Scientists have long theorized that the “magic spark” that created life on Earth may have come from meteors plunking into our primordial soup. Wired News reports that a team of Japanese scientists has set up a teeny tiny scale model which offers proof of concept that meteors could in fact have done the deed.
The origin of life on Earth has been the subject of popular myth, scientific theory, and religious debate for as long as myth, science, and religion have existed. The modern era for this line of scientific inquiry began early in the 19th century, when Italian scientist Francisco Redi disproved the prevailing theory of "spontaneous generation." The theory of spontaneous generation held that living animals arose from decaying organic material. Redi prevented flies from accessing a pile of rotting meat, thus proving that maggots did not spontaneously arise from the meat itself. Spontaneous generation sounds kooky to us today, but there’s no getting around the fact that at one point, the Earth was just one big, empty lump of rock. It has long been speculated that some or all of the chemicals necessary for life were carried to Earth by meteors. In the Late Heavy Bombardment or "lunar cataclysm" between 3,800 and 4,100 million years ago, the Earth (and the moon, and all the other planets in the solar system) suffered an extensive period of meteor strikes. The specific cause for this increase in meteor activity is unknown, but it would have both deposited large amounts of interstellar material on our planet, and made it a very tough place for wee little organisms to take hold. There is no single agreed-upon theory as to how life arose from early conditions on the planet. Before a living organism can arise, the basic building blocks of its biology have to form. But which came first, the cell membrane, or the DNA which it contains? In other words, proteins first, or nucleic acids? Scientists have argued all sides of this debate for many years. Recently, a team of Japanese scientists decided to throw their hat into the ring. The scientists constructed a microscopic scale model of the conditions they speculated were present on Earth, then used a propellant gun to shoot mock meteors (pellets of iron and carbon) into the "soup." The impact of the pellets generated temperatures as high as 5,000 degrees Fahrenheit, and caused fatty acids, amines, and amino acids to form. Although they have not yet repeated their experiment, and a number of scientists have criticized their methods and findings, the Japanese team’s results are intriguing. If the recipe for basic organic molecules is "(water + ammonia) + meteors" these conditions are not rare. Closest to home, NASA recently announced solid proof that Mars has water now, and was wet in the distant past. Farther from home, who can say? It appears that the Late Heavy Bombardment affected our solar system at just the right time. We still don’t know the causes or origin of the LHB, but meteors hit planets all the time. Based on this most recent experiment, maybe the origination of life isn’t as unusual an event as one might think. Photo courtesy Wired News/Yoshihiro Furukawa