• Question: why is earth the only planet that has life on it?

    • Keywords:
      • Click on a keyword to find out more on the RSC site:
      Asked by hughesy ;) to Waqar, Melissa, Jenni, Catherine, Angus on 17 Jun 2016. This question was also asked by Scott.
      • Photo: Melissa Ladyman

        Melissa Ladyman answered on 17 Jun 2016:

        Earth is the only planet we know of with life in our solar system. Life can survive in all sorts of places though and scientists are still looking for life on planets like Mars. Earth is just right for our kind of life though, and part of the reason is because we are just the right distance from the sun. The temperature is not too hot during the day, nor too cold at night.
        Because the temperature is just right water can exist as a liquid, and without liquid water we would have a very hard time surviving. We are also lucky to have an atmosphere that is just right for us- it has the right amount of oxygen, and not too much carbon dioxide. It just so happened that on our planet all of the right things happened. You can see why it’s hard to find life on other planets because the conditions have to be just right! That doesn’t mean there isn’t life out there in the universe somewhere. It’s a big place!

      • Photo: Angus Cook

        Angus Cook answered on 19 Jun 2016:

        One of the interesting things about searching for alien life, especially outside our solar system. is just how BIG our galaxy is.

        One of the ways we’re looking for life on other planets (intelligent life at least) is listening for radio signals, or some other electromagnetic communication that’s been broadcast by alien life.

        Now this might take ages. Radio signals travel at the speed of light, they can’t go any faster. That means that the very first radio signals we made on Earth (about 110 years ago) have only travelled 110 light years in that time (~1,000,000,000,000,000 km). That might sound like a long way, but the size of the milky way is 100,000 light years across. Our first signals have only travelled the equivalent of 1/1000th the way across the galaxy. Even if anyone heard us RIGHT NOW, it’s still take 110 years for the signal they send back to us to be picked up.

        This is part of the problem in contacting potential alien planets, the distances are just HUGE. So the reason that we’re the only planet that we know has life on it is because it’s really hard to look at any of the others (outside our solar system, any way. Going to look at planets WITHIN the solar system is merely ‘hard’).

    Comments