Scientists have discovered liquid water deep in the crust of Mars, a breakthrough that suggests life could have existed on the planet.

“Large volumes of liquid water transiently existed on the surface of Mars more than 3 billion years ago,” said a paper published on Monday in PNAS, a journal published by the US National Academy of Sciences.

The authors of the paper analysed data from Nasa’s Mars Insight Lander, which arrived on the planet in 2018 and stayed until the end of 2022. It measured seismic movements to determine the presence of liquid water billions of years ago.

“Our results have implications for understanding Mars’ water cycle, determining the fates of past surface water [and] searching for past or extant life,” the authors wrote.

Are you craving that $1.50 hot-dog-and-soda combo from Costco? Be sure to have your own membership card handy.

Over the coming months, shoppers will have to start scanning their membership cards at the entrances to Costco warehouses rather than just presenting them to a store employee, the retail giant announced.

The Washington-based company is the latest to crack down on membership sharing, as businesses seek to prevent consumers from glomming onto their friends’ and families’ paid accounts without forking over membership fees themselves.

Costco members with active memberships will have to scan their physical or digital cards at a machine at the store’s entrance. Members who have cards without a photo will have to show a valid photo ID, and guests will only be able to enter a Costco store with an active member.

“If you have any questions or concerns, there will always be an attendant at the door to assist you!” Costco said in a statement.

Costco isn’t the only company out to stop some consumers from getting a free ride. Disney recently announced that it would start blocking Disney+ account holders from sharing their passwords to the streaming service outside their households.

A similar move by Netflix last year led to an uptick in subscribers but may also have damaged the company’s reputation, Fast Company reported.

Costco executive Richard Galanti told MarketWatch in January that the company was aiming to prevent nonmembers from dodging fees by using a member’s card to shop, an issue that emerged after the company introduced self-checkout lines.

Costco relaxed the enforcement of its rules during the height of the COVID-19 pandemic, Galanti said, when people asked others to shop for them to avoid going outside.

In response to the problem, the company announced that it would begin asking customers in self-checkout lines — in addition to regular checkout lines — to show their membership cards and a photo ID.

Costco has 128 million members and reported that it earned $4.6 billion in revenue from membership fees last year.

Costco’s annual membership fees are set to increase beginning in September, from $60 to $65 for Gold Star members and from $120 to $130 for Executive members.

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Bangladesh’s new interim leader Muhammad Yunus has said the country of 170mn must reform its judiciary and ensure freedom of speech in order to fix the “complete mess” left by toppled prime minister Sheikh Hasina.

The Nobel Peace Prize-winning economist hailed as a “revolution” the ousting of Sheikh Hasina, who fled last week after a popular uprising against her authoritarian rule over Bangladesh, the world’s second-largest garments exporter.

“The monster is gone,” Yunus told foreign journalists in a briefing in the Bangladeshi capital Dhaka.

An estimated 500 people have been killed since Sheikh Hasina last month ordered a crackdown on student protesters, triggering anger that ultimately toppled her government and provoked a wave of retaliatory attacks. Police have mostly gone into hiding, with security on Dhaka’s streets temporarily taken over by the military and student volunteers. 

Yunus said his most urgent task was to restore law and order “so that people can sit down or get to work”, but that he hoped to turn to broader reforms. “The opposition, young people always are talking: ‘There is no freedom of speech’,” he said. “Give them the freedom of speech.”

The 84-year-old added that ensuring “the independence of the judiciary” was another priority.

Sheikh Hasina, who had ruled Bangladesh since 2009, claimed to have brought development to what had been one of the world’s poorest countries. Her critics accused her government of corruption, rights abuses, rigging elections and stacking the judiciary with loyalists from her Awami League.

Chief justice Obaidul Hassan, the head of Bangladesh’s judiciary, resigned at the weekend following new demonstrations against him by student protesters.

Yunus, who was celebrated internationally for founding microfinance pioneer Grameen Bank, was subject to a barrage of investigations under Sheikh Hasina that his supporters called a vendetta.

Yunus said he only agreed to lead the interim government because student protest leaders asked him to. He has two students in his new cabinet, and Yunus said they should play an even greater role. “Every ministry should have a student,” he said.

Yet he faces considerable obstacles in implementing his agenda. Legal experts debate how long his administration should be in power, with opinions ranging anywhere from three months to three years.

Opposition groups such as the Bangladesh Nationalist party are demanding new elections. And the Awami League is seeking to regroup following its routing last week.

The former prime minister’s son Sajeeb Wazed told the Financial Times that his mother, who is currently in neighbouring India, wanted to return to Bangladesh.

“We are waiting to see how things unfold in Bangladesh and her hope is that at some point she will be able to go back,” Wazed said in a video interview from the US. He said Sheikh Hasina had not requested asylum in a third country.

Wazed denied his mother was responsible for the violence against protesters and said she was “absolutely” ready to face charges if it came to that “because she did nothing illegal”. 

Wazed also attacked Yunus’s interim government, saying it was “an unconstitutional government. There is no democracy in Bangladesh right now.”

Yunus told foreign journalists that Sheikh Hasina’s rule left “a mess, complete mess . . . Whatever they did, just simply doesn’t make sense to me”.

But he acknowledged the early euphoria around his leadership might not last. “The moment you start taking decisions, some people will like your decisions, some people will not like your decisions,” he said.

“I’m doing this because this is what the youth of the country wanted, and I wanted to help them to do it. It’s not my dream, it’s their dream.”