A greenhouse covers plants with a glass frame, which conserves the energy the plants get from the sun and keeps the air temperature up. The atmosphere around the Earth acts in the same way. Only a very small amount of the heat and energy produced by the sun reaches the Earth. That heat would only be strong enough to keep our earth temperature at about -32°C. This heat does not escape into outer space, but is absorbed by the water vapour and gases of our atmosphere. - bigsiteofamazingfacts.com; motherearthnews.com; wiki.answers.com
A greenhouse covers plants with a glass frame, which conserves the energy the plants get from the sun and keeps the air temperature up. The atmosphere around the Earth acts in the same way. Only a very small amount of the heat and energy produced by the sun reaches the Earth. That heat would only be strong enough to keep our earth temperature at about -32°C. This heat does not escape into outer space, but is absorbed by the water vapour and gases of our atmosphere. - bigsiteofamazingfacts.com; motherearthnews.com; wiki.answers.com