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General Astronomy, Cosmology and Space Exploration Discussion

Discussion in 'Science' started by BlueRaven, Jul 23, 2013.

  1. JSmithDTV

    JSmithDTV Member

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  2. BurningFeetMan

    BurningFeetMan Member

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    From this "we're in one giant universal black hole" thought, I think an argument could be - that other galaxies in the same phase as ours, not accelerating away from us, but drawing closer to us, if we were to chart them then they should add up to a paraboloid of revolution-ish type signature, as we all draw nearer to our universal singularity.

    I've heard how the Andromeda galaxy is getting closer to us, but I've never really seen a map of other galaxies that are also no accelerating.
     
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  3. RnR

    RnR Member

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    Hmm...

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

    TIL...
     
    Last edited: Jun 17, 2022
  4. MUTMAN

    MUTMAN Member

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    BFM & RnR
    Yes like that, but I'm much dumber. So i try not to over think it or i go to bed with headaches :D
    i have wondered if we arnt part of a giant black hole or white hole thats just going through the motions.
    suck everything in, blow it back out. universes start again ??
     
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  5. JSmithDTV

    JSmithDTV Member

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    Not that far afield;

    [​IMG]

    ... observations show though the universe is not only expanding, but accelerating during expansion.



    JSmith
     
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  6. BurningFeetMan

    BurningFeetMan Member

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    And where my brain is lost, is on, is the universe accelerating outwards, or is it accelerating inwards?
     
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  7. MUTMAN

    MUTMAN Member

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    Thats the problem right, depending which side of the hole we are in it'll appear opposite to the other side ??
     
  8. RnR

    RnR Member

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    Might be that the acceleration is due to our black hole managing to consume more and more matter and energy in our parent universe ie its still getting bigger. At some point, the acceleration might pause or stop.

    If black holes have entire universes inside them, what happens to the stars, planets and inhabitants of these universes when two black holes collide and merge?
     
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  9. MUTMAN

    MUTMAN Member

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    Ummm.

    Oh fudge, there goes my sleep
     
  10. RnR

    RnR Member

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    Well looks like I had one win for the day :D
     
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  11. MUTMAN

    MUTMAN Member

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    Hahhaa. You owe me a flow x13, the good one too
     
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  12. RnR

    RnR Member

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    Been checking every day - nothing yet. Some store in Belgium has an order button, but no indication of stock...
     
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  13. OP
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    BlueRaven

    BlueRaven Brute force & optimism

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    So, I check in on this thread today and find that I wrote out this long-arse semi-coherent reply to the "black hole weirdness" thing but never posted it... must have been having a good night. :)
    What the hell, gonna post it anyway. Reply begins:

    It would be pretty wild if new missions like JWST etc. allow us to solidly pinpoint a "great attractor" beyond our local galactic cluster/supercluster, as was theorised some time back in the 30s or 40s iirc...
    Such a discovery could potentially throw a cloud of doubt over a lot of stuff e.g. the Hubble Constant not because he (and all the work that is based on his theories) was wrong per se, but because his (our) frame of reference was all out of whack.
    Although it's entirely possible that my understanding of those old theories and how they relate to what we're discussing here is also all out of whack, such theories having been rendered moot by more recent research... I'm not an astrophysicist. :)

    See, there's your problem, emphasis mine. :)

    The last time I checked in on the state of large-scale cosmology, it was known that our galaxy forms part of a local cluster which itself is part of a supercluster, with ever larger voids between these groups.
    This ties in neatly with a semi-harebrained theory of mine, which is that all matter at any scale behaves in the manner that atoms and molecules appear to behave at our hooman scale of distance/time.
    The four forces (gravity, electromagnetism, and the strong/weak nuclear forces) are all just one "superforce" manifesting at our local scale in various ways we don't fully understand; an idea which gained some popularity in the late 70's/early 80's when many physicists were still full steam ahead in the search for a Grand Unifed Theory which married Newtonian physics, quantum physics and the special/general theories of relativity.

    If this is true, any poorly understood phenomena such as strange black hole behaviour, the apparently unexplainable prevalence of "dark matter" and the accelerating rate of universal expansion (at the Big end of the scale) or subatomic particle behaviour and Quantum Weirdness (at the Little end) can be explained as Us simply lacking the required resolution in our measurements at either end of the distance/time scale.

    It's turtles all the way down, basically. And all the way up.
     
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  14. JSmithDTV

    JSmithDTV Member

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  15. OP
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    BlueRaven

    BlueRaven Brute force & optimism

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    And if they are, what are they "falling" into...? Other than a vague morass of cosmophilologlosophical concepts?

    Alright, I'll stop. Sorry.
    Let's get back to the cool space articles and links and vids and stuff. Sorry.

    Hold on, I'mma check Ars Technica for whatever Eric Berger just posted. :)
    Oh yeah, Ariane 6 is delayed again and NASA's about to have a fourth whack at putting a full fuel load in the big orange pork barrel.

    Honestly, I hope they manage to finally complete the wet-dress-rehearsal.
    Partially because it will be amazing if it actually flies (lol), but mostly because it will be even more amazing to watch that many Ameribucks go boom all at once if it RUDs.
    I realise that this is a pretty self-interested attitude towards a major human space exploration project, but since everything about this major human space exploration project has been managed in a self-interested way thus far I doubt it will make much difference to the mission outcomes.
     
    Last edited: Jun 20, 2022
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  16. OP
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    BlueRaven

    BlueRaven Brute force & optimism

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    More good news, NASA + Rocket Lab + CAPSTONE = great success! (well, the launch/TLI phase at least)



    There's a quick recap of terminal countdown/ignition/launch right at the end of the stream for anyone who just wants to watch Little Rocket Go Up. :)
     
    Last edited: Jun 28, 2022
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  17. adamsleath

    adamsleath Member

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    andromeda is headed right for us. in our little local area of the bigun.
    gravity has its way in local groups. despite whatever theories they dream up for cosmological expansion.

    ===
    https://www.space.com/23772-red-dwarf-stars.html
    theoretically, red dwarfs, the most common type of main sequence star, have 'lifetimes' of trillions of years. as the universe is supposedly 13+ ish billion years since the magical bang, i guess they've done the math. assuming all their theories are correct.

    proxima centauri, red dwarf, should last much longer than our sun therefore , whatever sol morphs into, red giant, white dwarf. whatevs.

    the hubble ultra deep field is showing galaxies that are 13 billion light years distant. so while some stars would have extinguished in that time, much would remain, in the stellarsphere, the big energetic mass=energy arena...

    it is proposed that galaxy clusters 'congregate' at intersections of dark energy filaments.

    "the star that burns twice as bright burns half as long, and you have burned so very very bright, leroy." - Bladerunner
    well. im not sure that is accurate with regard to stars...which don't "burn" but consume their nuclear fusion 'fuels', but the idea is basically correct it seems.
     
    Last edited: Jun 29, 2022
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  18. JSmithDTV

    JSmithDTV Member

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  19. OP
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    BlueRaven

    BlueRaven Brute force & optimism

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    I think it's correct over a suitably long timeframe, but at human time scales the metaphor is complicated by cyclical nature of the fusion reaction which powers many types of star, Sol being a good example.
    Gravity tries to compress the sun's matter, increasing the rate of fusion and generating more high-energy particles which literally try to rip it apart, causing expansion until the tipping point is reached again.
    Frequency is around the every-couple-of-weeks mark iirc, typically (but not always) punctuated by a big outgassing/radiation event every couple of months which can upset the cycles a bit until everything settles down again.

    As I understand it, both the magnitude and the frequency of these cycles will change at varying rates over a star's lifecycle depending upon numerous variables such as the original mass of the gas/dust cloud which formed the star (determining how big the "fuel tank" is), rate of initial expansion and how much extra matter it gobbled up during this phase (how brimmed the fuel tank was at the start of the journey), rate of reaction based on the particular composition of elements within the star (how hard the throttle is being pressed), and compression/expansion effects caused by the gravitational fields of other bodies in the local group (e.g. binary/twin systems). And this is just my layperson understanding of stellar physics, the amount I don't know is surely staggering.

    So given all of those variables over a 13-billion-year x-axis, I think it's kind of hard to compare one stellar-fusion-powered pressure cooker to another in an absolute sense.
    It is a great metaphor though. When a star goes supernova it becomes the brightest thing in the known universe for a very brief time, cosmologically speaking.
    But not every star ends its life that way, even those that possess the necessary characteristics for it to be possible. Some are unavoidably destined from birth to slowly fade away.
    Works on many levels. :)
     
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  20. BurningFeetMan

    BurningFeetMan Member

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