Life, the Universe and Everything

A new study is providing fresh evidence that the building blocks of life may have been delivered to early Earth via meteorites.

A research team led by Rayssa Martins from the University of Cambridge’s Department of Earth Sciences tracked the chemical element zinc in meteorites to understand the origins of Earth’s “volatiles.”

These are elements or compounds that vaporize at low temperatures and are essential for life as we know it.

“One of the most fundamental questions on the origin of life is where the materials we need for life to evolve came from,” Martins said in a statement. “If we can understand how these materials came to be on Earth, it might give us clues to how life originated here and how it might emerge elsewhere.”

Their findings showed that Earth’s zinc originated from two distinct parts of the solar system. About half came from planetesimals – small rocky bodies – that formed close to the Sun.

The other half likely came from planetesimals beyond Jupiter. These distant planetesimals were less affected by solar radiation, allowing them to retain more volatiles, according to Space.com.

Martins and her colleagues discovered that melted planetesimals contributed around 70 percent of Earth’s overall mass but only 10 percent of its zinc. In contrast, unmelted planetesimals delivered most of Earth’s zinc and other essential volatiles, including water.

“Our results show there’s no guarantee that planets incorporate the right materials to have enough water and other volatiles in the first place – regardless of their physical state,” Martins noted.

The study highlights that the distance between a planet and its star is important for determining habitability, with the authors adding that the findings could assist in the search for life beyond Earth.

“Similar conditions and processes are also likely in other young planetary systems,” Martins said.