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Gravitational field of a cubic planet:
Chappell, James Michael, et al. "The gravity field of a cube." Physics International 3.2 (2012): 50.
http://search.proquest.com/ope....nview/6c982d4a364d8b
More:
http://www.askamathematician.c....om/2011/05/q-what-wo
https://possiblywrong.wordpres....s.com/2011/09/09/if-

1884 claim of cubic planet discovery:
http://query.nytimes.com/gst/a....bstract.html?res=940

Hats off to the Minecraft wiki community at Gamepedia for collecting stats about the Minecraft world!
http://minecraft.gamepedia.com/Minecraft_Wiki



Have an idea for an episode or an amazing science question you want answered? Leave a comment or check us out at the links below!
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Why do we cry? It’s weird. Humans leak water out of their faces when they get sad. Are we the only animals that do this? What does it mean? What is it for? Here’s the science of human tears!

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It’s Okay To Be Smart is hosted by Joe Hanson, Ph.D.
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What is ”egg-shaped” even? I used to think it was the shape of a chicken egg. Then one day I saw a collection of eggs from lots of different bird species, and I realized just how many different kind of egg shapes there really are! I had to know why. And it turns out a couple teams of scientists had wondered the same thing. Here’s what science says about why eggs are egg-shaped, if that's even a thing, which I’ve learned it might not be. Evolution of bird eggs, go!
#egg #biophysics #eggvolution

References: https://sites.google.com/view/....why-are-eggs-egg-sha

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I met Molly Burke a few months ago. She’s awesome. I absolutely love what she’s done on YouTube to bring awareness to living with disability, and turning it into ability. And her guide dog Gallop is awesome too! When Molly and I first met, we started talking about how she navigates the world, because I’m a nerd and I always steer the conversation toward science. I was not prepared for what she told me. She said she uses echolocation! Molly’s brain has adapted to listen to sounds in her environment in ways that most of us sighted people can’t even imagine. I went to meet her in LA and brought a special surprise, to see if my brain could learn what hers has.
#echolocation #blind

For audio descriptions, go to Settings - Audio Track - English Descriptive.

Special thanks to Brian Bushway, Daniel Kish, Molly Burke and Gallop!
Learn more about Brian Bushway and echolocation at https://visioneers.org

Descriptive Audio & Captions provided by The Described and Captioned Media Program

References: https://sites.google.com/view/....echolcation-molly-bu

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Plants can do some amazing things.
But how do they respond to their environment with no brain?
↓ More info and sources below ↓

Learn more/references:

“What a Plant Knows” by Daniel Chamovitz http://amzn.to/2bfvdOg

“The Secret Life of Plants” by Peter Tompkins and Christopher Bird http://amzn.to/2bczCTf (this book is full of bad science mumbo jumbo, but it’s where the Cleve Backster story comes from)

Galil, J. "An ancient technique for ripening sycomore fruit in east-mediterranean countries." Economic Botany 22.2 (1968): 178-190.

Kost, C., & Heil, M. (2008). The Defensive Role of Volatile Emission and Extrafloral Nectar Secretion for Lima Bean in Nature. Journal of Chemical Ecology, 34(1), 2–13. http://doi.org/10.1007/s10886-007-9404-0

Gerbode, Sharon J., et al. "How the cucumber tendril coils and overwinds."Science 337.6098 (2012): 1087-1091.

Darwin’s writings on vines and climbing plants: http://darwin-online.org.uk/content/frameset?itemID=F836&viewtype=text&pageseq=1

Darwin’s writings on plant movement: http://darwin-online.org.uk/Ed....itorialIntroductions

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It’s Okay To Be Smart is written and hosted by Joe Hanson, Ph.D.
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Follow this link to more shark science videos by your favorite YouTubers!! http://bit.ly/1sugd0z

Sharks killed per hour infographic: http://bit.ly/1oXYT0Y

An estimated 100 million sharks are killed per year: http://bit.ly/1oE7uRS

Palau sharks are worth $2 million: http://nyti.ms/1kX4fua

Effect of shark overfishing on reefs: http://bit.ly/1opLhwF

Overfishing sharks led to scallop fishery collapse: https://www.sciencemag.org/content/315/5820/1846.short?related-urls=yes&legid=sci;315/5820/1846

Joe Hanson - Host and writer
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Earth has seasons, but what about the rest of the planets in the solar system? Let’s take a tour from Mercury to Pluto and see what seasons would be like on all our planetary neighbors. Bring a sweater!

LEARN MORE:

NASA Planet Fact Sheet:
https://nssdc.gsfc.nasa.gov/planetary/factsheet/

Winds of Mars:
http://bit.ly/2wvlH3p

Lakes of Titan:
https://sites.google.com/site/....alexanderghayes/Rese
http://www.nature.com/nature/j....ournal/v481/n7379/fu

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It’s Okay To Be Smart is hosted by Joe Hanson, Ph.D.
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Predictive analytics uses math and historical data to make predictions about the future. It’s used in commerce, sports, politics, social media and tons of other places. And as it turns out, people have been using math to predict people’s death for centuries. Can it predict mine?

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There are some startlingly black animals out there, whether they’re in the deep ocean or in the darkest corners of the rainforest. But humans have created some stunningly black substances too, using science and engineering. So who wins, nature or humans? In this video, I go in search of the blackest black things on Earth to see what’s really the blackest… and why.

Additional media provided by the Monterey Bay Aquarium Research Institute (MBARI)
Thank you to Ryan Lavery at the Smithsonian Institution: National Museum of Natural History

References: https://sites.google.com/view/....references-blackest-

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We may not know it, but averages affect our lives every day. Designers and manufacturers use averages to make our houses, cars, shoes and airline seats safer and more comfortable(ish). But calculating averages is way more complicated than one might think! And as long as we are at it - let’s talk about what the most average thing in the known universe might be!

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What holds the moon up? Moonbeams!
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According to Newton's law of gravitation, the sun should "pull" way harder on the moon than the Earth does. So does the moon actually orbit the Earth? Why?

Special thanks to Ariel for submitting this awesome question to our Facebook page!

Hill Spheres and lunar orbit: http://blogs.discovermagazine.....com/badastronomy/200

True shape of moon's orbit: http://www.math.nus.edu.sg/asl....aksen/teaching/conve

Newton's law of gravitation vs. Hill Sphere: https://van.physics.illinois.e....du/qa/listing.php?id
http://en.wikipedia.org/wiki/Hill_sphere

Have an idea for an episode or an amazing science question you want answered? Leave a comment or check us out at the links below!
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It's Okay To Be Smart is written and hosted by Joe Hanson, Ph.DFollow me on Twitter: @jtotheizzoe
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Produced by PBS Digital Studios: http://www.youtube.com/user/pbsdigitalstudios

Joe Hanson - Creator/Host/Writer
Joe Nicolosi - Director
Amanda Fox - Producer, Spotzen IncKate Eads - Associate Producer
Stephen Bohls - Editing/Motion Graphics/Animation
Katie Graham - Director of Photography
John Knudsen - Gaffer

Theme music:
"Ouroboros" by Kevin MacLeod

Other music via APM

Stock images from Shutterstock, stock footage from Videoblocks

French subtitles by Alessandro Dal Cero

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Last week's video:
What's The Loudest Possible Sound? https://www.youtube.com/watch?v=wi_aawsChqA

More videos:
Why Does February Have 28 Days? https://www.youtube.com/watch?v=AgKaHTh-_Gs
Why Vaccines Work https://www.youtube.com/watch?v=3aNhzLUL2ys
Why Are Some People Left-Handed? https://www.youtube.com/watch?v=NPvMUpcxPSA
Where Does the Smell of Rain Come From? https://www.youtube.com/watch?v=lGcE5x8s0B8

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We’re living longer. Dying less. Human life expectancy has doubled in just a couple centuries. Machines and meals and medicines keeping us alive long past the age where we can make babies. Does this mean our species is no longer under the influence of natural selection? Have humans stopped evolving?

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How can sand, blown by the wind, form such intricate and beautiful patterns as ripples and dunes? The answer is a surprising secret of self-organization. In this video, we travel to Great Sand Dunes National Park in Colorado to climb the largest sand dunes in North America and bring you the science of how wind and sand combine to create ordered landforms out of chaos. The science must flow.

References: https://sites.google.com/view/....sanddunesreferences/

Thank you to Dr. Mathieu Lapôtre (Stanford) and Dr. Orencio Duran Vinent (Texas A&M) for helpful discussions while researching this epsiode.

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Check out our whole series on ENERGY! http://bit.ly/1BnH5zu
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We use a LOT of energy, but we waste a lot too. Where that waste happens might surprise, you though. We don't just waste energy when we leave the lights on or the thermostat cranked down too low. It happens at the dinner table and the water faucet as too!

LEARN MORE:
Special thanks to Sheril Kirshenbaum and the Webber Energy Group at the University of Texas at Austin for their help with this series. http://www.webberenergygroup.com/

Check out their awesome online course "Energy 101" to learn about energy and energy policy from A to Z! http://www.energy101.com/

And to find out what people think about energy, check out the UT Energy Poll: http://www.utenergypoll.com/


Have an idea for an episode or an amazing science question you want answered? Leave a comment or check us out at the links below!
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It's Okay To Be Smart is written and hosted by Joe Hanson, Ph.DFollow me on Twitter: @jtotheizzoe
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Facebook: http://www.facebook.com/itsokaytobesmart
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For more awesome science, check out: http://www.itsokaytobesmart.com
Produced by PBS Digital Studios: http://www.youtube.com/user/pbsdigitalstudios

Joe Hanson - Creator/Host/Writer
Joe Nicolosi - Director
Amanda Fox - Producer, Spotzen IncKate Eads - Associate Producer
Andrew Matthews - Editing/Motion Graphics/Animation
Katie Graham - Director of Photography
John Knudsen - Gaffer

Theme music:
"Ouroboros" by Kevin MacLeod

Other music via APM

Stock images from Shutterstock, stock footage from Videoblocks

-----------------

Last week's video:
Does the Moon Orbit the Earth? https://www.youtube.com/watch?v=3cJ3AemeUFM

More videos:
Why Does February Have 28 Days? https://www.youtube.com/watch?v=AgKaHTh-_Gs
Why Vaccines Work https://www.youtube.com/watch?v=3aNhzLUL2ys
Why Are Some People Left-Handed? https://www.youtube.com/watch?v=NPvMUpcxPSA
Where Does the Smell of Rain Come From? https://www.youtube.com/watch?v=lGcE5x8s0B8

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It would be a lot easier to study the science of dreaming if we weren’t asleep every time we did it. Why do we dream? What does dreaming do for our brains? How did dreaming evolve? Here’s a look at the current theories from psychology and neuroscience.

References:
Barrett, D. (2017), Dreams and creative problem-solving. Ann. N.Y. Acad. Sci., 1406: 64-67. https://doi.org/10.1111/nyas.13412
Carlo Cipolli, Roberto Bolzani, Cesare Comoldi, Rossana De Beni, Iino Fagioli, Bizarreness Effect in Dream Recall, Sleep, Volume 16, Issue 2, March 1993, Pages 163–170, https://doi.org/10.1093/sleep/16.2.163
Eagleman DM, Vaughn DA (2021). The Defensive Activation Theory: REM Sleep as a Mechanism to Prevent Takeover of the Visual Cortex. Frontiers in Neuroscience. 15:632853. doi: 10.3389/fnins.2021.632853
El-Solh, A. A. (2018). Management of nightmares in patients with posttraumatic stress disorder: Current perspectives. Nature and Science of Sleep, 10, 409–420.https://pubmed.ncbi.nlm.nih.gov/30538593/
Hughes, J. Donald. (2000). Dream Interpretation in Ancient Civilizations. Dreaming. 10. 7-18. 10.1023/A:1009447606158.
Káli, S., Dayan, P. Off-line replay maintains declarative memories in a model of hippocampal-neocortical interactions. Nature Neuroscience 7, 286–294 (2004). https://doi.org/10.1038/nn1202
Montangero, Jacques & Ivanyi, Corinne & Saint-Hilaire, Zara. (2003). Completeness and accuracy of morning reports after a recall cue: Comparison of dream and film reports. Consciousness and cognition. 12. 49-62. 10.1016/S1053-8100(02)00029-6.
Stickgold, R., Malia, A.; Maguire, D., Roddenberry, D., O'Connor, M. (2000). Replaying the Game: Hypnagogic Images in Normals and Amnesics. Science. 290 (5490): 350–353. doi:10.1126/science.290.5490.350.
Valli, K., Revonsuo, A., Pälkäs, O., Ismail, K. H., Ali, K. J., & Punamäki, R.-L. (2005). The threat simulation theory of the evolutionary function of dreaming: Evidence from dreams of traumatized children. Consciousness and Cognition, 14(1), 188–218. https://pubmed.ncbi.nlm.nih.gov/15766897/
van der Linden, S. The Science Behind Dreaming. Scientific American. July 26, 2011
Erin J. Wamsley, PhD, Karen Perry, MD, Ina Djonlagic, MD, Laura Babkes Reaven, MD, Robert Stickgold, PhD, Cognitive Replay of Visuomotor Learning at Sleep Onset: Temporal Dynamics and Relationship to Task Performance, Sleep, Volume 33, Issue 1, January 2010, Pages 59–68, https://doi.org/10.1093/sleep/33.1.59
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Shows like The Walking Dead are full of hungry, mindless, surprisingly fleet-footed armies of brain-eating zombies. Could they actually exist? Are zombies real? Well, maybe if you're talking about zom-bees! This week I introduce you to some of nature's strangest mind-controlling parasites, who make zombies of the natural world. This one will make your brain tingle. That's just the awesome science, though… not a parasite. Promise!

Watch the full video clips used in this episode:
KQED zom-bees https://www.youtube.com/watch?v=fdZ3M8C6yhs
BBC cordyceps https://www.youtube.com/watch?v=XuKjBIBBAL8
Jewel wasp: https://www.youtube.com/watch?v=vl_9kghmChw
https://www.youtube.com/watch?v=UWAV1zj5TXQ
Cricket horsehair worm: https://www.youtube.com/watch?v=Df_iGe_JSzI
Red berry ants: https://www.youtube.com/watch?v=b4Rj89-wuDo
NatGeo zombie snails: https://www.youtube.com/watch?v=Go_LIz7kTok

LEARN MORE:
Ed Yong's TED talk: http://www.ted.com/talks/ed_yo....ng_suicidal_wasps_zo
Biochemistry of parasitic zombies: http://www.nytimes.com/2012/12/11/science/parasites-use-sophisticated-biochemistry-to-take-over-their-hosts.html?_r=1&
An entire issue of the Journal of Experimental Biology dedicated to parasitic control of hosts: http://jeb.biologists.org/content/216/1.toc


Have an idea for an episode or an amazing science question you want answered? Leave a comment below!
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http://twitter.com/jtotheizzoe
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It's Okay To Be Smart is written and hosted by Joe Hanson, Ph.DFollow me on Twitter: @jtotheizzoe
Email me: itsokaytobesmart AT gmail DOT com
Facebook: http://www.facebook.com/itsokaytobesmart
Google+ https://plus.google.com/+itsokaytobesmart
For more awesome science, check out: http://www.itsokaytobesmart.com
Produced by PBS Digital Studios: http://www.youtube.com/user/pbsdigitalstudios

Joe Hanson - Creator/Host/Writer
Joe Nicolosi - Director
Amanda Fox - Producer, Spotzen IncKate Eads - Associate Producer
Andrew Matthews - Editing/Motion Graphics/Animation
Katie Graham - Director of Photography
John Knudsen - Gaffer
Dalton Allen - Post-Production Intern

Theme music:
"Ouroboros" by Kevin MacLeod

Other music via APM

Stock images from Shutterstock

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Last week's video: Why Does February Have 28 Days? https://www.youtube.com/watch?v=AgKaHTh-_Gs

More videos:
Why Vaccines Work https://www.youtube.com/watch?v=3aNhzLUL2ys
Why Are Some People Left-Handed? https://www.youtube.com/watch?v=NPvMUpcxPSA
Where Does the Smell of Rain Come From? https://www.youtube.com/watch?v=lGcE5x8s0B8
Why Did We Blow on NES Games? https://www.youtube.com/watch?v=4Gf9mtXnJfM
The Science of Game of Thrones - https://www.youtube.com/watch?v=Utu-LpJn3Is
There Was No First Human - https://www.youtube.com/watch?v=xdWLhXi24Mo

You have the power to change your brain!
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Got a bad habit you just can’t seem to break? That’s because it’s literally wired into your brain.
Every single thought, action, and feeling changes your brain. When repeated enough times, a habit is formed. This week we’ll talk about how an advertiser in the early 1900s got half of Americans to pick up a new behavior - and make it a habit we all know today.
#habits #brain #neuroscience

REFERENCES:

The power of habit: Why we do what we do in life and in business, Charles Duhill, 2012.

Smith, K. (2016). Habit formation. Dialogues Clin Neurosci, 18(1), 33–43.

Schultz, W., Apicella, P., and Ljungbergb , T. (1993). Responses of Monkey Dopamine Neurons to Reward and Conditioned Stimuli during Successive Steps of Learning a Delayed Response Task. The Journal of Neuroscience, 13(3), 900-913

Christina M.Gremel, C. M., Chancey, J.H., Atwood, B.K., Luo, G., Neve, R., Ramakrishnan, C., Deisseroth, K., Lovinger, D.M., and Costa, R.M. (2016). Endocannabinoid Modulation of Orbitostriatal Circuits Gates Habit Formation. Neuron, 93(6), 1312-1324.

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It’s Okay To Be Smart is hosted by Joe Hanson, Ph.D.
Director: Joe Nicolosi
Writer: Kimberly McCoy, Ph.D.
Creative Director: David Schulte
Editor/animator: Karl Boettcher
Producers: Stephanie Noone and Amanda Fox

Produced by PBS Digital Studios
Music via APM
Stock images from Shutterstock http://www.shutterstock.com

Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/PBSDSDonate

Are you more of a cat person?
Follow me to MinuteEarth to discover the origin of our feline friends! https://youtu.be/LWB0-tGwb_E
↓↓↓More info and sources below ↓↓↓

Of all the species that humans have domesticated, dogs are our oldest animal friends. But how did a group of wolves become the furry pup at the end of the bed? New research is finally unlocking the paw-in-hand evolution of dogs and humans. In this episode we’re answering one big question: Did we domesticate dogs, or did dogs domesticate us?

Special thanks to our friends from MinuteEarth!

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REFERENCES:

Frantz, Laurent AF, et al. "Genomic and archaeological evidence suggest a dual origin of domestic dogs." Science 352.6290 (2016): 1228-1231.

Freedman, Adam H., and Robert K. Wayne. "Deciphering the Origin of Dogs: From Fossils to Genomes." Annual Review of Animal Biosciences 0 (2016).

Freedman, Adam H., et al. "Genome sequencing highlights the dynamic early history of dogs." PLoS Genet 10.1 (2014): e1004016.

Thalmann, Olaf, et al. "Complete mitochondrial genomes of ancient canids suggest a European origin of domestic dogs." Science 342.6160 (2013): 871-874.

Wang, Guo-Dong, et al. "Out of southern East Asia: the natural history of domestic dogs across the world." Cell research 26.1 (2016): 21-33.

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It’s Okay To Be Smart is hosted by Joe Hanson, Ph.D.
Director: Joe Nicolosi
Writer: Sarah Keartes
Producer/editor/animator: Andrew Matthews
Producer: Stephanie Noone and Amanda Fox

Produced by PBS Digital Studios
Music via APM
Stock images from Shutterstock http://www.shutterstock.com

You can learn more at https://curiositystream.com/smart
SUBSCRIBE so you don’t miss a video! ►► http://bit.ly/iotbs_sub
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You may have heard that a kilogram of feathers weighs the same as a kilogram of steel, but that all depends on where you weigh them. This video is all about the difference between mass and weight, and how weirdly awesome Earth’s gravity really is.

REFERENCES:
https://en.wikipedia.org/wiki/Mass_versus_weight
http://curious.astro.cornell.e....du/about-us/42-our-s
https://en.wikipedia.org/wiki/Equatorial_bulge
http://www.cleonis.nl/physics/....phys256/equatorial_b
https://en.wikipedia.org/wiki/Geoid
https://gracefo.jpl.nasa.gov/
http://www2.csr.utexas.edu/gra....ce/publications/fact

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Twitter: @DrJoeHanson @okaytobesmart
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BOOKS WE’VE FEATURED:
http://smart-books.tumblr.com/

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It’s Okay To Be Smart is hosted by Joe Hanson, Ph.D.
Director: Joe Nicolosi
Researcher: Matt Caplan, Ph.D.
Creative Director: David Schulte
Editors/animators: Derek Borsheim
Executive Producer: Amanda Fox
Producer: Stephanie Noone

Produced by PBS Digital Studios
Music via APM
Stock images from Shutterstock http://www.shutterstock.com

Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/PBSDSDonate

Hint: It's not black
Don’t miss our next video! SUBSCRIBE! ►► http://bit.ly/iotbs_sub
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When you stare up at the night sky, you might think that the universe is really black, but that's just because our eyes aren't sensitive enough to see the billions and billions of multicolored stars out there. Ever wonder why certain stars are certain colors? And what color is our sun, really? If we looked at enough stars, could we figure out the average color of the universe?

Read more:
Stellar classification: http://en.wikipedia.org/wiki/S....tellar_classificatio
What color is the sun: http://casa.colorado.edu/~ajsh..../colour/Tspectrum.ht
Star colors in hex code: http://blogs.discovermagazine.....com/badastronomy/201
Color of the Milky Way: http://www.news.pitt.edu/milkywaycolor
Average color of the universe (cosmic latte): http://apod.nasa.gov/apod/ap020702.html

Have an idea for an episode or an amazing science question you want answered? Leave a comment below!
Follow on Twitter: http://twitter.com/okaytobesmart
http://twitter.com/jtotheizzoe
Follow on Tumblr: http://www.itsokaytobesmart.com
Follow on Instagram: http://instagram.com/jtotheizzoe

-----------------
It's Okay To Be Smart is written and hosted by Joe Hanson, Ph.D
Follow me on Twitter: @DrJoeHanson
Instagram: @DrJoeHanson
Email me: itsokaytobesmart AT gmail DOT com
Facebook: http://www.facebook.com/itsokaytobesmart

Produced by PBS Digital Studios: http://www.youtube.com/user/pbsdigitalstudios

Joe Hanson - Creator/Host/Writer
Joe Nicolosi - Director
Amanda Fox - Producer, Spotzen IncKate Eads - Associate Producer
Andrew Matthews - Editing/Motion Graphics/Animation
Katie Graham - Director of Photography
John Knudsen - Gaffer
Dalton Allen - Post-Production Intern

Theme music:
"Ouroboros" by Kevin MacLeod

Other music via APM

Stock images from Shutterstock

-----------------

Last week's video: Attack of the Zombie Parasites https://www.youtube.com/watch?v=AgCQStTSMuk

More videos:
Why Does February Have 28 Days? https://www.youtube.com/watch?v=AgKaHTh-_Gs
Why Vaccines Work https://www.youtube.com/watch?v=3aNhzLUL2ys
Why Are Some People Left-Handed? https://www.youtube.com/watch?v=NPvMUpcxPSA
Where Does the Smell of Rain Come From? https://www.youtube.com/watch?v=lGcE5x8s0B8