Consumers have complained that the light emitted by LEDs is too harsh, however, there are several techniques manufacturers and consumers can employ improve light quality.

FORBES: How To Spur Mass Market Consumer Adoption Of LEDs

Because the universe is expanding, any wave of light emitted from a far-flung source is stretched out.

ECONOMIST: Fundamental physics

The Corot spacecraft detects the oscillations as subtle variations in the light emitted by the star as the surface wobbles.

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The Wise telescope instead looks at the infrared light emitted from space rocks, which is related to the temperature of the object.

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Infrared light is emitted from all objects, even if they are dark, allowing a much more accurate calculation of their size and therefore their age.

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It could vaporize a rock and identify its minerals from the spectrum of light they emitted, or drill a sample and tease apart its chemical constituents.

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Scientists are looking for tiny amounts of light, which would be emitted when dark-matter particles interact with xenon atoms.

WSJ: Physicists Look for Dark Matter Underground

Additionally, the introduction of traditional CFLs left a very negative impression with consumers, who did not like their odd corkscrew shape, delayed warm up time, light quality or the occasional buzzing sound they emitted.

FORBES: How To Spur Mass Market Consumer Adoption Of LEDs