NEW What Canada is doing about the toxic forever chemicals in drinking water
As the United States sets its first national limits on toxic forever chemicals in drinking water, researchers say Canada is lagging when it comes to regulations.
A new study suggests that clay minerals are the cause of radar reflections below the South Pole on Mars after initially being attributed to liquid water.
Researchers at Toronto's York University have found that smectites, a common type of clay, can explain the radar signals, casting doubt on their being subsurface lakes on the red planet.
"Since being first reported as bodies of water, the scientific community has shown skepticism about the lake hypothesis and recent publications questioned if it was even possible to have liquid water," lead researcher and York University assistant professor Isaac Smith said in a press release.
The findings were published Thursday, in peer-reviewed scientific journal Geophysical Research Letters.
In 2018, the MARSIS instrument aboard the European Space Agency’s (ESA) Mars Express orbiter found evidence of subsurface lakes deep below the ice cap on the southern side of Mars, lending to the possibility of a potentially habitable environment.
According to NASA, radar signals, which can penetrate rock and ice, change as they are reflected off different materials.
"In this case, they produced especially bright signals beneath the polar cap that could be interpreted as liquid water," NASA said in a press release on Thursday.
While water ice is plentiful on Mars due to its cold climate, NASA noted that any water warm enough to be liquid on the surface would last for only a few moments before turning into vapour in Mars’ dry air.
Other studies have also demonstrated that the amount of salt and heat required to thaw ice at the bottom of the polar cap was much more than Mars provides, drying up the lakes hypothesis further.
The latest research, which involved scientists from York University, the University of Arizona, Cornell, Purdue and Tulane universities, used experimental and modelling work to demonstrate why smectites can better explain the radar observations.
In doing so, researchers also found "spectral evidence" that smectites are present at the edges of Mars' South polar cap.
"Smectites are very abundant on Mars, covering about half the planet, especially in the Southern Hemisphere," Smith said in the release. “That knowledge, along with the radar properties of smectites at cryogenic temperatures, points to them being the most likely explanation to the riddle."
According to the study, smectites are a type of clay that is formed when basalt -- a volcanic rock that comprises most of the surface of Mars -- breaks down chemically in the presence of liquid water.
Experiments done at York University measured the radar characteristics of hydrated smectites at room temperature as well as at cryogenic, or extremely low, temperatures. The data was then evaluated using code.
With these simulations, researchers found that frozen clays produce dielectric values that are large enough to make the reflections, matching those of the initial ESA radar observations.
As these clay minerals are both present at the South Pole and can cause the reflections, the team "believes this to be a more viable scenario than the presence of liquid water."
"Because the liquid water theory required incredible amounts of heat which is six-to-eight times more than Mars provides, and more salt than Mars has, it was already implausible. Now, the clays can explain the observations with absolutely no qualifiers or asterisks," Smith explained.
Stefano Nerozzi, co-author and a post-doctoral fellow at the University of Arizona and co-author, says the bright reflectors cannot be water because some of them continue from underground onto the surface.
"If that is the case, then we should see springs, which we don't," Nerozzi said.
Additionally, Nerozzi said data shows that multiple reflectors found on Mars are stacked on top of each other, with some even being found in the middle of the polar cap. He said this would be "physically impossible" if the reflectors were in fact water.
While the researchers note that it is disappointing that liquid water may not be present, they say the new findings may help aid future studies on the conditions of ancient Mars.
Purdue University associate professor and study co-author Briony Horgan said having detected possible clay minerals in and below Mars' South Pole is important as it confirms the ice has sediments that previously interacted with water.
"While our work shows that there may not be liquid water and an associated habitable environment for life under the cap today, it does tell us about water that existed in this area in the past," Horgan said.
As the United States sets its first national limits on toxic forever chemicals in drinking water, researchers say Canada is lagging when it comes to regulations.
Calgary police have arrested a man and a charge is pending in connection with the death of a toddler in 2022.
Prince William will return to public duties on Thursday for the first time since his wife Kate revealed she was undergoing preventative chemotherapy for cancer.
A Winnipeg woman was sentenced to house arrest after a single date with a man she met online culminated in her harassing him for years, and spurred false allegations which resulted in the innocent man being arrested three times.
Almost 7,000 bars of pure gold were stolen from Pearson International Airport exactly one year ago during an elaborate heist, but so far only a tiny fraction of that stolen loot has been found.
Drivers in Eastern Canada face a big increase in gas prices because of various factors, especially the higher cost of the summer blend, industry analysts say.
Police say one former and one current employee of Air Canada are among the nine suspects that are facing charges in connection with the gold heist at Pearson International Airport last year.
MPs enacted an extraordinary, rarely used parliamentary power on Wednesday, summonsing an ArriveCan contractor to appear before the House of Commons where he was admonished publicly and forced to provide answers to the questions MPs said he'd previously evaded.
Scientists say it's highly unlikely cloud seeding is responsible for the heavy rains that have caused flooding in the United Arab Emirates this month, and that climate change is the more likely culprit.
When Les Robertson was walking home from the gym in North Vancouver's Lower Lonsdale neighbourhood three weeks ago, he did a double take. Standing near a burrow it had dug in a vacant lot near East 1st Street and St. Georges Avenue was a yellow-bellied marmot.
A moulting seal who was relocated after drawing daily crowds of onlookers in Greater Victoria has made a surprise return, after what officials described as an 'astonishing' six-day journey.
Just steps from Parliament Hill is a barber shop that for the last 100 years has catered to everyone from prime ministers to tourists.
A high score on a Foo Fighters pinball machine has Edmonton player Dave Formenti on a high.
A compound used to treat sour gas that's been linked to fertility issues in cattle has been found throughout groundwater in the Prairies, according to a new study.
While many people choose to keep their medical appointments private, four longtime friends decided to undergo vasectomies as a group in B.C.'s Lower Mainland.
A popular highway in Alberta's Banff National Park now has a 'no stopping zone' to help protect two bears.
B.C. resident Robert Conrad spent thousands of hours on Crown land developing an unusual bond with deer.
A Sudbury woman said her husband was bringing the recycling out to the curb Wednesday night when he had to make a 'mad dash' inside after seeing a bear.