The exosphere is almost a vacuum. Objects in the exosphere, like the Hubble Space Telescope (shown here), can be very hot when exposed to scorching sunlight or extremely cold when immersed in shadow.
Click on image for full size
Image courtesy NASA.
Temperature in the Exosphere
The exosphere is very nearly a vacuum. The technical definition of the temperature of a gas (even a very thin one) is related to the average speed of particles (atoms and molecules). Since most of the particles in the exosphere are moving very fast, the temperature there is technically quite high. However, objects in the exosphere don't really "feel" much heat from the particles - there are simply too few gas particles, no matter how quickly they fly about, to transfer much heat to the objects they collide with. In general, the exosphere would feel very, very cold to us.
The temperature of most objects (like satellites) in the exosphere depends on whether they are lit by sunlight or are kept dark in shade. Objects lit by the intensely bright sunlight in the exosphere can become very, very hot. However, objects (or parts of objects) in shade tend to get very, very cold.
Shop Windows to the Universe Science Store!
The Fall 2009 issue of The Earth Scientist
, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earth’s ancient atmosphere, is available in our online store
You might also be interested in:
At very high altitudes, the atmosphere becomes very thin. The region where atoms and molecules escape into space is referred to as the exosphere. This is the true upper limit of the Earth's atmosphere....more
Most things around us are made of groups of atoms bonded together into packages called molecules. The atoms in a molecule are held together because they share or exchange electrons. Molecules are made...more
Rainbows appear in the sky when there is bright sunlight and rain. Sunlight is known as visible or white light and is actually a mixture of colors. Rainbows result from the refraction and reflection of...more
The Earth travels around the sun one full time per year. During this year, the seasons change depending on the amount of sunlight reaching the surface and the Earth's tilt as it revolves around the sun....more
Scientists sometimes travel in specially outfitted airplanes in order to gather data about atmospheric conditions. These research aircraft have special inlet ports that bring air from the outside into...more
An anemometer is a weather instrument used to measure the wind (it can also be called a wind gauge). Anemometers can measure wind speed, wind direction, and other information like the largest gust of wind...more
Thermometers measure temperature. "Thermo" means heat and "meter" means to measure. You can use a thermometer to measure the temperature of many things, including the temperature of...more