The near-Earth object (875163) 1998 SH2, which is currently classified as an asteroid, has revealed a hidden identity: it’s actually a comet in disguise, according to a new study published in the journal Nature Astronomy. This artist’s concept depicts a near-Earth asteroid with an elongated orbit; a few objects such as these can exhibit significant perturbations in their motion around the Sun...

By analyzing nickel isotopes preserved in the 66-million-year-old debris left by the Chicxulub impact, researchers conclude that the asteroid responsible for Earth’s last mass extinction most likely belonged to an exceptionally rare class of primitive meteorites called carbonaceous chondrites of the Ornans type (CO chondrites). This painting depicts an asteroid slamming into tropical, shallow seas...

For as long as readers have pored over Homer’s Odyssey they have pictured Ithaca, the homeland Odysseus fights for ten years to reach, as an island unto itself. Now, two scholars say that assumption — held since antiquity — is simply wrong, arguing that Ithaca was a peninsula on the Greek island of Kefalonia. Paliki peninsula on the island of Kefalonia, Ionian Islands, Greece. Image...

A new genus and species of cryptobranchid salamander that lived in lakes in Japan about 3.5 million years ago has been identified from three fossil vertebrae, filling a major gap in the fossil record of one of the world’s oldest amphibian lineages. Life reconstruction of Limnospondylus ajimuensis. Image credit: Kanon Tanaka. The Cryptobranchidae is a family of giant, fully aquatic salamanders native...

Researchers have identified and formally described a new species of the African monkey genus Colobus living in the remote interior of the Democratic Republic of Congo, marking only the fifth new monkey species found on the continent in the past 75 years. Colobus congoensis. Image credit: Daniel Rosengren, Frankfurt Zoological Society. The newly described species is a small, black-furred monkey distinguished...

Using the largest sample yet of particles called beauty mesons, physicists with the CMS Collaboration at CERN’s Large Hadron Collider (LHC) refined a decades-old test of the subtle imbalance that let our Universe exist at all. Neutral beauty mesons can turn into their own antimatter opposite and back again. Image credit: Ansar Iqbal / CMS. One of the greatest mysteries in physics is why the Universe...

In a new review paper, Dr. Gregory Marcus from the University of California, San Francisco and colleagues analyzed decades of research on how caffeine — most often consumed as coffee — affects the heart and its risk factors. They defined moderate intake as up to about 400 mg of caffeine a day, roughly three to five 8-ounce cups (a fluid ounce is 30 ml) of coffee. Marcus et al. conclude...

In an analysis of 390 traditionally cultivated cacao trees representing traditional Amazonian varieties, researchers identified four previously unknown genetic lineages, with two showing ancestry linked to exceptional flavor potential and offering new opportunities for growers and chocolate makers. Motilal et al. collected cacao samples from eight departments of Peru. Image credit: Fernando Graniel. Cacao...

Zircon crystals and impact-altered minerals show that a massive asteroid slammed into what is now the Pilbara region of Western Australia about 3 billion years ago. The North Pole Dome crater: (A) simplified map of the East Pilbara Terrane (EPT, Western Australia), showing Paleoarchean granite domes (pink) and greenstone belts (greens and blues); the North Pole Dome (NPD) lies near the terrane center;...

In a new review paper, Dr. Gregory Marcus from the University of California, San Francisco and colleagues analyzed decades of research on how caffeine — most often consumed as coffee — affects the heart and its risk factors. They defined moderate intake as up to about 400 mg of caffeine a day, roughly three to five 8-ounce cups (a fluid ounce is 30 ml) of coffee. Marcus et al. conclude...