Not long ago, I had the chance to pick the mind of a rather outspoken member of the astrophysicist community regarding Fast Radio Bursts (FRB's), and how these may or may not signify the emanating echoes of a distant civilization.
Avi Loeb, a name gaining quite a bit of momentum of late, detailed to me that we simply don't have enough information to conclusively state one argument over another when it comes to explaining FRBs. An especially pragmatic stance to take, and a bit of a lackluster one given my greedy expectations.
Since that interview, Professor Loeb had made an appearance on the Joe Rogan Experience to provide his more exciting insights and opinions on a rather controversial interstellar object that had recently made its why through our solar system - 'Oumuamua.
The episode drew a lot of attention given Loeb's outcry over the institutionalized skepticism of the scientific community on the topic of extraterrestrial communications; more importantly, it had offered Loeb a platform whereby he could provide a voice for the discontent opinion of those who felt that astrophysicists had been too quick to write off 'Oumuamua as nothing more than, as he sarcastically phrased it, a 'pancake shaped nitrogen iceberg'.
In other words, Loeb threw the ball back at the skeptics, who didn't stay quiet for too long.
Only weeks after his appearance on JRE, an article had been circulated (emanating from www.phys.org) which sought to validate the postulation that 'Oumuamua was truly nothing to get excited about. With a conclusive tone, it set about detailing that two Arizona State University astrophysicists had determined that the comet had, in fact, been a solid chunk of nitrogen ice.
The proverbial (and seemingly deflated) ball was kicked back at Avi Loeb.
So I reached out to get his opinion on this subject, assuming that he had come across the article and assuming he had also picked it apart by the time my correspondence landed in his inbox.
I was right.
Ultimately, Professor Loeb didn't buy it, as none expected he would. Below is his email to me and his retort to the author of the piece that sought to take the wind out of all 'Oumuamua sails, published here if for no other reason than to demonstrate our passionate pursuits of curiosity, even in the face of institutionalized skepticism, even when we may be the only ones yelling in a quiet room.
At the end of the road, it's not necessarily about who was right so much as how we came to understand it. To maintain closed eyes simply for the sake of convenience, reputation, or who knows why, is to do the collective whole an injustice in the satisfaction of curiosity.
If `Oumuamua was made of nitrogen, it should have also included traces of carbon (because of the CNO cycle that makes them together in the interiors of stars), and well above the limits on carbon-based molecules imposed by the Spitzer space telescope. It is highly unlikely to have an object made purely of nitrogen without carbon.
The case of hydrogen is different, because hydrogen makes 90% of all the atoms in the Universe; it is the most abundant element.
But nitrogen is produced by stars in similar quantities to carbon, so if you want only nitrogen but no carbon in `Oumuamua, you need to make `Oumuamua out of material that separated nitrogen from
carbon (or else the Spitzer Space Telescope would have detected the carbon-based molecules in the cometary tail from this object, losing ~10% of its mass).
I do not know of a simple way of separating carbon from
nitrogen. Usually they come together because they are produced together in stellar interiors.
In addition, note that the discovery of Oumuamua requires a lot of mass ejected per star, more than expected from all the rocks that planetary systems are expected to eject.
This was discussed in two papers by Amaya Moro-Martin,
As a result, a rare and exotic origin from nitrogen icebergs is unlikely to provide the necessary mass budget.
Finally, about 10% of the mass of Oumuamua needed to evaporate in order to explain the excess force it exhibited via the rocket effect. This follows from momentum conservation. So much mass in nitrogen would scatter sunlight and be visible to us, but we had not seen any cometary tail around Oumuamua.
By the way, the fact that the shape of `Oumuamua was most likely flat (pancake-like) and not a cigar was already pointed out in the 2019 paper by Sergey Maschenko (https://arxiv.org/pdf/1906.
03696.pdf) and also discussed extensively in my new book, Extraterrestrial, `Oumuamua showed other anomalies; for example, it originated from the Local Standard of Rest and this has a probability of 1 in 500 if it came from a Pluto-like planet in a nearby star; see https://arxiv.org/abs/ 1710.11364.
Again, this peculiar fact is discussed in detail in my book and is unlikely to arise in the Nitrogen model.
Given all we know, I would say that an artificial origin is still more plausible than the `natural origin' models proposed so far. Note that all the alternative models suggest that `Oumuamua was "something that we had not seen before", unlike all the comets and asteroids detected so far in the Solar system. This implies that we cannot assume "business as usual" as many scientists argue. If we contemplate "something that we had not seen before", we must leave the artificial origin hypothesis on the table and collect more evidence on objects from the same class.
The best evidence would be a close-up photograph of a future `Oumuamua-like object. It is often said that “a picture is worth a thousand words”.
Follow Avi Loeb's work: https://lweb.cfa.harvard.edu/~loeb/