Did Life on Earth Begin in the Clouds Between Stars?

The Cosmic Companion
Sep 27 · 3 min read

The building blocks of life here on Earth may have formed in dust clouds floating between the stars. These molecules could have seeded life on planets and moons around the Universe.

A new experiment shows that nucleobases — the building blocks of DNA, may be produced in frozen clouds floating among the stars. This phenomenon could have seeded life here on Earth, as well as on worlds around other stars.

Researchers from Hokkaido University created conditions in a closed chamber similar to those found in interstellar clouds of gas and dust. This artificial environment produced nucleobases, a result never before seen in a laboratory.

A view inside a high-vacuum reaction chamber utilized to study chemical reactions inside interstellar clouds. Image credit: Hokkaido University

“Nucleobases play an essential role in the biology of terrestrial organisms since they are the basic units used to record genetic information,” researchers describe in an article published in Nature Communications.

Together with sugar and a phosphate group, nucleobases form nucleotides, the basic structure of DNA and its sister molecule, RNA. Phosphate and sugar were produced in early replications of interstellar clouds, but this experiment marks the first time nucleobases have been detected under these conditions.

If I Could Form Clouds in a Bubble…

The experiment consisted of filling a ultra-high vacuum reaction chamber with a mixture of water, carbon monoxide, ammonia, and methanol, in an environment featuring faux “cosmic dust.” This mixture, kept at a temperature of -263 Celsius (-440 degrees Fahrenheit), was subjected to ultraviolet light from a pair of deuterium discharge lamps, igniting chemical reactions.

Akira Kouchi (left), Yasuhiro Oba (center), and Naoki Watanabe (right) of the research team at Hokkaido University’s Institute of Low Temperature Science. Image credit: Hokkaido University

An icy film formed on the cosmic dust substitute inside the chamber, and this material (after warming) was analyzed by the research team. In addition to several nucleobases, the team found reactions in the chamber formed amino acids, the building block of proteins, as well as other organic chemicals.

Yasuhiro Oba and colleagues at Hokkaido University, Kyushu University, and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) utilized newly-developed techniques to test the sample. These methods were not available to researchers performing earlier experiments similar to this one, suggesting a possible reason nucleobases were not detected in earlier attempts to model interstellar gas clouds.

Space is a Lively Place

Video credit: NBC Classics

“There are those who believe that life here began out there, far across the universe…” — from the introduction of Battlestar Galactica (1978)

Many of the basic building blocks of life have been detected in asteroids, comets, and in the giant clouds of gas hover between stars. These organic chemicals may have fallen to Earth as our planet was bombarded by these bodies four billion years ago, seeding life on our world. Therefore, this experiment could help researchers better understand the development of early life on Earth.

Models of six nucleobases formed by a simulated interstellar cloud. Image credit: Hokkaido University

“This result could be key to unravelling fundamental questions for humankind, such as what organic compounds existed during the formation of the solar system and how they contributed to the birth of life on Earth,” explains Yasuhiro Oba of Hokkaido University’s Institute of Low Temperature Science.

The laws of physics and chemistry are very likely to be identical throughout the Universe. This idea suggests that if nucleobases and amino acids form in clouds between the stars, this process would likely seed bodies throughout the Universe with the building blocks of life.

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The Cosmic Companion

Written by

James Maynard is the author of two books, and thousands of articles about space and science. E-mail: thecosmiccompanion@gmail.com

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