Astronomy

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

8 ASTRONOMY • SEPTEMBER 2017

SNAPSHOT

Let’s

hear it for

abiogenesis

The origin of life? You can’t

“magic” it into existence.

One of the thorniest questions

we have is exactly how life origi-

nated on Earth. It’s been a mys-

tery for a very long time.

Scientists call the process abio-

genesis — how self-replicating

molecules began from nonliving

matter such as simple organic

compounds. The puzzle of

understanding abiogenesis

involves multiple sciences

including astronomy, physics,

biolog y, chem ist r y, a nd pa leon-

tology. It attempts to derive a

process that occurred nearly

4 billion years ago, on an Earth

that was very different from the

one we inhabit today.

One of astronomy’s most pow-

erful tools, spectroscopy, tells us

that chemistry is uniform

throughout the universe. So

although we don’t know exactly

when or how life originated, or

how its simplest form got going,

we do know it was governed by

the processes of organic chemis-

try that we understand well

today. As Richard Dawkins has

often said, life can’t be

“magicked” into existence.

The molecular hypothesis of

how life started originated in

the 1920s, and current ideas

build from it. Organic (carbon-

containing) molecules are com-

mon in the solar system and

universe. Going from simple

organics to self-replicating RNA

and DNA is a big step, but one

that is logical given the chemistry

of early Earth. We don’t yet know

what developed first or domi-

nated early: an RNA World, an

Iron-Sulfur World, a Protocell

World, a Deep Sea Vent World,

or a number of others?

It is a highly exciting time for

science. Understanding early

Earth and its chemistry is taking

us closer and closer to compre-

hending exactly how we got here.

— David J. Eicher

HOT BYTES >>

TRENDING

TO THE TOP

ROCKY PHOTO OP

NASA captured images

of Ceres at opposition,

when the Dawn space-

craft was positioned

directly between the

asteroid and the Sun.

LIGHT IT UP

Ice particles may be

responsible for hundreds

of mysterious flashes seen

between 2015 and 2016 by

the DSCOVR craft, which

monitors the solar wind.

FERMI MILESTONE

The Fermi Gamma-

ray Space Telescope

witnessed its billionth

gamma ray since its

launch in 2008.

Life on Earth may have originated in and around “black smokers” — hydrothermal vents on the ocean floor, like this one emitting

carbon dioxide in the Marianas Trench Marine National Monument in the South Pacific.

NOAA; TOP FROM LEFT: NASA/JPL-CALTECH/UCLA/MPS/DLR/IDA; NASA GODDARD; NASA GODDARD