Why is it Dark at Night?

Have you ever wondered why you look up and see a dark sky at night?
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Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!

Music by Nathaniel Schroeder

Thanks to Nima Doroud and Niayesh Afshordi for contributions and to Perimeter Institute for support.
http://www.perimeterinstitute.ca

• Category

  Science & Technology

[n00b4liciou5]

We don't talk much anymore...

[Idontcare9876543210]

This is about science please leave your mythology at the door.

[Achi Oragvelidze]

The sun's corona is several million degrees hotter than the surface.

The center of the earth is as hot as the sun.

Taos Hummings.

If it confuses you, just re read a physics book. It will help.

No need to insult beliefs. Nothings perfect. Though this is a great informative, video.

[pseudorandomly]

"... where else would that radiation have come from?"

Prior to 380,000 years after the Big Bang, the Universe was at a very high temperature, so atoms could not form. Instead, the Universe was filled with a dense soup of particles -- mostly charged particles like electrons and protons. Light cannot travel through this. At 380,000 years (at 3000 K), atoms began to form and the Universe became mostly neutral. Light does not interact (much) with neutral particles, so it was free to travel.

[deeldoable]

Question:

If I am following this correctly, then is it correct to assume in "X" billion amount of years, will space will be bright at night? Or will the universe expand quicker than the speed of light?

[Anton Sop]

God created day and night on the third morning. Wait a second.. so how did the first two mornings happen? No worry. If it confuses you, just pray harder.

[Jason Arevalo]

This wasn't a minute! Lol

[Omen715]

That was an interesting take on Olbers' Paradox. I thoroughly enjoyed it.

[Mohammed Kallsong]

There should be a nobel price for those who explain physic really really insanly good!

[Brian Theis]

I don't know why this causes any religious debate. The Catholic Church, who put the bible together, even says that you don't need to take that beginning part of Genesis literally word for word.

[TechWurst]

Wow, there are even German subtitles! Impressing

[GreenEyedGamer]

We don't know yet. Simple as that.