Ingredients for life revealed in meteorites that fell to Earth

Ingredients for life revealed in meteorites that fell to Earth
Blue halite and tweezer tips for scale. Credit: Dr. Queenie Hoi Shan Chan

Two wayward space rocks, which separately crashed to Earth in 1998 after circulating in our solar system's asteroid belt for billions of years, share something else in common: the ingredients for life. They are the first meteorites found to contain both liquid water and a mix of complex organic compounds such as hydrocarbons and amino acids.

A detailed study of the chemical makeup within tiny blue and purple salt crystals sampled from these meteorites, which included results from X-ray experiments at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), also found evidence for the pair's past intermingling and likely parents. These include Ceres, a dwarf planet that is the largest object in the asteroid belt, and the asteroid Hebe, a major source of meteorites that fall on Earth.

The study, published Jan. 10 in the journal Science Advances, provides the first comprehensive chemical exploration of and liquid water in salt crystals found in Earth-impacting meteorites. The study treads new ground in the narrative of our solar system's early history and asteroid geology while surfacing exciting possibilities for the existence of life elsewhere in Earth's neighborhood.

"It's like a fly in amber," said David Kilcoyne, a scientist at Berkeley Lab's Advanced Light Source (ALS), which provided X-rays that were used to scan the samples' organic chemical components, including carbon, oxygen, and nitrogen. Kilcoyne was part of the international research team that prepared the study.

While the rich deposits of organic remnants recovered from the meteorites don't provide any proof of life outside of Earth, Kilcoyne said the meteorites' encapsulation of rich chemistry is analogous to the preservation of prehistoric insects in solidified sap droplets.

Queenie Chan, a planetary scientist and postdoctoral research associate at The Open University in the U.K. who was the study's lead author, said, "This is really the first time we have found abundant organic matter also associated with that is really crucial to the origin of life and the origin of complex in space."

She added, "We're looking at the organic ingredients that can lead to the origin of life," including the amino acids needed to form proteins.

Ingredients for life revealed in meteorites that fell to Earth
A blue crystal recovered from a meteorite that fell near Morocco in 1998. The scale bar represents 200 microns (millionths of a meter). Credit: Queenie Chan/The Open University, UK

If life did exist in some form in the early solar system, the study notes that these salt crystal-containing meteorites raise the "possibility of trapping life and/or biomolecules" within their salt crystals. The crystals carried microscopic traces of water that is believed to date back to the infancy of our solar system - about 4.5 billion years ago.

Chan said the similarity of the crystals found in the meteorites - one of which smashed into the ground near a children's basketball game in Texas in March 1998 and the other which hit near Morocco in August 1998 - suggest that their asteroid hosts may have crossed paths and mixed materials.

There are also structural clues of an impact - perhaps by a small asteroid fragment impacting a larger asteroid, Chan said.

This opens up many possibilities for how organic matter may be passed from one host to another in space, and scientists may need to rethink the processes that led to the complex suite of organic compounds on these meteorites.

Ingredients for life revealed in meteorites that fell to Earth
Artist's rendering of asteroids and space dust. Credit: NASA/JPL-Caltech

"Things are not as simple as we thought they were," Chan said.

There are also clues, based on the organic chemistry and space observations, that the crystals may have originally been seeded by ice- or water-spewing volcanic activity on Ceres, she said.

"Everything leads to the conclusion that the origin of life is really possible elsewhere," Chan said. "There is a great range of organic compounds within these meteorites, including a very primitive type of organics that likely represent the early solar system's organic composition."

Chan said the two meteorites that yielded the 2-millimeter-sized salt crystals were carefully preserved at NASA's Johnson Space Center in Texas, and the tiny crystals containing organic solids and water traces measure just a fraction of the width of a human hair. Chan meticulously collected these crystals in a dust-controlled room, splitting off tiny sample fragments with metal instruments resembling dental picks.

"What makes our analysis so special is that we combined a lot of different state-of-the-art techniques to comprehensively study the organic components of these tiny ," Chan said.

Ingredients for life revealed in meteorites that fell to Earth
Ceres, a dwarf planet in the asteroid belt pictured here in this NASA-produced false-color image, may be the source of organic matter found on two meteorites that crashed to Earth in 1998. Credit: NASA

Yoko Kebukawa, an associate professor of engineering at Yokohama National University in Japan, carried out experiments for the study at Berkeley Lab's ALS in May 2016 with Aiko Nakato, a postdoctoral researcher at Kyoto University in Japan. Kilcoyne helped to train the researchers to use the ALS X-ray beamline and microscope.

The beamline equipped with this X-ray microscope (a scanning transmission X-ray microscope, or STXM) is used in combination with a technique known as XANES (X-ray absorption near edge structure spectroscopy) to measure the presence of specific elements with a precision of tens of nanometers (tens of billionths of a meter).

"We revealed that the organic matter was somewhat similar to that found in primitive meteorites, but contained more oxygen-bearing chemistry," Kebukawa said. "Combined with other evidence, the results support the idea that the organic matter originated from a water-rich, or previously water-rich parent body - an ocean world in the early solar system, possibly Ceres."

Kebukawa also used the same STXM technique to study samples at the Photon Factory, a research site in Japan. And the research team enlisted a variety of other chemical experimental techniques to explore the samples' makeup in different ways and at different scales.

Chan noted that there are some other well-preserved crystals from the meteorites that haven't yet been studied, and there are plans for follow-up studies to identify if any of those crystals may also contain water and .

Kebukawa said she looks forward to continuing studies of these samples at the ALS and other sites: "We may find more variations in organic chemistry."

Explore further

Unlocking the organic composition of ancient asteroids

More information: "Organic matter in extraterrestrial water-bearing salt crystals," Science Advances (2018).
Journal information: Science Advances

Citation: Ingredients for life revealed in meteorites that fell to Earth (2018, January 10) retrieved 22 September 2019 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Feedback to editors

User comments

Jan 10, 2018
Now it is my (unproven) opinion that Living Worlds such as Earth, are very few and very far. In both time and space.

However, the good news is that research as described in this article offers physical, verifiable, empirical evidence, that the resources to develop and sustain a planetary biosphere are a possibility for many of the stable Sol-type star systems.

This article does not confirm speculation that Living Worlds are common or even exist yet. This is just one more rung on a cosmically high ladder to discover positive proof or disproof or both.

Jan 10, 2018
"such as Earth"...
You mean 'rocky planets' rather than water worlds or moons ??

Jan 11, 2018
Really, really, really now.

There's a vast gulf between discovering some ingredients for life and actually having biological life in a rock.
Even if you have ALL the ingredients you still need to have them ARRANGED in the correct order. PLUS, you then have to kick off the life process itself in the right order everywhere it needs to be.

Let's take a simple amoeba that has just died of some non-violent cause, e.g. radiation overdose.
It mostly contains ALL the ingredients required for life, yet it's completely DEAD, with no way to come to life by ANY random means, all by itself with no outside help.

So if that amoeba cannot get back to life even with many, many more fully arranged ingredients of life, what chance does the isolated, disjointed and disconnected ingredients in a meteor have of popping into life all by itself?

Really, really, really. The mind boggles at the absolute (and almost idiotic) desperation to have life without an intelligent, powerful life-giver.

Jan 11, 2018
Really, really, really. The mind boggles...

My mind boggles at your absolute (and almost idiotic) desperation to have life with an intelligent, powerful life-giver.

Jan 11, 2018
Really, really, really. The mind boggles at the absolute (and almost idiotic) desperation to have life without an intelligent, powerful life-giver.

And the mind boggles at the lunacy of creationists. Who created the creator? At the end of the day, however you cut it, your inane beliefs come back to a reliance on supernatural woo. It isn't science.

Jan 14, 2018
N_2 : "such as Earth"...
You mean 'rocky planets' rather than water worlds or moons ??

No, I specifically mean Earth Planetary Type. As in our own star system, most all "rocky planets" will be lifeless failures. The randomness of reality dictates, like any other casino, there are few winners and a whole lot of losers.

An Earth Type world sustains a biosphere over billions of years. Within a limited mass range of 20/30% +/- 1G).

With a stable orbit in the GZ around it's sun. Have a strong magnetic shield due to an active iron core. Have a stable, moderately energetic Sun similar to Sol. That has not wandered out of the safe zone while orbiting the galaxy.

And I am talking about billions of years. Mars may have briefly produced life, maybe? But lacked all the other necessities to sustain a biosphere. So that gives us a minimum, a floor to our standards.

Even if we get lucky and discover any Living Worlds? Their biology will prove sophisticated alien.

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