Which Way Is Down?

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  • Published on:  Thursday, November 2, 2017
  • BRAIN CANDY LIVE http://www.braincandylive.com/tickets
    THE VSAUCE CURIOSITY BOX: https://www.curiositybox.com/
    Links to sources and to learn more below!

    my twitter https://twitter.com/tweetsauce
    my instagram https://www.instagram.com/electricpants

    Thanks to Eric Langlay (https://www.youtube.com/user/ericdraven30) for producing, editing, and animating this episode with me. Thanks also to Henry Reich (https://www.youtube.com/user/minutephysics) for his advice and guidance.

    Universe Sandbox² : http://universesandbox.com/

    Mass vs weight:

    https://en.wikipedia.org/wiki/Mass_versus_weight
    Great Veritasium video: https://anyclips.net/video/_Z0X0yE8Ioc
    two other great videos: https://anyclips.net/video/6ccIjRwYO9U and https://anyclips.net/video/aCqQzrPCcFM

    baseballs coming together under gravitational attraction can be simulated in Universe Sandbox 2. More math behind it can be found here: https://www.reddit.com/r/explainlikeimfive/comments/2vyxl7/eli5_will_two_baseballs_a_foot_apart_in_deep/

    Weight to mass (on surface of Earth) convertor: https://www.convertunits.com/from/kilograms/to/newton

    pencil and Earth falling numbers: https://www.quora.com/When-we-drop-a-pencil-the-earth-attracts-it-and-it-seems-that-the-pencil-is-falling-towards-earth-Why-doesnt-the-earth-come-up-towards-the-pencil

    NASA HD footage: https://archive.org/details/NASA-Ultra-High-Definition

    Buoyancy: https://en.wikipedia.org/wiki/Buoyancy

    Earth’s spin and its effect on ‘down’: http://www.freemars.org/jeff/Earth/down.htm

    The measurement of Earth and its gravity:

    https://en.wikipedia.org/wiki/Geodesy
    https://en.wikipedia.org/wiki/Physical_geodesy

    Movement of Earth’s center of mass:

    http://www.aiub.unibe.ch/research/slr_data_analysis/estimating_the_geocenter_and_earth_rotation_parameter/index_eng.html
    http://www.massentransporte.de/index.php?id=307
    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.650.4392&rep=rep1&type=pdf

    you get heavier before you get lighter as you descend into Earth: https://www.reddit.com/r/askscience/comments/4qfl52/do_you_get_lighter_the_further_underground_that/

    vertical deflection:

    https://en.wikipedia.org/wiki/Vertical_deflection

    practical uses of measuring gravity: https://en.wikipedia.org/wiki/Gravimetry

    geoid:

    https://en.wikipedia.org/wiki/Geoid
    https://oceanservice.noaa.gov/facts/geoid.html
    https://anyclips.net/video/jOQl8DRzQks

    Interactive Earth geoid: https://experiments.withgoogle.com/chrome/geoid-viewer

    your weight when moon is overhead: https://www.thenakedscientists.com/forum/index.php?topic=11639.0

    Hammer and feather drop on moon: https://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_15_feather_drop.html

    Why things fall at the same rate: https://www.quora.com/If-an-object-has-more-mass-then-its-pull-on-earth-would-be-greater-than-an-object-with-less-mass-and-therefore-should-fall-to-earth-faster-Why-do-objects-of-different-mass-fall-to-earth-at-the-same-speed

    Wolfram Alpha cone geodesic tool: http://demonstrations.wolfram.com/ConeGeodesics/

    General Relativity:

    simple animation showing geodesic on cone and how it causes motion DOWN in space: https://anyclips.net/video/DdC0QN6f3G4
    GREAT pbs spacetime video (watch the whole channel): https://anyclips.net/video/AwhKZ3fd9JA
    http://www.askamathematician.com/2009/10/q-why-does-curved-space-time-cause-gravity/
    https://www.av8n.com/physics/geodesics.htm#sec-straight
    http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/spacetime/
    http://www.einstein-online.info/spotlights/geometry_force

    time and gravity:

    https://anyclips.net/video/jlTVIMOix3I
    https://anyclips.net/video/1ENkP0h8nAg
    https://anyclips.net/video/gcvq1DAM-DE
    https://www.reddit.com/r/askscience/comments/30lt1o/bending_of_space_not_responsible_for_objects/
    https://www.reddit.com/r/AskScienceDiscussion/comments/3rfmtl/does_time_dilation_cause_gravity_or_the_other_way/

    tests of general relativity: https://en.wikipedia.org/wiki/Tests_of_general_relativity

    RECOMENDED BOOKS:

    great introductory texts:

    “Relativity Visualized” by Lewis Carroll Epstein https://www.amazon.com/Relativity-Explained-Classics-Science-Mathematics/dp/0486293157

    There’s also this PDF that takes Epstein’s diagrams into more detail: http://www.relativity.li/uploads/pdf/English/Epstein_en.pdf

    “Relativity Simply Explained” by Martin Gardener https://www.amazon.com/Relativity-Explained-Classics-Science-Mathematics/dp/0486293157

    great intro to the math of general relativity:

    “A Most Incomprehensible Thing: Notes Towards a Very Gentle Introduction to the Mathematics of Relativity” by Peter Collier https://www.amazon.com/Most-Incomprehensible-Thing-Introduction-Mathematics/dp/0957389469/

    Requires some background in relevant math topics (see above) but very very good:

    “Spacetime And Geometry: An Introduction To General Relativity” by Sean Carrol https://www.amazon.com/gp/product/9332571651/
  • Source: https://youtu.be/Xc4xYacTu-E

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