The 10 most intriguing science breakthroughs of 2024

By FD Flam

It was a bad year for good news, but only because the tumult and drama surrounding the 2024 US election and ongoing wars overshadowed some of the discoveries made in the world’s observatories, field studies and laboratories. Some of those findings could make us healthier, while others expand the outer limits of our knowledge of the universe.

Moon rocks from Terra Incognita

There’s something mysterious about the side of the moon that always faces away from us. Flyby missions show a very different, lighter surface with fewer craters and a thicker crust than the familiar face. China landed the first craft on the moon’s far side in 2019, and then in 2024, a Chinese craft, Chang’e-6, drilled beneath the surface and sent back two kilograms of rock and dirt.

Those samples could help scientists reconstruct how our own planet formed. And China’s enterprising program is fueling a new space race with the US.

NASA’s long-planned US crewed landing was recently pushed back to 2027. China plans to land a crewed mission in 2030.

A drug that prevents HIV

After nearly 40 years of failed attempts to develop a vaccine against HIV/AIDS, scientists found a drug that blocks infection if injected just twice a year. A clinical trial in South Africa and Uganda that wrapped up in 2024 showed 100 per cent efficacy among 2,134 women and girls.

In the control group, girls and young women were given existing prevention drugs, also known as PrEP, which need to be taken as a daily pill. While PrEP has nearly eliminated new cases of HIV in San Francisco, stigma in Africa makes it hard for women to take the drug regularly. Science named the new twice-yearly drug, lenacapavir, the 2024 Breakthrough of the Year.

The new drug, made by Gilead, doesn't work the way a vaccine would. But scientists aren't giving up on a vaccine, which likely would cost less and might protect people permanently. The Gilead drug is likely to be approved in mid-2025, though it’s unclear whether it will be affordable and accessible to those who need it.

AI delves into the human psyche

AI is shaking up every field of science, but social scientists have used it to gain particularly distinct new insights. They use large language models to study the way humans think and explore ways we might think smarter.

In a study published in September, psychologists surprised themselves when they trained an AI chatbot to persuade conspiracy theorists to consider that they might be wrong. It worked. People let go of their beliefs in nefarious plots to cover up alien landings or curb population growth with biological weapons.

Conspiracy theorists often gather mountains of dubious evidence to support their beliefs, wearing out humans who don’t have the time or energy to keep up. Chatbots can more than match them for the quantity of evidence.

Another study published this year found doctors often stuck with wrong diagnoses even after an AI suggested the correct answer. When pitted in a diagnosis contest against ChatGpt-4, the AI correctly diagnosed 90 per cent of conditions taken from case reports, while the doctors got 74 per cent correct. When doctors were allowed to confer with the AI, they were accurate only 76 per cent of the time. They were too sure of their first intuitions.

The doctors’ failure to fully benefit from AI shows that there is room for improvement in how they are trained to use it and how AI can be trained to help them.

According to another study, AI was not very good at helping people fact-check the news. ChatGPT-4 sometimes increased people’s belief in fake headlines when they were unsure and made them disbelieve actual headlines when it made an error. AI seems to do best when it stimulates us to think differently, not when we rely on it to think for us.

Craft sets off for distant ocean world

On October 14, the $5 billion spaceship Europa Clipper lofted far above budget cutters’ reach and embarked on a journey to the most promising abode of extraterrestrial life in our solar system.

Europa, a moon orbiting Jupiter, doesn’t look like a nice place on the surface, with a thick crust of ice and temperatures that never get above -120C. But previous flyby missions revealed signs of a vast ocean sloshing beneath the surface and occasionally bursting through.

Scientists estimate that Europa carries about twice as much water as all Earth’s oceans combined, warmed by friction generated by Jupiter’s monster tidal force. Astrobiologists consider liquid water the key ingredient for life — at least life of the kind earthlings could recognize.

When it arrives in 2030, the craft will make dozens of flybys over the surface, using its instruments to sniff for molecules that could serve as nutrients and map out the ice and ocean beneath. If the results are promising, a lander could follow.

The James Webb telescope recalculates universal expansion

New aspects of our distant universe came into view this year thanks to the James Webb Telescope, also known as JWST. Trained on distant galaxies, it showed stars “popping out” where the Hubble showed faint smudges, said astronomer Wendy Freedman of the University of Chicago. That’s allowed her to recalculate the rate at which the universe is expanding.

This is all part of a bigger quest to figure out why the universe is expanding and where we’re all headed — a dramatic collapse or dissipation into oblivion. Scientists are also looking back to the period known as “cosmic dawn” when the universe was 1 per cent of its current age and all the galaxies and stars within them first took shape from primordial gases. So when they announced they’d captured the most distant galaxy ever seen — it was also the deepest in time, appearing as it was more than 13 billion years ago.

Scientists thought they had nailed the expansion rate in 2001 using observations from the Hubble Space Telescope. However, it didn’t match the measurements made using leftover radiation from the Big Bang, known as the cosmic microwave background. Freedman says the new measurements her group did with JWST square with this radiation's behavior. She was recognized for this work as one of Nature’s top 10 scientists of the year.

Others, also using JWST, measure a faster expansion and argue that the incompatibility with other measurements is the universe trying to show us there’s some new physical phenomenon at play. As for our fate, we may yet end in a crunch or expand forever — it’s still unknown.

Aging spurts at 44 and 60

In an ambitious project aimed at fighting the ravages of aging, geneticist Michael Snyder and colleagues took blood and other biological samples from 108 volunteers. They monitored invisible age-related changes in a combination of microbes and molecules totaling 135,239.

That revealed a surprising pattern — sudden molecular-scale shifts when people turn 44 and again at 60. The changes indicated a loss of muscle mass, worse heart health, and a lessening ability to metabolize fats, alcohol and caffeine. At around 60, more changes indicated degeneration of the immune system.

At first, researchers thought that the shifts at 44 were associated with perimenopause in the women. However, the data showed the same thing happening in men, meaning either that this aging spurt happens independently from menopause or that male menopause is real.

Snyder said these changes could be the targets of interventions designed to help people stay healthy longer and eventually lead to ways to extend the human lifespan.

Reconstructing climate in deep time

A new reconstruction of Earth’s climate shows it fluctuated wildly over the eons. Scientists shocked the world in the 1990s with a graph of the last thousand years, using natural records to reveal temperatures shooting upward in the 20th century. This one goes back 485 million years — before dinosaurs, before forests, before fish started dragging themselves up primitive banks.

It shows that over the last 485 million years, the climate fluctuated between “hothouse” periods when the global temperature can be 30F hotter than it is now, and unstable “icehouse” periods when the temperature seesaws between ice ages and more temperate phases like recent history.

Sometimes, living things adapted to the hottest spells, with hippos and tropical palms slowly migrating to the Arctic. When change was sudden, the fossil record shows 80 per cent to 90 per cent of species went extinct, though life has never been extinguished completely. The researchers who made the plot say it has been a useful test of our climate models — they match these measurements-based approximations going back in time. So more steep warming is coming. The good news is that Earth will likely be a living planet for millions of years.

The health scare of the year: plastic in your brain

I've already made some effort to cut back on plastic, but the turn of a new year could give me more motivation. I don’t like plastic, but I like the convenience of food and drinks in plastic packaging. It’s also not something most of us can give up entirely — the stuff is everywhere, seeping into tap water, meat, poultry and seafood.

This year, several unnerving studies showed that plastic particles are building up in our organs. In mice, microplastic impairs male fertility, learning and memory. We don’t know exactly what these particles do in us, but it can’t be good.

One study found plastic in plaque that builds up in arteries, and more plastic was associated with a higher risk of stroke or heart attack. A review article associated plastic with oxidative stress, which is tied to aging.

But what really put the fear in me was a preprint released last summer of a study showing that microplastic is probably accumulating in our brains. Researchers looked for plastic during autopsies from 91 people and found their brains had stored up to 20 times as much microplastic as other organs. Those who had died from Alzheimer’s were carrying more plastic in their brains than those who were healthy but died from accidents or violence.

A study published in January showed that a typical bottle of water carries about 240,000 invisible particles of plastic, so cutting back on drinks in plastic bottles could be a starting point for a resolution.

Best occupations for fighting death and dementia

Two studies released this year provided some tantalizing hints about who is most likely to postpone mental decline and fend off the Grim Reaper. One, released in the British Medical Journal’s Christmas issue, used CDC statistics to show that ambulance and taxi drivers were less likely than those in other professions to die from Alzheimer’s disease. In another study released last summer, researchers compared male professional athletes and found pole vaulters and gymnasts lived longest, and volleyball players were surprisingly short-lived.

The lead author of the sports study told me that there might be something beneficial in the training regimens of pole vaulters and gymnasts and that many of the athletes with lower life expectancies did sports that put them at risk of injuries, especially blows to the head.

The taxi study excited scientists because it called to mind a fascinating finding from 2000. Compared to the general public, London taxi drivers had a more developed hippocampus — the part of the brain associated with memory and navigational skills. That was, of course, back when they didn’t use GPS.

Before considering taking up taxi driving or pole vaulting as part of a New Year’s resolution, scientists warn that both studies are preliminary. But studies like these can help set scientists in new directions.

A big step toward quantum computing

Until this year, quantum computing was one of those dream technologies that remained forever a decade away from doing anything useful. Now, things are happening faster than expected. Several groups have solved one of the major hurdles — an error problem. The units of information storage — called qubits — were error-prone in a way that stringing them together only multiplied the error rate.

If the latest round of optimistic predictions pans out, quantum computers could digest the real world’s complexity to make otherwise impossible predictions — how experimental drugs would work in the human body, for example, or how some new type of material would handle stress. While ordinary computers store information in bits, which can take the values 0 or 1, a qubit can take any value in between. Qubits can consist of supercooled matter or atoms that are confined with lasers.

Last summer, Microsoft and the California-based startup Quantinuum and Google announced they were making progress. They were able to string together qubits that decreased rather than increased the error rate.

Google extended the error correction yet further, connecting 105 qubits in a chip called Willow, which was announced in the journal Nature this month. The big sales line was that Willow could take five minutes to do a test problem that supercomputers couldn’t do in 10 septillion years, or the universe's age squared. The test problem wasn’t anything useful, and the experts say real-world problems are more complex. But it should start to happen in less than a septillion years, maybe by 2030, if some new issue doesn’t keep it perpetually five years away.