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Full Version: 2nd interstellar visitor not as odd as 1st + Galaxy might be full of micro-machines
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How the 2nd known interstellar visitor makes ‘Oumuamua seem even odder
https://www.sciencenews.org/article/bori...even-odder

EXCERPT: The second space rock seen visiting our solar system from another star is proving just how bizarre the first known interstellar object, ‘Oumuamua, really was. ‘Oumuamua raised eyebrows when it appeared in October 2017 looking more like a rocky asteroid than an icy comet. Because comets form farther from their host stars than asteroids, it should be easier for comets to escape their star’s gravity to wander the galaxy. So astronomers expect the vast majority of interstellar vagabonds to be icy bodies. But ‘Oumuamua didn’t sport the gaseous halo or tail that forms when sunlight vaporizes a comet’s ice.

Now, new telescope images confirm that a second interstellar object called 2I/Borisov (originally dubbed C/2019 Q4 (Borisov)) looks like a garden-variety comet ... The cometlike appearance of this object, first glimpsed August 30, suggests that ‘Oumuamua’s weirdness was a one-off... “It’s kind of relieving that finally we have something that meets our expectations,” says study coauthor Michał Drahus ... “Now we really can be absolutely sure that ‘Oumuamua was one weird object.”

... astronomers have several months to take a closer look at 2I/Borisov. (MORE - details)



The galaxy might be full of micro-machines
https://cosmosmagazine.com/space/the-gal...o-machines

EXCERPT: . . . If ET is out there, the logic runs ... some type of whizzbang alien machinery must be involved. All that has to be done, therefore, is work out a way to detect the tech, which is not easy when the object of any such search is completely unknown. This has led to some not entirely fanciful imagining.Flying saucers were an early example, although, despite attempts to build them here on Earth, the engineering challenges inherent in the design appear fatal. Dyson spheres were, and remain, a much stronger candidate...

[...] Hope, however, springs eternal for extraterrestrial tech hunters, and the other best-favoured hypothetical example is known as a von Neumann probe, named after a mathematician called John von Neumann, who came up with the idea.

These hypothetical machines overcome one of the principle objections to Fermi’s Paradox – that it assumes ET would actually want to physically colonise the galaxy. Von Neumann probes allow aliens to explore across vast distances while staying at home. Essentially, they are self-replicating devices that whizz off and then make copies of themselves, thus rapidly – indeed, exponentially – increasing in numbers and range. In terms of Fermi’s notion, however, von Neumann probes simply kick the can further down the road. The idea might explain why humans have never seen an alien, but fails to explain why it has never seen an alien machine.

[...] Recently, however, the idea has been tweaked, because, well, of course it has. In a paper lodged on the preprint site arxiv, astrophysicist Zaza Osmanov of the Free University of Tbilisi in Georgia suggests that theorists have been thinking about von Neumann probes at entirely the wrong scale. Using some very detailed calculations, Osmanov concludes that the probe idea works best if the machines are microscopic – about one nanometre long.

At that size, he notes, they would not require the substantial resources of rocky planets to reproduce, but could instead power up using hydrogen atoms whirling around in the interstellar dust. He calculates that this is altogether more efficient and much, much faster, with replications happening in a matter of a few years rather than the rather longer timescales thought necessary for macro-scale machines.Furthermore, nano von Neumanns would very quickly – at least on galactic timescales – become very numerous.[...] And that sort of mega-swarm, he suggests, might make them visible, if only someone was looking in the right direction...

Each individual emission would be tiny, but collectively they would add up to something observable, given that the mature von Neumann swarm, assuming they are in a level formation and comprise a “wave” at their leading edge, would collectively have the “typical mass of a comet having a length scale of several kilometres”.

At least in the infrared part of the spectrum, Osmanov calculates, that constitutes a target worth looking for. [...] It is also possible, of course, referencing Douglas Adams’ Hitchhiker books, that a huge and tightly packed swarm of nano von Neumanns has already swooped down through the atmosphere to take a closer look at Earth, only to be swallowed by a yawning dog. (MORE - details)
(Oct 14, 2019 10:40 PM)C C Wrote: [ -> ]Now, new telescope images confirm that a second interstellar object called 2I/Borisov (originally dubbed C/2019 Q4 (Borisov)) looks like a garden-variety comet

That's what you think. It's a decelerating starship. (Sent to abduct and probe MR, probably. And to pick up that strangely alien Jeff Bezos.)

Hubble photo:

[Image: heic1918a.jpg]