Science

Egyptians may have used hallucinogenic substances as part of a fertility rite, researchers said.

By Alexander Nazaryan

Balloon launches from around the world are part of a new kind of global alarm system: One that can detect if another country tries to dim the sun.

By Christopher Flavelle

As international talks continue this week, a dozen U.N. officials reveal scientists tracked their exposure to many chemicals found in plastics.

By Hiroko Tabuchi

Robert F. Kennedy Jr. and other candidates for top health posts are at odds with the drug industry, setting the stage for tense battles over regulatory changes.

By Rebecca Robbins, Christina Jewett and Kate Kelly

In “The Miraculous From the Material,” the best-selling author Alan Lightman examines the science behind the wonder.

By Adam Nicolson

When it comes to weeding out corporate influence, Robert F. Kennedy Jr.’s ideas often align best with some of Trump’s loudest critics.

By Emily Baumgaertner

As the director of the National Institutes of Health, Dr. Jay Bhattacharya would oversee the world’s premier medical research agency, with a $48 billion budget and 27 separate institutes and centers.

By Sheryl Gay Stolberg

The drug, which is named MariTide and delivered in a monthly injection, is some time away from being sold.

By Gina Kolata

Martha Schwartz Partners works around the globe to take on pollution and warming of the planet.

By Shivani Vora

A “weird city version” of common countryside wisdom saved my favorite outfits.

By Sarah Leonard

Cows and pigs produce a large share of planet-warming methane. A new tax is part of a plan to clean that up.

By Somini Sengupta and Charlotte de la Fuente

And it’s on the rise among middle-aged drinkers.

By Christina Caron

Cassava Sciences said that its drug did not significantly reduce cognitive decline in 1,900 people with mild to moderate Alzheimer’s disease.

By Teddy Rosenbluth

This Southeast Asian island, home to some of the world’s strangest and most iconic creatures, is a dream destination for a growing number of “mammal watchers.”

By Mihir Zaveri

Many nations hope to reduce the half a billion tons of plastic made each year. But pushback from plastic and oil producers, and Donald Trump’s election, could scuttle an agreement.

By Hiroko Tabuchi

The financing plan, which calls for $300 billion per year in support for developing nations, was immediately assailed as inadequate by a string of delegates.

By Max Bearak

Medical care can be wearying and time-consuming, especially for seniors. Researchers are beginning to quantify the burdens.

By Paula Span

A frequent Fox News commentator, Dr. Makary has a penchant for challenging the medical establishment, and stirred pandemic concerns with his views on Covid immunity and vaccine mandates.

By Christina Jewett

With thousands of advanced centrifuges on standby, Tehran says it is now spinning more, which could increase its stockpile of near-bomb-grade atomic fuel.

By William J. Broad

Nitrogen oxides, a group of gases from the burning of fossil fuels, is linked to a range of health effects.

By Austyn Gaffney

President-elect Donald J. Trump is set to nominate Robert F. Kennedy Jr. to lead the Health and Human Services Department, where he would have limited power over drugs.

By Gina Kolata

Americans are dying of illnesses related to alcohol at roughly twice the rate seen in 1999.

By Roni Caryn Rabin

Several recent TV series for adults have featured autistic lead characters. A new PBS show looks to expand that trend into children’s programming.

By Laurel Graeber

Every month so far has seen floods, fires, smashed heat records or some combination of extreme weather. Little time remains for leaders to agree on what to do about it.

By Somini Sengupta

Crowds in Anchorage have braved freezing temperatures and slippery ice to see the hulking carcass of a rare fin whale, which washed ashore a few miles from downtown.

By John Yoon

The hoppy pilsner from Singapore, where freshwater is scarce, is part of an effort to promote recycling solutions.

By Rebecca F. Elliott

Deadly landslides are becoming more common and large amounts of rain are a known trigger. An atmospheric river is dumping rain out West. What you should know about your risk.

By Austyn Gaffney

Experts are puzzling over which interventions are saving lives. The evolving illicit supply itself may hold important clues.

By Jan Hoffman and Noah Weiland

Astronomers zoomed in on a stellar behemoth in the Larger Magellanic Cloud, a galaxy that orbits about 160,000 light-years from the Milky Way.

By Dennis Overbye

Public health advocates worry that Donald Trump could unravel federal clean water efforts, including restrictions on lead pipes and chemicals known as PFAS.

By Hiroko Tabuchi

A second Trump administration could alter the lives of all sorts of animals, whether they live in laboratories, zoos, fields or forests.

By Emily Anthes and Catrin Einhorn

Iran has raised the possibility it would stop expanding its stockpile of uranium enriched to a purity of 60 percent — very close to the level needed for a weapon, the U.N.’s nuclear watchdog says.

By William J. Broad

President-elect Donald Trump joined Elon Musk in Texas and watched the launch from a nearby location on Tuesday. While the Starship’s giant booster stage was unable to repeat a “chopsticks” landing, the vehicle’s upper stage successfully splashed down in the Indian Ocean.

By Jamie Leventhal

Journals had retracted papers on superconductors that worked at room temperature and materials science that involved Ranga Dias.

By Teddy Rosenbluth

An analysis of newly released 19th-century census records offers more insight into the conflict’s costs.

By Emily Baumgaertner

President-elect Donald J. Trump joined Elon Musk, as his company’s prototype moon and Mars rocket carried out a sixth test flight that showed a mix of progress and setbacks.

By Katrina Miller, Erica L. Green and Kenneth Chang

If he is confirmed as H.H.S. secretary, the longtime vaccine critic would be in a position to change the government’s immunization recommendations and delay the development of new vaccines.

By Emily Anthes and Emily Baumgaertner

Some women are stocking up on the medications, saying they are concerned that the new administration could take steps to restrict access.

By Pam Belluck

As the glaciers of South America retreat, the supply of freshwater is dwindling and its quality is getting worse.

By Mitra Taj and Marco Garro

The ruling found that two state laws — one barring use of abortion pills, and one banning all forms of abortion — violated the state Constitution’s “fundamental right to make health care decisions.”

By Pam Belluck

The president-elect’s decision to witness the liftoff is another example of his close ties to the world’s wealthiest entrepreneur.

By Michael Gold and Theodore Schleifer

A rise in the disease in younger people was not followed by an increase in deaths, a study found, and might be a sign of overdiagnosis.

By Gina Kolata

An independent researcher found that noise recorded miles away from the site of a recent test flight was equal to standing 200 feet from a Boeing 747 during takeoff.

By Eric Lipton

Senior ministers are arriving in an effort to break a deadlock over the summit’s main goal: funding to help lower-income countries hit hard by global warming.

By David Gelles and Brad Plumer

President Biden pledged financial help to protect the Amazon during a visit to Brazil, making one final push to combat climate change before the end of his term.

A small study found ChatGPT outdid human physicians when assessing medical case histories, even when those doctors were using a chatbot.

By Gina Kolata

For a century, exoplanet hunters have “discovered” planets around a nearby star, only to retract the claims. But the latest find is for real.

By Dennis Overbye

The unidentified patient had recently returned from Africa, where the virus has caused a deadly epidemic, health officials said.

By The New York Times

At Dartmouth, long before the days of laptops and smartphones, he worked to give more students access to computers. That work helped propel generations into a new world.

By Kenneth R. Rosen

American officials are seeking to assure the world that U.S. climate action won’t end with the return of Donald Trump as president.

By David Gelles

Trends in child health are in fact worrisome, and scientists welcome a renewed focus on foods and environmental toxins. But vaccines and fluoride are not the cause.

By Roni Caryn Rabin

Processed foods are in the cross hairs of Robert F. Kennedy Jr., but battling major companies could collide with President-elect Donald J. Trump’s corporate-friendly goals.

By Christina Jewett and Julie Creswell

The event produces some of the year’s fastest meteors, although the nearly full moon may make them challenging to spot.

By Katrina Miller

Growing worldwide energy demand and other factors have shifted the calculus, but hurdles still lie ahead.

By Brad Plumer

Behind the scenes at a Chicago zoo, chimpanzees who spent years entertaining humans are learning to befriend their own kind.

By Emily Anthes

With the nomination of Robert F. Kennedy Jr. as health secretary, a formerly fringe opinion suddenly gets wide attention.

By Joseph Goldstein

The agency’s top medical official was responding to rumors that Suni Williams had lost an unusual amount of weight during an extended stay in orbit.

By Kenneth Chang

A researcher thinks he knows what has been coming ashore on miles of beaches. Canada’s environmental agency says it is still looking into it.

By Alan Yuhas

A sharp partisan divide remains over how involved researchers should be in policy decisions.

By Teddy Rosenbluth

A teenager in British Columbia was hospitalized in critical condition with the disease, and officials were working to find out how the person was exposed to the virus.

By Vjosa Isai

Negotiators agree that trillions are needed to help lower-income countries adapt and cope, but not on who should pay.

By David Gelles and Brad Plumer

A study of Gila monster venom helped start the revolution in weight-loss drugs. But scientists think that’s just the beginning.

By Kim Tingley

New research suggests symptoms of the disorder may be less severe in those with a demanding schedule.

By Christina Caron

Countries promised to move away from coal, oil and natural gas at last year’s climate summit. New research shows they’re burning more than ever before.

By Brad Plumer

The Justice Department and four Democratic state attorneys general argued that United’s takeover would limit competition and harm consumers needing home or hospice care.

By Reed Abelson

The prime minister announced more ambitious climate targets, charting a very different course from the United States, which is expected to roll back its energy transition plans.

By Somini Sengupta

Rates of gonorrhea declined in 2023, while diagnoses of syphilis and chlamydia held roughly steady, according to new C.D.C. data.

By Apoorva Mandavilli

No one saw a Mekong giant salmon carp for 15 years, but then the species was spotted in areas of Cambodia that suggest it may be found in more locations.

By Rachel Nuwer

Robert F. Kennedy Jr., one of President-elect Donald J. Trump’s advisers on health, is taking aim at the agency’s oversight on many fronts.

By Christina Jewett

Negotiators at the summit in Azerbaijan fear that the return of Donald Trump will sap momentum for global climate action.

By Brad Plumer and David Gelles

Excessive drinking persisted in the years after Covid arrived, according to new data.

By Roni Caryn Rabin

Much of the understanding of the seventh planet comes from a brief flyby nearly 40 years ago, which researchers now say overlapped with an exceptional solar event.

By Jonathan O’Callaghan

The economy of Azerbaijan, host of COP29, relies almost entirely on the fossil fuels that are the main driver of global warming.

By Max Bearak

The election of Donald J. Trump is sapping momentum from global climate talks as diplomats brace for his pro-fossil-fuel agenda.

By Lisa Friedman

The monkeys escaped after a worker at a research center left an enclosure unlocked. One monkey was captured Saturday, and another 24 on Sunday, while the rest remain at large.

By Sara Ruberg

What should be expected of an intimate partner when a companion suffers a health crisis? Seniors and their families increasingly confront the question.

By Paula Span

Californians voted for tougher penalties for dealers. Florida, North Dakota and South Dakota rejected proposals to legalize marijuana. Massachusetts denied a measure allowing possession of psychedelics.

By Jan Hoffman

In the Berlin Zoo, Mary demonstrated another example of clever elephantine tool use while another animal exhibited a form of mischief with a hose that resembled a prank.

By Emily Anthes

A basilica from the 4th century held a surprising number of tombs with women and children, researchers found.

By Alexander Nazaryan

The retired research chimpanzees, which had previously been deemed too frail to move, will be relocated to a Louisiana sanctuary.

By Emily Anthes