The dark night sky

[sparker1776]

The hypothesis that there aren't that many stars doesn't hold up.

Celestial objects brightness is measured by 'apparent magnitude'. This is a scale that currently runs from -26.73 to a hypothetical 38 (but is inverse - negative means 'really bright'). The human eye can see anything negative, and up to 6.5.

http://en.wikipedia.org/wiki/Apparent_magnitude

Thus, the reason the sky is dark at night is that most objects in the universe are so far away that not enough photons from them reach us per second, and our eyes are not that sensitive. Thus, they are just too dim to be seen.

[sparker1776]

To take it a step further, no matter where you look there are many, many stars and galaxies. To infer that that gaps between what we see is because 'there aren't enough stars' steps around the fact that within the gaps we see there are billions of galaxies and stars. They are just so far away that you don't get hit with photons from them often enough for them to be visible to you.

To put another way, if suddenly every object in the sky became visibly bright, the sky would indeed be filled with light.

[WoodenTaco]

Yeah, this one didnt make terribly much sense to me. Isn't the atmosphere a large factor? You can see more stars in space.

[sparker1776]

To go even further, you can calculate the pixelation you would get by using the Hubble Deep Field and some simple math.

Someone should do that :p

Take the number of objects in the deep field and multiply by its coverage ratio and thats how many pixels you would have lighting up the sky.. generally..

I believe the deep field is one-two millionth of the sky from an individuals perspective I believe. It contains 10,000 galaxies. So the visible sky would be lit up by about 20 billion pixels. A high def flatscreen has about a million pixels if Im correct. I think if you surrounded yourself with 20,000 flat screens edge to edge displaying white light, I would consider that 'lit up'.

No time to check my math, go for it.

[Asimovian]

Requisite link to article. (http://www.straightdope.com/classics/a4_174.html)

[vison]

I was hoping this thread was about the horrors of light pollution.

It's not dark at night any more and I hate it.

[DSYoungEsq]

The hypothesis that there aren't that many stars doesn't hold up.

Celestial objects brightness is measured by 'apparent magnitude'. This is a scale that currently runs from -26.73 to a hypothetical 38 (but is inverse - negative means 'really bright'). The human eye can see anything negative, and up to 6.5.

http://en.wikipedia.org/wiki/Apparent_magnitude

Thus, the reason the sky is dark at night is that most objects in the universe are so far away that not enough photons from them reach us per second, and our eyes are not that sensitive. Thus, they are just too dim to be seen.
You may want to rethink your answer. (http://en.wikipedia.org/wiki/Olbers_paradox) ;)


Unless, of course, you consider yourself much smarter than the entirety of the world's professional astronomy community. :dubious:

[John W. Kennedy]

Cecil answers this in the column itself. It doesn't matter how dim the farther stars are; in an unbounded Newtonian universe with an infinite number of stars, the sky would be infinitely bright. The dimming caused by the inverse-square law would be canceled out by the number of stars in any arbitrary cone of observation increasing with the square of the distance.

[AHunter3]

If a star of (let's say) magnitude 11 cannot be seen by the naked eye, I would assume that a thimbleful of hot glowing ionized hydrogen gas could not be seen at a distance of several million miles. It would be too small, we would be too far away from it, the total light output would not cause enough of it to head in the specific direction of our eyeballs for us to register it.

But if that thimbleful is adjoined top and bottom and left and right with other simlar thimblefuls, and those likewise, and so on, eventually you can see something, yes? After all, our sun is rather spectacularly visible, even much much farther away from it than we are, and if you started out with thimblefuls, somewhere between the first thimbleful and the volume of the sun you'd hit a point were it would be visible. Yes? With me so far?

OK, now suppose, having determined the exact number of thimblefuls sufficient to cause us to be able to see it, we arranged to have 2/3 of them removed, leaving a sort of swiss-cheese latticework of hydrogen-thimblefuls. The loss in light would mean we could no longer see it (it was just sufficiently bright when we started out). Still with me?

Now suppose we have the removed thimblefuls of hydrogen relocated an additional 500 yards farther away from us, and position them so that from our vantage point they are lined up with the holes created when we removed them from the original mass. If we could see them at that distance, they would be in our line of sight, just as the ones we did not remove are in our line of sight. Is the combined arrangement, consisting of the swiss-cheese latticework in front and the other, more spread-out haze 500 yards further away, visible to us? Well, no, because 2/3 of the light source that was just sufficient to be visible has been relocated farther away, making it dimmer.

But if we have someone come in and keep adding additional thimblefuls out there in the midst of the more diffuse haze, will the entire works eventually become visible? It seems a matter of common sense to me that the minimum number of additional thimblefuls required to accomplish that would be the number it takes to cover the same visual field: in other words to fill in the holes that we created when we removed the original thimblefuls. You would need a lot more of them of course because in their original location they took up space like this if you looked at them through binoculars:

O

but 500 yards farther away they look like this:

O


So to get enough light from them at that distance, you need to do something like this:




..O
.OO
OOO
.OO
..O



By extrapolation, it doesn't really matter how far away they are, as long as you've got enough of them to fill in all the holes. A loose latticework at any distance without more stars behind it to shine through the holes is going to mean you can't see anything in that direction once you're too far away from it.

But if the univere is infinite, then no matter how loose the latticework is at some randomly-chosen distance (and direction), every single little micropixel of space within the holes in the latticework is going to be filled — some spots at pretty close range, others not until you go a lot farther back, but every single bit of it sooner or later.

So the universe ought to be looking uninterrupted bright white.



(Unless it's expanding or something)

[Exapno Mapcase]

Unless, of course, you consider yourself much smarter than the entirety of the world's professional astronomy community. :dubious:
I know I'm getting crankier in my old age, but posts like the OP bother me more than they used to. Olber's paradox has lasted for 150 years and has been examined by some of the world's top minds. How could anyone even consider, let alone assert on a message board, that all of them have missed such a trivially simple answer? Wouldn't the thought occur to you instantly that you must have misunderstood some part of the question if the answer were this obvious? (Not to mention what some conventionally-minded people might deem to be a fairly serious obstacle: that the answer was specifically dismissed in Cecil's column[!])

This is just one example of a larger malady that occurs in all scientific fields, as when people construct "proofs" of trisecting the angle or announced they have proven that information can be sent faster than the speed of light by wriggling the end of a very long stick or insist that they can divide by zero. Somewhere along the way they've fundamentally misunderstood the terms and conditions of the problem.

In Olber's case, there are two essential underlying assumptions that must be addressed to remove the "paradox."

1) The number of stars is infinite.

2) The universe is of fixed size.

Once stated, it's easy to see that the OP's answer neglects assumption 1. It doesn't address infinity.

As others have already mentioned, even the addition of extremely small numbers can eventually produce an infinite result. (Take the arithmetic sequence 1/2 + 1/3 + 1/4 + 1/5 ... Although it adds up slowly, you can exceed any finite number by extending the sequence far enough.) Olber assumed that the universe and the number of stars in it was infinite, having no reason not to do do. In an infinite universe, any sun-sized circle of the sky would have to eventually hold the sum total of a sun's worth of photons. In fact, infinitely more than that.

As the arithmetic sequence shows, you don't even need to assume infinity. Since the series will eventually exceed any finite number, and the number of photons from the sun is a finite number, some early point in the sequence will exceed that number.

We now know that the number of stars we can see is a comparative small finite number, much smaller than would be required to add up to the sun.. The universe is also not fixed, but expanding. By showing that neither assumption is true, Olber is refuted, although by attributes of the universe he couldn't possibly know.

But both of these truths are basic high school level astronomy, available in any textbook or popular science book or science magazine or on the web.

That shouldn't matter. They could be terrifically obscure bits of postgraduate-level knowledge for all the difference it made. The important point is that posts like that of the OP show a lack of basic reasoning skills (and a frightening amount of ego).

If you think you've come up with an answer to an age-old problem that would occur to any scientist in the first ten seconds of thought, you've misunderstood the problem. Realizing this and what this means is the first step toward scientific understanding.

It will also make me less cranky. That's a boon to all humanity. :D

[essell]

The important point is that posts like that of the OP show a lack of basic reasoning skills (and a frightening amount of ego).
Surely you can understand this, from the sound of your post you're a teenager yourself. :p

[Baldwin]

I know I'm getting crankier in my old age, but posts like the OP bother me more than they used to.Be proud of your crankiness. Once again, you've stepped in and essentially written the post I would have written if I'd taken the time and put the necessary effort into it. You're like a great labor-saving device for me.

[Exapno Mapcase]

Surely you can understand this, from the sound of your post you're a teenager yourself. :p

Be proud of your crankiness. Once again, you've stepped in and essentially written the post I would have written if I'd taken the time and put the necessary effort into it. You're like a great labor-saving device for me.

Now we know what makes elections! :D

[RedSwinglineOne]

If you think you've come up with an answer to an age-old problem that would occur to any scientist in the first ten seconds of thought, you've misunderstood the problem.

Well at least the OP didn't title his thread Olbers's paradox solved! At least one POAT thread started like that.

[Baldwin]

Well at least the OP didn't title his thread Olbers's paradox solved! At least one POAT thread started like that.But wouldn't it be wild if someday a guest poster showed up here, posted an original, amazingly correct solution for a famous paradox, or proof for a famous unproven theorem, then vanished, to become one of those mysteries in the history of science?

[RedSwinglineOne]

But wouldn't it be wild if someday a guest poster showed up here, posted an original, amazingly correct solution for a famous paradox, or proof for a famous unproven theorem, then vanished, to become one of those mysteries in the history of science?
And in the future, our children will study the genuis of Newton, Einstein, Galileo, and BigBootyLover237.

[RiverRunner]

And in the future, our children will study the genuis of Newton, Einstein, Galileo, and BigBootyLover237.

Quote of the day.

RR

[sparker1776]

Those are some great attacks on independent thought! Science.. dogma.. great combo guys. Hey all you researchers out there - freeze! We're done!

I excluded the infinite universe half of the answer because it is so clearly correct (yes there are two parts to the 'why is the sky dark' question). I’m dealing with the more straightforward side of it, the observable - it's light already got here. 150 years ago no one knew the density side of the equation relating to the observable universe half of the answer. The hubble deep field gives us a great way to calculate it directly.

So far no one has actually attacked my hypothesis. To disprove my hypothesis of ‘density is plenty, it’s dimness that matters’, in my opinion you merely need to answer the following questions:

1. How dense would the pixelation be in the sky be if every object in the observable universe were visible to the naked eye (lets use current data, not data from 150 years ago, this time)
2a. Now that we know the pixelation, how dense does the pixelation have to be to consider it ‘lit up’. To me "the entire sky is uniformly white with light from my perspective" covers it.
2b. Conversely, you could calculate the actual amount of light, based on the pixelation and a minimum brightness for each object, and then ask yourself the same question

I used 2a, and my answer was “we’re way beyond that level of pixelation”, and I put my calculations out there. Not masterful, sure, but enough for someone to attempt to disprove it. Go for it.

If you think discussing this idea is a big deal, whatever, it's just a simple thought excercise to me. If it contradicts something old, good! If you think that is presumptuous, I think that thought makes you presumptuous. Don't be afraid to think and don't blindly bow to authority.

[sparker1776]

Forgot one thing.. Olber's Paradox doesn't show the sky is dark because the universe is infinite. It shows the universe is infinite because the sky is dark.

Cheers.

[John W. Kennedy]

No one disagrees with the notion that Olber's Paradox doesn't apply to a finite universe. That's the whole point of the original column.

[sparker1776]

er.. infinite and expanding that is...

Olber's Paradox doesn't show the sky is dark because the universe is infinite and expanding. It shows the universe is infinite and expanding because the sky is dark.

[sparker1776]

Actually the point of the original column was 'why is the sky dark' and the person who asked the question even stated 'aren't we overlooking the obvious here'. So I posted the obvious. It has been roundly criticized.

[essell]

Perhaps you could explain what you mean by "pixel-ating" the sky.
You lost me at that point.

[sparker1776]

Perhaps you could explain what you mean by "pixel-ating" the sky.
You lost me at that point.

Just a point of light in the sky, a small unit of lit up space. Like a pixel on a monitor.

If you look at the hubble deep field, every object would represent a pixel, and there are 10,000 of them. It would be like putting 10,000 LCD pixels on a dime 75 meters away. Now spread that out over the entire sky.

[bonzer]

I've done this on the Dope often enough before, but I'll again recommend Ed Harrison's book Darkness at Night (Harvard, 1987) for a history of the issue and why the different explanations proposed over the years either do or don't work.

Including lengthier explanations of John's point about why it's not enough just to claim that it's because the distant stars in the "gaps" are too faint to be visible.

[Exapno Mapcase]

I have made a most marvelous discovery that will just fit inside the margins of this text box. When a guest to a message board makes a post about science that he does not understand, the chances that when he returns his next post will not a) apologize for his previous mistakes or b) understand where he went wrong or the explanations to correct him exceed 100%. This can only be true if the amount of ignorance in the universe is a) infinite and b) expanding. I predict that Mapcase's Paradox will live through the ages and be rediscovered by future commentators and I also predict it will be misunderstood by those with insufficiently deep minds.

Why am I still cranky when what sparker1776 says in post #18 is clearly true? Because it is trivially true. What he writes amounts to no more than saying the night sky is dark because there isn't enough light. This is obvious - looks up at night sky; yep, it's dark - but it in no way addresses Olbers' Paradox. It may the first thought of those who don't understand the problem, but it's dismissed by those who do because it has no explanatory power except on itself (which it must because of its circularity). It doesn't contradict anything, old or not. It's just a statement of what everybody knew then and everybody knows now.

The true question that Olbers was asking was: what is the basic underlying structure of the universe? That's a deep problem and one that would take decades to solve.

However, it is not true that:
Olber's Paradox doesn't show the sky is dark because the universe is infinite and expanding. It shows the universe is infinite and expanding because the sky is dark.
No it doesn't. Olbers' Paradox is answered by showing that at least one of the two assumptions it makes - again, 1) The number of stars is infinite and 2) The universe is of fixed size - is not true. The paradox itself shows nothing. Only the answer as to why it is not a paradox shows anything. As I took care to demonstrate earlier, an infinite universe is not required. A sufficiently large finite number of stars would provide the illumination. A sufficiently large finite number of stars would be bright enough even if the universe were expanding, though that would be a true buttload of stars. A sufficiently small number of stars would also explain the finding even if the size of the universe were fixed.

While the paradox is easily shown to be nothing of the kind, figuring out the parameters of the actual universe to answer the questions of its size, density, age, light speed, shape, expansion, and other qualities is a much more difficult process and one that is still not fully answered. (Astronomers don't know whether the universe is infinite or not. An infinite universe would have to be infinite from the moment of creation but this plays havoc with the physics as we know it. Olbers' paradox can't possibly show that the universe is infinite when nobody even knows whether that's true.)

The "obvious" has probably never been the right answer in the entire history of astronomy. Real scientists go much deeper than the "obvious" to get answers: answers that often contradict earth-bound "common sense."

If you come across a problem in astronomy or any of the sciences don't expect to blurt out the first thought that comes into your mind and have anyone do anything other than roll their eyes. And eye-rolling makes some people cranky. :)

[sparker1776]

"figuring out the parameters of the actual universe to answer the questions of its size, density, age, light speed, shape, expansion, and other qualities is a much more difficult process and one that is still not fully answered."

You don't need to do all this in order to show what I'm talking about, it just overcomplicates the question.

I also don't need a lecture on how science works.

I think the differences between us on this thread are due to you having to defend things perpetually here for a long time. You saw my post and though 'oh another person attacking this'. But I'm not. I don't think you gave my post enough consideration to get past your initial incredulity.

However, I wrote my original posts quickly as I was in a hurry - it was a simple enough concept so I didnt think anything more refined was really necessary. I had no idea I would be entering a pissing contest, so I didn't spend much time on it. So I apologize if my post was not clear enough.

So, since we both claim to be educated and sane, let's start over here. I'll write this up in a more precise way:

___________________________________ <----- starting over here

There are two sides to the question "why is the night sky dark", as evidenced by the initial post which stated "Excuse me, but aren't we overlooking the obvious here?".

The two answers given to the two questions inherent in the overall question 'why is the night sky dark' were:

1. The whole Olbers paradox solution (there is an unobservable universe so infinity does not come into play)
2. "there just aren't enough stars in the observable universe to fill up the night sky"

The first answer is not up for debate. The second answer is seperate from the first, it is based on a different set of reasoning. Let me reiterate: this post is not at all about Olbers, I am specifically talking about the observable universe.

Later on in the answer there are two further statements, and one contains the correct answer in my opinion:

3. We don't really know how many stars there are. What we do know is that however many there are, we can see only a finite number of them
4. The few jillion stars in our corner of the cosmos (AKA the "observable universe") don't have the collective candlepower to illuminate the night sky

My hypothesis is that #2 is not correct.

#3 infers that #2 can't actually be validated at the time of the original statements, since it states we don't have evidence for #2. It is also no longer true. We have a picture of them back to almost the very edge of the observable universe, called the hubble deep field. #4 seems patently obvious.

But back to the point: #2 is incorrect. Here is why I feel there are "plenty of stars in the observable universe to fill up the night sky".

a. The hubble deep field has about 10,000 galaxies (collections of stars) within it.
b. This represents one-two millionth of the dark night sky as viewed by an individual (one-twelve millionth of a 360 degree view from earth)
c. You can multiply that out to literally calculate the density of objects from our perspective, and determine if that satisfies you as far as 'filling up the night sky' or not
d. After doing the math, in my opinion it's 'filled up' to an amazing, truly incredible actually, degree. Thus #2 above is incorrect.

Ok, so it's filled up. Why is the night sky still dark? They are too dim from our perspective (#4).

So #1 is true, #4 is true, #2 is not true, and #3 is half true (but not an answer to the original question.)

You may look at this and say 'well yes, that's obvious'. Excellent.

[John W. Kennedy]

Note that part of the original Olber's Paradox is that an infinite Newtonian universe with a finite number of stars would collapse upon itself. Practically speaking, therefore, an infinite Newtonian universe requires an infinite number of stars. And a Newtonian universe must be infinite.

[John W. Kennedy]

To "sparker1776": You can't just say, "they're too dim" without blowing off simple fact that the reason they're dim is that their light falls off with the square of the distance, which is exactly compensated for by the fact that their number, in a hypothetical infinite universe, keeps increasing with the square of the distance.

So unless they're getting extra dimming from magic, your argument doesn't pass the math test. The reason has to be of another kind.

[Ponderoid]

I think I see the OP's misunderstanding. The OP has stated that faraway objects are dimmer because they are distant. That is indeed true, but that cause is one step removed from what we're actually observing. They're not dimmer merely because they're far away... they're dimmer because their apparent size is smaller. They're taking up smaller chunks of the visible sky, and that's the reason they end up contributing less overall light to our sky when we look up.

Taking the example of the Hubble Deep Field, it most certainly is not completely filled up with stars. You see plenty of black in between the galaxies even at that intensely magnified and lengthened exposure. If it was truly "filled up," then the picture would be solid white. It's not.

*** Ponder

[sparker1776]

I think I see the OP's misunderstanding. The OP has stated that faraway objects are dimmer because they are distant. That is indeed true, but that cause is one step removed from what we're actually observing. They're not dimmer merely because they're far away... they're dimmer because their apparent size is smaller. They're taking up smaller chunks of the visible sky, and that's the reason they end up contributing less overall light to our sky when we look up.

Taking the example of the Hubble Deep Field, it most certainly is not completely filled up with stars. You see plenty of black in between the galaxies even at that intensely magnified and lengthened exposure. If it was truly "filled up," then the picture would be solid white. It's not.

*** Ponder

Having spaces between objects when looking at high magnification would always be true unless we live within a solid sphere, or Olbers wasnt a paradox (ok there are other possibilities but they are too wierd). Interestingly effectively the same thing as far as the Olbers question is concerned though.

The 'smaller chunks of the sky' question is great - but it's exactly what I'm talking about with pixelation. Once the granularity is beyond your eyes capability to detect it, you have it covered in the 'why is the night sky dark', individual perspective question. The question wasn't 'why is there dark space between objects under high magnification when looking through the most powerful telescopes in the world'.

My calculations show that the granularity would be well beyond the naked eye's ability to detect it. If every object out there was bright enough to be seen with the naked eye, you would not see any spaces between them as a person who is looking up at the night sky, you would see a pure white sky.

"You see plenty of black in between the galaxies even at that intensely magnified and lengthened exposure". As I interpret the original question, this is backwards. I interpret this as "At this intensely magnified exposure you can see plenty of black, but if it were not magnified, you would just see a white spot". You could calculate what kind of magnification you would need to get beyond a white spot, it seems to me it would have to have pretty good magnification.. I don't have time to figure that out right now though, perhaps later.

To be very clear, Im trying to answer the original question regarding 'the night sky', which infers the simplest question of an individual merely staring up at it without a telescope.

[Exapno Mapcase]

What then do you make of this?

Biggest void in space is 1 billion light years across (http://space.newscientist.com/article/dn12546-biggest-void-in-space-is-1-billion-light-years-across.html)
Radio astronomers have found the biggest hole ever seen in the universe. The void, which is nearly a billion light years across, is empty of both normal matter and dark matter. The finding challenges theories of large-scale structure formation in the universe. ...

The team was in for a surprise. They saw little or no radio sources in a volume that is about 280 megaparsecs or nearly a billion light years in diameter. The lack of radio sources means that there are no galaxies or clusters in that volume, and the fact that the CMB is cold there suggests the region lacks dark matter, too.

The void, which is about 6 billion to 10 billion light years away, is considerably larger than any found before. Until now, optical surveys have found no voids larger than 80 megaparsecs wide – making the new hole 40 times larger in volume than the previous record holder.

[sparker1776]

What then do you make of this?

Biggest void in space is 1 billion light years across (http://space.newscientist.com/article/dn12546-biggest-void-in-space-is-1-billion-light-years-across.html)

It's very interesting, but if it's 1 billion light years across then there is 12 billion light years of observable stuff in front of and behind it. In my scenario, that area of the sky would be... a little less than 8% dimmer than the rest of it.

But it's a cool find, it does have important implications.

[Exapno Mapcase]

It's very interesting, but if it's 1 billion light years across then there is 12 billion light years of observable stuff in front of and behind it. In my scenario, that area of the sky would be... a little less than 8% dimmer than the rest of it.
This is, well, obviously, not true. If there were observable stuff in back or in front of it would be observed. It is not 8% dimmer. It is a black void.

This scientific fact shows that your understanding of astronomy is dead wrong.

[sparker1776]

It's very interesting, but if it's 1 billion light years across then there is 12 billion light years of observable stuff in front of and behind it. In my scenario, that area of the sky would be... a little less than 8% dimmer than the rest of it.

I would add it's also 8% less dense; but for the eye to detect it at all, it would have to be more than 99.98% less dense (which brings it down to high def level of granularity), if my math is correct.

Back to the apparent size dimness thing. You brought up an interesting point so I've been thinking about it for a bit. Dimmer because apparent size is smaller is synonomous with dimmer because they are far away - their apparent size is so small because they are far away. But it still brings the question back to dimness rather than density.

More math - fact is, it blows me away how many galaxies are out there, which is why I'm so interested in this question. The hubble deep field is a picture of the sky representing 'a dime held at 75 meters', and it has 10,000 objects. If you magnify it 75 times, so that it is one meter away from you, in order to keep the density of the objects relatively identical, you would have to have 750,000 visible objects on that dime. So picure a dime held at arms length in the dark with 750,000 visible-to-the-naked-eye light emitting objects on it. You cannot possibly be able to see the dime behind it.

At arms length in order to get it down to high def (which you have to admit you cannot see the spaces between the pixels at one meter) you would lower the number down to... 750,000 / (however many dimes fit onto a high def screen, lets go with a 42" to be conservative). My extremely rough calculation on that (someone could do a lot better but it should be close) are:

The screen is about 36" x 22". A dime is less than 3/4 of an inch, I'll round to 3/4. So you should be able to fit... about 1400 dimes on a flat screen.

So in order to drop the granularity down to high def, you would have to drop from 750,000 visible objects to 535 on that dime at one meter. We can debate how much more def than high def is acceptable, but as you can see, we're so beyond the ballpark it's truly incredible. Again, if my math is right.

I also understand those pixels would be smaller than a high def pixel in open space, but the atmosphere helps with that quite a bit (like the diffraction on this image: http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Lunarcorona.jpg/180px-Lunarcorona.jpg )

Fun stuff.

[sparker1776]

This is, well, obviously, not true. If there were observable stuff in back or in front of it would be observed. It is not 8% dimmer. It is a black void.

This scientific fact shows that your understanding of astronomy is dead wrong.

Actually this isn't about astronomy, it's basic geometry.

The observable universe is a sphere 26 billion light years in diameter (actually likely more but Im being conservative), we're at the center of it (since we are the observers), and this is what the void sits inside of.

The void is not a tube (or cone) 13 billion light years long and a billion light years wide that leads down to earth. It is a sphere (for our purposes) with a 1 billion light year diameter which is sitting inside another 26 billion light year diameter (13bly radius) sphere.

Like this:

*us* [observable stuff] [void] [observable stuff]

If someone had found a 13-billion-light-year-tube-void that would be different.

How do I know it's not a tube? Let me quote your post.. "The void, which is about 6 billion to 10 billion light years away..." What's in front of the void? More void?

This shows that your understanding of basic geometry is dead wrong. Wee.

[sparker1776]

I'm not going to start anything, but if you attack me I'm not just going to bend over and ask for more.

Still, can you just quit the personal attacks already? They are pointless.

[DSYoungEsq]

I'm not going to start anything, but if you attack me I'm not just going to bend over and ask for more.

Still, can you just quit the personal attacks already? They are pointless.
I have a serious suggestion. Given that this issue has produced considerable attention from professional astronomers for, oh 400 years now, and given that the professional concensus is that your theory is not correct, perhaps you could/should send your explanation to, oh, say the Astronomy department at Cal Tech, or some similarly important institution. See what they say. :rolleyes:

[sparker1776]

So we're back to hiding behind Wikipedia? It's no longer necessary to think?

By your standards, the bible is the de facto keeper of all scientific fact. Unless we can find some heiroglyphics that show otherwise. Nice.

Fine, I'm done with this thread.

[sparker1776]

Ok that was unfair. I understand what you are saying, I knew the 400 year thing would come up (where is that 400 year quote from by the way.. other than Wikipedia that is..). I uinderstand that your de facto keeper of knowledge is not the bible. It's Wikipedia.

There are plenty of serious astronomy sites that state exactly what I'm saying. They go so far as to state that the 'not enough objects' model is unrealistic. I just thought a site like this would actually be interested in discussing simple topics, beyond just spouting dogma. But it seems the site is really not about that.

Ok I am completely done with this forum and site, I can use wikipedia if I need to look up popular opinion on almost anything.

[DSYoungEsq]

Ok that was unfair. I understand what you are saying, I knew the 400 year thing would come up (where is that 400 year quote from by the way.. other than Wikipedia that is..). I uinderstand that your de facto keeper of knowledge is not the bible. It's Wikipedia.

There are plenty of serious astronomy sites that state exactly what I'm saying. They go so far as to state that the 'not enough objects' model is unrealistic. I just thought a site like this would actually be interested in discussing simple topics, beyond just spouting dogma. But it seems the site is really not about that.

Ok I am completely done with this forum and site, I can use wikipedia if I need to look up popular opinion on almost anything.
Produce a link to such a site. I'm more than happy to listen.

And I note that your answer doesn't address what I said, which is: send your theory to reputable astronomers and see what they say. If you are asserting you don't need to because they already accept it, then produce the backing of such astronomers.

You see, this site is about more than just stating, "I say X is true." It's about establishing that to the satisfaction of others, which is most easily done by producing evidence that what you say is accepted to be true.

[Baldwin]

Ok that was unfair. I understand what you are saying. . .Everything you say indicates otherwise. Most of us here don't need to go to Wikipedia to come up with a rough figure of 400 years for the history of telescopic astronomy; we were already familiar with Galileo Galilei and the hundreds of astronomers and physicists since, many of them geniuses, who devoted their entire careers to considering such questions as the one occupying this thread.

[foolsguinea]

Oh, look. You drove away a newbie. Good job. :rolleyes:

I've been thinking about the argument that the universe must have a time-finite past due to the lack of a perfectly white sky, & I'm not convinced.

A. There is a lot of non-fusing, non-luminous mass out there. Admittedly, what we know of is not completely dark, just dark in the "visible light" range. Even a cold rock will emit black-body radiation in the longer wavelengths, but it's non-luminous to our eyes, with their narrow range of response.

B. Sufficient non-luminous mass could obscure distant luminous mass. Think of a forest. While I can see past the near trees, eventually I can't see my way out of the woods. Ultimately any given piece of non-luminous mass is being illuminated by a finite amount of luminous mass at any given time.

C. A mass being illuminated by a finite number of stars over an infinite period of time has two choices: It will heat to a point of equilibrium, where its own black-body radiation cancels out its heat gain from starlight; or it will eventually disintegrate on a sub-nuclear level. I suspect the point of equilibrium temperature for the universal average is somewhere below white-hot.

D. There are such things as endothermic processes, you know.

To claim that the universe, given infinite time, would eventually heat all mass within it to white-hot, demonstrates a wildly contrarian take on thermodynamics.

[Absolute Jackass]

The hypothesis that there aren't that many stars doesn't hold up.
.


When the sun goes down, there ain't enough energy to irradiate the hydrogen in our atmosphere to give us a "blue sky".

Now, I've never been south of the equator, so I can't say for myself; But I once asked a physicist if the whorl of a drain reverses at the equator. He said, "No we live on a ball, all physical properties are the same no matter where you stand".

I'm a practical guy. Anybody have science or experience to answer the whorl question?

[foolsguinea]

When the sun goes down, there ain't enough energy to irradiate the hydrogen in our atmosphere to give us a "blue sky".Exactly.Now, I've never been south of the equator, so I can't say for myself; But I once asked a physicist if the whorl of a drain reverses at the equator. He said, "No we live on a ball, all physical properties are the same no matter where you stand".

I'm a practical guy. Anybody have science or experience to answer the whorl question?That's the coriolis effect. On the scale of a small drain, it's overwhelmed by any number of other effects, like irregularities in the drain's structure. But it does set a norm for weather patterns, & since it's based on relation to the equator & the poles, those weather patterns do spin different ways in the different hemispheres.

[bibliophage]

I'm a practical guy. Anybody have science or experience to answer the whorl question?Cecil Adams on Do bathtubs drain counterclockwise in the Northern Hemisphere? (http://www.straightdope.com/classics/a1_161.html)