Meteorites: Tool kits for creating life on Earth

Aug 08, 2011

Meteorites hold a record of the chemicals that existed in the early Solar System and that may have been a crucial source of the organic compounds that gave rise to life on Earth. Since the 1960s, scientists have been trying to find proof that nucleobases, the building blocks of our genetic material, came to Earth on meteorites. New research, published next week in the Proceedings of the National Academy of Sciences, indicates that certain nucleobases do reach the Earth from extraterrestrial sources, by way of certain meteorites, and in greater diversity and quantity than previously thought.

Extensive research has shown that , which string together to form proteins, exist in space and have arrived on our planet piggybacked on a type of organic-rich meteorite called carbonaceous chondrites. But it has been difficult to similarly prove that the nucleobases found on meteorite samples are not due to contamination from sources on Earth.

The research team, which included Jim Cleaves of Carnegie's Geophysical Laboratory, used advanced spectroscopy techniques to purify and analyze samples from 11 different carbonaceous chondrites and one ureilite, a very rare type of meteorite with a different type of . This was the first time all but two of these meteorites had been examined for nucleobases.

Two of the carbonaceous chondrites contained a diverse array of nucleobases and compounds that are structurally similar, so-called nucleobase analogs. Especially telling was the fact that three of these nucleobase analogs are very rare in terrestrial biology. What's more, significant concentrations of these nucleobases were not found in soil and ice samples from the areas near where the meteorites were collected.

"Finding nucleobase compounds not typically found in Earth's biochemistry strongly supports an extraterrestrial origin," Cleaves said.

The team tested their conclusion with experiments to reproduce nucleobases and analogs using chemical reactions of ammonia and cyanide, which are common in space. Their lab-synthesized nucleobases were very similar to those found in the carbonaceous chondrites, although the relative abundances were different. This could be due to chemical and thermal processing that the meteorite-origin nucleobases underwent while traveling through space.

These results have far-reaching implications. The earliest forms of life on Earth may have been assembled from materials delivered to Earth by meteorites.

"This shows us that meteorites may have been molecular tool kits, which provided the essential building blocks for life on Earth," Cleaves said.

Explore further: Is space tourism safe or do civilians risk health effects?

Provided by Carnegie Institution

4.3 /5 (6 votes)

Related Stories

Scientists Find Clues to a Secret of Life

Mar 17, 2009

(PhysOrg.com) -- NASA scientists analyzing the dust of meteorites have discovered new clues to a long-standing mystery about how life works on its most basic, molecular level.

Meteorites rich with information, expert says

Mar 28, 2007

A Purdue University professor on Wednesday (March 28) said at national convention that meteorites hold many clues into the creation and evolution of the solar system. Michael Lipschutz, a professor of inorganic chemistry and ...

Shooting Meteorites in a Barrel

Feb 26, 2010

High-impact lab experiments simulate whether the building blocks of life could have survived the rough arrival on Earth via meteorite impact.

Recommended for you

Cassini sees sunny seas on Titan

18 hours ago

(Phys.org) —As it soared past Saturn's large moon Titan recently, NASA's Cassini spacecraft caught a glimpse of bright sunlight reflecting off hydrocarbon seas.

Is space tourism safe or do civilians risk health effects?

21 hours ago

Several companies are developing spacecraft designed to take ordinary citizens, not astronauts, on short trips into space. "Space tourism" and short periods of weightlessness appear to be safe for most individuals ...

An unmanned rocket exploded. So what?

Oct 30, 2014

Sputnik was launched more than 50 years ago. Since then we have seen missions launched to Mercury, Mars and to all the planets within the solar system. We have sent a dozen men to the moon and many more to ...

NASA image: Sunrise from the International Space Station

Oct 30, 2014

NASA astronaut Reid Wiseman posted this image of a sunrise, captured from the International Space Station, to social media on Oct. 29, 2014. Wiseman wrote, "Not every day is easy. Yesterday was a tough one. ...

Copernicus operations secured until 2021

Oct 30, 2014

In a landmark agreement for Europe's Copernicus programme, the European Commission and ESA have signed an Agreement of over €3 billion to manage and implement the Copernicus 'space component' between 2014 ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

scidog
1 / 5 (1) Aug 08, 2011
why need a meteorite when a forming earth would have been made from the same materials?at what point in attraction material to it's surface would the "magic rock" that started life arrive?
rwinners
1 / 5 (3) Aug 09, 2011
"These results have far-reaching implications. The earliest forms of life on Earth may have been assembled from materials delivered to Earth by meteorites."

They may have, indeed.
HenisDov
1 / 5 (4) Aug 14, 2011
DNA "Life Building Block"?

Meteorites contain chemicals linked to life
Space rocks could have delivered DNA building blocks to Earth.
http://www.scienc..._to_life

No end to pious obsequious AAAS trade-union religion devotees

Its time for introversion:

RNAs are Earths primal organisms.
Each and ALL other Earths self-replicating bio formats-conformations are products of evolution of RNAs.
Earths life has always been and still is an RNA world!

Dov Henis
(comments from 22nd century)
http://universe-l...olution/

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.