Scientists discover first-ever liquid water lake on Mars
Washington, July 25 : In a tantalising find, a team of Italian researchers on Wednesday announced they have discovered a large saltwater lake under ice near the south pole on Red Planet - raising a possibility that life may be there on Mars in some form.
The lake under the Martian ice stretches 20 kms across, said the team led by Roberto Orosei from the National Institute of Astrophysics in Bologna in a paper detailed in the prestigious journal Science.
The lake is about 1.5 km beneath Mars's surface and is at least one metre deep.
The detection was made using the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on European Space Agency's Mars Express spacecraft.
If confirmed, it would be the first confirmed news of liquid water ever detected on the Red Planet.
"We discovered water on Mars," said Orosei.
In 2015, in the first-ever definitive signs of the presence of liquid water on the Red Planet, NASA's Mars Reconnaissance Orbiter (MRO) captured strong evidence for seasonal flows of liquid salty water on the Martian surface.
In the new discovery, between May 2012 and December 2015, Orosei and colleagues used MARSIS to survey a region called Planum Australe, located in the southern ice cap of Mars.
They obtained 29 sets of radar samplings, mapping out an area exhibiting a very sharp change in its associated radar signal, about 1.5 km below the surface of the ice and extending sideways about 20 km.
The radar profile of this area is similar to that of lakes of liquid water found beneath the Antarctic and Greenland ice sheets on Earth, suggesting that there is a subglacial lake at this location on Mars.
"Although the temperature is expected to be below the freezing point of pure water, Orosei noted that dissolved salts of magnesium, calcium, and sodium -- known to be present in Martian rocks -- could be dissolved in the water to form a brine," said the study.
"Together with the pressure of the overlying ice, this lowers the melting point, allowing the lake to remain liquid, as happens on Earth," the researchers noted.
According to the journal Nature, if further studies confirm the existence of a lake, it could open new avenues for investigating Mars.
"It begins a new line of inquiry that's very exciting," Jim Green, NASA's chief scientist, was quoted as saying.
Nearly 4.5 billion years ago, Mars had six and a half times as much water as it does now and a thicker atmosphere.
But most of this water has disappeared into space and the reason is that Mars no longer has global magnetic fields, like on the Earth.
The magnetic field protects the Earth's atmosphere against degradation from energy rich particles from the Sun.
Orosei and team wrote: "There is no reason to conclude that the presence of subsurface water on Mars is limited to a single location."
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Rohit identifies Arshdeep, Hardik as key to India's chances in T20 World Cup
New Delhi (PTI): T20 World Cup-winning captain Rohit Sharma reckons all-rounder Hardik Pandya and left-arm seamer Arshdeep Singh will hold the key to India's prospects in the upcoming edition of the tournament.
Defending champions India will enter the T20 showpiece as one of the overwhelming favourites due to their massive depth and quality.
Rohit highlighted Arshdeep's effectiveness with the new ball and at the death.
"It is a big positive to have both Jasprit Bumrah and Arshdeep Singh together because they always attack for wickets. Arshdeep's biggest strength is swinging the new ball and taking early wickets. He mainly bowls with the new ball and at the death. Starting and finishing are the most important phases, and he is strong in both," Rohit told JioHotstar.
"With the new ball, he swings it to get left-handers caught in the slips and targets the pads of right-handers. He has also started taking the ball away from right-handers. These skills are key for a new-ball bowler. He always tries to take wickets, which is why he bowls the first over."
Rohit added, "In the 2024 T20 World Cup final against South Africa, he did a great job. I still remember he dismissed Quinton de Kock when he was set and batting well. In the 19th over, he gave away just two or three runs, which built pressure on the South Africans.
"That is his game, bowling with the new ball and at the death, and he will play a key role for India in the 2026 T20 World Cup."
India won the last edition of the tournament in the Americas under Rohit's captaincy, after which the dashing opener retired from the T20 format internationally.
Rohit also spoke about how Hardik's dual role as a finisher and multi-phase bowler provides crucial balance to the Indian team.
"Whenever Hardik Pandya is in the team, his role is huge. He bats and bowls very consistently. His batting is crucial when the team is stuck. If we have a score of 160 on the board in 15-16 overs and Hardik is batting, then he's the one who can help the team reach 210-220 from there or if we are 50 for 4, he has to build the innings.
"Batting in the middle order at 5, 6, or 7 is very tough. That is why Hardik's role is critical in any format. We know his bowling. He bowls in key phases, with the new ball, in the middle and in the death as well. His role is very important because he gives the team balance, letting us play six bowlers and keep our batting deep."
Rohit said accommodating both Kuldeep Yadav and Varun Chakravarthy together in the playing XI is going to be a big challenge for the Indian team management.
"The biggest challenge for captain Suryakumar Yadav and coach Gautam Gambhir will be how to play both Kuldeep Yadav and Varun Chakaravarthy together. If you want that combination, you can only do it if you play with two seamers, which is a big challenge.
"But honestly, I would be tempted to play both Varun and Kuldeep because they are wicket-takers and batters struggle to read them. I would surely pick them."
The former India skipper added, "Looking at the conditions in India, like in this New Zealand series, there is a lot of dew. In February and March, dew will be heavy across most parts as winter ends.
"Even in Mumbai, which doesn't get cold, there's still dew. I'd say 90-95 percent of grounds in India have dew. That's the challenge. What do the coach and captain think? Are they comfortable with three spinners? Then they can play spin, but there's no fixed rule. It depends on the team leaders' thinking."
Rohit also urged Kuldeep to stop appealing on every ball and to rely on the wicketkeeper's judgment for reviews.
"My one simple advice to Kuldeep is to just bowl quietly and go back to his mark. You can't appeal on every ball. This is basic. I keep saying it, but it still happens often. Even after telling him many times, he appeals at every chance. You have to use your head. Just because it touches the pad, it doesn't mean it's out every time. This isn't gully cricket.
"I get he is enthusiastic, but think of the team first. Each team only gets two DRS reviews. If I was the keeper, I could see where the ball pitched and if it was hitting, I could tell the bowler.
"But from covers or slip, you don't know the angle. You have to listen to what the keeper and bowler say. That's why when there's a review off Kuldeep's bowling, I don't look at him, I look at the keeper to decide."
The T20 World Cup is scheduled to be held in venues across India and Sri Lanka from February 7 to March 8.
