From The Science Asylum.

Ground News Holiday Sale: Compare news coverage. Spot media bias. Join Ground News today to get 40% off unlimited access: https://ground.news/scienceasylum. Sale ends December 31.

The speed you know is only your spatial speed, but you also have a speed through time. The two together make something called a 4-velocity and its size is always the speed of light.

Nick Lucid – Host, Writer, Editor, Animator
Em Lucid – Producer
________________________________
VIDEO ANNOTATIONS/CARDS

Speed of Light is Infinite:

________________________________
RELATED YOUTUBE VIDEOS

ScienceClic on 4-Velocity:

PBS Space Time on 4-Velocity:

________________________________
SUPPORT THE SCIENCE ASYLUM

Patreon:
http://www.patreon.com/ScienceAsylum

YouTube Membership:
https://www.youtube.com/channel/UCXgNowiGxwwnLeQ7DXTwXPg/join

Advanced Theoretical Physics (Paperback):
http://www.lulu.com/shop/nick-lucid/advanced-theoretical-physics-a-historical-perspective/paperback/product-24250687.html

Advanced Theoretical Physics (eBook):
https://gumroad.com/l/ubSc

Merchandise:
http://shop.spreadshirt.com/scienceasylum/
________________________________
HUGE THANK YOU TO THESE SUPPORTERS

Asylum Orderlies:
Dhruv Singhal, Medec Hurtz

Einsteinium Crazies:
Benjamin Sharef, Eoin O’Sullivan, Jonathan Lima, Joseph Salomone, Kevin Flanagan, Sean K, YouTubeviewer2014

Plutonium Crazies:
Al Davis, Compuart, Ellis Hall, Fabio Manzini, Kevin MacLean, Rick Myers, Vid Icarus

Platinum Crazies:
Clayton Bruckert, David Johnston, Jonathan Reel, Joshua Gallagher, Marino Hernandez, Mikayla Eckel Cifrese, Mr. Orn Jonasar, Olga Cooperman, Thomas V Lohmeier
________________________________
ADDITIONAL READING

http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/vec4.html
________________________________
LINKS TO COMMENTS

________________________________
IMAGE/VIDEO CREDITS

Rene Descartes:
https://commons.wikimedia.org/wiki/File:Frans_Hals_-_Portret_van_Ren%C3%A9_Descartes.jpg
________________________________
TIME CODES

00:00 Cold Open
00:37 Introduction
00:48 3D Velocity
01:31 What is a Tangent?
02:12 What is Speed?
02:46 Coordinate System
03:47 4D Spacetime
04:18 4-Velocity is just like 3-Velocity
04:57 Mathematical Definition
05:43 The 2 Points of View
06:23 Intuition
07:24 What about Photons?
08:08 Summary
08:26 Sponsor Message
09:48 Outro
09:54 Featured Comment