Why is the sky black/dark?

[AlphaJohn]

Yes I know some people here know the answer but it was something that bugged me for some time as theory states that light can not be destroyed, only obstructed or deflected and absorbed. Also we know that space is "infinite" so there must be stars all over the place filling the voids.

So anyway found a cool Video explaining why this is. Might be worth sharing esp to kids <-- at heart I am one.

[video=youtube;gxJ4M7tyLRE]http://www.youtube.com/watch?v=gxJ4M7tyLRE[/video]

TL;DR or W: Doppler effect and Time makes space black instead of white.

Can you imagine this not being the case, having daylight 24/7 would have been a pain to deal with, or I guess we would have evolved in such a manner that we would not have needed sleep.

 

[Picard]

Loved it.

 

[RaeesD]

The sky being mostly black is one of the proofs that the universe is expanding, no? That video's blocked here at work :/
Also, light is a form of energy and can't be "destroyed", but it can be turned into heat, electricity, kinetic energy...

Edit: And the doppler effect is why stars have colours shifted towards red, it wouldn't explain complete darkness :?

 

[AlphaJohn]

The sky being mostly black is one of the proofs that the universe is expanding, no? That video's blocked here at work :/
Also, light is a form of energy and can't be "destroyed", but it can be turned into heat, electricity, kinetic energy...

Edit: And the doppler effect is why stars have colours shifted towards red, it wouldn't explain complete darkness :?

Infra red is also a color, just one we can not see

http://www.scientificamerican.com/article.cfm?id=background-radiation-glows-in-space

 

[AlphaJohn]

Oh and I guess its not such a noob thing to ponder: As it has an actual name.

Olbers' paradox
In astrophysics and physical cosmology, Olbers' paradox, named after the German astronomer Heinrich Wilhelm Olbers and also called the "dark night sky paradox", is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. The darkness of the night sky is one of the pieces of evidence for a non-static universe such as the Big Bang model. If the universe is static and populated by an infinite number of stars, any sight line from Earth must end at the (very bright) surface of a star, so the night sky should be completely bright. This contradicts the observed darkness of the night.

http://en.wikipedia.org/wiki/Olbers'_paradox

 

[RaeesD]

Thanks for the link
Stephen Hawking's A Brief History of Time would be an interesting read, it gets a bit hectic in the later chapters though, lol

 

[seanyp00h]

What an awesome channel

 

[AlphaJohn]

What an awesome channel

If you referring to the Youtube channel, totally agree. That and http://www.youtube.com/user/scishow is my 2 favs when it comes to science.

 

[RiaX]

nice

 

[ponder]

What an awesome channel

+1 I subscribed

 

[agerbon]

Yes I know some people here know the answer but it was something that bugged me for some time as theory states that light can not be destroyed, only obstructed or deflected and absorbed. Also we know that space is "infinite" so there must be stars all over the place filling the voids.

So anyway found a cool Video explaining why this is. Might be worth sharing esp to kids <-- at heart I am one.



TL;DR or W: Doppler effect and Time makes space black instead of white.

Can you imagine this not being the case, having daylight 24/7 would have been a pain to deal with, or I guess we would have evolved in such a manner that we would not have needed sleep.

A couple of years back I pondered on the same thing. It was great finding the answer for it. It took me a couple of books though.

Another great thing to wrap your mind with is the Earth's path through space.

[video=youtube;IhqzW97_47w]http://www.youtube.com/watch?v=IhqzW97_47w[/video]

While a pretty awesome presentation of the Earth's path it lacks the motion of the sun. How would the path look like if we take that into consideration? I pondered over this many years back! unfortunately no satisfactory material was available to me back then. (Lack of resources on my side I guess) So I dropped it but my logic back then dictated that it should be a somewhat (dependent on the direction of the sun's motion) spiral path way. I never returned to it again. Ignorance is bliss I guess.

Your post reminded me of this. Time to go hit some books again and this time some sites too. (Thank goodness information is so cheap today)

Thanks.

 

[ezeey]

Great video

 

[Arthur]

I guess we would have evolved in such a manner that we would not have needed sleep.

Thicker eyelids, rather. We don't sleep because it gets dark.

 

[BigAl-sa]

Ask yourself the converse as well, what is light?

 

[AlphaJohn]

.

WOW Gread vid.

2 other questions that still bug me is:

• What is our true speed esp taking the sun's orbit in our galaxy and inflation. ie: if you could truly mark a stationary point in space, how fast would we move away from it. I'm calculating my time machine
• Why the hell does everything on the macro level settle as discs. Planets, galaxies and moons orbit as a disc hell even the gas around a black hole every thing circle's the drain in a disc and not a sphere. And I know its not perfect discs, the question is rather why is Saterns ring not a sphere.

 

[AlphaJohn]

Thicker eyelids, rather. We don't sleep because it gets dark.

I think we did, lack of light meant danger which caused us to do things other than hunt for food. A lot of lifeforms that live in total darkness evolved not to need sleep at all.

 

[ponder]

I pondered over this many years back! unfortunately no satisfactory material was available to me back then. (Lack of resources on my side I guess)

http://www.unisa.ac.za/qualificatio...qualifications/Qualifications/p_02089NAS.html

 

[agerbon]

WOW Gread vid.

2 other questions that still bug me is:

• What is our true speed esp taking the sun's orbit in our galaxy and inflation. ie: if you could truly mark a stationary point in space, how fast would we move away from it. I'm calculating my time machine
• Why the hell does everything on the macro level settle as discs. Planets, galaxies and moons orbit as a disc hell even the gas around a black hole every thing circle's the drain in a disc and not a sphere. And I know its not perfect discs, the question is rather why is Saterns ring not a sphere.

I can't help you with a time machine but if you get it right, I call shotgun.

If memory serves me well. The reason why it settles as a 'disc' is due to magnetic influence of a spinning body of which will always create an equatorial planar. Hence the almost flatness of our solar system.

http://www.unisa.ac.za/qualificatio...qualifications/Qualifications/p_02089NAS.html

If only I had the time. Suffice to say I learned a lot by myself and have a firm understanding of the mechanics behind it to the point where the mathematics don't scare me.

I didn't have the resources to go study but that didn't stop me from educating myself. You know self improvement and all that.

 

[zippy]

Infra red is also a color, just one we can not see

http://www.scientificamerican.com/article.cfm?id=background-radiation-glows-in-space

The red shift of distant objects moving away at high speed is what proves the expansion if the universe. However it's important to note that its only "really distant" objects. For example the Andromeda galaxy is not moving away. It's coming closer.

Stars in our galaxy are not moving away from us because if the expansion of the universe.