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
jcarrabout 12 yearsthis so amazing i just leared something
lchambersabout 12 yearsi know it is we can learn does things
Mrs. Peurachabout 12 yearsI found it interesting that even though stars are in the sky, they are simply too far away for them to shed much light that effects us here on earth. I think this article shows how being an inquirer and wanting to explore can lead to new learning.
silverstreamabout 12 yearsI learned that the universe is 13.7 billion years old. I think it would be cool to mot see any stars at night.
milostaralmost 12 yearsExtremely true......
bittercupabout 12 yearsAmazing...... Your writing skills are great.- silverstreamover 11 yearsThank U soo much!
winterstormalmost 12 yearsthat's totally true
fizbooalmost 12 yearsNice comment bittercup- silverstreamalmost 12 yearsThanks for liking my comment!
- Aryanna P.about 12 yearsI learned that the Earth is estimated to be 13.7 billion years old. And we cannot see the light given off by stars , especially with our naked eye. The first person to ponder this question was a German astronomer named Heinrich Olbers. This article was pretty interesting actually, I didn't know the reason why the other stars didn't light up our world like the sun.
twilightbeautyalmost 12 yearsI really like your comment. Your good at writing.
sizzyalmost 12 yearsYou have great writing skills. Your facts are completely true.
- China B.about 12 yearsi learned that people are just now trying to figure out why the sky gets dark ( but truly nobody will ever know why) and that the hubble telescope can't see EVERYTHING. i think people need to try harder to try to make science sound some bit true.
- twilightbeautyalmost 12 years:)
- alex blountabout 12 yearsi found out that the universe is growing and that in a billion years people might not be able to see stars with there own eyes. It is believed that maybe dust is blocking the stars durringt he day time. our Universe is still expanding to greater distances.
- Bailey E. about 12 yearsI did not know there was so many possibility that the skies go dark. I just thought it was cause we turn away from the sun for a few hours. That it wasn't just the Earth orbiting in circles. It could have been the dust blocking the stars but they areright cause if the stars were being blocked then the sun would be blocked as well.
- frankie sabout 12 yearsi found out that the universe is growing and that in a billion years people might not be able to see stars with there own eyes.
- sarah Babout 12 yearsIt is believed that maybe dust is blocking the stars durringt he day time. our Universe is still expanding to greater distances.
- Beverly Habout 12 yearsI learned that NASA's Hubble telescope discovered that our universe was still expanding ! Scientist now discovered that it could be a reason for our dark skies. I find this to be really interesting and its really cool to hear that scientist are discovering new things everyday. To us it may seen like nothing, but it may not be that easy.
