A comet has been observed for six days, with a substantially hyperbolic orbit (eccentricity 1.18). This suggests that it may not be in orbit of the Sun, but merely passing through our part of space.

If the hyperbolic orbit is confirmed by further observations, it will mark the first time that such an interstellar visitor has been discovered.

There appear to be no signs that the orbit of this object has been perturbed by a near pass at any of the major planets. Such passes can alter the elliptical orbits of ordinary comets, sending them off into the void, for good.
Conversely, an interstellar comet could have been thrown our way by just such an encounter within its own star system.
Below find a link to an article with more details on this newly discovered comet.

http://www.skyandtelescope.com/astronomy-news/astronomers-spot-first-known-interstellar-comet

After very careful observation at the Very Large Telescope found no cometary emissions whatever, the object has been redesignated an asteroid: A/2017 U1. They believe it passed nearest the Sun on September 9, and within 15 million miles of Earth on October 14.

The supposition that the object came from outside our solar system has been strengthened by further observations. The eccentricity is now calculated as 1.19, whereas before it was 1.18 .

The greatest hyperbolic eccentricity seen in a solar system object before was 1.057, which was caused by an encounter with a major planet. It was not considered an indication that the object came from outside our solar system

Please find below a link to an article on the newly classified object:

https://en.wikipedia.org/wiki/A/2017_U1

A Very Interesting object for sure!!!

No coma could be found around the object, which is why it was reclassified from a comet to an asteroid. It may have existed inside the 'snowline' of its star system, and lost any water it had by sublimation, over time.

The object could have been ejected from its system, and sent our way by interaction with a major planet. This might have been a near-in 'hot Jupiter'. Otherwise, inner system interactions, such as occur in our solar system, are reportedly considered unlikely to accomplish such an ejection.

More on this asteroid? Hope they find where it came from.


First Rock From Outside the Solar System Sails Past Earth




A/2017 U1 is most likely of interstellar origin. Approaching from above, it was closest to the sun on September 9. Traveling at 27 miles per second (44 kilometers per second), the comet is headed away from Earth and the sun on its way out of the solar system.
Courtesy NASA, JPL-Caltech

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dp

SETIQuest info, the website of the SETI Institute's Allen Telescope Array, has the following in it observer notes, for October 30:

"Calibrating to observe A/2017 U1, the mysterious object that has entered the solar system. 1 GHz to 2 GHz tonight." The latter was revised to 1 to 3 GHz, later.
Please find a link to this website, below:

http://www.setiquest.info

Observer notes at SETIQuestinfo report that the hyperbolic object A/2017 U1 will be observed again tonight at the Allen Telescope Array, in the range 1 to 2 GHz. Asteroids are not known sources of radio waves, so they appear to be considering the possibility that the object is something else altogether.

It was sighted by optical telescopes. No other radiotelescope besides the ATA seems to have observed it. Maybe Arecibo, if in working order, could have used its radar capabilities. On the NASA site there is no news about a possible use of the Goldstone radar to track it.
Tullio

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If I understand correctly, the Allen Telescope Array is not set up to emit radio waves, which can be used for asteroid tracking purposes, like Arecibo, and Goldstone. The reasonable inference seems to be that they are listening for intelligent signals from A/2017 U1.
It's obviously a very long shot that the object is not an asteroid, but a space vessel. Still, they seem to find it worth the effort to repeatedly test this hypothesis.

I think that the trajectory is a hyperbola, not an ellipse.
Tullio

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The trajectory of the object does look similar to a sling shot around the sun to give it some oomph on it's journey. But if it was a spaceship, then they would be able to detect life on earth and would likely have stopped and had a look, so I plump for a large asteroid or comet looking at the ellipse path printed so far wouldn't some sort of extrapolation give the far end of its path before returning again?

If it were an alien space ship using the sun for a speed boost and a course correction and if they detected us maybe,since this is not their destination, they are unable to slow down and check us out. Or better yet, they don't think our presence warrants any investigation. That was the main point in the original book by Arthur C. Clarke Rendezvous with Rama.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

They are now saying that the hyperbolic asteroid is about 30 meters wide by 180 meters long. This is based on the variability in the amount of light it reflects as it spins. That's a remarkably long, thin object, six times longer than its width. The longest, thinest asteroids found to reside in our solar system have less than half of that length to width ratio.

They are now saying that the hyperbolic asteroid is about 30 meters wide by 180 meters long. This is based on the variability in the amount of light it reflects as it spins. That's a remarkably long, thin object, six times longer than its width. The longest, thinest asteroids found to reside in our solar system have less than half of that length to width ratio.

Still not large enough to be a manned interstellar space ship, but maybe an unmanned probe of some sort. OK, that was a total fantasy.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

I don't quite see how we could know the necessary size an interstellar spacecraft, tenanted or otherwise.

One naturally wonders how an asteroid would assume such a shape; about the proportions of a thick cigar. An asteroid like Kleopatra appears to have stretched itself by spinning rapidly, but still managed less than a 3 to1 length to width ratio.

Toutatis, spinning much slower, pulled two asteroids together to make one, the result: a length /width ratio of less than 2.5 to 1.

Why have none longer been found? One suspects that they either pulled themselves apart , into two distinct asteroids, or that the coincidence of three or more asteroids becoming joined, end to end, was too improbable to be expected, or that it was too unstable a configuration.

It now has name.


Interstellar asteroid is given a name

The first known asteroid to visit our Solar System from interstellar space has been given a name.


Scientists who have studied its speed and trajectory believe it originated in a planetary system around another star.

The interstellar interloper will now be referred to as 'Oumuamua, which means "a messenger from afar arriving first" in Hawaiian.

The name reflects the object's discovery by a Hawaii-based astronomer using an observatory on Maui.

It was discovered on 19 October this year by Rob Weryk, a postdoctoral researcher at the University of Hawaii Institute for Astronomy.

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Considering where a probe goes, with dimensions like that do we ever want to meet up with them?

The BBC article, linked below, has some interesting new details about the hyperbolic object, now named Oumuamua. It seems that the 'fat cigar' has become a thin one!

Astronomers now think that the object could be at least 10 times as long as it is wide. This would require that its ends align directly with Earth when it's at minimum brightness, during its end-over-end rotation. Such a coincidence is very unlikely. If it points somewhat off our direction, the elongation would be even greater, they find.

They have serious trouble explaining how the object could come to be so long, or hold together, while spinning. If it were made of two elongated bodies, in end to end contact, like the asteroid Hektor, they think it'd be spinning too fast to hold together. Other even less probable explanations have been proposed.

http://www.bbc.com/news/science-environment-42053634

The trajectory of the object does look similar to a sling shot around the sun to give it some oomph on it's journey. But if it was a spaceship, then they would be able to detect life on earth and would likely have stopped and had a look, so I plump for a large asteroid or comet looking at the ellipse path printed so far wouldn't some sort of extrapolation give the far end of its path before returning again?

If it were an alien space ship using the sun for a speed boost and a course correction and if they detected us maybe,since this is not their destination, they are unable to slow down and check us out. Or better yet, they don't think our presence warrants any investigation. That was the main point in the original book by Arthur C. Clarke Rendezvous with Rama.

It is my thought exactly. But as some great minds used to say:


But in Randevous with Rama a space-craft slowed down. This one didn't!

Still, it could be the dormant probe without the propulsion activated. Dormant enough to listen only & detect. Maybe even seem like a asteroid?
If I were to conduct a research about alien development & check out some system, something similar could be used.

They are now saying that the hyperbolic asteroid is about 30 meters wide by 180 meters long. This is based on the variability in the amount of light it reflects as it spins. That's a remarkably long, thin object, six times longer than its width. The longest, thinest asteroids found to reside in our solar system have less than half of that length to width ratio.

Still not large enough to be a manned interstellar space ship, but maybe an unmanned probe of some sort. OK, that was a total fantasy.

Why does it have to be manned? All our missions to Mars, Venus, Pluto, Jupiter & it's moon, Saturn & it's moons, Sun, Mercury - all of them unmanned. ;)

& the lack of propulsion detection. Well, does EmDrive also has emission?
Someone else said:

It was sighted by optical telescopes. No other radiotelescope besides the ATA seems to have observed it. Maybe Arecibo, if in working order, could have used its radar capabilities. On the NASA site there is no news about a possible use of the Goldstone radar to track it.
Tullio

Be sure that NATO has it PINGED. ;)

Some more info from JPL:
- https://www.jpl.nasa.gov/news/news.php?feature=6983
- https://www.jpl.nasa.gov/news/news.php?feature=7006

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non-profit org. Play4Life in Zagreb, Croatia, EU

The trend in thinking about this object, now, is that it is quite dense. An asteroid would presumably have to be, so it could hold together, given its relatively fast spin (7.3 hours) and very peculiar, flimsy, shape.

The spectra taken of this object suggested a likeness to D and P class asteroids in our solar system. However, these are far from substantial, being only about 1.4 times the density of water. This thing just keeps getting weirder and weirder!