how is the speed of light measured

How was the speed of light first measured to some degree of accuracy? https://www.reddit.com/r/askscience/comments/50p6jc/how_was_the_speed_of_light_first_measured_to_some/ 7 comments 1/9/2016 askscience

How The Speed of Light Was Measured in 1676 http://www.amnh.org/education/resources/rfl/web/essaybooks/cosmic/p_roemer.html 44 comments 14/12/2012 technology

Sweet! Measure the Speed of Light using Chocolate http://www.wired.com/geekdad/2010/02/leftover-valentines-chocolate-use-it-to-measure-the-speed-of-light/? 7 comments 17/2/2010 reddit.com

Measuring the speed of light in the kitchen http://www.mrhood.co.uk/pub/?p=151 11 comments 28/6/2007 science

How they measured the speed of light if we don't know exactly our traveling speed into space? Or we do? https://www.reddit.com/r/askscience/comments/5gy9n2/how_they_measured_the_speed_of_light_if_we_dont/ 12 comments 7/12/2016 askscience

Chinese physicists measure speed of Einstein’s ‘spooky action at a distance’: At least 10,000 times faster than light http://www.extremetech.com/extreme/150207-chinese-physicists-measure-speed-of-einsteins-spooky-action-at-a-distance-at-least-10000-times-faster-than-light 1545 comments 7/3/2013 science

Use Your Microwave to Measure the Speed of Light http://io9.com/5526055/use-your-microwave-to-measure-the-speed-of-light 23 comments 29/4/2010 science

Measure the Speed of Light Using Your Microwave http://orbitingfrog.com/blog/2008/05/13/measure-the-speed-of-light-using-your-microwave/ 3 comments 30/9/2008 science

How do we know the speed of light when it already has been distorted before measuring? If not by nothing else than the instrument we measure it with? https://www.reddit.com/r/askscience/comments/73ku1m/how_do_we_know_the_speed_of_light_when_it_already/ 19 comments 1/10/2017 askscience

For the first time, astronomers have directly measured how fast a black hole spins, clocking its rotation at nearly half the speed of light. http://www.nasa.gov/mission_pages/chandra/news/black-hole-spin.html#.ux_xwz9dvn8 4 comments 12/3/2014 space

"Old" method of measurement of c (speed of light) http://www.physics.umd.edu/icpe/newsletters/n34/marshmal.htm 9 comments 13/1/2012 science

Measuring the speed of light with chocolate and a microwave oven http://morningcoffeephysics.wordpress.com/2008/10/05/measuring-the-speed-of-light-with-chocolate-and-a-microwave-oven/ 12 comments 13/1/2010 science

Chinese measure speed of gravity (same as speed of light) with solar eclipses (link to open access paper) http://link.springer.com/article/10.1007/s11434-012-5603-3 953 comments 27/12/2012 science

The faster-than-light neutrino saga is officially over. Today, at the Neutrino 2012 conference in Kyoto, Japan, the OPERA collaboration announced that according to their latest measurements, neutrinos travel at almost exactly the speed of light. http://www.newscientist.com/article/dn21899-neutrinos-dont-outpace-light-but-they-do-shapeshift.html 24 comments 8/6/2012 science

A repeat of the measurement of the speed of neutrinos finds they do not exceed light speed, in contrast to controversial results reported last year. http://www.bbc.co.uk/news/science-environment-17364682 47 comments 16/3/2012 science

ICARUS experiment at Gran Sasso laboratory reports new measurement of neutrino time of flight consistent with the speed of light. http://press.web.cern.ch/press/pressreleases/releases2011/pr19.11e.html 7 comments 16/3/2012 science

Our units of measurement are finally about to get an upgrade - the only thing that can threaten the new metric system definitions is if we suddenly discover that the constants of nature - such as the speed of light and Planck's constant - actually vary slightly throughout the Universe. http://www.sciencealert.com/our-units-of-measurement-are-finally-getting-an-upgrade 4 comments 4/11/2016 worldnews

Time dilation measured at 40 percent of the speed of light—in the lab; High-speed ions show that clocks do run slow when you are moving fast. http://arstechnica.com/science/2014/09/time-dilation-measured-at-40-percent-of-the-speed-of-lightin-the-lab/ 77 comments 19/9/2014 science

The Speed of Light, when unobstructed, equals zero meters per second which is another way of saying light travels instantaneously. The way we measured light before found the speed of electromagnetic waves. This revelation will lead to unknown explorations; and instantaneous communications. https://gitresearch.org/the-speed-of-light-is-zero-meters-per-second-979da182280d 82 comments 13/6/2022 futurology

In 1999 the Hubble telescope measured the speed of the relativistic jet of M87 at four to six times the speed of light. This was probably some sort of optical illusion but how fast IS it going? http://upload.wikimedia.org/wikipedia/commons/3/39/m87_jet.jpg 15 comments 28/5/2014 space

The star S62 orbits the Milky Way's central black hole. Its orbit was recently measured, and found to reach 7% of the speed of light (76 million km/h), making it by far the fastest known star. https://en.wikipedia.org/wiki/Sagittarius_A*#Orbiting_stars 4 comments 15/2/2020 space

Physicists have developed a fast and sensitive mechanical tool to measure light. The graphene nanomechanical bolometer is the fastest and most sensitive in its class. It is poised to detect nearly every color of light at high speeds and obtain measurements at and far above room-temperature. https://www.nature.com/articles/s41467-019-12562-2 4 comments 17/10/2019 science

Scientists measure spin of 5 quasars (black holes with accretion disk) located 8.8B-10.9B light years away, with X-ray observation of the multiple images produced by gravitational lensing, and conclude that the event horizon is spinning at half or near speed of light https://iopscience.iop.org/article/10.3847/1538-4357/ab1d56 9 comments 8/7/2019 science