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Home / Science / To pinpoint the nature of Oumuamua – it's probably a comet, but …

To pinpoint the nature of Oumuamua – it's probably a comet, but …

  Image of an alien spaceship from the movie Close Encounters of the Third Kind.
Enlarge / I mean, maybe, right? Could be? Probably not. Almost certainly not.

Just before Halloween, Harvard Astronomy Department Chairman Harald Openly stated that an interstellar object thrown through our solar system could only be part of an alien ship. And then … barbecue.

The astrophysics blog Centauri Dreams has broken the story three days later on the Cognoscenti. It presented a well-founded overview of the academic work in which this brazen option came up, supported by quotes and comments from the newspaper's co-author (and department head), Avi Loeb. It was well into November before outlets such as CNN, Time, and The Washington Post recorded the story with inevitable sarcastic quotes and sneaky headlines. The object named & # 39; Oumuamua had a number of peculiar and seemingly contradictory properties. It may be that these qualities appear as they do because our observations were not so good. There are other possibilities.

I read the newspaper by Loeb, which has since been adopted by the respected Astrophysical Journal for publication. A few days later, Loeb and I sat down for the longest and ̵

1; according to Loeb's own statement – the most serious and thorough interview on the subject. The embedded audio player after the colon at the end of this sentence contains an hourly editing of it, including all highlights:

If you do not use spoken word audio, we are & # 39; I have a transcript available as plain text as well as PDF (probably a bit easier to read).

"I'm not saying that they are aliens, but …"

Avi Loeb is clearly one of the most extraordinary claims in astronomy. Of course, this requires extraordinary evidence – a requirement that does not make Loeb's fancy job title an exception. But we should also avoid the reverse answer to the knee, which looks something like this: "Just because Harvard's chairman of astronomy says could be an alien vehicle is not and indeed It means that is not because irony! Oh, and complacency too. "

My interview with Loeb should not decide this debate for you, me, aliens or anyone (Loeb himself needs a lot more Evidence to take a closer look at the solution of the case). But the story of Oumuamua is fascinating. Non-astronomers can simply deal with learning one or three things about how the universe works. If you take this path, keep in mind that alien technology was taken into consideration and then lost as an explanation for many astronomical phenomena. & # 39; Oumuamua will probably one day definitely join this list. However, one learns a lot when looking for traces – both from the field of astronomy and from curious outsiders who follow the process.

If you listen to our interview (or read our probable-ok-ish protocol), you will understand this debate on a more subtle level than most people complaining about it. And that really cool thing? For reasons that we will discuss at the end of our conversation, the big issues here could be solved dramatically as early as 2022, when an important new telescope goes online.

For those in a hurry, I will now give an overview of our telescope interview timestamp so you can get to the places that interest you most.

There's something about 'Oumuamua'

Our story begins on October 19 last year (at the time stamp 07:55 of the above-mentioned interview audio material, if you look at more details than in The object, which should be named & # 39; Oumuamua & # 39 ;, was first discovered by Hawaii's Pan-STARRS system, which detects and detects objects near Earth.

It soon became clear that Oumuamua was traveling too fast to be bound to our sun, which meant that it originated in a distant star system, making it the first interstellar object to have been definitely identified in our solar system Fascinated, the astronomical community spent much of its hardware on the waning field, gaining a lot of observational data before Oumuamua was no longer seen in January.

  The impression of an artist from the e like-shaped interstellar asteroids & # 39; Oumuamua. "Src =" https://cdn.arstechnica.net/wp-content/uploads/2017/11/1I_eso_artistimpression-640x400.jpg "width =" 640 "height =" 400 "srcset =" https: //cdn.arstechnica .net / wp-content / uploads / 2017/11 / 1I_eso_artistimpression-1280x800.jpg 2x
Enlarge / Impression of an artist from the odd shaped interstellar asteroid & # 39; Oumuamua.

& # 39; Oumuamua was bizarre on several fronts from the beginning. Interestingly, it travels under our local star stacks on the "Local Standard of Recreation" (Timestamp 15:36 ). For reasons that Loeb explains, this is a fascinating feature – and an unlikely (though not impossible) one for a natural object.

In June (time stamp 23:22 ), Nature published a rigorous analysis of the trajectory of Oumuamua. The authors found – with 30 standard deviations of confidence – that the object accelerated while it deviated from the sun. This has been interpreted as proof that it is a comet and not an asteroid (the other possible candidate). Comets usually accelerate in this way, driven by the gases released by the solar heat, causing their characteristic tails.

However, several observations contradicted this. (Timestamp 25:44 ). For example, a tail was never observed on Oumuamua. Neither was a coma (the flaky head of a comet). There was no sign of water on it, and comets usually carry water. The surface reflection of Oumuamua was far beyond the limits of comets.

These and other peculiarities can each be explained or justified. For Loeb, however, the last straw was a September work by Roman Rafikov of Cambridge University (time stamp 28:39 ). It argues that "Oumuamuas spin rate (which was fairly nimble – another curiosity) – remained constant throughout the observation period, whereas outgassing should have significantly affected the spin.

Loeb concluded that outgassing could not have caused Oumuamuas acceleration He looked at alternative forces and opted for one that astronomers understand quite well: the pressure of the radiation emitted by the sun, but this is a much weaker force than outgassing, and if it were, Oumuamua would be much smaller than that Planned quarters of the miles of rock astronomers, in particular, Loeb had a diameter of only 20 meters and – here's the tiny one – less than a millimeter thick.

Close encounters of some kind

No known natural process can do anything create the distance, so thin in space, but that sounds very much like Sonnense And Loeb spent many hours modeling the awning physics and helped direct Yuri Milner's Breakthrough Starshot project (time stamp 18:55 ). Yes, the cliché of hammer owners, who do not mistake nails for nails, immediately springs to my mind, and Loeb acknowledges this ( 30:07 ). However, it is also known that hammer makers accurately identify nails.

The most exotic possibility that Loeb maintains in his paper ( 33:55 ) is that & # 39; Oumuamua was on a purposeful reconnaissance mission (not necessarily identifying the Earth). but perhaps in general through the habitable zones of star systems). This is based on calculations of the heritage regarding the relative abundance of interstellar objects and other factors.

Loeb and I then discuss the online archive in which he and his co-author, postdoc colleague Shmuel Bialy, first deposit their work ( 36:58 ) and the unusual speed with which Astrophysical Journal it both accepted and published ( 40:35 ). I then present Loeb with the sayings of some of his critics to whom he answers ( 44:51 ). This leads to a discussion of the philosophy of Loeb on the roles and responsibilities of scientists.

  The unusual approach of the object suggests that it came from outside our solar system. "Src =" https://cdn.arstechnica.net/wp-content/ uploads / 2018/06 / Screen Shot 2018-06-28-at-1.51.22-PM-640x379.png "width =" 640 "height =" 379 "srcset =" https://cdn.arstechnica.net/wp-content/uploads/2018/06/Screen-Shot-2018-06-28-at-1.51.22-PM.png 2x [19659016] Enlarge <span class= / The unusual approach of the object indicates that it comes from the object outside our solar system.

We conclude with the intriguing prospect that a large telescope debuting in 2022 could quickly answer questions that elude current hardware ( 56:56 ). This leads to a wealth of interstellar objects like & # 39; oumuamua. If they are as rare as stated in previous calculations, the more powerful new device will only detect a handful of new devices. However, if they are common enough not to surprise Oumuamua's discovery, the new telescope should quickly recognize thousands of them.

This argument is too extensive to fully explore here (I'm a podcaster, not a journalist). So I ask you to listen to this section. Loeb's controversial statement has everything but an expiration date, and it's only been a few years.

Personally, I can not wait to follow events closely as they approach. Listen to this section, and you know the underlying issues as much as I do. Although it is so slim, there is at least a small chance that 2022 will provide a deterrent indication that Oumuamua is an artificial relic. And whatever the outcome, would not it be cool to follow that story as it unfolds?

This interview is the last episode of my podcast After On. If you enjoy it, you can find a complete archive of my episodes on my website or through your favorite podcast app by looking under the words "After On." The broader series is based on in-depth interviews with world-class thinkers, founders, and scientists, and tends to be technically and scientifically difficult.

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