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.

Kendall Jenner mannequin la mieux payée en 2017, selon Forbes
Dans le reste du top 10, on trouve Chrissey Teigen (la compagne du chanteur John Legend) qui complète le podium avec 13,5 millions de dollars estimés.

Kate Middleton & Prince William Make Appearances in Birmingham
The monarch has loaned the piece out once before - to Princess Diana in 1982 when she wore it at a state banquet for the Netherlands.

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

Lahore court orders release of 26/11 Mumbai attacks mastermind Hafiz Saeed
Kasab was executed after a court found him guilty and handed down death sentence. Whereas, Saeed's four aides were set free in the last week of October.

Un avion militaire américain s'abîme en mer des Philippines
L'appareil de transport C-2 "Greyhound" a plongé dans l'océan à environ 925 kilomètres au sud-est de l'île japonaise d'Okinawa. Nous ne pouvons ainsi pas garantir son accessibilité à tous les utilisateurs.

Insolite : Ryan Colclough marque un doublé pour Wigan et file à l'hôpital
Ryan Colclough n'est pas prêt d'oublier cette soirée du mardi 21 novembre 2017. Sur et en dehors du terrain, le joueur de Wigan a fait le show.

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 .

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.

L'absentéisme augmente dans le privé — Arrêt maladie
En 2016, près d'1 salarié sur 5 a déclaré avoir renoncé à un arrêt maladie prescrit par son médecin traitant. A contrario, chez les cadres , on compte 27,8 % d'absents pour une durée de 25,9 jours en moyenne.

Denver Nuggets' Paul Millsap to undergo surgery on left wrist
Standing at 10-7, the Nuggets have started well enough to be considered playoff contenders. Harden is averaging 31.6 points, 4.4 rebounds and 9.9 assists.

North Korea defector recovering after being shot while fleeing south
On November 13, the North Korean soldier began his escape by speeding toward a bridge in a jeep at around 3:20 p.m. local time. For several minutes the driver appears to try to free the vehicle, but the wheels spin uselessly in fallen leaves.

Nick Carter denies raping singer Melissa Schuman
Schuman went on to detail her account of Carter allegedly raping her and terrorizing her with violent, angry voicemails afterward. Carter was a founding member of the Backstreet Boys when they formed in 1993.

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".