CAMBRIDGE, MASSACHUSETTS — A recent attempt to explain the origins of Oumuamua, the first interstellar object ever detected passing through our Solar System, has been countered by two Harvard astrophysicists, one of whom, Avi Loeb, has famously suggested that it could be a piece of alien technology, according to SciTechDaily.
Detected on October 19, 2017, Oumuamua was initially difficult to categorize, before the “nitrogen iceberg” theory of the object emerged and satisfied many scientists.
That theory, presented in the AGU Journal of Geophysical Research: Planets, suggested the 45-meter object appears to be made of frozen nitrogen, like the surface of Pluto.
Astrophysicists behind it said Oumuamua likely ejected from the surface of a Pluto-like exoplanet during a collision half a billion years ago and, what’s more, this type of collision was common enough to satisfy the statistical likelihood of Oumaumua being detected in our solar system.
This origin story would explain Oumuamua’s strange, flat shape, as its outer layers would have been evaporated by cosmic radiation, and it would also explain why, like a comet, Oumuamua sped up erratically as it approached the Sun and sunlight vaporized the ices it is made of.
However, SciTechDaily explains that Harvard astrophysicists have cast doubt over this theory because it requires the existence of too many Pluto-like exoplanets.
Writing in the New Astronomy journal, they say Oumuamua’s size, plus the number of theoretically similar objects required to make its discovery likely, requires much more nitrogen than is predicted to exist in the universe, according to Live Science.
The new paper explains that pure nitrogen is rare — in our solar system it has been found on Triton and Pluto, where it represents around 0.5 percent of the total mass of the dwarf planet, and star systems likely do not contain enough nitrogen ice to allow for such a large population of Pluto-like exoplanets or the theoretically abundant nitrogen ice Oumuamuas they might produce.
This counter-position itself is now controversial, though, with one of the authors of the original nitrogen theory, Steven Desch, telling Universe Today that the estimates of the number of likely Oumuamua-equivalents used by the Harvard astrophysicists was too high, and as a result, so was their estimate of the amount of nitrogen required to create them.
Desch explained that with a lower estimate of the total number of Oumuamua-equivalents floating around in space used in the original theory, a lower amount of nitrogen is required to exist, and thus so is a more reasonable number of Pluto-like exoplanets.
“They are attempting to manufacture controversy when none exists,” he added.