which is the coldest layer
The mesosphere is a layer of Earth's atmosphere. The mesosphere is above the stratosphere layer. The layer above the mesosphere is called the thermosphere. The mesosphere starts at 50 km (31 miles) above Earth's surface and goes up to 85 km (53 miles) high. As you get higher up in the mesosphere, the temperature gets colder. The top of the mesosphere is the coldest part of Earth's atmosphere. The temperature there is around -90 C (-130 F)! The boundaries between layers in the atmosphere have special names. The mesopause is the boundary between the mesosphere and the thermosphere above it.