How We'll Someday Be Able To See Past the Cosmic Microwave Background 64
StartsWithABang writes: When it comes to the farthest thing we can see in the Universe, that's the Cosmic Microwave Background, or the leftover glow from the Big Bang, emitted when the Universe was a mere 380,000 years old. But what, exactly, does this mean? Does it mean that we're seeing the "edge" of the Universe? Does it mean that there's nothing to see, farther back beyond it? Does it mean that, as time goes on, we're going to be able to see farther back in time and space? The answers are no, no, and yes, respectively. If we want to see farther than ever before, we've got two options: either wait for more time to pass, or get moving and build that cosmic neutrino background detector.
We'll see past it. (Score:1, Funny)
As soon as somebody replaces the 17 year old microwave in the cafeteria of the observatory, since scientists can't be bothered to wait until the cycle is done.
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Allah and God and Jesus and Yaweh are all the same self-hating guy.
Ermm they are not. In all 3 monotheistic religions, 'God' is qualitatively different.
The oldest Hebrew has a monotheistic God with NO recognized prophet.
The Christians have a tripart God as 3 identities, the total of which is a monotheistic god that also predates itself.
The newest - Allah who is further removed from 'man', is based on the Hebrew God (the first 4 books of the Hebrew bible) and comes with a prophet.
(I don't believe any of this btw)
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"Burma Shave"
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Slashdot (Score:1, Interesting)
Your #1 source for links to medium.com
Can we lose the daily barrage of pop-sci please.
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Medium (Score:2)
Medium.com: Because Small.com and Large.com don't exist.
Gee, I wonder (Score:2)
Gee... I wonder who the linked astronomy-related Slashdotted story will have been written by.
Click...
Yup. Thought so. Is there nobody else writing astronomy blogs these days? Or is Slashdot just in love with Ethan?
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No.. Startwithabang is in love with Ethan.
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Well, they had to fill the site with something once they got over their Bennett Haselton love-fest.
Well (Score:4)
It's not like it's going anywhere, right guys?
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It's not like it's going anywhere, right guys?
Actually, the cosmic background is going everywhere.
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The neutrino is the trendy particle, now?
Bah! Wake me when the tetryon is discovered.
Wake me an hour before the chroniton is discovered.
The "edge" of the universe? (Score:1)
So how do they know that the "background" microwaves are from the edge of the universe? I thought that the primordial microwaves are scattered throughout the universe, so what we see when we look in some direction is the sum of all the background microwaves coming from that direction.
If we're actually seeing the edge, doesn't that shoot down the idea that the universe doesn't actually have an edge, and everywhere appears to be at the "center" of the universe? How was this idea disproved? I seem to hav
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It's the limit of what's observable.
It's like how a light beam can have an edge, but it doesn't mean there isn't anything in the shadow.
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"It's like how a light beam can have an edge, but it doesn't mean there isn't anything in the shadow."
In this case the shadow is in front of the pulse of light that was the big bang.
We will never be able to see further than that since it is moving away at the speed of light.
Unless we can invent a (much) faster than light drive, and go chase it down.
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http://www.merriam-webster.com/dictionary/further
Definition 1) Farther
Heh; I think you've got it. ;-)
This is one of the favorite "language peevery" examples that get discussed often in (English) language forums (or fora if you prefer ;-). The confusion about any purported difference goes back to before there were any actual English dictionaries, and probably 99% of the world's native speakers of English treat them as synonyms. The few that don't can't hardly agree about what their "correct" usages should be. But that doesn't stop such people from harrassing the rest of u
Re:The "edge" of the universe? (Score:5, Informative)
So how do they know that the "background" microwaves are from the edge of the universe? I thought that the primordial microwaves are scattered throughout the universe, so what we see when we look in some direction is the sum of all the background microwaves coming from that direction.
If we're actually seeing the edge, doesn't that shoot down the idea that the universe doesn't actually have an edge, and everywhere appears to be at the "center" of the universe? How was this idea disproved? I seem to have missed the discovery of an actual edge, somehow.
The cmb is simply the first light that was able to freely travel through space. There is no actual 'edge' but there is always the apparent virtual edge beyond which you cannot see. It's easiest to think of it as space being infinite in size but finite in age. Light needs to travel to your eye to see so the farthest you can see is simply the age of the universe x the speed of light. As the universe cooled right after the Big Bang, initially light could not directly pass through all the hot plasma, only after it cooled and became transparent to visible light did light spread out in significant amounts. The heavily red shifted version of this light is the cmb we see today. Your own two eyes see a slightly different virtual 'edge' as every point in the universe looks as if it is the center.
It took about 380k years for the universe to become transparent to light neutrinos pass through ionized material easily and the surface of last scattering is nearly as old as the Big Bang. It's a very old concept but has been researched lately as each kind of neutrino would have a slightly different background. The article is just random click bait there is nothing new or interesting about it really.
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Imagine a hot Universe at an early time (which may be very large, even infinite). Photons are suddenly released and go in all directions.
The Universe expands (meaning the distance between everything increases). The photons are still traveling through the Universe.
At any point in time you can observe photons arriving at your position, and they are as old as their origin is away in light-distance (well, space expanded in the meantime, that makes it a bit harder to imagine).
So, you can observe the background a
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Wait is that not The Edge you were talking about?
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four (4) questions three (3) answers (Score:2, Flamebait)
>> The answers are no, no, and yes, respectively.
If I'm reading this right, you just said:
But what, exactly, does this mean? no
Does it mean that we're seeing the "edge" of the Universe? no
Does it mean that there's nothing to see, farther back beyond it? yes
Does it mean that, as time goes on, we're going to be able to see farther back in time and space? (no response)
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Ah...the "respectively." However, I think that's just part of the last answer, so I'll update this to:
But what, exactly, does this mean? no
Does it mean that we're seeing the "edge" of the Universe? no
Does it mean that there's nothing to see, farther back beyond it? yes, respectively
Does it mean that, as time goes on, we're going to be able to see farther back in time and space? (no response)
Personally, I like his "what, exactly, does this mean" answer: it would have avoided a lot of religious wars. :)
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One Daft Question (Score:2)
Does it mean that, as time goes on, we're going to be able to see farther back in time and space?
Obviously the answer is yes because, as time goes on, the period at which the CMB was emitted moves further into the past so obviously we are seeing "further back in time" but only at the rate of one year further per year past (on average). Since the universe is also expanding we are also looking further. This is about as insightful as pointing out that as time goes by I can remember events further back in time.
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In other words, we see further into the past by much more than a single year for every elapsed year
No, the universe was opaque until the plasma cooled and released what is now the CMB. We cannot see further back in time with light. Hence the only reason we can see further into the past each year is because that event (the universe becoming transparent) is getting further away from the present. Currently the amount of that event we can see is increasing - a trend which will eventually reverse due to dark energy - but it all occurred ~380k years after the Big Bang. So the only way we see further back is t
Well written article (Score:2)
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The microwave background radiation is what remains from the red-shifting of a burst of light when electrons became bound to protons and was stretched by the subsequent expansion of space. Wasn't there an earlier burst, of gamma rays, when quarks condensed from the quark-gluon plasma to form baryons? Has that been absorbed/scattered to obscurity by interaction with matter since then?
The entire universe was quite opaque then, much like the core of the sun. Those photons didn't ravel far before finding an electron, which of course would emit a new photon (also gamma frequencies at first) soon. The dominant forces in the universe between the first few seconds and 300K years were gravity and light pressure. The photons of the CMBR were still fairly high energy at the point the universe became transparent - there's just been a significant redshift since then.
Why hasn't the microwave background has not similarly been obscured by interaction with matter (exciting rotational energy levels of molecules?)
For the same reason we can see
Any hope of seeing gravitational background? (Score:1)
The BICEP2 experiment was designed to look for these, and last year announced detecting b-modes in the CMB. Of course, as we now know thanks to Planck their discovery is probably due to dust polarization. Are there any current or plan