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The First Known Interstellar Comet



 
 
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  #1  
Old October 25th 17, 08:55 PM posted to sci.astro.amateur
palsing[_2_]
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Default The First Known Interstellar Comet

http://www.skyandtelescope.com/astro...stellar-comet/

Wow, this is fascinating...

"... an object swept up just a week ago by observers using the PanSTARRS 1 telescope atop Haleakala on Maui has an extreme orbit — it's on a hyperbolic trajectory that doesn't appear to be bound to the Sun. Preliminary findings, published earlier today [10/25/2017] by the International Astronomical Union's Minor Planet Center (MPC), suggest that we are witnessing a comet that escaped from another star."
  #2  
Old October 26th 17, 04:10 AM posted to sci.astro.amateur
RichA[_1_]
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Default The First Known Interstellar Comet

On Wednesday, October 25, 2017 at 3:55:26 PM UTC-4, palsing wrote:
http://www.skyandtelescope.com/astro...stellar-comet/

Wow, this is fascinating...

"... an object swept up just a week ago by observers using the PanSTARRS 1 telescope atop Haleakala on Maui has an extreme orbit — it's on a hyperbolic trajectory that doesn't appear to be bound to the Sun. Preliminary findings, published earlier today [10/25/2017] by the International Astronomical Union's Minor Planet Center (MPC), suggest that we are witnessing a comet that escaped from another star."


I wonder how it escaped the star?
  #3  
Old October 26th 17, 04:51 AM posted to sci.astro.amateur
palsing[_2_]
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Default The First Known Interstellar Comet

On Wednesday, October 25, 2017 at 8:10:56 PM UTC-7, RichA wrote:
On Wednesday, October 25, 2017 at 3:55:26 PM UTC-4, palsing wrote:
http://www.skyandtelescope.com/astro...stellar-comet/

Wow, this is fascinating...

"... an object swept up just a week ago by observers using the PanSTARRS 1 telescope atop Haleakala on Maui has an extreme orbit — it's on a hyperbolic trajectory that doesn't appear to be bound to the Sun. Preliminary findings, published earlier today [10/25/2017] by the International Astronomical Union's Minor Planet Center (MPC), suggest that we are witnessing a comet that escaped from another star."


I wonder how it escaped the star?


Great question... but I think the answer has already been considered. Here, read here...

https://en.wikipedia.org/wiki/Interstellar_comet

"Current models of Oort cloud formation predict that more comets are ejected into interstellar space than are retained in the Oort cloud, by a factor of 3–100.[2] Other simulations suggest that 90–99% of comets are ejected.[7] There is no reason to believe comets formed in other star systems would not be similarly scattered.[1]"

We are so lucky to live in an era where the instruments used to view the universe are producing results that could not even have been imagined 100 years ago. I'm just a little depressed that I won't be around to see what is to be found in another 50 or 100 years, stuff that I can't imagine today :(

Oh well, I can still marvel at today's astronomical bounty.

\Paul A
  #4  
Old October 26th 17, 07:38 AM posted to sci.astro.amateur
Chris.B[_3_]
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Default The First Known Interstellar Comet

On Thursday, 26 October 2017 05:51:22 UTC+2, palsing wrote:

We are so lucky to live in an era where the instruments used to view the universe are producing results that could not even have been imagined 100 years ago. I'm just a little depressed that I won't be around to see what is to be found in another 50 or 100 years, stuff that I can't imagine today :(

Oh well, I can still marvel at today's astronomical bounty.

\Paul A


Perhaps, one day, we shall all have gravity wave sensors embedded in our wrists?

Mass interferometry, constantly collected as data for our personal, built-in, quantum computers to crunch on between meals. ;-)
  #5  
Old October 26th 17, 08:16 AM posted to sci.astro.amateur
Gerald Kelleher
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Default The First Known Interstellar Comet

On Thursday, October 26, 2017 at 4:51:22 AM UTC+1, palsing wrote:


We are so lucky to live in an era where the instruments used to view the universe are producing results that could not even have been imagined 100 years ago. I'm just a little depressed that I won't be around to see what is to be found in another 50 or 100 years, stuff that I can't imagine today :(

Oh well, I can still marvel at today's astronomical bounty.

\Paul A


It is good that you marvel today at imaging Paul because a few years ago it was somewhat different -

https://lh3.googleusercontent.com/-T...015%2Beng..jpg

You already know that Venus and Mercury are seen to run their circuits from a slower moving Earth therefore the perspectives change for the slower moving Mars,Jupiter and Saturn seen from a faster moving Earth.

So don't be depressed, you were among the first to see the partitioning of perspectives and how to account for a moving Earth, a central Sun and the change in relationship between an evening and morning appearance of the background stars as the Earth runs its circuit of the Sun.



  #6  
Old October 27th 17, 12:36 AM posted to sci.astro.amateur
palsing[_2_]
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Default The First Known Interstellar Comet

On Thursday, October 26, 2017 at 12:16:38 AM UTC-7, Gerald Kelleher wrote:

It is good that you marvel today at imaging Paul because a few years ago it was somewhat different -

https://lh3.googleusercontent.com/-T...015%2Beng..jpg


Gerald... you don't actually think that you have referenced a photo here, do you? I shudder while waiting for your response...

You already know that Venus and Mercury are seen to run their circuits from a slower moving Earth therefore the perspectives change for the slower moving Mars,Jupiter and Saturn seen from a faster moving Earth.

So don't be depressed, you were among the first to see the partitioning of perspectives and how to account for a moving Earth, a central Sun and the change in relationship between an evening and morning appearance of the background stars as the Earth runs its circuit of the Sun.


No, Gerald, I was definitely NOT among the first to know about these things, several centuries have elapsed since these motions were first understood. Just because you think that you were the first to recognize this material does not mean you were, you were simply late to the party.

Don't be depressed, there are still lots and lots of facts about astronomy left for you to learn... if only you were a just little more capable of learning anything at all. You have SO much of it wrong now, it would take a long time just for you to un-learn what you think you know now, years and years, I'm guessing.

I know you are sincere and confident of your vast knowledge, but that is no substitute for the reality of it all.

  #7  
Old October 27th 17, 07:58 AM posted to sci.astro.amateur
Gerald Kelleher
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Default The First Known Interstellar Comet

On Friday, October 27, 2017 at 12:36:46 AM UTC+1, palsing wrote:
On Thursday, October 26, 2017 at 12:16:38 AM UTC-7, Gerald Kelleher wrote:

It is good that you marvel today at imaging Paul because a few years ago it was somewhat different -

https://lh3.googleusercontent.com/-T...015%2Beng..jpg


Gerald... you don't actually think that you have referenced a photo here, do you? I shudder while waiting for your response...


It is a simple sequence of images that tells half the story of the motions of Venus with an accompanying table of the dates when the images were taken..


You already know that Venus and Mercury are seen to run their circuits from a slower moving Earth therefore the perspectives change for the slower moving Mars,Jupiter and Saturn seen from a faster moving Earth.

So don't be depressed, you were among the first to see the partitioning of perspectives and how to account for a moving Earth, a central Sun and the change in relationship between an evening and morning appearance of the background stars as the Earth runs its circuit of the Sun.


No, Gerald, I was definitely NOT among the first to know about these things, several centuries have elapsed since these motions were first understood. Just because you think that you were the first to recognize this material does not mean you were, you were simply late to the party.


Knowing that even you enjoy the partitioning of perspectives is satisfaction enough for me. The original Sun centered astronomers (including Galileo who first put the size and phases of Venus in correct context) were working off a framework where direct/retrograde motion were common to all planets but the solutions for slower moving and faster moving planets depending on what planet you are standing on -

"Now what is said here of Jupiter is to be understood of Saturn and Mars also. In Saturn these retrogressions are somewhat more frequent than in Jupiter, because its motion is slower than Jupiter's, so that the Earth overtakes it in a shorter time. In Mars they are rarer, its motion being faster than that of Jupiter, so that the Earth spends more time in catching up with it. Next, as to Venus and Mercury, whose circles are included within that of the Earth, stoppings and retrograde motions appear in them also, due not to any motion that really exists in them, but to the annual motion of the Earth." Galileo






Don't be depressed, there are still lots and lots of facts about astronomy left for you to learn... if only you were a just little more capable of learning anything at all. You have SO much of it wrong now, it would take a long time just for you to un-learn what you think you know now, years and years, I'm guessing.


You enjoyed the sequence of images showing the trajectory of Venus to the left of the Sun as it swings out from behind the Sun to its widest point before swinging back in front of the Sun (direct/retrograde in geocentric terms) so the other half of the story is a morning appearance that precedes the appearance of the Sun where Venus shows itself to the right of the Sun.

http://www.popastro.com/images/plane...ary%202012.jpg


I know you are sincere and confident of your vast knowledge, but that is no substitute for the reality of it all.


Venus and Mercury are unique in this case so what you do is add the Mars,Jupiter,Saturn and the rest to this scheme. Then you add the background stars and a complete narrative emerges.

Go ahead and try it as I left the slower moving planets (seen from a faster moving Earth) more or less unexplained using the left/right, evening/morning appearance scheme. Who will be the first in human history to distinguish the faster moving and slower moving planets this way ?.



  #8  
Old October 27th 17, 08:37 AM posted to sci.astro.amateur
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Default The First Known Interstellar Comet

On Friday, October 27, 2017 at 12:36:46 AM UTC+1, palsing wrote:
Just because you think that you were the first to recognize this material does not mean you were, you were simply late to the party.


.... and in fact Gerald still does not understand retrogrades of the inferior planets even as well as Hipparchus did. When shown the actual path of Venus against the background stars, he does not believe it.
  #9  
Old October 26th 17, 03:54 PM posted to sci.astro.amateur
Chris L Peterson
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Default The First Known Interstellar Comet

On Wed, 25 Oct 2017 12:55:23 -0700 (PDT), palsing
wrote:

http://www.skyandtelescope.com/astro...stellar-comet/

Wow, this is fascinating...

"... an object swept up just a week ago by observers using the PanSTARRS 1 telescope atop Haleakala on Maui has an extreme orbit — it's on a hyperbolic trajectory that doesn't appear to be bound to the Sun. Preliminary findings, published earlier today [10/25/2017] by the International Astronomical Union's Minor Planet Center (MPC), suggest that we are witnessing a comet that escaped from another star."


To be clear, a number of comets, and possibly some meteoroids, have
been observed to have hyperbolic orbits. But these have always had
eccentricities just fractionally greater than one... explainable as
either measurement error or by the conversion of elliptical to
hyperbolic orbits due to gravitational perturbations. What makes this
object interesting is its very high eccentricity of 1.19. That's way
outside of measurement error, and it's far too high to reasonably
explain by interactions with the gas giants and Sun.
 




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