Strange Streaks on Mars Are Sand, Not Water

23 Novembre, 2017, 00:23 | Auteur: Therese Cote
  • Strange Streaks on Mars Are Sand, Not Water

Authors of the report propose possibilities that include involvement of small amounts of water, indicated by detection of hydrated salts observed at some of the flow sites.

There are still unanswered questions, such as why the streaks appear and vanish with the seasons, and what makes them dark in color.

Scientists, including those from the University of Arizona in the USA and Durham University in the United Kingdom analysed narrow, down-slope trending surface features on Mars that are darker than their surroundings, called Recurring Slope Linea (RSL).

Speaking about this research, US Geological Survey's Colin Dundas explains, "We've thought of RSL [recurring slope lineae] as possible liquid water flows, but the slopes are more like what we expect for dry sand".

"This new understanding of RSL supports other evidence that shows that Mars today is very dry", said Dundas, lead author of the study published in the journal Nature Geoscience. This is based in part on assessments made with the Mars orbiter's telescopic camera. The data include 3-D models of slope steepness using pairs of images for stereo information.

However, all of the 151 RSLs examined in the study were found to all end on similar slopes despite very different lengths.

Strange Streaks on Mars Are Sand, Not Water

One of the reasons for the change is that scientists found that RSL were only visible on steep slopes.

The scientists concluded that the range "matches that of slipfaces for active Martian and terrestrial dunes, interpreted as the range of critical angles for which granular flows of sand can terminate".

It was previously thought that this could provide evidence of water flow.

"RSL probably form by some mechanism that is unique to the environment of Mars, so they represent an opportunity to learn about how Mars behaves, which is important for future surface exploration", said Alfred McEwen from the University of Arizona, Tucson, a co-author on the study.

These findings indicate that it is hard for Earth-like life to exist near the surface of Mars owing to the water-restricted conditions that exist on the planet.

SCIENTISTS have dashed hopes of Mars supporting alien life after realising the mysterious "water" marks were actually left by SAND.

Sa femme Chrissy Teigen est de nouveau enceinte — John Legend
Le mannequin Chrissy Teigen et son mari, le chanteur John Legend , ont annoncé la bonne nouvelle sur les réseaux sociaux. C'est en effet avec leur fille, Luna , âgée d'un an et demi, que la femme de John Legend a annoncé l'heureux événement.

Arrestation de six Syriens soupçonnés d'un projet terroriste — Allemagne
D'après la chaîne HR qui cite les enquêteurs, les suspects envisageaient de commettre un attentat sur le marché de Noël d'Essen. L'Allemagne a accueilli quelque 1,2 million de personnes depuis 2015.Un niveau de menace élevé depuis l'attentat de.

Corée du Nord : les images spectaculaires de la défection d'un soldat
La scène se déroule dans le seul secteur de la "zone démilitarisée", où se font face les deux armées coréennes. Grièvement blessé , le militaire défecteur est par la suite secouru par plusieurs soldats sud-coréens.

Conseillé:



Populaire

U.S. prosecutors charge Iranian in 'Game of Thrones' hack (TWX, T)
Included was an image of " Game of Thrones " Night King character, leader of an army of zombies, with the words, "Good luck HBO ". Mesri was a "sophisticated" hacker, Kim said, who had carried out attacks on other computer systems across the world.

Black Friday better for retailers, including small stores, than Small Business Saturday
Small businesses, like those in the village's six block shopping district, provide a friendly reprieve, she added. Also Cotton Tails Children's Boutique is rewarding customers with a $15 gift card for purchases of $100 or more.

Animal Crossing Pocket Camp: How to Sell Items
Taking after the main franchise for the Nintendo DS and 3DS, Animal Crossing: Pocket Camp starts small and gets progressively big. The Leaf Tickets will speed certain things up for you in-game if you don't want to wait, but they're completely optional as well.

The struggle is not over — Zimbabwe
The nationalist discourse of many independence movements, which still shapes African politics today, has little room for women. The commanders are also bona fide members of the ruling party and guarantors of Zanu-PF power .

Half Of Voters Think Al Franken Should Resign From The Senate
Earlier this week, a CNN report said another woman accused Franken of inappropriately grabbing her during a photo op in 2010. He has apologized to Tweeden, and she has accepted the apology, but a handful of Democrats have called for him to resign.

Tillerson declares Myanmar violence as 'ethnic cleansing'
Burke said Myanmar's Catholic cardinal, Charles Bo, had proposed during a weekend audience with Francis that he meet with Gen. But while Washington has shifted gears rhetorically, it hasn't taken any steps to punish Myanmar's government just yet.

Delhi not a state; can't claim powers, privileges, Centre tells SC
Earlier, The Delhi High Court in August 2016 had held the Delhi Lieutenant Governor as the administrative head to the National Capital Territory (NCR).

Disney aussi éclaboussé par un scandale sexuel
Il reconnaît également " avoir échoué " à insuffler une culture " de la confiance et du respect " dans ses studios. Par ailleurs, Lasseter tenterait régulièrement de mettre ses mains sur les jambes de ses collaboratrices.

Brexit could lead to united Ireland, says Richard Haass
The DUP leader, Arlene Foster , said it was a "talking shop which has not met since 2007". The DUP leader warned against "playing about with Northern Ireland".

Soutenu par son arrivée sur le marché Pakistanais — RENAULT
Il y a deux ans, Renault annonçait son ambition de poser ses jalons dans un marché sur lequel il était absent, le Pakistan. Pays de 200 millions d'habitants, représente un marché en plein essor, avec un taux de croissance annuel de 10%.