Have you ever seen a greenhouse? The one where farmers can grow their vegetable when it’s colder outside. When the temperature outside is colder than vegetation requires, nothing will grow in the soil. Unless it is protected by a greenhouse.
Greenhouse captures the heat from the sun, allowing it to enter the greenhouse construction, but makes it harder to escape, which keeps part of the heat inside. The temperature is then warmer inside the greenhouse than on the outside, which allows plants to grow, creating adequate conditions.
The Earth is one big greenhouse, with atmosphere playing the role of the protective shield that helps to keep the warmth inside. How does it happen? Let’s see from the beginning.