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Sunlight on the surface of Earth is attenuated by Earth's atmosphere, so that less power arrives at the surface (closer to 1,000 W/m 2) in clear conditions when the Sun is near the zenith. [100] Sunlight at the top of Earth's atmosphere is composed (by total energy) of about 50% infrared light, 40% visible light, and 10% ultraviolet light. [101]
Although Early Earth had a reducing prebiotic atmosphere prior to the Proterozoic eon, starting at about 2.5 billion years ago in the late Neoarchaean period, the Earth's atmosphere experienced a significant rise in oxygen and transitioned to an oxidizing atmosphere with a surplus of molecular oxygen (dioxygen, O 2) as the primary oxidizing agent.
The amount of heat energy received at any location on the globe is a direct effect of Sun angle on climate, as the angle at which sunlight strikes Earth varies by location, time of day, and season due to Earth's orbit around the Sun and Earth's rotation around its tilted axis.
This integrated solar irradiance is called solar irradiation, solar radiation, solar exposure, solar insolation, or insolation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Irradiance in space is a function of distance from the Sun, the solar cycle, and cross-cycle changes. [2]
Mars has been studied by Earth-based instruments since the 17th century, but it is only since the exploration of Mars began in the mid-1960s that close-range observation has been possible. Flyby and orbital spacecraft have provided data from above, while landers and rovers have measured atmospheric conditions directly.
The idea of transforming Mars into a world more hospitable to human habitation is a regular feature of science fiction. Scientists are now proposing a new approach to warm up Earth's planetary ...
Here, too, as with Hermann Oberth, production on the Moon, the use of an electromagnetic Moon slingshot (lunar coilgun) and the transport of the components from the Moon to the Lagrange point 1 between the Earth and the Sun are discussed by means of electric spaceships (alternatively with sun sails) assumed. The authors refer to the many ...
Solar forcing should warm Earth's atmosphere roughly evenly by altitude, with some variation by wavelength/energy regime. However, the atmosphere is warming at lower altitudes while cooling higher up. This is the expected pattern if greenhouse gases drive temperature, [67] [68] as on Venus. [69]