Scientists now claim proof that life came from space
Scientists now claim proof that the seeds of life on Earth came from space.
- How did life first arise on Earth?
- Life from space?
- Proof of extraterrestrial life?
- The odds for intelligent extraterrestrial life
How did life first arise on Earth?
Scientists experimenting with simulations of the conditions on the early Earth have long been able to create simple organic molecules but the creation of complex proteins and the components of DNA, the building blocks of life, have so far eluded them. A long held theory has been that the seeds of life may have come from space, contained in comet fragments and meteorites. Spectrometry has found complex organic molecules, including alcohols, in clouds in space but, until recently, there has been no proof of the components for life arriving on Earth from space.
Life from space?
Scientists searching for the components of life of extraterrestrial origin on a planet full of life in every nook and cranny face the problem of potential sample contamination. Extreme care is required to combat this. In 2006, researchers found amino acid molecules, the molecules essential for the formation of proteins, in the Wild2 meteorite. This spurred a study of 12 different meteorite samples, 9 taken from the pristine environment of Antarctica, an area of increasing importance in ancient meteorite research.
During the study, the researchers found organic molecules, some of which are extremely rare on our planet and which were not found in the Antarctic ice so could not have infiltrated the rock from this source. The samples also contained a heavy form of carbon, not found on Earth, as well as molecules of adenine and guanine, two of the four components (along with thymine and cytosine) necessary for the formation of DNA. The meteorites studied fell to Earth around four billion years ago, around the period when the first forms of life arose.
When finally published on Monday, August 8, 2011, the study confirmed that most, if not all the molecules existing on Earth that provide the source for DNA, are of extra-terrestrial origin. This does not mean that organic molecules may not already have been present on the early Earth but the influx of complex organics from space certainly encouraged the genesis of early life. Essentially, the researchers are stating that life on Earth came from space.
Proof of extraterrestrial life?
There is a wider significance, however, than simply how life may have started on Earth. If amino acids and the components of DNA m came to Earth in space rocks billions of years ago, how did they get into the rocks in the first place?
Are they rock from planets already bearing life based on similar components: rock blasted into space by impact with a large meteorite (in the same way as the meteorites of Martian origin found in Antarctica) or from an extra-terrestrial super-volcano or even a planetary explosion? This would mean that there were or are life-bearing planets relatively close by.
Are organic molecules incorporated into the grains of stony material formed in the galactic dust clouds, and the planets that ultimately form from these, already seeded with the building blocks of life? Meteorites as bringers of life are just icing on the cake in this instance: the seeds of life were already there. Complex organic molecules have been detected in galactic clouds, including a variety of alcohols – celestial cocktail parties must really be something!
The odds for intelligent extraterrestrial life
If life molecules are present in meteorites that may have traversed the depths of space for billions of years before plunging to near extinction in Earth’s atmosphere, this could mean, of course, that life may have evolved very early in the Universe, aeons before life on Earth.
If the building blocks of life as we know it have been around for such a long time, this must increase the odds that sentient life exits elsewhere in the Universe, indeed, life could be everywhere. The science fiction writers may be right: the galaxy may be full of sentient life in a wide variety of forms (albeit, all represented as vaguely humanoid for ease of portrayal). Let us hope that other sentient life exhibits more intelligence and maturity than the human version.
This raises the possibility that life may have been seeded on Earth aeons ago by sentient beings … and for what purpose?