Australasian Science: Australia's authority on science since 1938

Bringing the Building Blocks of Life Down to Earth

By David Reneke

Astronomers find more evidence for how life began in Earth, and send a greeting to a red dwarf with two habitable planets.

Where did we come from and how did we get here? How life began on Earth, roughly four billion years ago, is the eternal question and the basis for almost all of cosmology. New results from scientists at McMaster University and the Max Planck Institute for Astronomy suggest a key role for meteorites landing in warm little ponds, delivering essential organic molecules that kick-started the emergence of life in the shape of self-replicating RNA molecules.

The astronomers reached their conclusions after assembling models about planet formation, geology, chemistry and biology into a coherent quantitative model for the emergence of life. Perhaps the most interesting result from these calculations is that life must have emerged fairly early while Earth was still taking shape, only a few hundred million years after the Earth had cooled sufficiently to allow liquid surface water such as ponds or oceans to form.

The building blocks of life would have been brought to Earth by meteorites during an era when Earth’s bombardment by such small extraterrestrial rocks was much more intense than today.

The new work supports the “warm little pond” hypotheses for the origin of life, with RNA polymers forming in shallow ponds during cycles in which the pond water evaporates and is refilled periodically. It shows how meteorites could have transported a sufficient number of biological compounds to thousands of such ponds on Earth, helping to kick-start the emergence of self-replicating RNA molecules in at least one of those ponds.

Based on what we know about planet formation and the chemistry of the solar system, the researchers have proposed a consistent scenario for the emergence of life on Earth. Now it’s the experimentalists’ turn to find out how life could also form on suitable planets like ours around other stars.

Phoning ET at Home

Scientists have been searching for extraterrestrial planets for signs of life for over 50 years. Now it’s about to ramp up a few notches.

In the hope of making contact with aliens, a message has been beamed by scientists towards two planets potentially capable of supporting life. The message was directed towards GJ 273, known as Luyten’s star, a red dwarf 12.36 light years away from Earth that hosts two potentially habitable planets.

Nearby? Yes and no. It’s not reachable yet, but that’s only until technology catches up with science fiction. At light speed it would take 12 years to reach GJ 273. If any aliens reside on the planets when the message is received and understood by them, and a reply is sent, it will arrive here on 21 June 2042!

The contents of the message consisted of a scientific and mathematical “tutorial” of sorts, as well as 33 musical excerpts beamed out in binary code at two different radio frequencies from the European Incoherent Scatter Scientific Association radio antenna in Tromso, Norway.

Prof Stephen Hawking maintains that actively sending messages into space is a risky operation due to the fact that we are completely unaware of the levels of benevolence any extra-terrestrial life may or may not possess.

Despite all of this, the collective belief of the scientific community is that beaming a message to Luyten’s star poses no risk whatsoever. Indeed, the technological leap forward could be astounding!

A second message is planned to be set out to Luyten’s star in April 2018 at different radio frequencies in the hope that someone might hear the voice of humanity.

The success of the project of course will depend on whether someone remembers to look for a response 24 years from now.


David Reneke is an astronomy lecturer and teacher, a feature writer for major Australian newspapers and magazines, and a science correspondent for ABC and commercial radio. Subscribe to David’s free Astro-Space newsletter at www.davidreneke.com