India and China have so many people today because they’re good for farming and big, but they’ve always been that way, so they’ve actually had a huge proportion of Earth’s people for thousands of years.

Thanks to the University of Minnesota for sponsoring this video! http://twin-cities.umn.edu/

Thanks also to our supporters on https://www.patreon.com/MinuteEarth

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If you liked this week’s video, you might also like:

A very detailed map of world population density: https://populationexplorer.com/
Info about world population growth: https://ourworldindata.org/world-population-growth/

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Credits (and Twitter handles):

Script Writer: Alex Reich (@alexhreich)

Script Editor: Kate Yoshida (@KateYoshida)

Video Illustrator: Qingyang Chen (@QCVisual)

Video Director: Emily Elert (@eelert)

Video Narrator: Kate Yoshida (@KateYoshida)

With Contributions From: Henry Reich, Ever Salazar, Peter Reich, David Goldenberg

Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

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References:

Eraly, A., Khan, Y., Michell, G. & Saran, M. 2008. India. DK Publishing, New York.

Gidwani, V.K., April 2017, personal communication.

Goldewijk, K.K., Beusen, A., & Janssen, P. 2010. Long-term dynamic modeling of global population and built-up area in a spatially explicit way: HYDE 3.1. The Holocene, 20(4), 565-573. https://goo.gl/BuwJLQ

Goldewijk, K.K., Arthur Beusen, Jonathan Doelman, and Elke Stehfest. "New anthropogenic land use estimates for the Holocene; HYDE 3.2.” Unpublished manuscript. https://goo.gl/z73PNr

Goldewijk, K.K., April 2017, personal communication.

Maddison, A. 2006. The World Economy: A Millennial Perspective. OECD. https://www.stat.berkeley.edu/~aldous/157/Papers/world_economy.pdf

Roberts, E., March 2017, personal communication.

Ruggles, S., March 2017, personal communication.

Stearns, P. N. (Ed.). 2001. The encyclopedia of world history: Ancient, Medieval, and Modern, chronologically arranged. Houghton Mifflin. Chicago.

Thanks also to Deepak Ray, Jamie Gerber, Emily Cassidy, and Ryan Loomis.

Give Blinkist a try! https://www.blinkist.com/MinuteEarth

What exactly makes sugary syrups so sticky, when neither water nor sugar is very sticky on its own?

Support MinuteEarth on Patreon: http://www.patreon.com/minuteearth

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Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd
And visit our website: https://www.minuteearth.com/

Say hello on Facebook: http://goo.gl/FpAvo6
And Twitter: http://goo.gl/Y1aWVC

And download our videos on itunes: https://goo.gl/sfwS6n
___________________________________________

Credits (and Twitter handles):
Script Writer: Emily Elert (@eelert)
Script Editor: Kate Yoshida (@KateYoshida)
Video Illustrator: Jesse Agar
Video Director: Emily Elert (@eelert)
Video Narrator: Emily Elert (@eelert)
With Contributions From: Alex Reich, Henry Reich, Peter Reich, David Goldenberg, Ever Salazar
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

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References:
Brown, T.L, LeMay, H.E., Bursten, B.E. (2006). Chapter 11: Intermolecular Forces, Liquids, and Solids. In Chemistry, The Central Science 10th edition. Retrieved from: http://alpha.chem.umb.edu/chemistry/ch115/Mridula/CHEM%20116/documents/chapter_11au.pdf

Elert, M., Personal Communication, July 2017.

Husband, T. (2014). The Sweet Science of Candymaking. Retrieved from: https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2014-2015/candymaking.html

Longinotti, M.P. & Corti, H.R. (2008) Viscosity of concentrated sucrose and trehalose aqueous solutions including the supercooled regime. Journal of Physical and Chemical Reference Data, 37: 1503-1516.

Molinero, V., Cagin, T., Goddard, W.A. (2003) Sugar, water and free volume networks in concentrated sucrose solutions. Chemical Physics Letters, 377:469–474. Retrieved from: https://pdfs.semanticscholar.org/8b49/ce63d9430af305c87c1dadfa0ec9bc646461.pdf

Wang, L.P., Personal Communication, February 2017.

Xia, J., & Case, D. A. (2012). Sucrose in Aqueous Solution Revisited: 1. Molecular Dynamics Simulations and Direct and Indirect Dipolar Coupling Analysis. Biopolymers, 97(5), 276–288. http://doi.org/10.1002/bip.22017

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Image Credits:
Sugar - Melissa Wiese
https://www.flickr.com/photos/42dreams/2452033439/

Sugar beet field - Gilles San Martin
https://www.flickr.com/photos/sanmartin/4799481326/

Sugar Cubes - David Pacey
https://www.flickr.com/photos/63723146@N08/7164573186/

Watch Henry’s MinutePhysics video: https://www.youtube.com/watch?v=NucdlR9EGbA

MinuteEarth & MinutePhysics are on Patreon: http://www.patreon.com/minuteearth & http://www.patreon.com/minutephysics

It’s becoming harder and harder to categorize moons as moons.
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To learn more, start your googling with these keywords:
Moon: a natural satellite of a satellite of a star.
Satellite: A celestial body orbiting a larger celestial body.
Orbit: The path followed by one object revolving around another object under the influence of gravity.
Barycenter: The center of mass that two or more bodies orbit around.
Binary System: A system in which two similarly sized object orbit the same barycenter.
Hydrostatic equilibrium: Roundness that occurs when gravity is balanced by a pressure gradient force.
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If you liked this week’s video, you might also like:
That’s no moon … it’s a space station! https://www.youtube.com/watch?v=JGp_5gOww0E.
And here's a tidy illustrated difference between geocentrism and heliocentrism: http://www.malinc.se/math/trigonometry/geocentrismen.php
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Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd
Support us on Patreon: https://goo.gl/ZVgLQZ
And visit our website: https://www.minuteearth.com/

Say hello on Facebook: http://goo.gl/FpAvo6
And Twitter: http://goo.gl/Y1aWVC

And download our videos on itunes: https://goo.gl/sfwS6n
___________________________________________

Credits (and Twitter handles):
Script Writer: David Goldenberg (@dgoldenberg)
Script Editor: Henry Reich (@MinutePhysics)
Video Illustrator: Ever Salazar (@eversalazar)
Video Director: Henry Reich (@MinutePhysics)
Video Narrator: Kate Yoshida (@KateYoshida)
With Contributions From: Alex Reich, Emily Elert, Peter Reich
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

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References:

Norton, J. (2008) Could a moon have moons? Popular Science. Retrieved from: http://www.popsci.com/scitech/article/2008-04/could-moon-have-moons

H. A. Weaver, S. A. Stern, M. J. Mutchler, A. J. Steffl, M. W. Buie, W. J. Merline, J. R. Spencer, E. F. Young, L. A. Young (2006). The Discovery of Two New Satellites of Pluto. Nature. 439: 943-945. Retrieved from: http://www.nature.com/nature/journal/v439/n7079/abs/nature04547.html?foxtrotcallback=true

Tiscareno, M., Burns, J., Sremcevi, M., Beurle, K., Hedman, M. Copper, N., Milano, A., Evans, M., Porco, C., Spitale, J., and WEiss, J. (2010) Physical Characteristics And Non-Keplerian Orbital Motion Of “Propeller” Moons Embedded In Saturn’s Rings. The Astrophysical Journal Letters, 718: 92-96. Retrieved from: http://iopscience.iop.org/article/10.1088/2041-8205/718/2/L92

Spahn, F., and Schmidt, J. (2006) Saturn’s Bared Mini-Moons. Nature, 440: 30-31. Retrieved from: https://www.nature.com/nature/journal/v440/n7084/full/440614a.html

Get your FREE 2-month Skillshare trial: http://skl.sh/minuteearth2

The "Mountain or Valley?" illusion makes our brains turn valleys inside out. But inside-out valleys are a real thing, both on Earth and on Mars.

Thanks to Skillshare for sponsoring this video, and to our supporters on https://www.patreon.com/MinuteEarth
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If you want to learn more about this topic, start your googling with these keywords:
Inverted relief: a topographic feature, such as an old riverbed, that has reversed its elevation relative to other features.

Duricrust: a hard mineral crust formed at or near the surface of soil in semiarid regions by the evaporation of groundwater.

Geomorphology: the study of the physical features of the surface of the earth and their relation to its geological structures.

Exhumed paleochannel: a remnant of an inactive river or stream channel that has been either filled or buried by younger sediment, and then subsequently uncovered by erosion.

Erosion: the action of surface processes, including wind and water, that move dirt and rock from their original location to some other place.

Capillary action: the tendency of a liquid in a capillary tube or absorbent material to rise or fall as a result of surface tension.

Mineral precipitation: when dissolved compounds in a solution bond together to form a solid (a simple example is how dissolved sodium and chloride ions come together to form salt as water evaporates)
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Credits (and Twitter handles):
Script Writers: David Goldenberg (@dgoldenberg) & Emily Elert (@eelert)
Video Illustrator: Ever Salazar (@eversalazar)
Video Narrator: Emily Elert (@eelert)
With Contributions From: Henry Reich, Alex Reich, Kate Yoshida, Emily Elert, Peter Reich
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

Image Credits: Yardangs and Ridges of the Edge of Aeolis Planum - NASA JPL University of Arizona
https://hirise.lpl.arizona.edu/PSP_006683_1740

Raised Footprints - Alan Light
https://www.flickr.com/photos/alan_light/5904493388/
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Like our videos?
Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd
Support us on Patreon: https://goo.gl/ZVgLQZ
And visit our website: https://www.minuteearth.com/

Also, say hello on:
Facebook: http://goo.gl/FpAvo6
Twitter: http://goo.gl/Y1aWVC

And download our videos on itunes: https://goo.gl/sfwS6n
___________________________________________

If you liked this week’s video, we think you might also like:
The "Mountain Or Valley?" Illusion by MinutePhysics
https://www.youtube.com/watch?v=V7C318DGB38

Inverted Relief at Green River, Utah
https://www.google.com/maps/@38.8744077,-110.2558884,867m/data=!3m1!1e3

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References:

Clarke, J., July 2016, personal communication.

Clarke, J. D., & Stoker, C. R. (2011). Concretions in exhumed and inverted channels near Hanksville Utah: implications for Mars. International Journal of Astrobiology, 10(03), 161-175. doi:10.1017/s1473550411000048

Harris, D.R. (1980). Exhumed paleochannels in the Lower Cretaceous Cedar
Mountain formation near Green river. Utah: Brigham Young Univ. Geol.
Stud. 27, 51–66.

Malin, M. C. (2003). Evidence for Persistent Flow and Aqueous Sedimentation on Early Mars. Science, 302(5652), 1931-1934. doi:10.1126/science.1090544

Miller, R. P. (1937). Drainage Lines in Bas-Relief. The Journal of Geology, 45(4), 432-438. doi:10.1086/624550

Pain, C.P & Ollier, C.D. (1996). Regolith stratigraphy: principles and problems. Journal of Australian Geology & Geophysics, 16(3), 197-202.

Pain, C., Clarke, J., & Thomas, M. (2007). Inversion of relief on Mars. Icarus, 190(2), 478-491. doi:10.1016/j.icarus.2007.03.017

Pain, C., July 2016, personal communication.