APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Comments and questions about the APOD on the main view screen.
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Keyman » Wed Nov 22, 2017 8:18 pm

An extra special holiday bonus for me.
APOD and XKCD hitting on the same topic today.
https://xkcd.com/1919/

And their own follow on disussion:
http://forums.xkcd.com/viewtopic.php?f=7&t=123841

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby BDanielMayfield » Wed Nov 22, 2017 9:51 pm

Wayne Jepson wrote:My understanding, from the various articles I've read about this object so far, is that the only arguments supporting this being a natural 'asteroid' are:

1) it's trajectory can be defined solely by it's initial velocity and direction of motion, as influenced by the gravity of our sun during its close pass
(i.e. there is no evidence that its path is influenced by any sort of active, on-board propulsion system; it is adrift / tumbling in space)
2) it is red; and,
3) of course its natural, there's no such thing as aliens.

On the other hand, arguments for it not being "natural" include:

1) we are tracking over half a million asteroids in our solar system, none of them are known to have an aspect ratio as great as 10:1.
2) a spacecraft that is no longer functional could easily have a similar observed trajectory, you can speculate on how and when it achieved its observed velocity; and,
3) it is red. Why not paint your spacecraft red?

Anyone else have any further insights to add to either side of the debate?


Good post Wayne. I agree that the redness adds nothing to the debate, as any object, natural or not, will accumulate reddish dust after millions of years in deep space. Might even be rust.

I know, it's a giant crystal of dilithium unobtainium oxide. :lol2:

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Phantor48 » Thu Nov 23, 2017 6:51 am

Cue the music: Also Sprach Zarathustra!

Tszabeau

Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Tszabeau » Thu Nov 23, 2017 1:26 pm

Surely, it is tumbling and not moving like a javelin through space, as depicted.

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Chris Peterson » Thu Nov 23, 2017 2:40 pm

Tszabeau wrote:Surely, it is tumbling and not moving like a javelin through space, as depicted.

"Tumbling" means rotating around more than one axis. Some asteroids do tumble, but most do not. There's no particular reason we should expect this one to do so. And there is nothing in the image which suggests the direction of motion of the body. You are assuming it is "moving like a javelin", but it could be moving in any direction relative to its shape.
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby neufer » Thu Nov 23, 2017 2:59 pm

Chris Peterson wrote:
Tszabeau wrote:
Surely, it is tumbling and not moving like a javelin through space, as depicted.

"Tumbling" means rotating around more than one axis. Some asteroids do tumble, but most do not. There's no particular reason we should expect this one to do so. And there is nothing in the image which suggests the direction of motion of the body. You are assuming it is "moving like a javelin", but it could be moving in any direction relative to its shape.
https://www.etymonline.com/word/tumble wrote:
tumble (v.) c. 1300, "to perform as an acrobat," also "to fall down," perhaps from a frequentative form of Old English tumbian "dance about, tumble, leap." This is of unknown origin but apparently related to Middle Low German tummelen "to turn, dance," Dutch tuimelen "to tumble," Old High German tumon, German taumeln "to turn, reel."
https://en.wikipedia.org/wiki/Herpolhode wrote:
Click to play embedded YouTube video.
<<A herpolhode is the curve traced out by the endpoint of the angular velocity vector ω of a rigid rotor, a rotating rigid body. The endpoint of the angular velocity moves in a plane in absolute space, called the invariable plane, that is orthogonal to the angular momentum vector L. The fact that the herpolhode is a curve in the invariable plane appears as part of Poinsot's construction.

The trajectory of the angular velocity around the angular momentum in the invariable plane is a circle in the case of a symmetric top, but in the general case wiggles inside an annulus, while still being concave towards the angular momentum.>>
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby rstevenson » Thu Nov 23, 2017 5:57 pm

Zoomer wrote:" ...because it is the first asteroid ever detected from outside our Solar System -"
How is this possible unless Voyager1 somehow reported it?
Or is this just a simple and too common grammatical error? :|

It's not considered a grammatical error anymore. It is an all too common way of making what could have been an unambiguous statement into an ambiguous one. This casual way of speaking and writing is a plague, but it seems unstoppable. Most people just puzzle out the most likely meaning and move on.

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Chris Peterson » Thu Nov 23, 2017 6:22 pm

rstevenson wrote:
Zoomer wrote:" ...because it is the first asteroid ever detected from outside our Solar System -"
How is this possible unless Voyager1 somehow reported it?
Or is this just a simple and too common grammatical error? :|

It's not considered a grammatical error anymore. It is an all too common way of making what could have been an unambiguous statement into an ambiguous one. This casual way of speaking and writing is a plague, but it seems unstoppable. Most people just puzzle out the most likely meaning and move on.

It would never have been considered a grammatical error. And language is, by its nature, often ambiguous. But if anybody actually had to "puzzle out" the meaning here, they've got much deeper problems to deal with.
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby neufer » Fri Nov 24, 2017 12:35 am

Chris Peterson wrote:
rstevenson wrote:
Zoomer wrote:
" ...because it is the first asteroid ever detected from outside our Solar System -"
How is this possible unless Voyager1 somehow reported it?
Or is this just a simple and too common grammatical error? :|

It's not considered a grammatical error anymore. It is an all too common way of making what could have been an unambiguous statement into an ambiguous one. This casual way of speaking and writing is a plague, but it seems unstoppable. Most people just puzzle out the most likely meaning and move on.

It would never have been considered a grammatical error. And language is, by its nature, often ambiguous. But if anybody actually had to "puzzle out" the meaning here, they've got much deeper problems to deal with.
Click to play embedded YouTube video.
Art Neuendorffer

FOARP

Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby FOARP » Mon Nov 27, 2017 10:24 am

InfinitiesLoop wrote:Someone mentioned it in this thread already, but I think it deserves discussion -- what is the feasibility of a mission to outfit a visitor like this with sensors? Why build a probe when nature has provided one?

We'd have to match its speed to be able to land on it, perhaps at that point you don't even need to land on it anymore. So I suppose the trick would be in getting something onto it without having to match its speed, like a snare or something. The more I think about it the more untenable it sounds, but there's gotta be something to it. Plenty of comets and asteroids with predictable orbits to practice on.


The problem here is: what exact problem are you solving by placing sensors on this rock (other than examining the rock itself, which is definitely worth doing)?

To put anything on 'Oumuamua you need to match its velocity, so you're not solving a velocity problem. Getting anything there requires a space-craft capable of holding all the instrumentation so there's no structural issue you're solving. I suppose the rock could act as a dust-shield (so long as it's not tumbling too much) but that's about it. On the down-side it's not going anywhere we want to go (other than "To infinity! And beyond!") and so any instrumentation placed there will likely see a whole load of nothing outside of the rock itself that it wouldn't have seen otherwise going at the speed it would be going at.

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby neufer » Mon Nov 27, 2017 9:28 pm

FOARP wrote:
InfinitiesLoop wrote:
Someone mentioned it in this thread already, but I think it deserves discussion -- what is the feasibility of a mission to outfit a visitor like this with sensors? Why build a probe when nature has provided one? We'd have to match its speed to be able to land on it, perhaps at that point you don't even need to land on it anymore. So I suppose the trick would be in getting something onto it without having to match its speed, like a snare or something. The more I think about it the more untenable it sounds, but there's gotta be something to it. Plenty of comets and asteroids with predictable orbits to practice on.

The problem here is: what exact problem are you solving by placing sensors on this rock (other than examining the rock itself, which is definitely worth doing)? To put anything on 'Oumuamua you need to match its velocity, so you're not solving a velocity problem. Getting anything there requires a space-craft capable of holding all the instrumentation so there's no structural issue you're solving. I suppose the rock could act as a dust-shield (so long as it's not tumbling too much) but that's about it. On the down-side it's not going anywhere we want to go (other than "To infinity! And beyond!") and so any instrumentation placed there will likely see a whole load of nothing outside of the rock itself that it wouldn't have seen otherwise going at the speed it would be going at.

The rock interior could act as a safe time capsule for frozen Earth species specimens and various artifacts.

The rock should be covered with optical & radar corner reflectors so that it can be tracked from Earth for a long time as well as making it easily locatable for aliens.
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby MarkBour » Fri Dec 01, 2017 1:23 am

I wonder what kind of magnetic moment Oumuamua has ...

(I recognized that shape immediately ... and it is well-named. Every righteous surfboard needs a good Hawai'ian name.)
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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby Garthok Gnarfle » Mon Dec 04, 2017 1:32 am

neufer wrote:The rock interior could act as a safe time capsule for frozen Earth species specimens and various artifacts.

The rock should be covered with optical & radar corner reflectors so that it can be tracked from Earth for a long time as well as making it easily locatable for aliens.

Maybe instead of a vessel as in Rama it's a shard of diamond thrown off by a birthing star as in Odyssey.

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Re: APOD: 'Oumuamua: Interstellar Asteroid (2017 Nov 22)

Postby neufer » Mon Dec 04, 2017 3:28 am

Garthok Gnarfle wrote:
Maybe instead of a vessel as in Rama it's a shard of diamond thrown off by a birthing star as in Odyssey.
https://en.wikipedia.org/wiki/Cave_of_t ... _Naica.JPG wrote:
<<Cave of the Crystals or Giant Crystal Cave (Spanish: Cueva de los Cristales) is a cave connected to the Naica Mine at a depth of 300 metres, in Naica, Chihuahua, Mexico. The main chamber contains giant selenite crystals (gypsum, CaSO4·2 H2O), some of the largest natural crystals ever found. The cave's largest crystal found to date is 12 m in length, 4 m in diameter and 55 tons in weight. The cave is extremely hot, with air temperatures reaching up to 58 °C with 90 to 99 percent humidity. The cave is relatively unexplored due to these factors. Without proper protection, people can only endure approximately ten minutes of exposure at a time.

The caves are accessible today because the mining company's pumping operations keep them clear of water. If the pumping were stopped, the caves would again be submerged in water. The crystals deteriorate in air, so the Naica Project is attempting to visually document the crystals before they deteriorate further. When mineral exploitation is ended in the area it is likely the pumps will be shut off and the cavern's water level allowed to rise again.>>
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