Discoveries suggest icy cosmic start for amino acids and DNA ingredients

Feb 28, 2013
The Green Bank Telescope and some of the molecules it has discovered. Credit: Bill Saxton, NRAO/AUI/NSF

(Phys.org)—Using new technology at the telescope and in laboratories, researchers have discovered an important pair of prebiotic molecules in interstellar space. The discoveries indicate that some basic chemicals that are key steps on the way to life may have formed on dusty ice grains floating between the stars.

The scientists used the National Science Foundation's Green Bank Telescope (GBT) in West Virginia to study a giant cloud of gas some 25,000 light-years from Earth, near the center of our . The chemicals they found in that cloud include a molecule thought to be a precursor to a key component of DNA and another that may have a role in the formation of the amino acid alanine.

One of the newly-discovered molecules, called cyanomethanimine, is one step in the process that chemists believe produces adenine, one of the four nucleobases that form the "rungs" in the ladder-like . The other molecule, called ethanamine, is thought to play a role in forming alanine, one of the twenty amino acids in the genetic code.

"Finding these molecules in an interstellar gas cloud means that important building blocks for DNA and can 'seed' newly-formed planets with the chemical precursors for life," said Anthony Remijan, of the (NRAO).

In each case, the newly-discovered interstellar molecules are intermediate stages in multi-step chemical processes leading to the final . Details of the processes remain unclear, but the discoveries give new insight on where these processes occur.


In the above video, students and their astronomer-advisor share the excitement of discovery.

Previously, scientists thought such processes took place in the very tenuous gas between the stars. The , however, suggest that the chemical formation sequences for these molecules occurred not in gas, but on the surfaces of in interstellar space.

"We need to do further experiments to better understand how these reactions work, but it could be that some of the first key steps toward biological chemicals occurred on tiny ice grains," Remijan said.

The discoveries were made possible by new technology that speeds the process of identifying the "fingerprints" of cosmic chemicals. Each molecule has a specific set of rotational states that it can assume. When it changes from one state to another, a specific amount of energy is either emitted or absorbed, often as radio waves at specific frequencies that can be observed with the GBT.

New laboratory techniques have allowed astrochemists to measure the characteristic patterns of such radio frequencies for specific molecules. Armed with that information, they then can match that pattern with the data received by the telescope. Laboratories at the University of Virginia and the Harvard-Smithsonian Center for Astrophysics measured radio emission from cyanomethanimine and ethanamine, and the frequency patterns from those molecules then were matched to publicly-available data produced by a survey done with the GBT from 2008 to 2011.

A team of undergraduate students participating in a special summer research program for minority students at the University of Virginia (U.Va.) conducted some of the experiments leading to the discovery of cyanomethanimine. The students worked under U.Va. professors Brooks Pate and Ed Murphy, and Remijan. The program, funded by the National Science Foundation, brought students from four universities for summer research experiences. They worked in Pate's astrochemistry laboratory, as well as with the GBT data.

"This is a pretty special discovery and proves that early-career students can do remarkable research," Pate said.

The researchers are reporting their findings in the Astrophysical Journal Letters.

Explore further: New mass map of a distant galaxy cluster is the most precise yet

Related Stories

Mining for Molecules in the Milky Way

Jun 02, 2008

Scientists are using the giant Robert C. Byrd Green Bank Telescope (GBT) to go prospecting in a rich molecular cloud in our Milky Way Galaxy. They seek to discover new, complex molecules in interstellar space ...

Research center to free chemistry from Earth's bonds

Oct 08, 2008

A new research center combining the tools of chemistry and astronomy will use the unique laboratory of interstellar space to free the study of basic chemistry from the restrictive bonds of Earth.

Astronomers unveiling life's cosmic origins

Feb 12, 2009

(PhysOrg.com) -- Processes that laid the foundation for life on Earth -- star and planet formation and the production of complex organic molecules in interstellar space -- are yielding their secrets to astronomers ...

Astrochemistry enters a bold new era with ALMA

Sep 20, 2012

(Phys.org)—Combining the cutting-edge capabilities of the ALMA telescope with newly-developed laboratory techniques, scientists are opening a completely new era for deciphering the chemistry of the Universe. ...

Recommended for you

Image: Chandra's view of the Tycho Supernova remnant

4 hours ago

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

Satellite galaxies put astronomers in a spin

Jul 24, 2014

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

Jul 24, 2014

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

User comments : 0