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Thread: The Observational Astronomy Thread

  1. #31
    Senior Member Room2201974's Avatar
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    On why studying variable stars is important:

    https://www.msn.com/en-us/news/techn...n5iE?ocid=AMZN
    The more I compose, the more I know that I don't know it all. I think it's a good way to start. If you think you know it all, the work becomes a repetition of what you've already done. ~ A. R. Rahman

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  3. #32
    Senior Member Room2201974's Avatar
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    I haven't had a chance to do any observational astronomy for months and was unaware of the story above. Last night I took a quick look at Orion and it's noticable. Betelgeuse has dimmed quite a lot. Wow!!!! It used to rival Rigel but now it's not even close. Looks like it's about as bright as Bellatrix, Alnitak or Alnilam.
    The more I compose, the more I know that I don't know it all. I think it's a good way to start. If you think you know it all, the work becomes a repetition of what you've already done. ~ A. R. Rahman

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  5. #33
    Senior Member Luchesi's Avatar
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    Quote Originally Posted by Room2201974 View Post
    I haven't had a chance to do any observational astronomy for months and was unaware of the story above. Last night I took a quick look at Orion and it's noticable. Betelgeuse has dimmed quite a lot. Wow!!!! It used to rival Rigel but now it's not even close. Looks like it's about as bright as Bellatrix, Alnitak or Alnilam.
    Yeah, they called me and they said they'd be here in 3000 or 4000 years, Earth time.

    Their large ships had been mothballed for millions of years since Betelgeuse initially expanded and they had to move to an outer planet. So they're furiously working to bring them back into operation.

    They want OUR jewel of planet so they warned that we should start terraforming Mars as soon as we’re able. It's not up for negotiation!

    Such are the ways of the universe ( Eminent domain), but they said they will protect our solar system from the other predators out there. ...So that's something..
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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    Senior Member Strange Magic's Avatar
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    The info about Betelgeuse leads to an article in the latest issue of Sky & Telescope on giant carbon stars like Hind's Crimson Star (R Lep) and Herschel's Garnet Star (Mu Ceph), and how they might trigger the birth of companion carbon dwarf stars. Since the 1970s, astronomers have been studying carbon dwarf stars which are far dimmer than the giants but most of whom seem to orbit white dwarfs or invisible companions. The thesis is that a blue star a few times more massive than the sun, and a red dwarf are born together. The blue stars runs out of hydrogen quickly and expands to be a red giant, burning helium to make carbon and oxygen. If the carbon enters the giant's atmosphere, it may become a carbon giant like R Lep, and shed massive amounts of carbon onto its red dwarf companion, turning it into a carbon dwarf. The carbon giant meanwhile dies to become itself a white dwarf and can cool to invisibility. S&T lists 4 carbon dwarfs as possible targets for amateurs but they are challenging, with magnitudes ranging from 13.9 to 16.7, too dim for me!

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    Senior Member KenOC's Avatar
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    Here's an interesting YouTube video about the dimming of Betelgeuse.



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    Senior Member Strange Magic's Avatar
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    While we're on big stars, here's Wikipedia on The Biggest, with UY Scuti up there with another contender, VY Canis Majoris, both possibly reaching the orbit of Saturn if occupying the sun's position. Now that's a Big Star!

    https://en.m.wikipedia.org/wiki/List_of_largest_stars

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  12. #37
    Senior Member Luchesi's Avatar
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    Default https://www.youtube.com/watch?v=v9sh9NpL4i8

    Very intelligent tech-civs will go to sleep and wait trillions of years for the universe to cool down and that way they'll have much longer lifespans.

    https://www.youtube.com/watch?v=v9sh9NpL4i8
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

  13. #38
    Senior Member Room2201974's Avatar
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    We are stardust
    We are golden
    We are billion year old carbon

    https://www.msn.com/en-us/news/techn...UQy4?ocid=AMZN
    The more I compose, the more I know that I don't know it all. I think it's a good way to start. If you think you know it all, the work becomes a repetition of what you've already done. ~ A. R. Rahman

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  15. #39
    Senior Member KenOC's Avatar
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    Quote Originally Posted by Room2201974 View Post
    We are stardust
    We are golden
    We are billion year old carbon
    Sometimes even the best atom can fall on hard times. See the sad story here.
    Last edited by KenOC; Jan-14-2020 at 18:48.


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  17. #40
    Senior Member Luchesi's Avatar
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    The Methuselah Planet's globular cluster is M4, 7200 LYs away. For 10 billion years it orbited a yellow star like ours in a nearly circular orbit, somewhere between 2 and 8 AU from its primary. Then, in this crowded cluster 2 billion yrs ago, the yellow star and its planet were dislodged and plunging into the crowded core of M4, they passed too close to an old neutron star that had an orbiting companion star. The gravitational interaction booted the neutron star's companion into space. But the neutron star held on to the yellow sun-like star and its planet. Eventually the sun-like star aged, bloating into a red giant. The red giant's gas flowed onto the neutron star, energizing it. The neutron star spun faster. Today, it rotates 100 times a second. Age can be calculated from pulsar spin-down rates. Methuselah from the Bible

    They say this is enough info to reliably date the planet to 12.7 billion yrs ago. The planet's globular has been dated, the planet's original star has been dated and the pulsar spin-down rate from its last mass interaction spin-up encounter has been dated, within accepted ranges.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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  19. #41
    Senior Member Luchesi's Avatar
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    Recently there's been gravitational waves detected in the direction of Betelgeuse, but not exactly from the star it would seem.

    Betelgeuse has much more nitrogen than it should have. This might be a clue.

    Betelgeuse is moving from its birth place 8.5 million years ago very quickly in the galaxy to its present location.

    Betelgeuse is rotating much faster than it should for its size.

    If it was a binary system then when it got booted out of its stellar nursery the two stars would eventually coalesce, and that would account for the rapid rotation. And if this is true then Betelgeuse has much more than 100,000 years left before it collapses. The nitrogen was stirred up during the coalescence so that it can be detected today.

    It's another one of those detective stories.
    Last edited by Luchesi; Jan-26-2020 at 03:17.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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  21. #42
    Senior Member mikeh375's Avatar
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  23. #43
    Senior Member Strange Magic's Avatar
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    Quote Originally Posted by mikeh375 View Post
    A very interesting article. Many thanks for posting! The scientific method and its human and sociological aspects all at play, as with every important new idea, ultimately confirmed or rejected. It will take some serious research, experimentation, theorizing to modify General Relativity--it's held up remarkably well now for a hundred years.

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  25. #44
    Senior Member mikeh375's Avatar
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    Quote Originally Posted by Strange Magic View Post
    A very interesting article. Many thanks for posting! The scientific method and its human and sociological aspects all at play, as with every important new idea, ultimately confirmed or rejected. It will take some serious research, experimentation, theorizing to modify General Relativity--it's held up remarkably well now for a hundred years.
    Yes GR has held up so brilliantly. It's wonderful to know that even that paragon of human achievement is able to be questioned and scrutinised without bias nor prejudice - there is hope for us all still.
    Lousy weather in my part of the UK so no lugging a heavy telescope out tonight. We had some wonderful clear skies a few days ago but not for the next few days. I keep looking at Betelgeuse hoping to see her blow. Speaking of which apparently a white dwarf companion fell into a stars heart and went supernova. The explosion reacted with the layers of the star it fell into and created one of the biggest explosions ever witnessed.

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  27. #45
    Senior Member Luchesi's Avatar
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    Quote Originally Posted by mikeh375 View Post
    20 years ago the supernova data seemed to show that the universe began to expand in an accelerated mode as you would expect from a large event (the big bang and the inflationary changes of state).

    But by about 9 billion years ago the acceleration was slowing down so that it was still accelerating, but less than before. This should be expected from the physics of an explosion with the gravity of the universe acting to slow the expansion rate.

    By about 5.5 billion years ago the accelerating rate picked up again! according to the data.

    So the explanation for this was that Dark Energy was the result of the repulsion resulting from virtual particle activity. The per-unit strength of this activity remained constant, but the ever expanding space-time between the galactic filaments was adding more and more repulsion between those huge filaments.

    More recently with better data this picture has become murkier.
    Last edited by Luchesi; Jan-26-2020 at 18:12.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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