Discoveries about dinosaurs’ death knell, a watery exoplanet, a new hominid species and more are keeping us on the edge of our seats. But these reports require more proof before they can earn a spot on our list of top stories of the year.
When an asteroid smashed into Earth about 66 million years ago, it triggered an immense earthquake. A fossil site in North Dakota records the mayhem in the hours after impact, scientists reported in the Proceedings of the National Academy of Sciences. But what’s more tantalizing is what the researchers may have left out of their scientific paper. Robert DePalma, a paleontologist at the University of Kansas in Lawrence and an author on the paper, told the New Yorker that the team found fossilized dinosaurs, pterosaurs and even feathers at the site (SN: 4/27/19, p. 10). Because so few dinosaur fossils from just before the impact have been found, some scientists think that the animals were already dying out. If dinosaur fossils do exist at the site, that’s more evidence that the asteroid impact was to blame.
Water vapor detected in the atmosphere of an exoplanet 110 light-years away from Earth had astronomers saying K2 18b is the first known planet orbiting a distant star that might have liquid water (SN: 10/12/19 & 10/26/19, p. 6). K2 18b might even have water clouds and rain, scientists suggest. Observations with NASA’s James Webb Space Telescope, slated to launch in 2021, could help determine if and how much liquid water, thought to be a key ingredient for life, K2 18b has. But even if the exoplanet is awash in the wet stuff, that doesn’t mean the planet is habitable (SN Online: 10/4/19).
What lies beneath
A cache of tiny animal carcasses was dredged up from Antarctica’s perpetually ice-covered Lake Mercer, scientists revealed this year. The find was a surprise because this extreme environment was thought to be friendly only for microbes (SN: 2/16/19, p. 11). The limits of habitability may be less narrow than previously thought. But it’s also possible that the remains — including what look like tardigrades, crustaceans, spiders and worms — were carried into the lake by ice or water.
Hello, Homo luzonensis
Fossils discovered in a Philippine cave suggest that an unknown hominid species roamed the island now called Luzon at least 50,000 years ago. The proposed new species, dubbed Homo luzonensis, lived around the same time that small hominids wandered the Indonesian island called Flores. The shape and size of some of the fossils match corresponding bones from known Homo species. But the combination of features is unique, researchers say. If confirmed as a separate species, H. luzonensis would be the latest addition to the human evolutionary family tree. The find would also indicate that several Homo groups inhabited East Asia and Southeast Asian islands by the time humans reached southern China, complicating scientists’ view of hominid evolution in Asia (SN: 5/11/19 & 5/25/19, p. 7).
When two neutron stars crashed into each other, as reported in Science News’ top story of 2017 (SN: 12/23/17 & 1/6/18, p. 19), the collision blasted a jet of charged particles into space, new observations suggest (SN: 3/30/19, p. 7). The find supports a theory that mysterious flashes of high-energy light called short gamma-ray bursts are actually jets from neutron star collisions. But researchers will need to observe more of these stellar smashups to figure out if the jets are the norm, or if the 2017 jet was a fluke.
Similar to birds and fish, humans may sense Earth’s magnetic field, a study of brain waves suggests (SN: 4/13/19, p. 6). In lab tests, people displayed a distinct brain wave pattern when exposed to an Earth-strength magnetic field. But the pattern formed only when the field pointed and moved in a certain way. Even if the finding is confirmed, it’s not clear what we would do with this “sixth sense,” or how we would pick up the signal.
Clearing the way
Flickering lights and clicks improved memory in mice with signs of Alzheimer’s disease. The light and sounds boosted gamma waves in the brain, which seemed to wipe away disease-related plaques (SN: 4/13/19, p. 9). Mice that received treatment had fewer amyloid-beta plaques in areas of the brain usually hit hard by the disease, plus less of a harmful version of tau protein. Plaque-eating immune cells were kicked into a feeding frenzy, scientists reported. If the treatment works in people (tests are now under way), it would open a new way to target the degenerative disease. But many treatments that have reduced signs of the disease in mice haven’t had the same effect in humans.