Science

The World Health Organization chief announced Friday that it is "with great hope that I declare Covid-19 over as a global health emergency."

WHO Director-General Tedros Adhanom Ghebreyesus had declared the emergency of international concern on January 30, 2020, when there were fewer than 100 reported cases outside of China.

Humans make decisions using statistical information every day. Imagine you’re selecting a packet of jellybeans. If you prefer red jellybeans, you will probably try to find a packet that shows the most red (and less of the dreaded black ones) through the small window.

Since you can’t see all the jellybeans at once, you’re using statistical reasoning to make an informed decision. Even infants have this capability.

Microorganisms – in particular bacteria – are skillful chemists that can produce an impressive diversity of chemical compounds known as natural products. These metabolites provide the microbes major evolutionary advantages, such as allowing them to interact with one another or their environment and helping defend against different threats. Because of the diverse functions bacterial natural products have, many have been used as medical treatments such as antibiotics and anti-cancer drugs.

The microbial species alive today represent only a tiny fraction of the vast diversity of microbes that have inhabited Earth over the past 3 billion years. Exploring this microbial past presents exciting opportunities to recover some of their lost chemistry.

Those Transportation Security Administration requirements are drilled into every frequent flyer’s head: You can carry on liquids that are only less than 3.4 ounces (100 milliliters) in volume each.

But when the TSA recently confiscated a jar of Jif under this rule, peanut butter lovers were up in arms. Some skeptics of security may suspect hungry officers just wanted to make their own PB&Js. TSA, however, contends that peanut butter is a liquid – and a full-size jar of Jif is over the 3.4-ounce limit.

An international team of researchers has recovered DNA from the owner of a deer-tooth pendant that was buried inside a remote Siberian cave for tens of thousands of years.

In research published in Nature, Elena Essel of the Max Planck Institute for Evolutionary Anthropology in Germany and colleagues detail how they developed a new technique to extract DNA left behind on an artifact.

The next time NASA goes to the Moon, it intends to stay. Under the Artemis program, the US space agency plans to maintain a human presence, for the very first time, on a celestial body other than Earth.

But building a lunar base is no small feat. It will need power generators, vehicles and habitats, and the space industry is racing to meet the technological challenges.

The United States on Wednesday approved the world's first vaccine for the Respiratory Syncytial Virus (RSV), the culmination of a decades-long hunt to protect vulnerable people from the common illness.

Drugmaker GSK's Arexvy was green-lighted for adults aged 60 and older, with similar shots from other makers including Pfizer and Moderna expected to follow soon.

Scientists said Wednesday that they have observed a dying star swallowing a planet for the first time, offering a preview of Earth's expected fate in around five billion years.

But when the Sun finally does engulf Earth, it will cause only a "tiny perturbation" compared to this cosmic explosion, the US astronomers said.

US pharmaceutical giant Eli Lilly on Wednesday announced its experimental Alzheimer's drug significantly slowed cognitive and functional decline, results hailed as "remarkable" by experts despite some patients experiencing serious side effects.

In an analysis of nearly 1,200 people in the early stages of the disease, donanemab slowed the progression of symptoms by 35 percent over a period of 18 months compared to placebo.

The famous first image of a black hole just got two times sharper. A research team used artificial intelligence to dramatically improve upon its first image from 2019, which now shows the black hole at the center of the M87 galaxy as darker and bigger than the first image depicted.

I’m an astronomer who studies and has written about cosmology, black holes and exoplanets. Astronomers have been using AI for decades. In fact, in 1990, astronomers from the University of Arizona, where I am a professor, were among the first to use a type of AI called a neural network to study the shapes of galaxies.