On September 28, 1969, when the people of Murchison, Australia were preparing to go to the church, at around 10:48 a.m., an orange fireball appeared in the sky, accompanied by a trail of blue smoke. to the ground. A few minutes later, this asteroid fell in the area near Murchison and made a huge noise, fortunately no one was injured except for a damaged barn roof.
And the emergence of the Murchison meteorite has spurred scientists’ understanding of human history and helps us to better understand the question: The chemical composition of life is derived from evolution. of the Earth or from space?
The stardust particles in the Murchison meteorite are the oldest solid matter on Earth. Some particles are up to 7 billion years old, however, the Sun in our solar system is only 4.6 billion years old. Therefore this asteroid is thought to have formed during the star-stellar period.
The process of asteroid formation is also extremely complex, they will roam through space and their size will also increase over time. Hence the composition of meteorites includes matter from stars, supernovae and other extraterrestrial fragments. Experts are currently speculating that the history of the Murchison meteorites could be traced back 7 billion years ago.
The Murchison meteorite belongs to the type of carbon chondrite, with 2% carbon content (very rare for meteorites) and small chondrite particles called silicate spheres. The organic matter in meteorite clumped together and smelled like rotten peanut butter.
Chondrites are the first solid matter to condense from the ruins of gas clouds. Gas clouds include star dust that forms the solar system. Chondrites are considered to be the rarest and most primitive space rocks because they rarely appear.
These meteors still retain important information about the birth of the sun, unlike other meteorites, they will be heated causing chemical changes and erasing their tracks.
Stardust particles are made of silicon carbide and will sometimes interact with high-energy cosmic rays and cause silicon to split into neon and helium isotopes. Therefore, scientists can use this feature to calculate its age, then calculate the specific formation time of stardust.
The scientists extracted the silicon carbide spherulites from the meteorite in the laboratory. These samples are then placed on a mass spectrometer. The mass spectrometer heats the silicon carbide spherulites to a certain temperature and then begins to release the gas trapped in the particles. Isotope analysis of the released gases will help determine whether they were produced by the interaction of cosmic rays. By counting the number of neon isotope molecules, scientists can also calculate the age of the meteor material.
Meteors can be said to be the cheapest tool for space exploration because they fall on the surface of the Earth. These rare “stones” provide us with proof of the existence of complex carbon matter in the universe.
Fortunately, the Murchison meteorite was still “fresh” when it fell to Earth, when it was sent to the University of Melbourne, it was still releasing gas and has not been contaminated by ground contact. Given the important research value of this sample, NASA and other research institutions will study and analyze it along with the collected lunar rock samples.
Preliminary studies on meteorites have shown the existence of several important biochemical molecules, such as: amino acids (the basic substance of life), glycine, alanin, proline, valine and 4 amino acids. Other essentials.
Amino acids in meteorite are mixture of raemic (mixture of left-handed molecules and right-handed molecules). They, unlike living organisms, tend only to choose left-handed amino acids.
Amino acid molecules do not have arms like humans, but their structure will not be symmetrical, when you try to stack the amino acid molecules together, you can still see the parts stick out in other directions. together.
Likewise, several complex organic molecules share the same molecular formula, but their binding abilities may differ. These are called “antagonistic molecules” and are distinguished by “prosity”.
After 50 years of intensive analysis, scientists finally discovered that there are several “sweet” molecules in the Murchison meteorite, containing complex sugars and polyols, which are the basic components of DNA and RNA. In addition, there are some bio-essential sugars in meteorites such as dihydroxyacetone (precursor of body enzymes), glycerol (helping to construct cell membranes), and ribose (DNA component).
This discovery has great implications for chemists and biologists, because the chemical pathways of extraterrestrial objects may be the missing link in finding the origin of life.
Some scientists believe that meteors accidentally fell to Earth billions of years ago, the elements most important to life, such as carbon, oxygen, nitrogen, sulfur and hydrogen. thereby being transferred to the surface of the Earth.
This view stems from the Miller-Yuri experiment, which opened up the world of chemistry before the origin of life, a field of chemical evolution that seeks to understand the formation of complex biological substances from simple molecules. .
In 1952, Stanley Miller and professor Harold Yuri designed an experiment to simulate the environment when life on a young Earth began to bloom. In their tool, they recreated an oceanic environment full of primitive elements. It contains a mixture of gases and chemicals, which can create complex life structural chemicals.
After the mixture is heated, it is exposed to light to simulate the heat of the Sun and Earth, and sometimes with sparks to simulate thunder, after several days of continuous operation. of the device, the color of the solution gradually darkens. Tests on the mix showed that many complex chemicals began to form, and some of them were amino acids.
In 1972, Miller continued to refine his device and obtained coded amino acids and various proteins similar to those found in the Murchison meteorite, arousing the curiosity of experts. about trying to trace the original part of life.
It can be said that the Murchison meteorite is like a “time capsule” that can help us understand the characteristics of the early Sun and the chemical composition of the solar system during its formation.
After thousands of years of human civilization, we still cannot answer the question of how simple chemicals turned into complex biology can self-repair and reproduce. .
These ancient black rocks can help us find the right answer. The closer we look, the more we can uncover unknown mysteries, as Carl Sagan said: “The universe is in our hearts. We are made of stars. is a way for us to know ourselves “.