A study of fossilized feces and vomit attempts to piece together why dinosaurs were so evolutionarily successful.

Researchers used fossilized poos, known scientifically as coprolites, to learn more about how dinosaurs came to rule the Earth. Researchers have conducted what could be the largest study ever of dinosaur poop.

The research has shed light on the emergence of large dinosaurs and their geographic spread, as well as the role of environmental changes in their evolution.

"The fact that terrestrial microbes are the Earth's best colonizers means we can never completely discount terrestrial contamination."

Scientists have found microorganisms crawling over a sample retrieved from the 200 million-mile-distant asteroid Ryugu. But they almost certainly came from Earth.

Excitement turned to surprise when scientists studying asteroid Ryugu samples found elongated microorganisms. Were they alien life? Not quite. Despite rigorous handling, the samples were contaminated with Earth-based bacteria.