I saw four shooting stars this morning! It was the last of the Perseid display so I hauled myself out of bed and sat on the grass under a clear, pre-dawn sky.
Sitting there surrounded by trees, it was hard to imagine that Earth was once as barren as Mars. How did life get started? There are several credible hypotheses , but watching meteorites fall to earth brought to mind the recent news that nucleobases have been found on meteorites.
What’s a nucleobase and why is that a big deal? You’ve heard of the famous nucleobases. They go by the nicknames A, G, C and T, and are the building blocks of DNA – the molecule that carries the code for life as we know it. Some of our DNA’s nucleobases were found in the meteorites, but more intriguing were the “related but exotic nucleobases never seen before,” according to NASA, as reported by the Washington Post.
Furthermore, the exotic molecules were absent from the surrounding dirt and ice. “The detection of the exotic nucleobases, and their absence from surrounding material, helped rule out contamination,” the Post continued.
The NASA team led by Michael Callahan have also shown by experiment that it’s fairly simple to produce nucelobases from ammonia, water and hydrogen cyanide, which are all found on meteorites.
Although nothing is proven, it’s eerie to think that the building blocks of life might have arrived on this planet from the same sorts of meteorites I saw this morning.