When it appeared that the mysteries of Oumuamua, the first known object of interstellar origin, had been solved, Harvard University astrophysicists Amir Siraj and Avi Loeb, who have advocated the hypothesis that it is an ancient extraterrestrial spacecraft to wander through space, disagreed.

Indeed, a team of academics recently recognized Oumuamua as a “nitrogen iceberg,” which would solve the dilemmas of its enormous reflectivity and seemingly unexplainable acceleration potential.

However, Siraj and Loeb demonstrate in this new paper that this is impossible.

But first, let’s go over the plot. Astronomers initially saw Oumuamua in October 2017, but it was too late: the first object of interstellar origin captured by man had already crossed the Solar System and was about to leave it. Its incredible speed, at 92,000 km/h, already indicated that it had not formed in our system but was rapidly traversing it. Oumuamua hails from a different solar system than our own.

But the real surprise came when Oumuamua, whose shape is flat and elongated, passed close to the Sun. In theory, solar gravity should have slowed it down, but the strange object did the opposite: it passed close to our star and began to accelerate. At that time, it was thought that this acceleration could be due to the evaporation of water or an emission of gases, excited by the heat of the Sun, which would have given it a forward momentum, as happens in many comets. But the astronomers found no evidence that Oumuamua was emitting gas, or steam, or absolutely nothing.

Where then did the energy necessary for acceleration come from?

Furthermore, the experts were unable to ascertain the unusual object’s material composition. Nothing like it had ever been seen before. Furthermore, there was something that shined much brighter than polished metal. Several papers have been read in recent years in an attempt to find a satisfying answer, but each one given had some flaws or was inconsistent.

The ‘definitive solution’

Last March, though, Arizona State University astrophysicists Alan Jackson and Steven Desch provided a “definitive solution.” The researchers reported in two publications that Oumuamua was most likely a nitrogen ice piece that broke off from a Pluto-like planet beyond our Solar System.

Because when Oumuamua drew closer to the Sun, the evaporating nitrogen gas, which is invisible to telescopes, would have pushed the object, giving it the recorded acceleration, the mystery of the invisible propellant was solved. While nitrogen ice is not something that can be observed every day, astronomers know it exists in our Solar System because it has been discovered on Pluto, thus it is not unreasonable to believe that fragments of frozen Nitrogen can be split from the’exo-Pluto’on occasion.

In the universe, there isn’t enough nitrogen

Siraj and Loeb, on the other hand, do not agree with that conclusion and debunk it in their new study. According to the two Harvard astrophysicists, there isn’t enough nitrogen in the universe to construct an object the size of Oumuamua, which is between 400 and 800 meters long and 35 to 167 meters wide.

Pure nitrogen, according to Siraj, is a highly uncommon element that has only been discovered on Pluto, where it makes up around 0.5 percent of the dwarf planet’s entire mass. Even if all of the nitrogen ice in the Universe was scraped from all of the Pluto-like planets projected to exist, there would still be insufficient nitrogen to ‘make’ Oumuamua.

According to Siraj and Loeb, the mass of ‘plutons’ required to make a nitrogen iceberg the size of Oumuamua would exceed even the mass of stars. In fact, it would take, at a minimum, more than 60 times the mass for each existing star that is capable of forming all the planets in our Solar System.

“But that’s crazy,” Siraj said. “It’s preposterous.”

The researchers further explain that they used numerous cautious assumptions in their calculations, including excluding the impacts of cosmic rays, subatomic particles that constantly travel at the speed of light through space and degrade everything they collide with, including objects like ‘Oumaumua. Taking cosmic rays into account, Siraj calculated that it would take around 1,000 times the mass of all the stars in the galaxy to manufacture all the exo-Plutos required to construct ‘Oumuamua.

Jackson and Desch react

However, Jackson and Desch asserted that their meticulous calculation of the number of nitrogen pieces circling in space is not an overestimate and is consistent with earlier research estimating the number of ‘Oumuamua-like particles in space.

“Siraj and Loeb”, Desch told Live Science in an email, “did not find that we made a mistake, and so they should have accepted the numbers we got.”

“Instead, they attempted their own back-of-the-envelope calculation and made a great number of approximations and estimates, and came up with different numbers that they say aren’t favorable.”

For his side, Jackson feels that a very broad error window is required to estimate the number of objects based on a single observation, such as Oumuamua, because astronomers have never seen anything like it.

Siraj and Loeb predicted the mass required to create Oumumua to be extremely large, he explained, “because they used a very high estimate for the number of ‘Oumuamua-like objects in space”.

“They are attempting to manufacture controversy when none exists,” Desch said.

However, according to Siraj, the riddle of ‘Oumuamua remains unsolved. Certain specialists may be impatient to reach conclusions regarding ‘Oumuamua, he said, for as long as the mystery remains, the option of an artificial origin remains open.

“If it’s still unexplained, you have to consider all possibilities.”

But that’s what makes ‘Oumuamua so fascinating, he added.

“I don’t really care what it is, because every single possibility is an astrophysical object we’ve never seen before, so that’s why it’s exciting.”

Thus, the Oumuamua controversy persists. And it is unlikely to be addressed until astronomers discover another object comparable to Oumuamua and can examine it for a longer period of time than was feasible with Oumuamua.

Image Credit:

You were reading: The bizarre cigar-shaped intruder called ‘Oumuamua’ continues to elude explanation