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Thread: Sirius neutron star

  1. #1
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    Sirius neutron star

    E8E47C6B-FD2D-4ECB-87A7-DCCC133175E1.pngE8E47C6B-FD2D-4ECB-87A7-DCCC133175E1.png

    I have read that this is the closest neutron star to earth at 8.7 light years and it is constantly getting closer. how long before it’s effects reach earth and cause havoc?
    I am just asking because of how close it is to us
    Last edited by Sinbad; 2020-Jan-19 at 01:34 PM.

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    That is unmoderated online jibberjabber that appears to have no scientific merit. I would not give them the satisfaction of knowing I read it.

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    Sirius B is a white dwarf, and is not a neutron star. The closest neutron star is probably Calvera in Ursa Minor. it is between 250 and 1000 light years from here, and poses no danger.
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    I understand that and have looked it up online but am still curious about the information from here.

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    Quote Originally Posted by Sinbad View Post
    I understand that and have looked it up online but am still curious about the information from here.
    If something is just made up lies is it really information? Certainly shouldn't be discussed here.
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    So is the white stage moving towards us then? And how long before it reaches us.

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    Quote Originally Posted by Sinbad View Post
    So is the white stage moving towards us then?

    The Sirius system (including a white dwarf, not a “white stage” or neutron star) is gradually moving closer to the solar system. It will become brighter over tens of thousands of years. You could read this on Wikipedia. I would suggest trying to do some basic fact checking for yourself if you’re going to read silly claims like those in the tweets.

    Incidentally I would suggest adding a language warning to your post given what is said in the tweet.

    And how long before it reaches us.
    It won’t. Did you read what I wrote in the “New Waves” thread? Space is big. The Sirius system will get a bit closer over tens of thousands of years and then it will pass by and move away.

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    Quote Originally Posted by Sinbad View Post
    So is the white stage moving towards us then? And how long before it reaches us.
    See this answer to your question. The short answer is that it will never reach us, but will make it's closest approach at 7.8 light years away 60,000 years from now.
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    Thank you

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    Quote Originally Posted by antoniseb View Post
    Sirius B is a white dwarf, and is not a neutron star. The closest neutron star is probably Calvera in Ursa Minor. it is between 250 and 1000 light years from here, and poses no danger.
    Are we fairly sure we know most/all of the neutron stars within 1000 light years of us, or only those pulsars "aimed" towrd the solar syste? Can a neutron star not be a pulsar?
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    Quote Originally Posted by Tom Mazanec View Post
    Are we fairly sure we know most/all of the neutron stars within 1000 light years of us, or only those pulsars "aimed" towrd the solar syste? Can a neutron star not be a pulsar?
    Calvera is not a pulsar. We don't think that we know ALL of the neutron stars in the galaxy, but the closest seven (non-binary) are fairly strong x-ray sources. It is plausible that there might be some much older neutron stars that were created billions of years ago and have cooled off enough that they don't emit a plentiful enough supply of x-rays, but the number of these should not be large, and even such an object cannot be very close or else it's x-rays would have been spotted.
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    The Sirius system isn't even remotely moving in our direction. It's currently at 8.6 light years, and the closest it will ever come (according to a spreadsheet I keep always to hand) is 7.5 light years, in 66,000 years time. Then it will start drifting farther away again, equally slowly.
    I can't say that your Twitter informant is an idiot, because I've never met him; I can only say that the tweet in your screenshot is indistinguishable from the tweet of an idiot.

    Grant Hutchison

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    By analogy itís a bit like watching something to the front and well to the side when driving down the road. It will get closer, pass by and move away, but will never be in any danger of intersecting with you.

    If you want to wait for a star that actually will get fairly close, just wait about 1.3 million years for Gleise 710:

    https://en.wikipedia.org/wiki/Gliese_710

    It might just get close enough to send extra comets into the solar system.

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    I am a little busy 1.3 million years from now can we go with 1.4?

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    Quote Originally Posted by Sinbad View Post
    I am a little busy 1.3 million years from now can we go with 1.4?
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    Quote Originally Posted by grant hutchison View Post
    The Sirius system isn't even remotely moving in our direction. It's currently at 8.6 light years, and the closest it will ever come (according to a spreadsheet I keep always to hand) is 7.5 light years, in 66,000 years time. Then it will start drifting farther away again, equally slowly.
    I can't say that your Twitter informant is an idiot, because I've never met him; I can only say that the tweet in your screenshot is indistinguishable from the tweet of an idiot.
    Perhaps my use of Wiki data is the reason for my somewhat little variance with your calculations, or, and all too likely these days, my calculation itself is flawed. But the graphic itself may serve to show that Sirius isn't a... significant... concern.

    Sirius closest approach.jpg
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    Quote Originally Posted by George View Post
    Perhaps my use of Wiki data is the reason for my somewhat little variance with your calculations, or, and all too likely these days, my calculation itself is flawed. But the graphic itself may serve to show that Sirius isn't a... significant... concern.

    Sirius closest approach.jpg
    Nice graphic, that sums it up.

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    Quote Originally Posted by Ken G View Post
    Nice graphic, that sums it up.
    Thanks, I "picture is worth a thousand words", but better in my case due to my poor grammar.
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    Quote Originally Posted by George View Post
    Perhaps my use of Wiki data is the reason for my somewhat little variance with your calculations, or, and all too likely these days, my calculation itself is flawed. But the graphic itself may serve to show that Sirius isn't a... significant... concern.
    The difference lies in the low radial velocity quoted by Wikipedia. I wonder if it's the velocity of the A component.
    My figure (and my spreadsheet) is relatively old, but it's within a km/s of the value given in The Sirius System and its Astrophysical Puzzles (2017).

    Grant Hutchison

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    So is it closer or further lol graphics wont load on my phone

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    Quote Originally Posted by grant hutchison View Post
    The difference lies in the low radial velocity quoted by Wikipedia. I wonder if it's the velocity of the A component.
    My figure (and my spreadsheet) is relatively old, but it's within a km/s of the value given in The Sirius System and its Astrophysical Puzzles (2017).
    Yeah, Wiki is off. It seems their reference may be more of a mean velocity for this portion of the MW, perhaps. They used 40k stars from Hipparcos.

    I found a couple of articles showing -7.6 kps, for instance here which is dubious given ...

    Sirius-and-the-Sun-comparison.jpg

    They obviously erred in... centering their labels. [sorry]

    Your reference adjusts for GR to get from -7.7 kps to-8.47 kps. Isn't this SOP? My results are now very close to yours.

    Thanks. This spreadsheet is one I want to use from time to time and it yields the ETA for travelers.
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  22. #22
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    After adjusting to the proper vectors, thanks to Grant, the following is the corrected graphic, though reduced in file size to possibly allow Sinbad's viewing

    Sirius closest approach small.jpg
    Attached Images Attached Images
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  23. #23
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    If you can't see the graphic, Sirius will only get about 10% closer than it is now, and even that will take over 60,000 years.

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    Even a mile sized rock is a great threat to earth. There are probably literally trillions of those, much closer to earth, than any neutron star. See Oort cloud. https://en.wikipedia.org/wiki/Oort_cloud
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    Quote Originally Posted by Copernicus View Post
    Even a mile sized rock is a great threat to earth. There are probably literally trillions of those, much closer to earth, than any neutron star. See Oort cloud. https://en.wikipedia.org/wiki/Oort_cloud
    This has nothing to do with the topic of the thread. Don't list every possible threat to Earth and don't derail this thread.
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    Quote Originally Posted by Ken G View Post
    If you can't see the graphic, Sirius will only get about 10% closer than it is now, and even that will take over 60,000 years.
    That's a good way to put it. [Saying is not as serious as it sounds may not be better at all. ]
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