• Question: is it possible for life to be on earth without the sun?

    Asked by bvbmonster to Davie, Gemma, James P, James V, Nuala on 25 Jun 2012.
    • Photo: James Pope

      James Pope answered on 25 Jun 2012:

      Hi bvbmonster,

      Nope, if the sun was suddenly switched off, then life on earth wouldn’t be possible. The sun warms the planet, without the sun the temperature of the Earth would plummet to just above absolute zero (-273.15°C), warmth only coming from the core of the planet (but it is a tiny amount of heat).

      But the sun also is the reason why plants can photosynthesis to make energy and also to replenish the oxygen in the atmosphere. Also without the sun’s energy there would be no weather, as water wouldn’t be evaporated to form clouds and eventually rain.

      So, the sun is our biggest friend in the sky, our nearest star and the reason we can live today!

    • Photo: James Verdon

      James Verdon answered on 25 Jun 2012:

      I would pretty much agree with James P – without the sun’s energy life would be pretty challenging. However, it’s possible that some life could exist, around things like volcanic vents on the ocean floor. Such so-called extremophile organisms (called extremophile because they appear to love extreme conditions) can live without the sun because they use the heat from the vents for energy, rather than the sun. Some scientists believe that all life started out like this, before plants later evolved photosynthesis and were able to get their energy from the sun. Also, extremophile organisms might be our best bet for finding life on other planets and moons.

      However, these extremophile organisms are mainly single celled bacteria. There’s no way complex animals like us could have developed without the sun.

    • Photo: Gemma Purser

      Gemma Purser answered on 25 Jun 2012:

      Hi bvbmonster,

      Like James Verdon said there is life that exsists around volcanic vents that occur deep down in the oceans where there is no sunlight. There is a type of bacteria that instead of using the sun for photosynthesis they use the gases coming out of the vent such as hydrogen sulphide to provide energy in a process called chemosynthesis. These bacteria form biofilms, like a mat of bacteria all joined together. tiny creatures called amphipoda feed on these mats and then large types of creature such as worms, snails, crabs and shrimps even octapus feed on the tiny creatures.