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In recent years, researchers have made considerable progress toward producing renewable energy in the form of hydrogen fuel through the electrolysis of water. In the most basic electrolytic cell, an electric current drives a chemical reaction at two…

Atmospheric ozone plays a critical role in the biosphere by absorbing harmful ultraviolet radiation in the stratosphere—the layer of the atmosphere about 10 to 50 km (6 to 30 mi) above Earth’s surface. Since the adoption of the Montreal Protocol in…

Cosmochemists have discovered the oldest solid material known to exist on Earth. The material, stardust, consists of silicon carbide grains measuring around one micrometer in size. The grains date back approximately 7 billion years, or about 2.5…

Microplastics are raining down on national parks and other protected areas in the western United States at the rate of about 132 pieces of microplastic per square meter every day, according to a report in the journal Science (June 2020).…

If you think converting seawater to fuels that can power ships is a fantasy, think again. Researchers at the U.S. Naval Research Laboratory in Washington, D.C., have, in fact, accomplished this feat. In addition, the U.S. Navy has received a patent…

Using an artificial intelligence technique known as deep learning and high-resolution remote sensing, scientists have counted and mapped the location of trees in 11,000 satellite images covering more than 1.3 million square kilometers (500,000…

Fingerprint identification is a widely used forensic method for linking an individual to a crime scene. Investigators at a crime scene can find invisible (latent) fingerprints, which consist of natural skin oils, by "dusting" surfaces with carbon…

The earliest representatives of modern humans—those belonging to Homo sapiens—evolved from more archaic humans approximately 150,000–300,000 years ago in eastern Africa. During succeeding years, the geographical range of anatomically modern humans…

Life on Earth has been punctuated by a number of catastrophic mass extinctions throughout history. During these events, diverse taxonomic groups collapsed from the relatively rapid and widespread extinction of large numbers of species. Precipitated…

Heroin (C21H23NO5) is a white, crystalline powder synthesized from morphine, a natural alkaloid extracted from the seedpod of the Asian opium poppy plant, Papaver somniferum. It is a powerful opioid drug prepared by the addition of two acetyl groups…