• Question: How does the sun heat up our planet when it is so far away?

    Asked by near520muon on 12 Feb 2025.
    • Photo: Ana-Maria Raclariu

      Ana-Maria Raclariu answered on 12 Feb 2025:

      The sun is huge and really hot so it emits a lot of radiation. The closer you are, the hotter you will feel. Earth is just about at the right distance to experience a pleasant temperature. Just think about a heater in a huge room: you need to be close enough to feel the heat!

    • Photo: Martin McCoustra

      Martin McCoustra answered on 13 Feb 2025:

      It’s a process called radiative forcing or the Greenhouse Effect. Our atmosphere and planet absorbs some of the energy incident on it from the Sun and warms up. This is turn warms the surface of the Earth which in turn warms up the atmosphere. This feedback system keeps going an means we have a liveable environment.

Comments

  • Photo: Steve P

    Steve P commented on :

    Further to Martin’s comment: 2 thought experiments:
    1) Consider the Moon – that is really cold even though it is about the same distance from teh Sun as the Earth. Because the Moon has nearly no atmosphere then the warming effects Martin describes don’t apply.
    2) Also, consider a house which may have radiators and/or a fire. The walls of the house drastically slow the escaping of the heat generated in the house – this is similar in some ways to the Earth’s atmosphere retaining heat close to the Earth’s surface.