Astronomy

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EVERYTHING YOU NEED TO KNOW ABOUT THE UNIVERSE THIS MONTH...

8 ASTRONOMY • MAY 2018

SNAPSHOT

Life in the

universe

may be

common

New research from experts

in early life on Earth

points toward life in the

universe at large.

J. William Schopf is an old friend

of Astronomy magazine who has

consulted with us in the past.

He’s also one of the world’s

sharpest researchers on the ori-

gin of life and the existence of

ancient microfossils. Recently,

Schopf and his team at UCLA,

along with scientists at the

University of Wisconsin, released

studies of early microfossils that

could shed light on how common

life is in the universe.

The oldest known microfossils

on Earth come from Western

Australia and date to 3.465 bil-

lion years ago. In a study pub-

lished in December 2017 in the

Proceedings of the National

Academy of Sciences, Schopf and

his team report that two species

they studied appeared to undergo

a primitive form of photosynthe-

sis, another produced methane

gas, and two more used methane

to build their cellular walls.

In a world of growing under-

standing that early, primitive

microbes on Earth were diverse,

the team suggests that this diver-

sity, coupled with the increasing

number of known exoplanets and

the sheer number of stars in the

universe, points toward life being

common throughout the cosmos.

“By 3.465 billion years ago,”

said Schopf, “life was already

diverse on Earth; that’s clear —

primitive photosynthesizers,

methane producers, methane

users. These are the first data that

show the very diverse organisms

at that time in Earth’s history,

and our previous research has

shown that there were sulfur

users 3.4 billion years ago as well.”

To Schopf and his team, the

new evidence adds credence to

the fact that life formed quickly

on early Earth, and also under-

scores that primitive life evolved

quickly into more advanced

microorganisms.

— David J. Eicher

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This fossil microorganism from Western Australia is 3.465 billion years old and suggests that life may be spread throughout the cosmos.

J. WILLIAM SCHOPF/UCLA CENTER FOR THE STUDY OF EVOLUTION AND THE ORIGIN OF LI

FE; TOP FROM LEFT: NASA/LRO/SETI/MARS INSTITUTE/P.

LEE; GOETHE

UNIVERSIT Y/L. REZZOLLA; ANU/CSIRO