Extraterrestrial atmosphere reaching 70 m/s or more in the upper troposphere. The stratosphere and mesosphere extend from 65 km to 95 km in height. The thermosphere and exosphere begin at around 95 kilometres, eventually reaching the limit of the atmosphere at about 220 to 250 km. The air pressure at Venus' surface is about 92 times that of the Earth. The enormous amount of CO in the atmosphere creates a strong greenhouse effect, raising the surface temperature to around 470 °C, hotter than that of any other planet in the Solar System. The Martian atmosphere is very thin and composed mainly of
Observational astronomy spectrum observed: In addition to using electromagnetic radiation, modern astrophysicists can also make observations using neutrinos, cosmic rays or gravitational waves. Observing a source using multiple methods is known as multi-messenger astronomy. Optical and radio astronomy can be performed with ground-based observatories, because the atmosphere is relatively transparent at the wavelengths being detected. Observatories are usually located at high altitudes so as to minimise the absorption and distortion caused by the Earth's atmosphere. Some wavelengths of infrared light are heavily absorbed by water vapor, so many infrared observatories are located in dry places at high altitude, or in space. The