Scientific Discoveries

Science • Nature
An asteroid and not a volcanic eruption killed the dinosaurs, study finds
Artist's impression of a 1000km-diameter planetoid hitting a young Earth.
Artist's impression of a 1000km-diameter planetoid hitting a young Earth. Credit: Don Davis (work commissioned by NASA) / Public domain

For decades scientists believed the reason for the mass extinction of dinosaurs and three-quarters of all life on earth 66 million years ago was a prolonged period of climate change caused by volcanic activity. A new study by researchers from the Imperial College London just disproved this theory: turns out it was an asteroid impact that struck Earth which also created the Chicxulub impact crater in southeast Mexico. According to the study, only an asteroid impact could have created conditions that made Earth uninhabitable.

“We show that the asteroid caused an impact winter for decades, and that these environmental effects decimated suitable environments for dinosaurs. In contrast, the effects of the intense volcanic eruptions were not strong enough to substantially disrupt global ecosystems,” so the lead researcher Alessandro Chiarenza in his statement. “Our study confirms, for the first time quantitatively, that the only plausible explanation for the extinction is the impact winter that eradicated dinosaur habitats worldwide.”

Science • Animals
First animal discovered that doesn't need oxygen

In a study published in the journal of PNAS, Proceedings of the National Academy of Sciences, scientists described their findings of a jellyfish-like parasite without oxygen dependency, called Henneguya salminicola. The microscopic parasite has less than 10 cells and has been found to live in salmon muscles. This discovery has changed the assumption that multicellular organisms need a mitochondrial genome to live. The paper further states that "H. salminicola provides an opportunity for understanding the evolutionary transition from an aerobic to an exclusive anaerobic metabolism".