Experiment on the origin of life on Earth repeated. A new, surprising factor has appeared

 

"In what conditions did the first organic molecules on Earth arise? Researchers have repeated a groundbreaking experiment from the 1950s. The results indicate a possible, important role for so-called microdischarges in water drops. What exactly was examined and what results were obtained?

 

According to researchers, microdischarges in water drops could have given rise to the first organic matter on Earth

 

A study published on March 14 in the journal "Science Advances" describes a new version of the so-called Miller-Urey experiment, conducted in the 1950s. The latest version of the experiment obtained a similar result, but a new, surprising factor has appeared.

 

How did life arise on Earth? The famous experiment from the 1950s

 

In 1953, two American chemists created a mixture of gases that imitated the composition of the Earth's primordial atmosphere. Researchers Stanley Miller and Harold Urey combined water (H2O), methane (CH4), ammonia (NH3) and hydrogen (H2) and then enclosed them in a sterile system of two glass flasks. The system also included electrodes, between which electrical discharges were passed. The entire system was to simulate the conditions in which the first life on Earth could theoretically have arisen. The experiment produced simple amino acids containing carbon and nitrogen. Similar experiments – with various modifications – were carried out in subsequent years.

 

New version of the experiment. The role of an energy catalyst

 

The authors of the latest version of the experiment repeated the study from the 1950s by mixing ammonia, methane, nitrogen and carbon dioxide. This time, attention was paid to the issue of electrical activity on a “micro” scale. Scientists sprayed the gas mixture with water mist. Thanks to a high-speed camera, it was possible to capture weak micro-electric discharges during this process. - Large drops are positively charged. Small drops are negatively charged. When drops with opposite charges are close together, electrons can jump from the negatively charged drop to the positively charged drop, explains Dr. Richard Zare, a professor of chemistry at Stanford University in California, to CNN.

 

The study authors looked closely at the exchange of electricity between water drops with a diameter of 1 micron to 20 microns, which is much smaller than, for example, the diameter of a human hair (about 100 microns). After the process was completed, the contents of the test tube were examined, which found organic molecules such as glycine (a simple amino acid) and uracil (a nitrogenous base that is part of RNA nucleotides). "For the first time, we saw that small droplets, when they were created from water, actually emit light and create a spark," explains Dr. Zare. He adds that this spark could have initiated various chemical changes, key to the formation of organic matter.

 

Water, micro-discharges and the beginnings of life

 

Dr. Amy J. Williams from the University of Florida also draws attention to the role of an "energetic catalyst" in the possible process of the origin of life on Earth. The expert explains on CNN that the formation of amino acids, the key building blocks of life, requires nitrogen atoms. However, releasing them from nitrogen gas requires enormous energy. "(...) a micro-discharge has the energy to break molecular bonds and thus facilitate the generation of new molecules, which are key to the origin of life on Earth," the expert sums up.

 

According to the authors of the study, the results of the latest experiment may change the idea of ​​the beginnings of life on our planet. There are several main hypotheses in the scientific community with possible scenarios for the origin of primordial organic matter. They concern, for example, the role of hydrothermal vents on the seabed or particles of matter that came to Earth thanks to the debris of comets and asteroids. The hypothesis of the key role of atmospheric discharges is also being considered. However, some scientists have doubts whether in the primitive environment of the Earth these discharges were frequent enough to influence the "production" of organic matter. The theory of microdischarges may turn out to be a more likely scenario. Dr. Zare directly proposes calling it "a new mechanism of prebiotic synthesis of molecules that constitute the building blocks of life"."