(Phys.org)—As if space travel was not already filled with enough dangers, a new study out today in the journal PLOS ONE shows that cosmic radiation – which would bombard astronauts on deep space missions to places like ...
Space Exploration
Dec 31, 2012
119
0
(Phys.org)—A nearby short duration gamma-ray burst may be the cause of an intense blast of high-energy radiation that hit the Earth in the 8th century, according to new research led by astronomers Valeri Hambaryan and Ralph ...
Astronomy
Jan 21, 2013
55
0
Since the beginning of human history, people have understood that the sun is a central part of life as we know it. It's importance to countless mythological and cosmological systems across the globe is a testament to this. ...
Astronomy
May 10, 2016
1
49
Newly discovered layers of ice buried a mile beneath Mars' north pole are the remnants of ancient polar ice sheets and could be one of the largest water reservoirs on the planet, according to scientists at The University ...
Space Exploration
May 22, 2019
8
1843
The first of the gas-giant orbiter's back-to-back flybys will provide a close encounter with the massive moon after over 20 years.
Space Exploration
Jun 4, 2021
5
562
Venus may have been a temperate planet hosting liquid water for 2-3 billion years, until a dramatic transformation starting over 700 million years ago resurfaced around 80% of the planet. A study presented today at the EPSC-DPS ...
Space Exploration
Sep 22, 2019
85
1943
A small but evolving dent in Earth's magnetic field can cause big headaches for satellites.
Space Exploration
Aug 17, 2020
14
4579
Physicist Pekka Janhunen with the Finnish Meteorological Institute has developed a novel idea to colonize a place other than the Earth—and it is not the moon or Mars. Instead, Janhunen is suggesting in a paper posted on ...
Tiny iron nanoparticles unlike any found naturally on Earth are nearly everywhere on the moon—and scientists are trying to understand why. A new study led by Northern Arizona University doctoral candidate Christian J. Tai ...
Space Exploration
Aug 20, 2021
14
2450
NASA-funded researchers are monitoring a big event in our planet's atmosphere. High above Earth's surface where the atmosphere meets space, a rarefied layer of gas called "the thermosphere" recently collapsed and now is rebounding ...
Earth Sciences
Jul 15, 2010
45
0
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
