Imagine a medicine that stops seizures at their source, switches off instructions that keep a cancerous tumor growing and prevents Alzheimer's from stealing memories and wreaking havoc on the brain.

The basis for such treatment is already here. Known as oligonucleotides [pronounced ah-lee-go-noo-klee-oh-tides], these drugs are made from small bits of DNA or RNA—the blueprint cells use to make proteins.

While most drugs act on the finished products, oligonucleotides cut to the chase and intervene upstream, before the proteins have a chance to roll off the cellular assembly line. They can block production of harmful proteins or help cells make ones they need by tinkering with the instructions.

There's one big catch, however.

"Knowing what gene to target is only part of the problem," said Northeastern chemistry and chemical biology professor Ke Zhang, who is developing ways to make oligonucleotides more effective. "The other part is getting the drug to the right place in the right cells."

In the Journal of the American Chemical Society, Zhang and his colleagues present research that suggests a new way to get oligonucleotides into body tissues. The molecular structures his lab is developing shuttle the drugs to their destinations.

They resemble tiny bottlebrushes, with bristles that protect the medicines attached to them. The secret to their success lies in a short sequence of chemical building blocks incorporated into their structure. It acts as a set of delivery instructions to steer the medicine toward particular tissues.

By helping genetic medicines reach their target, this approach could unlock their potential to tackle diseases that are currently untreatable...

When Christopher Columbus made landfall in the Americas on Oct. 12, 1492, he encountered Indigenous Lucayans living on the Bahamian island now called San Salvador. Columbus wrote in his diary about "great multitudes of men" who greeted him that day, bartered with him and told him about other groups who lived on nearby islands.

But within a few decades after Columbus' arrival, the Indigenous people of the Americas were decimated by what anthropologist Eric Wolf called the "Great Dying" — a combination of epidemic disease, warfare and enslavement that led to a rapid decline in the Native population.

For centuries, researchers have been trying to figure out how many Indigenous people lived in the Americas just prior to the fateful arrival of European colonizers.

The answer to that question has been surprisingly elusive, and estimates based on historical censuses, archaeological sites and land carrying capacity in the Western Hemisphere have varied wildly.

Recent research into Native American demography has revealed that the population peaked several centuries before Europeans showed up on the shores of North America — and that if Europeans had arrived at that peak, the entire history of the continent may have been different...

After five-and-a-half years on Mars, NASA's Perseverance Rover has set a distance record for travel on another world. Since landing in Mars' Jezero Crater, an ancient paleolake, on February 18, 2021, Perseverance has travelled 45.22 km, or 28.10 miles. That puts it slightly ahead of NASA's Opportunity rover, which travelled 45.16 kilometers (28.06 miles) during its mission. It must be noted, however, that Perseverance took only 5.5 years to travel this far, while Opportunity required almost 15 years.

Comparing the plutonium-powered Perseverance to the solar-powered Opportunity is unfair. But in any case, Perseverance deserves recognition for this milestone.

“The original mission called for no more than 12.4 miles of driving. We’ve blown well past that..." - Steven Lee, Perseverance and Curiosity project manager, JPL/NASA.

Perseverance is currently in a region named “Lac de Charmes,” which is off the western end of Jezero Crater. It reached its new milestone while heading toward a feature named "Idubi," a scientific target notable for its ancient rocks. On Earth, there are no rocks as old as these because they've all been destroyed by plate tectonics.

Perseverance has found igneous rocks, a surprising result considering that scientists expected to find mostly sedimentary rocks. In fact, a primary reason Jezero Crater was chosen as the mission's landing site is because sedimentary rocks are good at preserving evidence of ancient life. While the rover found plenty of sedimentary rocks, it found igneous rocks, along with fluorite, which forms when rock interacts with heated water. This is evidence of hydrothermal activity, and scientists are hoping Perseverance will find more traces of ancient hydrothermal systems at Idubi...

Plastics are supposed to be chemically inert. It's the reason they're used so frequently to package food, bottle water and create children's toys: They're safe. But something important happens when a large piece of plastic fragments into micro- and nanoparticles. Its surface area increases dramatically relative to its volume. Vastly more of the material is now exposed to its surroundings.

A new study by researchers from Columbia University and the University of California, Berkeley, found that this newly created surface is not necessarily safe and identified the chemical reasons why.

"As plastic fragments into smaller and smaller particles, its surface area increases enormously. Then microplastics change the water that surrounds them, generating high-energy, reactive radicals (reactive oxygen species, ROS) that very likely contribute to biological damage that we see in animals and potentially in humans as a result of microplastic exposure," said Wei Min, a Columbia professor of chemistry and biomedical engineering.

The work challenges the common view of microplastics as largely passive fragments of inert material and contributes to a growing understanding of why the large-scale presence of microplastics is a cause for concern. The research was published today in the journal Nature.

Water-rich tissues raise health concerns
This is particularly noteworthy for human health because human blood is approximately 50% water, and individual human cells are generally 60% to 80% water. The new research suggests that microplastics that enter the bloodstream or cells could remain chemically active in this water-rich biological environment.

DYK that you’re moving at about 67,000 miles per hour right now?!

Earth is carrying you on its orbit around the Sun. When Roman launched, it inherited that motion and will undergo a series of maneuvers before its final orbital insertion at L2.

nasa.tumblr.com/post/830641383…

The year 2026 has been an expensive one for social media platforms. Since March, YouTube and Meta, the parent company of Instagram and Facebook, have settled or paid out in multiple lawsuits totaling more than $17 billion for allegedly acting negligently, deliberately designing their platforms to hook kids and misleading the public about safety and privacy. If these suits are any indication of how states and the public are starting to view social media platforms, more may follow.

On top of these lawsuits, social media platforms are facing a loss of business as bans for minors are accelerating and spreading worldwide. Australia was one of the first with a ban on kids under 16 on social media starting in December 2025, followed soon after by the U.K. with a similar prohibition.

The current list of countries looking to ban minors from these platforms includes more than 20, from Greece to the United Arab Emirates to Canada. The proposed and enacted bans around the world vary in terms of age restriction, parental consent rules and age verification methods. Different countries are looking at restricting different platforms, but most include a mix of Snapchat, YouTube, TikTok, Instagram, Facebook and X.

These bans aren't necessarily for mental health reasons only—some are motivated by political concerns about foreign-owned platforms, and others aim to protect young people's privacy. But nearly every government banning social media platforms for young people mentions their mental health as a reason.

The question is, are these bans the solution to the mental health problems young people are facing? I research digital media and marketing and measure the impact of new technologies, and I'm skeptical about whether prohibiting access to these platforms will improve young people's mental health.

Mental health concerns
Since Jonathan Haidt's 2024 book "The Anxious Generation," critics of social media have increasingly focused on young people's mental health. Haidt argues that social media disrupts kids' social and neurological development, contributing to rising anxiety and depression through sleep loss, fragmented attention, addiction, loneliness, social comparison and perfectionism.

A 2026 study found that young people between 14 and 20 are more than 100% more likely to experience mental illness than 14- to 20-year-olds 50 years ago.

Increased use of social media and screen time is compounding an already precarious time for minors. In 2021, it was estimated that 20.5% of young people experienced elevated symptoms of anxiety, and 25.2% of youth reported elevated symptoms of depression globally.

Many factors contribute to this, including better screening and awareness of kids' mental health problems, as well as societal disruptions as a result of the COVID-19 pandemic. As the world sheltered in place and moved online for work, school and social interactions, there was an increase in isolation and loneliness.

Not all bad
In light of these concerns, some researchers argue that bans on social media platforms are like putting an age restriction on buying alcohol or cigarettes.

But unlike these addictive and potentially harmful substances, there are benefits to social media, especially for teens who feel disconnected from their local communities and want to build relationships with others who feel similarly.

Social media platforms allow for global connectivity and community-building with like-minded groups. They also provide a place for self-expression and civic engagement...

On the evening of 8 September 1930, the German mathematician David Hilbert stepped up to a microphone in Königsberg and addressed his countrymen by radio. He was 68, recently retired, and at the height of his fame. The talk was a defence of pure reason, delivered in the city of Immanuel Kant, and it ended with two phrases that would later be carved on his tombstone: Wir müssen wissen. Wir werden wissen. We must know. We shall know.

Are certain questions closed to the human mind? Are there truths about the world that we can never know? Hilbert thought that, at least within mathematics, this could not be the case. For him, mathematics was a game played with symbols: one could fix the right axioms as rules of the game and every mathematical problem could be solved. He was wrong.

The day before his Königsberg address, at a small academic meeting in the same city, a 24-year-old Austrian named Kurt Gödel had quietly announced that no such system for arithmetic could exist. Whatever reasonable set of rules you fix, something true must lie beyond them and thus beyond our knowledge. We can’t know. We won’t know. Gödel’s results, known as the Incompleteness Theorems, are landmark achievements of 20th-century logic. Recent work in philosophy and mathematics has begun to illuminate the gap they opened, and with it something deeper about the foundations of knowledge itself. The story begins in the same city, but two centuries earlier.

When Kant remembered a book by David Hume he’d read years earlier, he was woken from what he called his ‘dogmatic slumber’. Kant had believed that pure reasoning could teach us every absolute truth about the world, but Hume had asked a question that that stumped him: what reason do we actually have to believe that the future will resemble the past? We may have seen the Sun rise a thousand times, but how do we know it will rise tomorrow? The belief that the future will resemble the past is, Hume argued, merely a kind of habit. Kant couldn’t answer Hume’s challenge and was silenced for a decade.

For Hume, proving a theorem was like unpacking a suitcase to find an outfit. Kant could not leave it there

When Kant finally broke his silence with the Critique of Pure Reason (1781), he offered a radical answer. We can know the world only as it appears to our minds, and that is where our science sits; the noumenal world – the Ding an sich (the ‘thing-in-itself’) – simply lies beyond our reach. Causation is not something we discover in the world, but something the mind supplies for experience to be coherent at all. When we watch a cat push a glass off a table, we don’t see a bare sequence of motions and then infer, by some metaphysical principle, that the push caused the fall. No: we see the push as causing the fall. The causal structure is not a hypothesis we add to the experience; it is part of how the experience comes to us in the first place. It is in our minds already.

So far, so good: Kant has met Hume’s challenge, and the workings of science are intelligible: we are structuring our experiences. But the work is not done, for there remains mathematics, the very language in which the sciences are framed. Hume was content that arithmetic and algebra are merely the unpacking of definitions; that proving a theorem is like unpacking a suitcase to find an outfit. Kant could not leave it there. If mathematics were only such unpacking, how could it underwrite the sciences? Either the sciences tell us nothing new about the world, or something has gone missing from the account...