Posts Tagged ‘Curiosity rover’
Water on Mars?
Posted on: May 26, 2017
Water on Mars?
Mars has liquid water just below its surface, according to new measurements by Nasa’s Curiosity rover.
Until now, scientists had thought that conditions on the red planet were too cold and arid for liquid water to exist, although there were known to be deposits of ice.
Prof Andrew Coates, head of planetary science at the Mullard Space Mullard Space Science Laboratory, University College London, said: “The evidence so far is that any water would be in the form of permafrost. It’s the first time we’ve had evidence of liquid water there now.”
The latest findings suggest that Martian soil is damp with liquid brine, due to the presence of a salt that significantly lowers the freezing point of water.
When mixed with calcium perchlorate liquid, water can exist down to around -70C, and the salt also soaks up water vapour from the atmosphere.
New measurements from the Gale crater show that during winter nights until just after sunrise, temperatures and humidity levels are just right for liquid brine to form.
Morten Bo Madsen, a senior Mars scientist at the University of Copenhagen and a co-investigator on the Curiosity rover, said: “The soil is porous, so what we are seeing is that the water seeps down through the soil. Over time, other salts may also dissolve in the soil and now that they are liquid, they can move and precipitate elsewhere under the surface.”
Liquid water is traditionally considered an essential ingredient for life as we known it, but Mars remains hostile for other reasons, the scientists said. The latest findings are unlikely to change the view that if life ever blossomed on Mars, it probably died out more than a billion years ago.
“There are organisms on Earth, halophiles, that can survive in salty environments, but if it’s also very cold and very dry that’s a problem” said Madsen. “The radiation on Mars nails it – that environment is very hostile.”
Prof Coates agreed: “Liquid water is one of the conditions you need for life, it’s not all of them.”
On Earth, the global magnetic field protects the atmosphere from being degraded by harmful cosmic radiation from the Sun. In the past, scientists believe that Mars had a similar magnetic field and thicker atmosphere, but that the field was lost around four billion years ago.
Today, cosmic radiation penetrates at least one metre into the Martian surface and would kill even the most robust microbes known on Earth.
Surface temperatures on Mars range from around 20C at noon, at the equator, down to lows of around −153C at the poles.
The presence of perchlorate salts was discovered in 2008, but until now if was not known whether temperatures and humidity would be high enough to produce liquid brine.
The latest paper, published in Nature, analyses humidity and temperature data for a full Martian year, showing that liquid brine ought to form. Instruments on-board Curiosity also measured estimates of subsurface water concentration, which suggested that water was indeed being absorbed from the air and the surface frost by the salty soil.
The water would be present in tiny quantities between the grains of soil, rather than in droplet form. “If you dug a trench you might see that the soil at the base was a bit darker,” said Madsen.
Curiosity landed on Mars in 2012 in the large crater, Gale, located just south of the equator. The giant crater is 154 kilometres in diameter and the rim of the crater is almost five kilometres high.
In the middle of the crater lies Mount Sharp, which Curiosity is currently ascending.
Observations by the Mars probe’s stereo camera have previously shown areas characteristic of old riverbed, with rounded pebbles that indicate there were flowing rivers up to one metre deep in the past.
The latest close-up images show slanting expanses of sedimentary deposits, lying one above the other. “These kind of deposits are formed when large amounts of water flow down the slopes of the crater and these streams of water meet the stagnant water in the form of a lake,” said Madsen.
And then there was water! smile emoticon
A few of the “45 Most powerful pictures” in BuzzFeed for 2012
1. A boy in Nepal being evicted from his home
A boy cries as he holds his sister in his lap after a confrontation with squatters and police personnel in Kathmandu, Nepal.
2. A couple discovering their family records survived Hurricane Sandy
Rosemary McDermott and her husband opened a safe containing a family genealogy in the Breezy Point section of Queens.
They salvaged the safe from the basement of Rosemary’s mother’s home after Superstorm Sandy.
3. Mars
Thanks to Curiosity, this is one of the clearest images of Mars ever taken.
4. Felix Baumgartner’s 24-mile free-fall from space
5. A man being pepper-sprayed directly in the face
Israeli border police officers use pepper spray as they detain an injured Palestinian protester during clashes on Land Day in March.
Security forces fired rubber bullets, tear gas, and stun grenades to break up groups of Palestinian stone-throwers as annual Land Day rallies turned violent.
A Tibetan exile runs through a street during a protest against the upcoming visit of Chinese President Hu Jintao.
7. A Bolivian woman taking on a group of riot police
Thousands of people with crutches and in wheelchairs protested against the government of Bolivia in February. They were protesting what they believe to be an inadequate welfare system.
8. The Waldo Canyon fire
The Waldo Canyon fire burns an entire neighborhood near the foothills of Colorado Springs, Colorado.
In June, Colorado endured nearly a week of 100-plus-degree days and low humidity, creating a devastating formula for volatile wildfires across the state.
9. Outside the Century 16 movie theater in Aurora, Colorado
Storm clouds gather above a memorial for the victims in the shooting across the street from the Century 16 movie theater in Aurora, Colorado, in July.
10. Anti-gay hate crimes in Ukraine
Unidentified people beat Svyatoslav Sheremet, head of Gay-Forum of Ukraine, in May.
Sheremet was attacked after meeting with members of the media to inform them that a scheduled gay parade was canceled due to threats of violence from neo-Nazis and other hate groups.
The attackers ran off when they realized members of the media were documenting the attack.
11. People who lost family members during the uprising in Egypt react to Hosni Mubarak’s prison sentence
Relatives of people who died during Egypt’s revolution react after a court sentenced President Hosni Mubarak to life in prison in June.
12. Kicking riot police in Greece
A man in Greece kicks riot police back.
13. Family being forced to go back to Myanmar
Mohammad Rafique, a Rohingya Muslim from Myanmar, begs a Bangladeshi coast guard official not to send his family back to Myanmar.
14. Nik Wallenda tightroping over Niagara Falls
Nik Wallenda tightroped over Niagara Falls on a 2-inch-wide wire. He’s the first person to ever cross directly over the falls from the U.S. into Canada.
15. The father saving his daughter’s life in Syria
A Syrian man carries his wounded daughter outside a hospital in the northern city of Aleppo in September. Syrian troops shelled several districts in Aleppo and clashed with rebels.
16. Manhattan without lights
Before and after shots of Manhattan after Hurricane Sandy. Nearly 200,000 people lost power in downtown Manhattan for about a week.
17. A little Palestinian girl vs. an Israeli soldier
A Palestinian girl tries to punch an Israeli soldier during a protest against the expansion of the nearby Jewish settlement of Halamish.
18. The Space Shuttle Enterprise flying above New York City
19. The wedding held during a monsoon in Manila
Ramoncito Campo kisses his wife Hernelie Ruazol Campo on a flooded street during a southwest monsoon that battered Manila, Philippines, in August.
The newlywed couple pushed through with their scheduled wedding despite severe flooding that inundated wide areas of the capital and nine nearby provinces.
Adonis Diaries 