Glaciers flowed on ancient Mars, but slowly

The weight and grinding movement of glaciers has carved distinctive valleys and fjords into Earth's surface. Because Mars lacks similar landscapes, researchers believed ancient ice masses on the Red Planet must have been ...

Video: Does space trash ever naturally break down?

Remember when Elon Musk launched a car into space? That car's not just peacefully drifting through a vacuum—it's hurtling around the sun at 63,592 miles per hour, being bombarded by solar radiation. It might be in pieces, ...

NOAA shares first imagery from GOES-18 SUVI instrument

The Solar Ultraviolet Imager, or SUVI, onboard NOAA's GOES-18 satellite, which launched on March 1, 2022, began observing the sun on June 24, 2022. SUVI monitors the sun in the extreme ultraviolet portion of the electromagnetic ...

SIRI-2 to qualify technologies for radiation detection in space

U.S. Naval Research Laboratory scientists launched the second Strontium Iodide Radiation Instrument (SIRI-2) instrument in December 2021 onboard Space Test Program (STP) Sat-6. SIRI-2, a gamma-ray spectrometer, will demonstrate ...

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Sunlight

Sunlight, in the broad sense, is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon. Near the poles in summer, the days are longer and the nights are shorter or non-existent. In the winter at the poles the nights are longer and for some periods of time, sunlight may not occur at all. When the direct radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and heat. Radiant heat directly produced by the radiation of the sun is different from the increase in atmospheric temperature due to the radiative heating of the atmosphere by the sun's radiation. Sunlight may be recorded using a sunshine recorder, pyranometer or pyrheliometer. Sunlight takes about 8.3 minutes to reach the Earth. The World Meteorological Organization defines sunshine as direct irradiance from the Sun measured on the ground of at least 120 watts per square metre.

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared, visible, and ultra-violet light. Bright sunlight provides luminance of approximately 100,000 candela per square meter at the Earth's surface.

Sunlight is a key factor in photosynthesis, a process crucially important for life on Earth.

This text uses material from Wikipedia, licensed under CC BY-SA