Nowadays, scientists think they have a pretty good idea of the composition of the universe. By detecting revealing signatures of various elements in celestial bodies such as stars, asteroids and other planets, scientists can estimate the abundance or rarity of each of the known elements. Iron, however, has proven difficult to fix.
We know that iron is abundant on Earth as well as in the stars, where the intense heat allows it to exist in the form of gas. This suggests that the element should also exist in relative abundance in the interstellar medium – the space between the star systems of galaxies such as the Milky Way – but scientists have not detected much. So where is it? A new study published in the Astrophysical Journal could have the answer.
The "missing" iron is not lacking at all, say the researchers. The research team of Arizona State University in partnership with WM The Keck Foundation now says that it is likely that iron exists in the form of iron pseudocarbynes, which is a combination of iron molecules and carbon.
Carbon is known to be abundant in interstellar space, and the team said it would be easy to disregard ferrous pseudocarbons when looking for it. These molecular chains of carbon and iron seem identical to carbon molecules from a distance, which prevents us from saying how much carbon visible to scientists also hides iron.
"We have calculated what the spectra of these molecules would look like, and we found that they had spectroscopic signatures almost identical to the iron-free carbon chain molecules," said Pilarasetty Tarakeshwar, of the Faculty of Molecular Sciences of the United States. # 39; ASU. "The previous astrophysical observations could have neglected these carbon-iron molecules."
If the theory turns out to be correct, the iron that scientists were looking for between the star systems is essentially hidden, we just do not see it.