Forums > Astronomy > Why is the Sky Dark at Night?
HB


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Subject : Why is the Sky Dark at Night?
Very informative VDO.




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Posted on June, 17 2011 01:22:22 AM


umairarif2001


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In 1826, the astronomer Heinrich Olbers asked, "Why is the sky dark at night?" By his time, physicists had learned enough to realize that, in a stable, infinite universe with an even distribution of stars, the entire universe should gradually heat up. Think about it — if there are stars generating energy throughout the universe (energy sources), and if there is no way ultimately to dispose of that energy (energy sinks), then all the objects in the universe must rise in temperature, in time achieving the temperature of the stars themselves.

Scientists and physicists had to learn quite a lot about the behavior of energy before they were even prepared to ask Olbers' question. In fact, for millennia the dark night sky provided an answer to a question no one thought to ask.

In these pages you will learn the simple physics behind Olbers' question, some of the answers that have been proposed, and the currently accepted answer. You will also discover the connection between a rubber band, your refrigerator, and the universe.

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Posted on June, 18 2011 12:16:39 AM

HB


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umairarif2001 said:

In 1826, the astronomer Heinrich Olbers asked, "Why is the sky dark at night?" By his time, physicists had learned enough to realize that, in a stable, infinite universe with an even distribution of stars, the entire universe should gradually heat up. Think about it — if there are stars generating energy throughout the universe (energy sources), and if there is no way ultimately to dispose of that energy (energy sinks), then all the objects in the universe must rise in temperature, in time achieving the temperature of the stars themselves.

Scientists and physicists had to learn quite a lot about the behavior of energy before they were even prepared to ask Olbers' question. In fact, for millennia the dark night sky provided an answer to a question no one thought to ask.

In these pages you will learn the simple physics behind Olbers' question, some of the answers that have been proposed, and the currently accepted answer. You will also discover the connection between a rubber band, your refrigerator, and the universe.

Which Pages?


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Posted on June, 18 2011 06:23:26 PM

umairarif2001


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what do u mean by which pages

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Posted on June, 18 2011 11:02:06 PM

HB


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umairarif2001 said:

what do u mean by which pages

This is what you said in your earlier post.
In these pages you will learn the simple physics behind Olbers' question

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Posted on June, 19 2011 03:22:24 AM

reddotlinks


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BECUSE OF SUN SET

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Posted on June, 24 2011 12:52:37 AM

90779077


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seems an excrept from some book; where are the said pages?

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Posted on July, 09 2011 04:38:45 PM

agha11


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becz of sun

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Posted on July, 09 2011 05:31:31 PM

sonia55


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i think umair has done copy paste stuff

HB like this.

Posted on July, 29 2011 12:26:51 AM

Sarakhan25pk


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Definitely bcz of sun...when sun sets it create darkness everywhere


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Posted on September, 06 2011 11:24:19 AM

cute4cute


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It is the law Of Nature......!And Nobody have the power to change this Law Except ALLAH

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Posted on September, 16 2011 09:24:00 PM

Boldbrave


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"Tulijul lyala [Raat] finnahri wa tulijun nihara [Day] fil layli"

Meaning. Allah hi raat ma se din ko or din ma sa raat ko nikalta hy.

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Posted on September, 30 2011 11:01:07 AM

Summyia


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wat i think is that the colour of sky is due to scattering phenomenon of water droplets n by sun's light they give some colour to sku like blue n at nite the rest appears

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Posted on October, 22 2011 09:54:23 AM

ijazali2020


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i think umair has done copy paste stuff


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Posted on December, 29 2011 01:13:06 PM

ijazali2020


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BECUSE OF SUN SET


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Posted on December, 30 2011 07:23:10 PM

bawa125


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nice sharing Sir .......

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Posted on September, 25 2012 01:06:49 PM

Rohama


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vide nazar nhee arhiii

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Posted on September, 25 2012 01:42:29 PM

HB


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Youtube is blocked in Pakistan.

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Posted on October, 01 2012 04:36:42 PM

SHAGIRDeIQBAL


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ok, dekhen gy ji,
jab youtube open hui

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Posted on October, 05 2012 03:20:30 PM

BeHappy


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Mujhy youtube ki bata do main check kr laita hon agar aap k pas link hai tu?
And Youtube mobiles pe open ho jati hai main kisi se mobile ly kr check kr lon ga.

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Posted on October, 05 2012 03:55:35 PM

lailagul


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hahahaha da allah pa karunu ke gute ma wahy khuwagu


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Posted on October, 14 2012 12:45:56 AM