Pompeii’s plaster cast human figures aren’t who they were assumed to be, genetic tests have revealed, highlighting the way idealised stories can be projected onto archaeological evidence.

The analysis also reveals that the demography of Pompeii was also far more complicated and diverse than previously thought.

When Vesuvius erupted in AD 79, it buried several Roman towns, including Pompeii. Many of Pompeii’s residents were completely smothered in compacted ash during the eruption and, as their bodies decayed, cavities formed that perfectly preserved their positions in their final moments.

In the 19^th century, archaeologists developed a method of pouring plaster into the cavities to make life-like casts. Since then, more than 100 of these casts have been made, preserving the victims’ shapes along with any remaining bones that hadn’t decayed over the centuries.

However, it has long been known that many of the plaster casts were manipulated into different poses and sometimes placed together to add to the drama of the Pompeii story, says Valeria Amoretti at the Archaeological Park of Pompeii in Naples, Italy.

To learn more about who these people were, Amoretti and her colleagues examined 14 of the plaster casts and extracted DNA from bones in five of them.

What they found has completely altered the established interpretations of who they were. An adult wearing a golden bracelet with a child on their lap was long believed to be the child’s mother. The DNA analysis shows they are actually an adult male who is biologically unrelated to the child. A nearby figure, formerly interpreted as being the father, was also unrelated to the supposed mother and child.

Another pair, who were thought to be sisters or a mother and daughter who died in an embrace, included at least one genetic male and were also unlikely to have been related.

The genetic analysis further revealed that the people of Pompeii had diverse ancestry, with components related to modern eastern Mediterranean, Levantine and North African Jewish populations.

Amoretti says it is no surprise that the Roman world was multicultural, and that the Mediterranean and its ports united people.

“But it is extremely interesting to discover the extent of this melting pot, even in an average provincial town like Pompeii, and to have scientific proof of it from ancient DNA,” she says.

Alissa Mittnik at Harvard University says the study highlights the importance of applying science before interpreting archaeology at face value.

“Ultimately, it reminds us that the most intuitive, dramatic or sensational explanations do not always hold true, encouraging us to stay aware of and question our preconceived notions,” she says.

A possible ancient shoreline has been found in the region of Mars explored by the Chinese rover Zhurong, providing further evidence that an ocean may once have covered a vast area of the lowlands in the planet’s northern hemisphere.

The rover landed in southern Utopia Planitia in May 2021 and remained active for almost a year. Researchers studying data from the rover have found hints of an ancient ocean or liquid water as recently as 400,000 years ago.

Now, Bo Wu at Hong Kong Polytechnic University and his colleagues have conducted a comprehensive analysis of the topographic features in the landing area, combining remote sensing data from satellites with observations from the rover.

They say they have found features consistent with the existence of a shoreline in southern Utopia, including troughs and sediment channels. They also dated and identified the composition of surface deposits in the area. Based on this, the team thinks the ocean existed 3.68 billion years ago, but froze and then disappeared around 260 million years later.

“The findings not only provide further evidence to support the theory of a Martian ocean but also present, for the first time, a discussion on its probable evolutionary scenario,” says Wu.

The area can be divided into a shallow section to the south and a deep section in the north. Even the shallow part of the ocean may have been up to 600 metres deep, says Wu, but there isn’t enough data to estimate the maximum depth of the ocean.

“Water is a key ingredient for life, and the past presence of an ocean on Mars raises the prospect that Mars once might have been capable of harbouring microbial life at its early stage,” he says.

Mathieu Lapôtre at Stanford University in California says whether oceans existed on early Mars is a highly contentious question with critical implications for the planet’s past habitability. He says future missions will need to test the findings of this new research.

“Utopia Planitia may constitute an invaluable record of early Mars’s near-shore and coastal environments,” says Lapôtre.

Flights taken on private jets should be subject to a carbon tax to curb the runaway growth in carbon emissions from the sector, researchers have said.

Emissions from private aviation jumped 46 per cent between 2019 and 2023, according to analysis of 18.7 million flights by almost 26,000 aircraft.

Flights were mainly for leisure reasons, with 1846 private flights to the 2022 FIFA World Cup in Qatar alone. Other popular destinations were the Cannes Film Festival, the Super Bowl, the COP28 climate conference in Dubai, and the World Economic Forum in Davos. Trips to the south of France, Ibiza and other destinations in Spain peaked during the summer months as travellers jetted in for long weekends of sun.

“A rather small group of very wealthy individuals, because of their lifestyles and investments, is pushing emissions quite quickly up,” says Stefan Gössling at Linnaeus University, Sweden.

Alongside colleagues, Gössling used flight tracker data for millions of flights to build a picture of private aviation use around the world.

Flying by private jet is the most polluting way to travel, with a single flight emitting 3.6 tonnes of CO2 on average, equivalent to the annual carbon impact of someone living in Sweden.

Most flights on private jets are short, the analysis found, with almost half of all flights covering a distance less than 500 kilometres. Most were within the US and Europe.

Total emissions from private jets in 2023 were 15.6 megatonnes of carbon dioxide, equivalent to the annual emissions of Tanzania. That is up from 10.7 megatonnes in 2019.

Growth rates were distorted by the covid-19 pandemic. Unlike commercial aviation, which was heavily restricted in 2020 and 2021, private aviation only showed a small dip in flight numbers and emissions in 2020 before rebounding to growth the following year.

Many of the most extensively used private jets are owned by very rich celebrities, including Tesla CEO Elon Musk, former Google CEO Eric Schmidt, pop star Jay-Z and entertainment personality Kim Kardashian, according to data compiled by the website Celebrity Jet.

“This is about the inequality in the production of greenhouse gases,” says Mark Maslin at University College London. “It’s not even the 1 per cent – it’s the 0.1 per cent richest people in the world who click their fingers and use a private jet.”

The high personal emissions of the super-rich risks eroding public appetite for cutting personal emissions, says Gössling. “If the very wealthy don’t don’t have to reduce their emissions… then we don’t have any reason for anybody else to reduce their emissions, because everybody else is emitting less,” he says.

Gössling would like to see a carbon tax applied to private jet use. “We can put a price tag on every tonne [of carbon] that is emitted, and I think everybody will agree that it’s fair that the affluent should pay the cost of the damage that they are causing,” he says.

Others would like governments to go even further. Sean Currie at the campaign group Stay Grounded wants to see a total ban on the use of private jets. “Around half of these flights are short-haul flights,” he says. “They could easily be replaced by trains if we were to ban private jets and then invest in real infrastructure.”