Once again, sea creatures took the biggest hit. Theories point to rising and falling sea levels, climate change, or even asteroid impacts. One idea suggests that expanding plant life on land may ...

The calculations suggested 2.5 supernovas might affect Earth in some way every 1 billion years, equating to one ... a mass extinction. During the Devonian geological era, life thrived on land ...

However, many years ago, the Earth looked ... years ago, all of the continents were joined together as one supercontinent called Pangea. Over time, this huge mass of land split apart due to ...

Dino-killing asteroidCelestial events have triggered at least one mass extinction, according to scientific evidence. A city-size asteroid slammed into Earth off ... water and land over a ...

Violent supernovas may have caused two of Earth ... one at the end of the Late Ordovician 445 million years ago. The team suggested a supernova may have stripped the ozone layer that shields the Earth ...

The mass extinction that killed 80% of life on ... At that time, the supercontinent Pangea was in the process of breaking up, but all land on Earth was still largely clustered together, with ...