Light is a strange thing. It isn’t just what we can see; light can be broken up into different types and we call the whole family “the electromagnetic spectrum,” so even when it’s dark, light is still all around us.
Learn about visible light as well as the light we can’t see, including high-frequency gamma rays, x-rays, and ultraviolet light, and lower frequency infrared, microwaves, and radio waves, with this Royal Observatory explainer from Slurpy Studios Animation.
As the Royal Observatory Greenwich explains, “Humankind has invented lots of different instruments to show us where our eyes can’t see,” from giant optical telescopes that gather visible light, like the Giant Magellan Telescope, to radio telescopes that “collect weak radio light waves, bring it to a focus, amplify it and make it available for analysis.” Two other examples from the video above:
The Royal Observatory is overrun with squirrels. They’re hard to miss during the day because they reflect visible light from the Sun but at night it’s more difficult. However, they do emit infrared light and if our eyes could detect it we would be able to see them in the dark. If we pass high-energy x-rays through them the squirrels look very different.
Related reading at How Stuff Works: How Light Works. Plus, at Khan Academy: Introduction to Light.
Watch more from the Royal Observatory Greenwich:
• How do we measure the universe?
• How do we know how old the sun is?
• How shadows on other worlds would behave differently than on Earth
Plus, all kinds of waves and light, including The Spitzer Space Telescope, one of NASA’s ‘Great Observatories’ and A Visual History of Light, animated.
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