A Mesmerizing Look at Year 4 of the Solar Dynamics Observatory

Coronal Mass Ejection as viewed by the Solar Dynamics Observatory on June 7, 2011. A similar type of outburst triggered aurorae during a strong geomagnetic storm in February 1872. Image Credit: NASA/SDO
Coronal Mass Ejection as viewed by the Solar Dynamics Observatory on June 7, 2011. A similar type of outburst triggered aurorae during a strong geomagnetic storm in February 1872. Image Credit: NASA/SDO

Four years ago today, the Solar Dynamics Observatory embarked on a five-year mission to boldly go where no Sun-observing satellite has gone before. SDO uses its three instruments to look constantly at the Sun in ten different wavelengths. Called the “Crown Jewel” of NASA’s fleet of solar observatories, SDO is a technologically advanced spacecraft that takes images of the sun every 0.75 seconds. Each day it sends back about 1.5 terabytes of data to Earth — the equivalent of about 380 full-length movies.

SDO launched on Feb. 11, 2010, and it has since captured the amazing views of the ever-changing face of the Sun — the graceful dance of solar material coursing through the Sun’s the corona, massive solar explosions and giant sunspot shows. Enjoy this latest highlight video from year 4 from SDO!

I was priveldged to be able to attend the launch of SDO, and you can read our article about the launch here.

The launch included a little “special effects” that wowed the crowd. The Atlas rocket soared close to a sundog just as the spacecraft reached Max-Q, and a ripple effect was created around the spacecraft. You can watch the launch below to see what happened:

Music Video From Saturn Shows Off Dazzling Aurora Light Show

An aurora around Saturn's north pole in 2013. Credit: NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University

Above is the latest rave-like video from NASA. While the images are reminiscent of what could play during an awesome Friday night party, what you’re actually seeing is a timelapse of auroras on Saturn. These pictures are pretty to look at, but they also tell us more about how the sun’s belches of stuff influence the magnetic field around the ringed gas giant.

“Saturn’s auroras can be fickle — you may see fireworks, you may see nothing,” stated Jonathan Nichols of the University of Leicester in England, who led the work on the Hubble Space Telescope images shown in the video. “In 2013, we were treated to a veritable smorgasbord of dancing auroras, from steadily shining rings to super-fast bursts of light shooting across the pole.”

The light show was captured by both the Saturn-orbiting Cassini spacecraft and the Earth-orbiting Hubble. Cassini managed to nab its images from three Saturn distances away (which is apparently an unusually close vantage point.) This location “provided a look at the changing patterns of faint emissions on scales of a few hundred miles (kilometers) and tied the changes in the auroras to the fluctuating wind of charged particles blowing off the sun and flowing past Saturn,” NASA stated.

Here are a few things scientists are learning (or hoping to learn soon) from the light show:

  • How auroras are formed. The Cassini images suggest that as magnetic field lines forge new links, this is where the storms are centered. This process happens on Earth, so it would make sense for it to happen elsewhere. Researchers also found that some of the auroras stick close to the orbital position of Mimas, suggesting that the moon may be influencing some of the storms (a process already known to happen with Enceladus).
  • The nature of Saturn’s atmosphere. While the answers are still forthcoming, scientists are examining why the top of Saturn’s atmosphere (and other gas giants) are warmer than would be expected given how far they are from the sun. “By looking at these long sequences of images taken by different instruments, we can discover where the aurora heats the atmosphere as the particles dive into it and how long the cooking occurs,” stated Sarah Badman, a Cassini visual and infrared mapping spectrometer team associate at Lancaster University, England. 
  • What color the auroras are. Red on the bottom, and purple on the top, depending on how Saturn’s hydrogen is excited and what light it emits. (For reference, Earth’s is green on bottom and red at top due to excitement of nitrogen and oxygen).
  • Where charged particles around Saturn go. More data from the W.M. Keck Observatory and NASA’s Infrared Telescope Facility (both in Hawaii) could show “how particles are ionized in Saturn’s upper atmosphere,” NASA stated. Better yet, scientists can compare that information to the stuff gathered from outside of Earth’s atmosphere by Hubble and Cassini. This will allow them to see what distortions the ground-based observatories experienced due to Earth’s atmosphere, and improve the accuracy of the observations.

Not bad work for a single music video, isn’t it? For more information on auroras on Saturn, check out these past Universe Today stories:

Source: NASA Jet Propulsion Laboratory

The Joy of Discovery, Featuring Bill Nye

“We are, you and I, at least one of the ways that the Universe knows itself.” – Bill Nye

Did you manage to (or choose to) watch the much-anticipated debate between Science Guy Bill Nye and Ken Ham on the “merits” of Creationism on Feb. 4? While clearly nothing more than a publicity event cooked up by Ham to fund his Creation Museum in Kentucky (yes, I’m afraid that’s actually a thing here in America) Nye felt it to be in his — as well as the country’s — best interest to stand up and defend science and its methods in the face of unapologetic fundamentalist denial.

The video above, just released by John D. Boswell — aka melodysheep, creator of the excellent Symphony of Science series — takes some of Bill’s statements during the debate and puts them to music and images of our fascinating world.

Continue reading “The Joy of Discovery, Featuring Bill Nye”

New Technique Puts Exoplanets on the Scale

Meet Kepler-22b, an exoplanet with an Earth-like radius in the habitable zone of its host star. Unfortunately its mass remains unknown. Image Credit: NASA

Astronomers constantly probe the skies for the unexpected. They search for unforeseen bumps in their data — signaling an unknown planet orbiting a star, a new class of astronomical objects or even a new set of physical laws that will rewrite the old ones. They are willing to embrace new ideas that may replace the wisdom of years past.

But there’s one exception to the rule: the search for Earth 2.0. Here we don’t want to find the unexpected, but the expected. We want to find a planet so similar to our own, we can almost call it home.

While, we can’t exactly image these planets with great enough detail to see if one’s a water world with luscious green plants and civilizations, we can use indirect methods to find an “Earth-like” planet — a planet with a similar mass and radius to the Earth.

There’s only one problem: the current techniques to measure an exoplanet’s mass are limited. To date astronomers measure radial velocity — tiny wobbles in a star’s orbit as it’s tugged by the gravitational pull of its exoplanet — to derive the planet-to-star mass ratio.

But given that most exoplanets are detected via their transit signal — dips in light as a planet passes in front of its host star — wouldn’t it be great if we could measure its mass based on this method alone? Well, astronomers at MIT have found a way.

Graduate student Julien de Wit and MacArthur Fellow Sara Seager have developed a new technique for determining mass by using an exoplanet’s transit signal alone. When a planet transits, the star’s light passes through a thin layer of the planet’s atmosphere, which absorbs certain wavelengths of the star’s light. Once the starlight reaches Earth it will be imprinted with the chemical fingerprints of the atmosphere’s composition.

The so-called transmission spectrum allows astronomers to study the atmospheres of these alien worlds.

But here’s the key: a more massive planet can hold on to a thicker atmosphere. So in theory, a planet’s mass could be measured based on the atmosphere, or the transmission spectrum alone.

Of course there isn’t a one to one correlation or we would have figured this out long ago. The atmosphere’s extent also depends on its temperature and the weight of its molecules. Hydrogen is so light it slips away from an atmosphere more easily than, say, oxygen.

So de Wit worked from a standard equation describing scale height — the vertical distance over which the pressure of an atmosphere decreases. The extent to which pressure drops off depends on the planet’s temperature, the planet’s gravitational force (a.k.a. mass) and the atmosphere’s density.

According to basic algebra: knowing any three of these parameters will let us solve for the fourth. Therefore the planet’s gravitational force, or mass, can be derived from its atmospheric temperature, pressure profile and density — parameters that may be obtained in a transmission spectrum alone.

With the theoretical work behind them, de Wit and Seager used the hot Jupiter HD 189733b, with an already well-established mass, as a case study. Their calculations revealed the same mass measurement (1.15 times the mass of Jupiter) as that obtained by radial velocity measurements.

This new technique will be able to characterize the mass of exoplanets based on their transit data alone. While hot Jupiters remain the main target for the new technique, de Wit and Seager aim to describe Earth-like planets in the near future. With the launch of the James Webb Space Telescope scheduled for 2018, astronomers should be able to obtain the mass of much smaller worlds.

The paper has been published in Science Magazine and is now available for download in a much longer form here.

Google Subsidiary To Negotiate For Giant Eight-Acre NASA California Facility, Hangar One

A 1999 image of Hangar 1 taken in Moffett Field, Calif. Credit: NASA Ames Research Center

Back in late 2011, three Google executives reportedly approached NASA because they knew the agency was facing a problem. NASA was managing the eight-acre Hangar One, which is best remembered for being an airship construction facility 80 years ago. Renovations were getting expensive, though, and the executives had a proposal: it would take over the fixing-up, as long as they could park several private jets in the facility.

Fast-forward a couple of years, and after a competitive process Google real estate subsidiary Planetary Ventures LLC is going to negotiate on a lease with two goals: fix up Hangar One and manage Moffett Federal Airfield. If approved, the lease would remove the NASA Ames Research Center’s management costs.

It’s another example of NASA looking to lease out its historic facilities to the private sector (examples: here and here) to save money amid cost-consciousness by federal legislators, something that administrator Charles Bolden highlighted in a statement. “The agreement announced today will benefit the American taxpayer and the community around Moffett,” he said. “It will allow NASA to focus its resources on core missions, while protecting the federal need to use Moffett Field as a continued, limited-use airfield.”

An undated photo showing a blimp inside Hangar One. The facility began as a facility for airships in the 1930s. Credit: NASA Ames Research Center
An undated photo showing a blimp inside Hangar One. The facility began as a facility for airships in the 1930s. Credit: NASA Ames Research Center

Lease terms are still being negotiated, but these are some of the things expected to be a part of it: rehabilitating Hangars One, 2 and 3, fixing up a golf course, starting a public use and educational facility, and getting rid of NASA’s operation and maintenance cost of the area, among other things. In a press release, NASA did not give a date as to when these negotiations would conclude.

As Wired points out, this is an indication that Google and NASA are becoming trusted partners in ventures such as this. “It underscores the increasingly tight relationship between Google and the space agency research center, located just three miles from Google’s headquarters,” wrote Robert McMillan. “Google has already leased more than 40 acres of NASA Ames space to build a 1.2-million-square-foot R&D facility, and the company is working with NASA to test the world’s first quantum computer at Ames too.”

You can read the request for proposals and other information on Hangar One at this NASA website.

Saturn’s Ring Shows A Twist In Cassini’s Glimpse Of Planet

Saturn's F ring appears distorted in this October 2013 picture from the Cassini spacecraft. The twisting may be because the F ring is crashing repeatedly into a "single small object", NASA stated. Credit: NASA/JPL-Caltech/Space Science Institute

What’s up with this distortion? This picture from the Cassini spacecraft shows some kind of twist happening in the F ring of Saturn. Scientists in fact have seen other strange shapes in this delicate ring, indicating that something is disturbing it from time to time.

“Saturn’s F ring often appears to do things other rings don’t. In this Cassini spacecraft image, a strand of ring appears to separate from the core of the ring as if pulled apart by mysterious forces. Some ring scientists believe that this feature may be due to repeated collisions between the F ring and a single small object,” NASA stated this month.

There’s a debate in the scientific community about where the rings arose in the first place. “It’s been going back and forth for ages and it still goes back and forth. Are they old, or have they been there a long period of time? Are they new? I don’t know what to think, to be quite honest. I’m not being wishy-washy, I just don’t know what to think anymore,” Kevin Grazier, a planetary scientist with the Cassini mission for over 15 years, told Universe Today in December.

While this picture dates from October, you can check out Cassini images as they come in to NASA’s raw image database. Even in unprocessed form, the planet and its rings look beautiful — as you can clearly see in samples below.

The bulk of Saturn looms to the side of this shot of Saturn's rings taken in February 2014 by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute
The bulk of Saturn looms to the side of this shot of Saturn’s rings taken in February 2014 by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute
The variety of Saturn's rings is visible in this raw shot from the Cassini spacecraft taken in February 2014. Credit: NASA/JPL/Space Science Institute
The variety of Saturn’s rings is visible in this raw shot from the Cassini spacecraft taken in February 2014. Credit: NASA/JPL/Space Science Institute
Although Saturn's rings look solid and substantial in images such as this, they are made up of many tiny, icy objects collecting as thin as 6.2 miles (10 kilometers) deep.  Image taken by the Cassini spacecraft in February 2014. Credit: NASA/JPL/Space Science Institute
Although Saturn’s rings look solid and substantial in images such as this, they are made up of many tiny, icy objects collecting as thin as 6.2 miles (10 kilometers) deep. Image taken by the Cassini spacecraft in February 2014. Credit: NASA/JPL/Space Science Institute

Awaiting Yutu’s Phone Home on Lunar Day 3

This composite view shows China’s Yutu rover heading south and away forever from the Chang’e-3 landing site about a week after the Dec. 14, 2013 touchdown at Mare Imbrium. This cropped view was taken from the 360-degree panorama. See complete 360 degree landing site panorama herein. Chang’e-3 landers extreme ultraviolet (EUV) camera is at right, antenna at left. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm

Will Yutu Phone Home ?
This composite view shows China’s Yutu rover heading south and away forever from the Chang’e-3 landing site about a week after the Dec. 14, 2013 touchdown at Mare Imbrium. This cropped view was taken from the 360-degree timelapse panorama. See complete 360 degree landing site timelapse panorama below. Chang’e-3 landers extreme ultraviolet (EUV) camera is at right, antenna at left. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com
See our Yutu timelapse pano at NASA APOD Feb. 3, 2014:
http://apod.nasa.gov/apod/ap140203.html[/caption]

Will ‘Yutu’ phone home? Will Yutu live to see another Earthrise?

Those are the million dollar questions we’re all awaiting the answer to on pins and needles as Lunar Day 3 begins for China’s world famous ‘Yutu’ moon rover and Chang’e-3 lander, following a significant malfunction as night fell two weeks ago.

With the Sun due to rise over the Mare Imbrium landing site, China’s maiden pair of lunar probes are due to awaken at any moment now – and hopefully send good news.

Yutu – which means ‘Jade Rabbit’- and the mothership lander have been sleeping through the utterly frigid two week long lunar night since they entered their second hibernation period on Jan. 24th and 25th respectively, according to Chinese space agency officials.

No communications are possible during the period of dormancy.

To get a clear view of Yutu’s traverse across the Moon’s magnificently desolate gray plains, be sure to check out our timelapse panoramic mosaic showing the rover’s movements at three different positions around the stationary lander – above and below.

360-degree time-lapse color panorama from China’s Chang’e-3 lander This 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at three different positions during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com
360-degree time-lapse color panorama from China’s Chang’e-3 lander
This 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at three different positions during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day.
Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com
See our Yutu timelapse pano at NASA APOD Feb. 3, 2014:
http://apod.nasa.gov/apod/ap140203.html

The 360 degree panorama by the imaging processing team of Ken Kremer and Marco Di Lorenzo was also newly featured on Astronomy Picture of the Day (APOD) on Feb 3, 2014.

However, as I reported earlier here, Yutu suffered a rather serious mechanical anomaly just as the sun was setting and causing China’s moon mission team to urgently sprang into action.

“Scientists are organizing repairs,” wrote the People’s Daily, the official government newspaper of China’s ruling Communist Party.

Apparently one of the solar panels did not fold back properly over Yutu’s instrument laden mast after it was lowered to the required horizontal position and into a warmed electronics box to shield and insulate it from the extremely frigid lunar night time temperatures.

The potentially deadly malfunction could spell doom for the unprotected mast mounted instruments and electronic systems, including the color and navigation cameras and the high gain antenna, if true.

Chang’e-3 lander and Yutu rover – from Above And Below  Composite view shows China’s Chang’e-3 lander and Yutu rover from Above And Below (orbit and surface) – lander color panorama (top) and orbital view from NASA’s LRO orbiter (bottom). Chang’e-3 lander color panorama shows Yutu rover after it drove down the ramp to the moon’s surface and began driving around the landers right side to the south. Yellow lines connect craters seen in the lander panorama and the LROC image from LRO (taken at a later date after the rover had moved), red lines indicate approximate field of view of the lander panorama. Credit: CNSA/NASA/Ken Kremer/Marco Di Lorenzo/Mark Robinson
Chang’e-3 lander and Yutu rover – from Above And Below Composite view shows China’s Chang’e-3 lander and Yutu rover from Above And Below (orbit and surface) – lander color panorama (top) and orbital view from NASA’s LRO orbiter (bottom). Chang’e-3 lander color panorama shows Yutu rover after it drove down the ramp to the moon’s surface and began driving around the landers right side to the south. Yellow lines connect craters seen in the lander panorama and the LROC image from LRO (taken at a later date after the rover had moved), red lines indicate approximate field of view of the lander panorama. Credit: CNSA/NASA/Ken Kremer/Marco Di Lorenzo/Mark Robinson

During each 14 Earth-day long night, the Moon’s temperatures plunge dramatically to below minus 180 Celsius, or minus 292 degrees Fahrenheit.

A radioisotopic heater unit keeps the Mast instruments warm, during lunar night, in the absence of solar power.

Dust accumulation on the rover and gears may possibly be to blame for the failure to retract, based on unofficial accounts.

China has not released any official or detailed information on the cause of the malfunction or recovery actions taken by Chinese space engineers.

So, no one knows the ‘Jade Rabbits’ fate at this time.

‘Jade Rabbit’ has been immensely popular with the Chinese public.

Over 36,000 well wishes were posted on an unofficial Sina Weibo account shortly after word of the mechanical anomaly was announced.

Lunar Day 3 at Mare Imbrium was due to start around this past weekend Feb. 8 or 9.

Traverse Path of Yutu rover from Dec. 14 landing to Dec. 21. Landscape textured with Chang'e 3 imagery from space and ground.  Credit: CNSA/BACC
Traverse Path of Yutu rover from Dec. 14 landing to Dec. 21, 2013. Landscape textured with Chang’e 3 imagery from space and ground. Credit: CNSA/BACC

An anonymous writer on Weibo, China’s twitter equivalent, reported; “We will hopefully get back news of the rabbit after sunrise today February 10 at 15:00 hrs (3 pm), Beijing local time, and confirm whether safe or unable to move.” That is according to a google translation I used.

Both vehicles depend on their life giving solar panels to produce power in order to function and accomplish their scientific tasks during each Lunar day which lasts approximately 14 days.

They had been functioning perfectly and collecting science measurement as planned during Lunar Day 2.

‘Jade Rabbit’ had departed the landing site forever, and was journeying southwards as the incident occurred – about six weeks into its planned 3 month long moon roving expedition.

In a historic feat for China, the Chang’e-3 spacecraft safely touched down on the Moon at Mare Imbrium near the Bay of Rainbows some two months ago on Dec. 14, 2013 .

Seven hours later, the piggybacked 140 kg Yutu robot drove off a pair of ramps, onto the Moon and into the history books.

The 1200 kg stationary lander is expected to return science data about the Moon and telescopic observations of the Earth and celestial objects for at least one year.

Chang’e-3 and Yutu landed on a thick deposit of volcanic material.

The hugely popular probes could be the forerunners to a manned Chinese Moon landing mission a decade from now.

China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.

Stay tuned here for Ken’s continuing Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, LADEE, Mars and more planetary and human spaceflight news.

Ken Kremer

Photo of Chang'e-3 moon lander emblazoned with Chinese national flag taken by the panoramic camera on the Yutu moon rover on Dec. 22, 2013. Credit: CNSA
Photo of Chang’e-3 moon lander emblazoned with Chinese national flag taken by the panoramic camera on the Yutu moon rover on Dec. 22, 2013. Credit: CNSA

How Massive Is A Neutrino? Cosmology Experiment Gives A Clue

Artist's conception of Planck, a space observatory operated by the European Space Agency, and the cosmic microwave background. Credit: ESA and the Planck Collaboration - D. Ducros

There have been a lot of attempts over the years to figure out the mass of a neutrino (a type of elementary particle). A new analysis not only comes up with a number, but also combines that with a new understanding of the universe’s evolution.

The research team investigated the mass further after observing galaxy clusters with the Planck observatory, a space telescope with the European Space Agency. As the researchers examined the cosmic microwave background (the afterglow of the Big Bang), they saw a difference between their observations and other predictions.

“We observe fewer galaxy clusters than we would expect from the Planck results and there is a weaker signal from gravitational lensing of galaxies than the CMB would suggest. A possible way of resolving this discrepancy is for neutrinos to have mass. The effect of these massive neutrinos would be to suppress the growth of dense structures that lead to the formation of clusters of galaxies,” the researchers stated.

The HST WFPC2 image of gravitational lensing in the galaxy cluster Abell 2218, indicating the presence of large amount of dark matter (credit Andrew Fruchter at STScI).
The HST WFPC2 image of gravitational lensing in the galaxy cluster Abell 2218, indicating the presence of large amount of dark matter (credit Andrew Fruchter at STScI).

Neutrinos are a tiny piece of matter (along with other particles such as quarks and electrons). The challenge is, they’re hard to observe because they don’t react very easily to matter. Originally believed to be massless, newer particle physics experiments have shown that they do indeed have mass, but how much was not known.

There are three different flavors or types of neutrinos, and previous analysis suggested the sum was somewhere above 0.06 eV (less than a billionth of a proton’s mass.) The new result suggests it is closer to 0.320 +/- 0.081 eV, but that still has to be confirmed by further study. The researchers arrived at that by using the Planck data with “gravitational lensing observations in which images of galaxies are warped by the curvature of space-time,” they stated.

“If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists, but it would also be an important extension to the standard model of cosmology which has been developed over the last decade,” the researchers stated.

The research was done by the University of Manchester’s Richard Battye and the University of Nottingham’s Adam Moss. A paper on the work is published in Physical Review Letters and is also available in preprint version on Arxiv.

Are These Water Flows On Mars? Quite Possibly, New Observations Reveal

Palikir Crater as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called "recurring slope linea" that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL

What a tangled web of water and water ice stories on Mars. There’s likely some underground. There’s definitely some at the north pole. And we are pretty certain water flowed there in the ancient past. But what about surface water today, right now, in the view of our many orbiting cameras at the Red Planet?

One hotspot of debate are flows called “recurring slope lineae”, which are features that appear in warmer temperatures. These would seem to imply some kind of briny water flowing. A team recently checked out 13 of these sites. While they didn’t find any water or salt evidence in the spectra, they did find more iron-bearing minerals on “RSL slopes” compared to those that aren’t. So what’s going on?

“We still don’t have a smoking gun for existence of water in RSL, although we’re not sure how this process would take place without water,” stated Lujendra Ojha, a graduate student at the Georgia Institute of Technology in Atlanta who led two reports on these features. Pictures were taken using NASA’s Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), which is led by the University of Arizona.

Palikir Crater as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called "recurring slope linea" that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL
Palikir Crater as seen by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called “recurring slope linea” that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL

It’s possible that the grains are being sorted by size (more plainly speaking, taking the fine dust away and leaving the larger grains behind), which could happen either with water or without it. Or, water might be present but not in a way that is obvious immediately if the area got darker because of moisture, or the minerals became oxidized. Water could be “missing” from these observations because they took place in the afternoon (meaning they could miss morning dew), or because the dark flows are smaller than the sample size in the picture.

While researchers still aren’t sure, the team says they still believe it’s salty water of some sort that is flowing despite very cold temperatures on Mars.

“The flow of water, even briny water, anywhere on Mars today would be a major discovery, impacting our understanding of present climate change on Mars and possibly indicating potential habitats for life near the surface on modern Mars,” said Richard Zurek, MRO project scientist who is at NASA’s Jet Propulsion Laboratory in California.

A related paper also found that RSL sites are rare on Mars, appearing in only 13 of 200 sites surveyed with similar slopes, latitudes and other features. You can read the accepted versions of the reports as they appear in Geophysical Research Letters and Icarus.