NASA astronomers have notched up another victory in their continuing quest for extra-terrestrial life. For the first time the ingredients that make up life as we know it have been found in superhot meteorites.
Amino acids inside meteors
The new study—outlined in 20 research papers published in the Meteoritical Society’s journal “Meteoritics and Planetary Science”—recognizes that amino acids precede proteins and have been discovered in a number of carbonaceous meteorites in the past. That material, however, was embedded inside relatively cool rocks. The newly analyzed fragments discovered during a 2008 expedition to the northern region of Sudan found meteoric samples subjected to intensely high heat.
The study leader, Daniel Glavin, an astrobiologist at NASA’s Goddard Space Flight Center in Maryland, spoke with NationalGeographic.com and explained, “Previously, we thought the simplest way to make amino acids in an asteroid was at cooler temperatures in the presence of liquid water,” Yet the study proved the assumption wrong. Instead, the astrobiologist explained, “This meteorite suggests there’s another way involving reactions in gases as a very hot asteroid cools down.”
Therefore, the landmark study has revealed something very exciting in the search for life “out there.” No longer do scientists need to concentrate only on cooler meteoric fragments. The chemical soup of life survives even the extreme heat of atmospheric friction during the headlong plunge into planetary atmospheres.
When analyzed, the Sudan fragments were found to have been subjected to 2,000 degrees Fahrenheit. When solar objects reach such incendiary temperature the thought was that any shred of organic material inside would be destroyed. Yet the Goddard team discovered that organic substances can—and do—survive.
Cosmic billiards
The winding path the meteor fragments took through the solar system before arriving on the surface of the Earth is stunning and a windfall for exobiological research.
The Sudan meteoroid fragments originated from a tiny asteroid about 13-feet across. Astronomers were able to calculate that approximately 15 million years in the past the asteroid’s orbit caused it to collide with a much larger object. That collision tossed the 59 ton rock into an orbit much closer to Earth. Scientists took advantage of their good luck and for the first time in history were able to track and observe a minuscule asteroid as it approached the planet during 2008.
When the asteroid crossed the Earth’s orbit it was captured by gravity and began its plunge into the upper atmosphere where it exploded. Through careful tracking, some of the fragments were seen to land in the northern region of Sudan.
An expedition sent to collect the fragments found almost 600 identifiable fragments that had survived the spectacular meteor shower.
ET seeding
For many years scientists have hypothesized that Earth and other planets may have been seeded with life by deep space comets and asteroids. The meteoric samples analyzed for the study lend credence to that idea for they “provide additional support for the theory that life’s ingredients were delivered to the Earth by asteroids,” Galvin told National Geographic.
“Finding evidence for the extraterrestrial amino acids in this meteorite is a big deal,” the scientist was quoted during the interview, “since we can learn about the chemistry that took place in space prior to the origin of life on Earth.”
Galvin is excited about the prospect of future research along these lines because, “these meteorites would have contributed to the amino acid inventory of the early Earth and other planets in our solar system, including Mars.”
As the study points out, the organic compounds needed to ignite life could very well have been transported through the solar system—or even via interstellar means—and may be many times more common than once thought.
