For years, scientists have wondered what role meteorites may have played in the beginnings of life as we know it, thanks in part to a 2008 study that suggested that chemical building blocks in genetic material found on Earth were discovered on a meteorite that hit our planet in the late 1960s. However, another meteorite that flew over the planet earlier this year and trailed fragments across parts of the Western United States, offers a potentially upsetting contradiction to the idea that meteorites seeded Earth with ingredients necessarily to create life.
In April, a meteor explosion scattered space rock across parts of Nevada and northern California. It was tracked at speeds approaching 64,000 mph before it exploded with a force roughly equivalent to a 4-kiloton bomb, reaching temperatures of around 1,3000 degrees Fahrenheit and dumping residue across the area. Thanks to a number of videos, photographs and other sources recording the event — including weather radar data — scientists have managed to gather more than 70 fragments left from the explosion from various locations across the two western states. As expected, scientists have studied the fragments they’ve managed to find from areas including Sutter’s Mill, known as the heart of the California Gold Rush, and even a Mountain View, Calif. parking lot.
According to a report in New Scientist, investigations into the fragments have revealed that theories regarding the amount of organic material that could have been carried to Earth via meteorites in the past may have been flawed — assuming this particular event isn’t a fluke. Researchers investigating fragments collected before a heavy rainstorm have discovered that organics are “less abundant by a factor of 1,000 than in previously studied [similar meteorites].” The team, led by Peter Jenniskens of the Search for Extraterrestrial Intelligence Institute in Mountain View, found that the rocks do contain amino acids, including some not found naturally on Earth. Nevertheless, the three rocks found prior to the rainstorm — an event that essentially bathed the other rocks with contaminated material — showed substantially lower levels of amino acids.
To account for the difference, Jenniskens’ team believes that the organic material may have been destroyed in space as other debris impacted the asteroid, heating it to the point where the material simply ceased to be.
According to Bill Bottke, a scientist at the Southwest Research Institute in Boulder, Colo., the discovery has implications beyond the three rocks. “It shows that not all asteroids can deliver sufficient qualities [of organic materials],” he said in an interview with New Scientist. “One of the disappointments is that, from a prebiotic organic chemistry perspective, it was very limited.”
However, Bottke said the discovery doesn’t necessarily disprove the earlier theories.
“This is an unusual case,” he said. “Most [similar meteorites] are loaded with organic compounds.”