Pre-life molecules present in comets

July 26, 2006

Evidence of atomic nitrogen in interstellar gas clouds suggests that pre-life molecules may be present in comets, a discovery that gives a clue about the early conditions that gave rise to life, according to researchers from the University of Michigan and the Harvard-Smithsonian Center for Astrophysics.

The finding also substantially changes the understanding of chemistry in space.

The question of why molecular nitrogen hasn't been detected in comets and meteorites has puzzled scientists for years. Because comets are born in the cold, dark, outer reaches of the solar system they are believed to be the least chemically altered during the formation of the Sun and its planets.

Studies of comets are thought to provide a "fossil" record of the conditions that existed within the gas cloud that collapsed to form the solar system a little more than 4.6 billion years ago. In this cloud, since nitrogen was thought to be in molecular form, and it follows that comets should contain molecular nitrogen as well.

But the reason it isn't there is because it isn't present in the gas clouds whose microscopic solid particles eventually form comets, said Sйbastien Maret, research fellow in astronomy at the University of Michigan, and Edwin Bergin, a professor of astronomy at the University of Michigan. Those clouds contain mostly atomic nitrogen, not molecular nitrogen, as previously thought.

Maret, Bergin, and collaborators from Harvard-Smithsonian Center for Astrophysics will publish their findings in the July 27 issue of the journal Nature.

The nitrogen bearing molecules in comets that crashed into Earth millions of years ago may have provided a sort of "pre-biotic jump start" to form the complex molecules that eventually led to life here, Bergin said.

"A lot of complex and simple biotic molecules have nitrogen and it's much easier to make complex molecules from atomic nitrogen," Bergin said. "All DNA bases have atomic nitrogen in them, amino acids also have atomic nitrogen in them. By that statement what we're saying is if you have nitrogen in its simplest form, the atomic form, it's much more reactive and can more easily form complex prebiotic organics in space". These complex organics were incorporated into comets and were provided to the Earth.

"What we're seeing in space is telling us something about how you make molecules that led to us," Bergin said.

Also of importance is the fact that odd anomalies in isotopic values in meteorites can also be explained if the nitrogen is not molecular, Bergin said.

Source: University of Michigan

Explore further: Neil deGrasse Tyson weighs in on New Horizons' Pluto discoveries

Related Stories

In unexpected discovery, comet contains alcohol, sugar

October 23, 2015

Comet Lovejoy lived up to its name by releasing large amounts of alcohol as well as a type of sugar into space, according to new observations by an international team. The discovery marks the first time ethyl alcohol, the ...

What are asteroids made of?

September 14, 2015

What are asteroids made of? Asteroids are made mostly of rock—with some composed of clay and silicate—and different metals, mostly nickel and iron. But other materials have been found in asteroids, as well.

What is life?

October 20, 2015

"Why would NASA want to study a lake in Canada?"

Telescope detects rare form of nitrogen in comet ISON

February 20, 2014

A team of astronomers, led by Ph.D. candidate Yoshiharu Shinnaka and Professor Hideyo Kawakita, both from Kyoto Sangyo University, successfully observed the Comet ISON during its bright outburst in the middle of November ...

Recommended for you

Getting into the flow on the International Space Station

December 1, 2015

Think about underground water and gas as they filter through porous materials like soil and rock beds. On Earth, gravity forces water and gas to separate as they flow through the ground, cleaning the water and storing it ...

Exiled exoplanet likely kicked out of star's neighborhood

December 1, 2015

A planet discovered last year sitting at an unusually large distance from its star - 16 times farther than Pluto is from the sun - may have been kicked out of its birthplace close to the star in a process similar to what ...

Cassini mission provides insight into Saturn

December 1, 2015

Scientists have found the first direct evidence for explosive releases of energy in Saturn's magnetic bubble using data from the Cassini spacecraft, a joint mission between NASA, the European Space Agency, and the Italian ...

Timing a sextuple quasar

December 1, 2015

Quasars are galaxies with massive black holes at their cores around which vast amounts of energy are being radiated. Indeed, so much light is emitted that the nucleus of a quasar is much brighter than the rest of the entire ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.