The particles in the exosphere are moving very quickly, so the temperature there is quite hot. However, the exosphere would feel quite cold to us.

6,200 miles

5.1 Exosphere. The exosphere is an atmosphere so thin that its few atoms or molecules are unlikely to collide with one another. In Earth’s atmosphere, the exosphere is the highest part of the atmosphere where the density of gas molecules is very low.

The exosphere extends into a black/dark blue region beyond the earth, while the mesosphere is dark blue, and closer to the earth are the cloudy areas of the stratosphere and troposphere. Because the air is so thin in the exosphere the molecules do not collide like they do in lower layers of the atmosphere.

Most satellites, including cable TV satellites, cell phone satellites and the ones that broadcast XM radio orbit the earth in the exosphere. The International Space Station, however, orbits lower in the thermosphere!

The exosphere is the uppermost region of Earth’s atmosphere as it gradually fades into the vacuum of space. Some scientists consider the thermosphere the uppermost part of Earth’s atmosphere, and think that the exosphere is really just part of space.

Mercury and several large natural satellites, such as the Moon and three Galilean satellites of Jupiter (all except Io), have exospheres without a denser atmosphere underneath, referred to as a surface boundary exosphere.

The exosphere is the outermost layer of Earth’s atmosphere. Although it is thin, it absorbs radiation that the sun gives off, shielding the layers of the atmosphere underneath. This is a sign that the exosphere has an important role in absorbing radiation and protecting the layers underneath.

The different layers of the atmosphere. The atmosphere can be divided into layers based on its temperature, as shown in the figure below. These layers are the troposphere, the stratosphere, the mesosphere and the thermosphere. A further region, beginning about 500 km above the Earth’s surface, is called the exosphere.

Fact Sheet

• The troposphere contains 75% of the atmosphere’s total mass.
• In either space or time the troposphere is not constant.
• Weather occurs in the troposphere.
• The troposphere is 10 miles from the equator.
• The troposphere is 5-7 miles above the poles.
• Does not contain ozone.

The main components of air in the thermosphere include helium, atomic nitrogen, and atomic oxygen. The thermosphere absorbs a lot of the UV radiation and X-ray given off by the sun. When the sun is more active and the thermosphere heats up more, this layer of earth’s atmosphere increases in size.

Because there are relatively few molecules and atoms in the thermosphere, even absorbing small amounts of solar energy can significantly increase the air temperature, making the thermosphere the hottest layer in the atmosphere.

The epidermis: a thin outer portion, that is the keratinised stratified squamous epithelium of skin. The epidermis is important for the protective function of skin. The basal layers of this epithelium are folded to form dermal papillae. Thin skin contains four types of cellular layers, and thick skin contains five.

The skin is the largest and fastest growing organ of the human body. For some people, however, it can grow too fast, caused by a condition called scleroderma. Although the cause of the disease is unknown, experts say it results in an overproduction of collagen in the body. …