – but only at a certain location and at a certain time of year.

May 6th, 2019

Dust storms may have stolen all of Mars’ water

Rotating globes from May 28 and July 1 show a global dust storm completely obscuring the surface of Mars.
Credits: NASA/JPL-Caltech/MSSS

In May 2018, Opportunity had been doing science on Mars since 2004, and there was no reason to think that the plucky rover wouldn’t carry on. Then, a dust storm hit that completely obscured the planet from view. After fine dust coated Opportunity’s solar panels, the rover apparently lost power and was declared dead by NASA in February 2019. Now, scientists think similar storms may have also delivered a coup de grace to water on Mars, stripping it from its surface for good.

At one point, Mars had a thick atmosphere and up to 20 percent of its surface was covered by liquid water, scientists figure. Around 4 billion years ago, however, Mars lost its magnetic field and with little to protect it from destructive solar winds, the red planet lost much of its atmosphere.

That left water on the surface vulnerable, and according to new observations from the ExoMars Trace Gas Orbiter (TGO), dust storms may have helped finish off the oceans and lakes. While water particles in the atmosphere normally linger at around 12 miles (20 km) in altitude, TGO noticed that the dust storms that killed Opportunity lifted H20 molecules up to 50 miles (80 km) above the ground.

April 24th, 2019

NASA’s InSight Lander Captures Audio of First Likely ‘Quake’ on Mars

NASA’s Mars InSight lander has measured and recorded for the first time ever a likely “marsquake.”

The faint seismic signal, detected by the lander’s Seismic Experiment for Interior Structure (SEIS) instrument, was recorded on April 6, the lander’s 128th Martian day, or sol. This is the first recorded trembling that appears to have come from inside the planet, as opposed to being caused by forces above the surface, such as wind. Scientists still are examining the data to determine the exact cause of the signal.

“InSight’s first readings carry on the science that began with NASA’s Apollo missions,” said InSight Principal Investigator Bruce Banerdt of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “We’ve been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology!”

The new seismic event was too small to provide solid data on the Martian interior, which is one of InSight’s main objectives. The Martian surface is extremely quiet, allowing SEIS, InSight’s specially designed seismometer, to pick up faint rumbles. In contrast, Earth’s surface is quivering constantly from seismic noise created by oceans and weather. An event of this size in Southern California would be lost among dozens of tiny crackles that occur every day.

“The Martian Sol 128 event is exciting because its size and longer duration fit the profile of moonquakes detected on the lunar surface during the Apollo missions,” said Lori Glaze, Planetary Science Division director at NASA Headquarters.

April 10th, 2019

Largest dust storm on Mars ever recorded may reveal why it’s so dry

A dust storm on Mars photographed by the European Space Agency’s Mars Express
SA/Roscosmos/CaSSIS, CC BY-SA 3.0 IGO

Dust storms on Mars aren’t all about dust — they’re also full of water. A satellite orbiting Mars has taken the most detailed measurements yet of how these rare events trap water at lower altitudes, which may help reveal what happened to the water that used to be abundant on the Red Planet.

In 2018, the largest recorded dust storm circled the entire Martian globe, so thick that it hid the surface from the sun and killed the Opportunity rover. The ExoMars Trace Gas Orbiter watched this cataclysmic storm from orbit. Just before sunset and just after sunrise on Mars, it examined the atmosphere to determine how the dust storm absorbed sunlight.

Ann Carine Vandaele at the Royal Belgian Institute for Space Aeronomy and her colleagues used this data to determine how water was behaving in the storm. They found that just before the storm, there were water ice clouds in the atmosphere, but no water vapour more than 40 kilometres above the surface. This changed a few days later when water vapour appeared at altitudes of 40 and 80 kilometres, seemingly replacing the water ice clouds.

April 1st, 2019

Mars Express matches methane spike measured by Curiosity

Mars Express results ESA/Giuranna et al (2019)

A reanalysis of data collected by ESA’s Mars Express during the first 20 months of NASA’s Curiosity mission found one case of correlated methane detection, the first time an in-situ measurement has been independently confirmed from orbit.

Reports of methane in the martian atmosphere have been intensely debated, with Mars Express contributing one of the first measurements from orbit in 2004, shortly after its arrival at the Red Planet.

The molecule attracts such attention because on Earth methane is generated by living organisms, as well as geological processes. Because it can be destroyed quickly by atmospheric processes, any detection of the molecule in the martian atmosphere means it must have been released relatively recently – even if the methane itself was produced millions or billions of years ago and lay trapped in underground reservoirs until now.

While spacecraft and telescopic observations from Earth have in general reported no or very low detections of methane, or measurements right at the limit of the instruments’ capabilities, a handful of spurious spikes, along with Curiosity’s reported seasonal variation at its location in Gale Crater, raise the exciting question of how it is being generated and destroyed in present times.

Now, for the first time, a strong signal measured by the Curiosity rover on 15 June 2013 is backed up by an independent observation by the Planetary Fourier Spectrometer (PFS) onboard Mars Express the next day, as the spacecraft flew over Gale Crater.

March 27th, 2019

Rivers raged on Mars late into its history

via GIPHY

Long ago on Mars, water carved deep riverbeds into the planet’s surface—but we still don’t know what kind of weather fed them. Scientists aren’t sure, because their understanding of the Martian climate billions of years ago remains incomplete.

A new study by University of Chicago scientists catalogued these rivers to conclude that significant river runoff persisted on Mars later into its history than previously thought. According to the study, published March 27 in Science Advances, the runoff was intense—rivers on Mars were wider than those on Earth today—and occurred at hundreds of locations on the red planet.

But it’s a puzzle why ancient Mars had liquid water. Mars has an extremely thin atmosphere today, and early in the planet’s history, it was also only receiving a third of the sunlight of present-day Earth, which shouldn’t be enough heat to maintain liquid water. “Indeed, even on ancient Mars, when it was wet enough for rivers some of the time, the rest of the data looks like Mars was extremely cold and dry most of the time,” Kite said.

Seeking a better understanding of Martian precipitation, Kite and his colleagues analyzed photographs and elevation models for more than 200 ancient Martian riverbeds spanning over a billion years. These riverbeds are a rich source of clues about the water running through them and the climate that produced it. For example, the width and steepness of the riverbeds and the size of the gravel tell scientists about the force of the water flow, and the quantity of the gravel constrains the volume of water coming through.

Their analysis shows clear evidence for persistent, strong runoff that occurred well into the last stage of the wet climate, Kite said.

March 19th, 2019

Minitremors detected on Mars for first time

NASA’s InSight lander places a protective, dome-shaped shield above its seismometer. JPL-CALTECH/NASA

After months of delicate maneuvering, NASA’s InSight lander has finished placing its hypersensitive seismometer on the surface of Mars. The instrument is designed to solve mysteries about the planet’s interior by detecting the booming thunder of “marsquakes.” But just a few weeks into its run, the car-size lander has already heard something else: the minute tremors that continually rock our red neighbor. If marsquakes are the drum solo, these microseisms, as they’re known, are the bass line.

The signal first became apparent in early February, as soon as the lander placed a protective shield over the seismometer, said Philippe Lognonné, a planetary seismologist at Paris Diderot University who heads the team that runs the instrument, in a talk here today at the annual Lunar and Planetary Science Conference. “We do believe that these signals are waves coming from Mars.” This is the first time, he said, that such microseisms have been detected on another planet.

On Earth, microseisms are ubiquitous, caused largely by the sloshing of the ocean by storms and tides. Mars, despite the dreams of science fiction writers, has no present-day oceans. Instead, this newly discovered noise is likely caused by low-frequency pressure waves from atmospheric winds that rattle the surface, inducing shallow, longer-period waves in the surface, called Rayleigh waves, Lognonné said.

March 5th, 2019

Mars InSight’s Rock-Hammer is About Half a Meter Down and Has Already Run into Rocks

NASA’s InSight lander is busy deploying its Heat Flow and Physical Properties Package (HP3) into the Martian soil and has encountered some resistance. The German Aerospace Center (DLR), who designed and built the HP3 as part of the InSight mission, has announced that the instrument has hit not one, but two rocks in the sub-surface. For now the HP3 is in a resting phase, and it’s not clear what will happen next.

The HP3 is designed to measure the heat coming from Mars’ interior and to tell us something about the source of that heat. The basic idea is to determine how Mars formed, and if it formed the same way Earth did. It’ll also tell us something about how rocky planets in general form and evolve. But to do that, it has to get underground.

The HP3 uses a hammer system to pound itself into the ground. It works in phases, spending about four hours at a time hammering into the surface. But all that hammering creates a lot of friction and heat, so the HP3 rests for a couple days while things cool down. Then it measures the heat before continuing the cycle.

February 28th, 2019

First Evidence of Planet-Wide Groundwater System On Mars

Evolution of water-filled basins over time

Mars Express has revealed the first geological evidence of a system of ancient interconnected lakes that once lay deep beneath the Red Planet’s surface, five of which may contain minerals crucial to life.

Mars appears to be an arid world, but its surface shows compelling signs that large amounts of water once existed across the planet. We see features that would have needed water to form – branching flow channels and valleys, for example – and just last year Mars Express detected a pool of liquid water beneath the planet’s south pole.

A new study now reveals the extent of underground water on ancient Mars that was previously only predicted by models.

“Early Mars was a watery world, but as the planet’s climate changed this water retreated below the surface to form pools and ‘groundwater’,” says lead author Francesco Salese of Utrecht University, the Netherlands.

“We traced this water in our study, as its scale and role is a matter of debate, and we found the first geological evidence of a planet-wide groundwater system on Mars.”