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Thread: Can someone explain the article below in layman terms

  1. #31
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    The galaxies are 680 million years younger than the Big Bang.
    The galaxies haven't reached us. The plasma bubbles haven't reached us. Their light has reached us.
    We're currently receiving light emitted 400,000 years after the Big Bang (the Cosmic Microwave Background), from farther away than these galaxies - it's been travelling for 680 million years longer than the light from the galaxies, so it is arriving now, at the same time as the light from the galaxies.

    Grant Hutchison

  2. #32
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    So these bubbles And galaxies are about to hit us? What effect will this have on us?and when you say about to hit us how long before it does ?
    Last edited by Sinbad; 2020-Jan-15 at 12:36 AM.

  3. #33
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    Quote Originally Posted by Sinbad View Post
    So these bubbles And galaxies are about to hit us? What effect will this have on us?and when you say about to hit us how long before it does ?
    The universe is expanding. This means that almost nothing other than light is actually moving towards us once you look outside our galaxy. Andromeda galaxy is probably the most famous, but there are perhaps only 100 or so galaxies moving towards us in the whole observable universe, and most if them are in our local group.

    Those bubbles, the galaxies, they are not about to hit us. They are now even further away from us than when the light we are seeing was emitted.

  4. #34
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    Quote Originally Posted by Sinbad View Post
    So these bubbles And galaxies are about to hit us? What effect will this have on us?and when you say about to hit us how long before it does ?
    I'm kind of repeating myself. But really, you need to understand something, or rather two things. First of all, the whole thing with the Big Bang and the expanding universe and how the Big Bang took place everywhere and the age of the light we are seeing, is really hard to grasp. I'm not very good at understanding it myself, meaning that I can repeat what I read but don't really understand it intuitively. So don't worry if you don't understand it well. The other thing is that there is nothing dangerous going on. Nothing is going to hit us except photons (light), which we have been seeing since long, long, ago, and will continue to see.
    As above, so below

  5. #35
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    The galaxies are 680 million years younger than the Big Bang.
    The galaxies haven't reached us. The plasma bubbles haven't reached us. Their light has reached us.
    We're currently receiving light emitted 400,000 years after the Big Bang (the Cosmic Microwave Background), from farther away than these galaxies - it's been travelling for 680 million years longer than the light from the galaxies, so it is arriving now, at the same time as the light from the galaxies.
    Sorry this comment says they are arriving now? I am confused I read bubbles and am not sure what is just about to hit us. This is the oldest thing we have ever captured and the furthest thing away from us and it seems like a bubble is just about to hitbusbso I am confused?

  6. #36
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    Quote Originally Posted by Sinbad View Post
    Sorry this comment says they are arriving now? I am confused I read bubbles and am not sure what is just about to hit us. This is the oldest thing we have ever captured and the furthest thing away from us and it seems like a bubble is just about to hitbusbso I am confused?
    Nothing mentioned in the article is about to hit us. We have received the light from these things. That is all.

  7. #37
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    So the light hit us but what about the bubble it is also about to hit us no?

  8. #38
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    Quote Originally Posted by Sinbad View Post
    So the light hit us but what about the bubble it is also about to hit us no?
    No, the bubble is very far away and happened very long ago. The galaxies that caused the bubble have been moving away from us for the whole lifespan of the Universe, and are now much further away than they were when they emitted the light we see.

    Nothing is going to hit us, apart from a few photons that bring information about this distant and ancient event.

    Grant Hutchison

  9. #39
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    Quote Originally Posted by Sinbad View Post
    So the light hit us but what about the bubble it is also about to hit us no?
    As I said. The light reached us. The bubble isn't going to.

    Not sure why you think that just because you can see something it is going to hit us. The Moon isn't. The Sun isn't. Look outside your window and you'll see lots of things that are not going to hit you.

  10. #40
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    In fact, only a tiny minority of all the objects you ever see in your entire life will actually hit you. And if they are very far away, and moving farther away, then they are pretty definitely not going to hit you.

    Grant Hutchison

  11. #41
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    So the light has hit us already cause it travelled the speed of light but could nothing else have travelled with it

  12. #42
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    Quote Originally Posted by Sinbad View Post
    So the light has hit us already cause it travelled the speed of light but could nothing else have travelled with it
    Just like with a car that is moving away from you--you still see light from it. And nothing comes with the light. So yes, nothing else has traveled with it.
    As above, so below

  13. #43
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    The galaxies are 680 million years younger than the Big Bang.
    The galaxies haven't reached us. The plasma bubbles haven't reached us. Their light has reached us.
    We're currently receiving light emitted 400,000 years after the Big Bang (the Cosmic Microwave Background), from farther away than these galaxies - it's been travelling for 680 million years longer than the light from the galaxies, so it is arriving now, at the same time as the light from the galaxies.
    So what then is arriving now along with the light from the galaxies, I assumed arriving now means it arrived already now.

  14. #44
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    Quote Originally Posted by Sinbad View Post
    So what then is arriving now along with the light from the galaxies, I assumed arriving now means it arrived already now.
    The Cosmic Microwave Background Radiation. Which doesn't have anything to do with that galaxy or its plasma bubbles. Carefully re-read what Grant said, I can't think of a way he could have put it more clearly.

  15. #45
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    I get the cosmic microwave background and light from this have reached us here on earth. It’s not something that we felt when it reached us.

  16. #46
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    Quote Originally Posted by Sinbad View Post
    I get the cosmic microwave background and light from this have reached us here on earth. Itís not something that we felt when it reached us.
    And the CMB and light from the galaxies and their bubble are still reaching us. But that's all that's ever going to arrive from these galaxies and their bubble - they're too far away, and they're moving very quickly away from us.

    Grant Hutchison

  17. #47
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    What do you mean by still reaching us are you talking about these 3 galaxies in question? How long before they have fully reached us?

  18. #48
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    Quote Originally Posted by Sinbad View Post
    What do you mean by still reaching us are you talking about these 3 galaxies in question? How long before they have fully reached us?
    There's something odd about the way you're writing about this - I can't tell if you're confused about what's going on, or just not writing clearly.

    The galaxies are not "reaching us". They will never reach us. No physical part of these galaxies will ever reach us.
    The light from the galaxies is reaching us. It has been reaching us continuously during the whole history of the Earth, and will continue to reach us for at least a very long part of the future of the Earth, if not forever. That's how we see the galaxies. So it's not a matter of the galaxies "fully reaching us" or even their light "fully reaching us" - we just keep receiving photons of light that these galaxies emitted a very long time ago.

    If you look out your window at a tree, there's never a point at which the light from the tree "fully reaches" you - it just keeps on coming, day after day, year after year. And, like the galaxies and their bubble, the tree never gets any closer during all the time you can see it.

    Grant Hutchison

  19. #49
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    Oh I am sorry, I thought that the light has just starting hitting us I did not realize that the light and cmb from these galaxies has always been reaching us.

    Sorry I am confused I thought this is new teaching from these galaxies the way the article makes it sound.

  20. #50
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    Quote Originally Posted by Sinbad View Post
    Oh I am sorry, I thought that the light has just starting hitting us I did not realize that the light and cmb from these galaxies has always been reaching us.

    Sorry I am confused I thought this is new teaching from these galaxies the way the article makes it sound.
    We're bathed in light (and other EM radiation) from all over the sky, all the time. But there's a lot of it, and much of it is very faint, so we keep discovering new stuff as our instruments become more sensitive. The fact we've just noticed something new to us doesn't mean that it has just appeared.

    Grant Hutchison

  21. #51
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    So this specific light and cmb have already been hitting us for a while now and we have just noticed it and we will continue to be hit from it for a long long time. I get it

    What is a plasma bubble?

  22. #52
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    When sufficiently energetic radiation hits a gas, it ionizes it (knocks electrons off the atoms). The resulting gas of ions and electrons is called a plasma. If you have a load of gas sitting in space, and a nearby radiation source (like the stars in a new galaxy) heats up and ionizes part of it, that heated part expands like an inflating balloon - that's a plasma bubble.

    Grant Hutchison

  23. #53
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    So these are not the only galaxies we have seen with plasma bubbles and they disappear fro. The galaxy eventually

  24. #54
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    There are plasma bubbles related to other galaxies, yes. Including our own. I think the mechanism is different in these very distant galaxies we've been talking about, but wherever you have some source of energy that locally heats the interstellar/intergalactic medium, you're going to have the potential for a bubble.

    Grant Hutchison

  25. #55
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    Now the reference of bubbles comes up often is a plasma bubble same as a vacuum
    bubble
    Also does our galaxy have a plasma bubble or has it disappeared
    Last edited by Sinbad; 2020-Jan-15 at 08:51 PM.

  26. #56
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    A vacuum bubble is a theoretical possibility, a region of space that has spontaneously changed its fundamental properties. We don't know if such a thing could occur, and we haven't witnessed such a thing.
    A plasma bubble is a real object, as I've described, and many have been observed.
    So they're completely different things.

    Our galaxy has a pair of "Fermi bubbles", very large plasma bubbles extending north and south of the galactic core, which were probably created by energetic outflow from the central black hole, hundreds of thousands or millions of years ago. They're still there, and detectable by the gamma rays they emit.

    Grant Hutchison

  27. #57
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    Thank you

  28. #58
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    Quote Originally Posted by Grey View Post
    The period usually referred to as the "cosmic dark ages" was after the universe became cool enough for neutral atoms to form, at which time the universe became largely transparent to both visible and ultraviolet light, and the decoupled photons cooled enough to no longer be visible. At that point, light could travel easily through the universe, but since there were no stars, there were few sources of light to do so.
    So what happened to the visible light emitted by the first stars? Was it intercepted by the neutral gas the first stars had not yet managed to ionize, or did it freely travel through the neutral gas to be visible to us if we can recognize them?

  29. #59
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    Quote Originally Posted by chornedsnorkack View Post
    So what happened to the visible light emitted by the first stars? Was it intercepted by the neutral gas the first stars had not yet managed to ionize, or did it freely travel through the neutral gas to be visible to us if we can recognize them?
    I think it's out there, and we see some of it. That's what we're seeing when we see the very earliest stars and galaxies, after all. Those early galaxies are quite small and faint, of course, because they are so far away, and the light is heavily redshifted. The formation of those first stars marks the end of the "cosmic dark ages", since at that point the universe was no longer dark.
    Conserve energy. Commute with the Hamiltonian.

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