Mesosphere

{
  "id": "MLC-T-ENV-017001",
  "term": "Mesosphere",
  "field": "Environment",
  "definition": "1. The atmospheric shell between about 20 km and about 70 to 80 km, extending from the top of the stratosphere (the stratopause) to the upper temperature minimum that defines the mesopause (the base of the thermosphere).\n\n2. This layer extends from around 31 miles (50 km) above the Earth's surface to 53 miles (85 km). The gases, including the oxygen molecules, continue to become more dense as one descends. As such, temperatures increase as one descends rising to about 5°F (-15°C) near the bottom of this layer. The gases in the mesosphere are now thick enough to slow down meteors hurtling into the atmosphere, where they burn up, leaving fiery trails in the night sky. Both the stratosphere (next layer down) and the mesosphere are considered the middle atmosphere. The transition boundary which separates the mesosphere from the stratosphere is called the stratopause.\n\n3. The mesosphere, 50 to 80 km above the Earth, has diminished ozone concentration and radiative cooling becomes relatively more important. The temperature begins to decline again (as it does in the troposphere) with altitude. Temperatures in the upper mesosphere fall to -70 degrees to -140 degrees Celsius, depending upon latitude and season. Millions of meteors burn up daily in the mesosphere as a result of collisions with some of the billions of gas particles contained in that layer. The collisions create enough heat to burn the falling objects long before they reach the ground.",
  "references": [
    "NOAA National Weather Service Glossary",
    "NOAA National Weather Service JetStream - Online School for Weather at http://http://www.srh.noaa.gov/jetstream/index.htm",
    "NASA Earth Observatory Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/mesosphere/"
}