The Real Reason Skies Go Dark After The Sun Sets
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Why does the sky go dark at night? You are all probably thinking that this is a question even a kindergartner can answer - The simple answer and the one that is pretty obvious is that as the Earth rotate on its axis it moves away from the sun and therefore, causes the skies to go dark. Sounds logical to us but what about the zillions of sparkly stars? Why don't they pitch in and make the sky all shiny?
This was a question that German astronomer Heinrich Olbers pondered over at length all the way back in 1823. There were many possibilities - Maybe the light from the stars was being blocked by dust, but then that would also have the same effect on the sun. Then there was that possibility that maybe there were just not enough stars or that they were all stacked behind each other - Both facts that we all know are not true.
After thinking about the conundrum at length, astronomer could only blame the darkness to one thing - the finite age of our Universe, or what scientists refer to as our Observable Universe. Since this according to the experts is estimated to be 13.7 billion years old, any light from stars beyond cannot be observed by us especially with our naked eyes, giving us the impression that the sky is dark.
While this phenomenon called Olbers' Paradox is still considered to be the primary reason for the lack of light, when NASA's Hubble telescope discovered that our Universe was still expanding, scientists realized that there could also be another reason for our dark skies - The ever-growing Universe is pushing the stars further and further away, so much so, that millions of years from now, humans may not be able to see any stars unless they use infrared telescopes, because the speeding stars do leave behind a streak of faint infrared light!
Still a little confused? Then be sure to watch this easy to follow video put together by 24-year old Harry Reich. Scientifically trained in physics, Harry is is now focusing on cinematography and creating a series of videos dubbed Minute Physics that makes science simple and fun to learn, for those of us not as passionate about the subject.
Resources NPR.org, math.ucr.edu
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180 Comments
- MMSVictoriaH10about 12 yearsthis is so interesting. I add mite that i have asked me dad this sometimes and he never knew but know i can help him understand why the sky gets dark at night and light in the morning i want to try to find a article that tells me about the time difference between central and pacific.
- MMSAlyssaRabout 12 yearsThis article is about why it get's dark at night after the sun sets. In Heinrich Olbers an astronomer found many answers like that the stars were blocked with dust. People have thought that there was not enough stars, so they thought they were stacked behind eachother. Astronimers estimated that it's 13.7 billion years old so the only one that they can blame is the universe.
mmstreannababout 12 yearsFrom this article the only reason the sky look blue in the day is because the sunlight scatter on the atmephare.on the moon the sky will be dark in space but the sun will be shining . Space has no edge but some of the stars are really bright .But since light take time to across the unnerves when we use a telescope at something far away we are looking at the part of the unnerves. The only reason the sky look dark when the NASA telescope it took a picture of the galaxy and that's why the sky appear dark. And as you can see this is what I learn for this article.- MMSColinS67about 12 yearsI really like this article because the author said and described what the people that she got the information from said. the reason the sky goes dark at night is because the universe is still expanding so the stars are getting pushed back. In 1823 scientist thought that stars light is getting blocked by dust. Then they thought that the suns light is probably getting blocked by dust as well. Scientist say that our finete universe will expand so far as to which that we will only be able to see stars from an infared telescope.
mmsaustinmabout 12 yearsThis article is about why it get's dark at night. It was a very clever idea for making something to inform us. I honestly never really knew why. But now I understand. I really think that it is interesting to me how it actually does happen. I am very intrigued about this article. It is one of my favorites so far!- MMSDanielleS11about 12 yearsIn this article it talks about the real reason why the sky turns dark at night. It also talks about why the sky is dark and bright at night. The stars are as bright as the sun, since the sun is a star, but why don't they light up the night sky like the sun lights up the sky in the morning? The reason is because the universe is still expanding, it always will, so therefore the stars are moving farther away from us. The farther away the stars get they turn red, well only if you're looking in an infrared camera that is. Still, you don't need an infrared camera to tell you the stars are moving away. We can all just tell because one day we just might not be able to see the star becuase it finally expanded too far from our sight by the naked eye. I personally think this is amazing because just seeing a star one day and then never seeing that star again would be cool.
- meabout 12 yearscool!!!!!!!!!!!!!!!!!!!!
- Naomi A. Lloydabout 12 yearsThe big bang isn't real if you want to know why reply.
- Nameabout 12 yearstime=universe. no time=exploding universe
- mmsthomasf6about 12 years.it makes sense. the universe is expanding, so stars get farther away all the time. the farther they get away, they turn red--INFARED. we cannot see infared light w the human eye. the farther we look with a telescope we see the older parts of the universe. THEREFORE the sky is dark.
