Researchers Making Strides in Recreating the Origins of Life
Some 4.5 billion years ago, the newly formed planet Earth was devoid of animals, plants, and bacteria. Yet, just a few hundred million years later, the first primitive life forms emerged. How exactly this happened has long puzzled scientists, but recent advancements may bring us closer to understanding what sparked the origins of life. Researchers are now making strides in recreating the process in the lab.
During the early stages of Earth, the conditions were too inhospitable for life to thrive. Violent volcanic eruptions released hydrogen sulphide into the atmosphere, there was a lack of oxygen, and the planet faced frequent bombardment from asteroids. However, fossil records indicate that around 3.7 billion years ago, Earth became a more welcoming place as simple single-celled organisms appeared. The question is, how did these first life forms come to be?
Scientists generally agree that for life to exist, certain conditions must be met: organic, carbon-containing compounds like methane, water, and a source of energy. This combination would initiate the chemical reactions necessary to form more complex molecules such as amino acids, the building blocks of proteins, and RNA, a nucleic acid present in all living cells with structural similarities to DNA. The mystery lies in what provided the initial spark, and if it is possible to recreate it.
One theory suggests that intense ultraviolet radiation and lightning on the early Earth could have supplied the necessary energy for amino acids and, later on, molecules like DNA and RNA to form in the oceans. In 1952, researchers Stanley Miller and Harold Hey conducted an experiment attempting to recreate the atmospheric conditions of early Earth. They introduced ammonia, methane, and water vapor into a sealed container and passed an electrical spark through it, simulating a lightning strike. Astonishingly, amino acids spontaneously formed. However, subsequent research revealed that the atmospheric conditions modeled by Miller and Hey were unlikely to have existed on Earth at the time. Another challenge is the presence of ice covering most of the planet for four billion years, making lightning strikes rare in those conditions.
Nevertheless, Jeffrey Bada, a marine chemistry professor at the Scripps Institution of Oceanography, offers a different perspective. Bada, a former student of Miller, believes that lightning could have occurred within volcanic ash clouds. He points to instances like the 2022 eruption of the underwater volcano Hunga Tonga–Hunga Haʻapai, where intense lightning storms were observed after a mix of gases, ash, and seawater vapor were released into the atmosphere.
Bada suggests that the early Earth contained numerous small volcanic islands that erupted violently, resulting in frequent lightning storms. These conditions could have contributed to the formation of amino acids and kickstarted the development of early life forms.
While there is still much to learn about the origins of life on Earth, researchers are continually making progress in uncovering the mysteries surrounding this fundamental process. By recreating and refining experiments, scientists hope to gain insights into the fascinating journey from a lifeless planet to a teeming biosphere.