Extraterrestrial Amino Acids - CM2 Carbonaceous Chondrites
Extraterrestrial Amino Acids - CM2 Carbonaceous Chondrites
Above: The front of the specimen card
Each year nearly 40,000,000 kilograms (88.1 million pounds) of meteoritic material rains down on the Earth from outer space. Less than 1% of these falls holds traces of organic compounds, and within this tiny subset scientists sometimes come across even rarer material: amino acids.
Above: Working on samples of the Murchison meteorite.
Crafted in our workshop, this specimen is composed of two special carbonaceous chondrites: Murchison and Jbilet Winselwan. The specimen measures roughly 1.5cm in length or three times the size of the specimen included in the Fourth Edition Mini Museum.
Above: Preparing specimens. Each sheet is made by hand.
Both of these meteorites are CM2 class carbonaceous chondrites, a class known to contain the highest density of amino acids. Murchison in particular is one of the most studied of all meteorites, displaying over 70 different amino acids, including 8 of the 20 proteinogenic amino acids used to build proteins encoded in our DNA found in all life here on Earth.
Above: The Extraterrestrial Amino Acids (CM2 Class Carbonaceous Chondrites) Specimen with two fragments of the Murchison meteorite.
The specimen is housed in an acrylic jar that is encased within a glass-topped riker display box. The box measures 4 1/2" x 3 1/2". A small information card is also included, which serves as the certificate of authenticity.
Please Note: The distribution of the meteoritic material in each specimen will be unique. Product images are representative samples. The approximate size is 2 cm wide by 1 cm tall (e.g. twice the size of the specimen in the Fourth Edition).
More about the Murchison Meteorite and CM2 Class Carbonaceous Chondrites
"The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff." ~ Carl Sagan, Cosmos, 1980
Above: An early solar system (Image Credit: NASA's Goddard Space Flight Center courtesy of NASA/JPL-Caltech)
At 10:58 am on September 28th, 1969, a bright fireball appeared in the sky near the small, riverside town of Murchison, Australia. Under tremendous stress, the bolide separated into three main pieces, spreading fragments across 13 square kilometers (5 sq mi), including one lump which crashed through a barn roof and landed in a pile of hay.
As astronomical as the odds might be for this soft landing, the Murchison meteorite would turn out to be literally one of the rarest of all meteorite finds: a remnant formed at the very birth of the solar system, which also happened to carry the building blocks of life.
Known as a carbonaceous chondrite, this type of meteorite is distinguished by calcium–aluminum-rich inclusions (CAI), minerals that are among the first solids to condense in the high-temperature gases of a young, protoplanetary disk. In addition to CAIs, Murchison also carries a fantastic array of more than 70 different amino acids, including 8 of the 20 proteinogenic amino acids used to build proteins encoded in our DNA as well as all life here on Earth.
Above: CM2 Carbonaceous Chondrites Murchison and Jbilet Winselwan.
Since the discovery of amino acids in the Murchison meteorite, scientists have discovered that other carbonaceous chondrites also contain amino acids. Recent studies suggest that the amino acids present in these meteorites may even pre-date the formation of the solar system. Further studies have revealed that the diversity of amino acids in a particular meteorite can be used to study the original parent or "host body" and how geological processes (including aqueous alteration) may have enriched these early organic chemicals prior to the emergence of life in this solar system.
If you are interested in learning more about this fascinating process, we highly recommend reading this 2016 study, "Meteoritic amino acids: diversity in compositions reflects parent body histories." Led by Dr. Jamie Elsila (Cook), an astrochemist with NASA Goddard Space Flight Center’s Solar System Exploration Division, the study walks through the entire process and talks about other types of meteorites which also carry amino acids.
Even now, after decades of study, the Murchison meteorite continues to surprise science with new discoveries. The latest is that materials in this meteorite are likely far, far older than our own solar system. Billions of years older, in fact.
In "Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide", scientists at the Field Museum in Chicago, studied cosmic ray exposure of silicon carbide grains extracted from samples of the Murchison meteorite. In 12 samples, they discovered strong evidence that these grains originated in stars formed roughly 7,000,000,000 years ago and were parts of aggregates traveling through the Interstellar Medium.
"Interstellar dust is an important component of our galaxy. It influences star formation as well as the thermal and chemical evolution of the galaxy. Although dust only presents ∼1% of the mass in the interstellar medium (ISM), it carries a large fraction of the elements heavier than Helium, including the elements that form terrestrial planets and are essential for life. Thus, interstellar dust is a key ingredient of stars and habitable planetary systems, making increased knowledge about its composition and lifecycle desirable."
Whether any of these particular grains are in a single specimen is hard to say but it is incredible to think about!
Further Reading
Elsila, Jamie E., et al. "Meteoritic amino acids: diversity in compositions reflects parent body histories." ACS central science 2.6 (2016): 370-379.
Taylor, G. J. "Wet, Carbonaceous Asteroids: Altering Minerals, Changing Amino Acids." Planetary Science Research Discoveries Report (2011).
Above: The back of the specimen card.