As the midsummer Sun beats down on the southern mountains of Mars, bringing daytime temperatures soaring up to a balmy 25ºC (77ºF), some of their slopes become darkened with long, rusty stains that may be the result of water seeping out from just below the surface.
The image above, captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter on Feb. 20, shows mountain peaks within the 150-km (93-mile) -wide Hale Crater. Made from data acquired in visible and near infrared wavelengths the long stains are very evident, running down steep slopes below the rocky cliffs.
These dark lines, called recurring slope lineae (RSL) by planetary scientists, are some of the best visual evidence we have of liquid water existing on Mars today – although if RSL are the result of water it’s nothing you’d want to fill your astro-canteen with; based on the first appearances of these features in early Martian spring any water responsible for them would have to be extremely high in salt content.
According to HiRISE Principal Investigator Alfred McEwen “[t]he RSL in Hale have an unusually “reddish” color compared to most RSL, perhaps due to oxidized iron compounds, like rust.”
See a full image scan of the region here, and watch an animation of RSL evolution (in another location) over the course of a Martian season here.
Hale Crater itself is likely no stranger to liquid water. Its geology strongly suggests the presence of water at the time of its formation at least 3.5 billion years ago in the form of subsurface ice (with more potentially supplied by its cosmic progenitor) that was melted en masse at the time of impact. Today carved channels and gullies branch within and around the Hale region, evidence of enormous amounts of water that must have flowed from the site after the crater was created. (Source.)
The crater is named after George Ellery Hale, an astronomer from Chicago who determined in 1908 that sunspots are the result of magnetic activity.
Read more on the University of Arizona’s HiRISE site here.
Sources: NASA, HiRISE and Alfred McEwen
UPDATE April 13: Conditions for subsurface salt water (i.e., brine) have also been found to exist in Gale Crater based on data acquired by the Curiosity rover. Gale was not thought to be in a location conducive to brine formation, but if it is then it would further strengthen the case for such salt water deposits in places where RSL have been observed. Read more here.
Given that gravity on Mars is 62% lower, I have to wonder about people who are optimistic about terra forming Mars . . . . how would you get an atmosphere dense enough to compare with that of Earth? It seems to me that that would prove to be a major difficulty. Yet the lava tubes of the Moon could be pressurized, and, the low escape velocity of the Moon would make it an ideal spaceport.
I believe that it is only a matter of time before we find proof of bacterial life on Mars, Then there will be a whole new ball game….
Why only THEN?? To me it’s a certainty that there is life out there… around the next corner… almost everywhere.
It’s kinda funny that, whenever one comes up with a new idea like E.T. / Aliens the first “reaction” is: No, I don’t believe it… SHOW ME ONE! (like: all stars have planets). The fact that YOU / we don’t see it right now means just we haven’t got the right Telescope / sensor…. yet!
The dust is like talk there on Mars. The wind moves and drops it anywhere.
You can’t expect on some steep cliff it won’t accumulate until it produces some dust avalanches. Also, the seasonal changes implying CO2 frost accumulation is likely to trigger it much more easely.
This has nothing to do with water.
“This has nothing to do with water”… Oh, you have access to their data and have analysed it yourself? I’m glad you’re so sure that you understand this more than NASA… Why they don’t hire you amazes me. They’d obviously save so much time chasing blind leads.
WOW! Way cool! This story along with the recent finding that Mars has frozen glaciers beneath all that dust in the polar regions (Peta tons of water! Enough to cover the whole planet to the depth of three feet!) is absolutely the best news ever!
Salty? Yes probably.. How can we use those salts?
Allow me to go on about this? We see ice caves under glaciers on the earth. MIGHT they also occur on Mars? There has been a lot of talk about using lava tubes as shelter(s) on the Moon and Mars. How about ice caves? Water ices work well absorbing radiation… and is far less difficult to drill, or melt tunnels into?
SciFi short story subject: Universe Today dateline 04.12.31: LIFE FOUND ON MARS! What follows is in part, NASA’s press release from earlier today. NASA: Mars Expedition IV has found evidence for life while exploring an under-glacier river and has begun more detailed explorations. After much effort and many set backs. the ME-IV team were able to drill/melt a hole large enough to accommodate the Sub Surface Rover (SSR). The SSR with it’s suite of instruments was then lowered into the melt chamber. The rover reached the bottom of the drill string, a place where earlier the well ‘dropped out’ and found a huge underground cavern. (See images above and following) The first cavern appears to be connected to a series of chambers in succession. In the middle of the LZ the rover found a liquid salt water river. In fact it had ‘landed’ in the middle of it! Thankfully flotation devices were deployed and no harm done. The source of the water flow has been determined, via ground penetrating radar, to be from the slopes of a nearby volcano group. Exploration continues as first samples from the underground river have apparently shown right handed chirality radiolarian and tardigrade-like lifeforms! Imagine! The first life found of non-earthly origins! (Updates follow) NASA has assured Congress that they can launch Expedition V in as short as one month’s time!
Editors comment: We’ll see if that holds true…
Aqua4U, Great story I cant wait for it to happen 🙂
there must be something wrong here. i can’t see the pictures of the cavern. Chrome strikes again…