Vitamin B3 is an essential part of our diet. Its deficiency in humans can lead to nausea, anemia and tiredness. Fortunately, it can be gobbled up from sources such as salmon, avocados and nuts, but now scientists are eager to find out if there's another unexpected source: space.
A team of researchers thinks that Vitamin B3 could have been made on icy dust grains in the depths of space. It would, in this scenario, have been delivered to Earth via cosmic delivery service, on the structures of comets and asteroids.
These predictions come from analysis of meteorites. Past research has shown that vitamin B3 is present on carbon-rich meteorites in ratios between 30 and 60 parts-per-billion. The team decided to try to recreate the formation of vitamin B3 in space-like conditions. They used a mixture of gases, including pyridine, which can be found in space in carbon dioxide ice. Pyridine is one of the building blocks for vitamin B3, so the team was interested to see if it could manifest itself as vitamin B3 in these space-like conditions. The results from the experiments were promising.
"We found that the types of organic compounds in our laboratory-produced ices match very well to what is found in meteorites," said Karen Smith from NASA. "This result suggests that these important organic compounds in meteorites may have originated from simple molecular ices in space. This type of chemistry may also be relevant for comets, which contain large amounts of water and carbon dioxide ices. These experiments show that vitamin B3 and other complex organic compounds could be made in space and it is plausible that meteorite and comet impacts could have added an extraterrestrial component to the supply of vitamin B3 on ancient Earth."
This has implications for the origins of life on Earth, because many structures essential to metabolism rely on vitamin B3. It might be possible that vitamin B3 from space helped to fast-forward the formation of life on Earth, and this could have implications for how life may form on other planets.
A picture of the aluminum plate with a chemical deposit on it. Karen Smith/NASA Goddard.
To test this, the researchers cooled an aluminum plate to –253oC (–423oF) in a vacuum to replicate the freezing environment of space. The team observed how gases containing water, carbon dioxide and pyridine froze onto the plate. The plate was then bombarded with protons to mimic space radiation that would give the gas mixture the energy to create reactions.
When the sediment formed on the plate they found a wide range of complex molecules, including vitamin B3. This is an exciting result, although it is far from proving that vitamin B3 on Earth originated from space. The next stage for these researchers will be to wait for someone to find some B3 out in space.
For example, the Rosetta orbiter that is circling comet 67P (the one that the Philae lander is sitting on, struggling to wake up) "could help validate these experiments if it finds some of the same complex organic molecules in the gases released by the comet or in the comet’s nucleus," said Smith.