• Question: How is sperm formed? Are aliens real? Is heaven real?

    Asked by caluml to Adam, Catherine, Karen, Leila, Nazim on 11 Mar 2012.
    • Photo: Adam Stevens

      Adam Stevens answered on 10 Mar 2012:

      Seems like three very different questions!

      Sperm is formed in exactly the same way as all the other cells in your body – from these things called stem cells. These are generic human cells that receive a command to start to develop into a particular type of cell.

      Cells are just collections of particular molecules in a particular structure, they are built in little factories (yes, testicles!) by putting molecules together in a certain way.

    • Photo: Leila Battison

      Leila Battison answered on 10 Mar 2012:

      Wow! Lots of questions…

      Sperm is constantly being formed in the testicles, by special cells dividing into four, with each sperm containing half the normal amount of DNA (it gets the other half from the female egg when they meet). The sperm are mixed with a fluid to make semen when it is needed (!).

      Aliens, like in AI or Alien, or ET are probably not real – in that we haven’t been visited by extraterrestrial creatures that look a lot like us but with bigger heads. But because the universe is so huge, there are plenty of places where ‘aliens’ of one form or another, will have evolved. They probably won’t look much like us though – just think of how many animals and plants and things on Earth look completely different to us and each other. They may be tiny or huge, or may not even have bodies. We might not even recognise them when we find them!

      The idea of heaven as a place that good people go when they die, comes from religions that involve a God and some kind of afterlife. If you are strongly religious, then the idea of a heaven is as real to you as anything else. But there is no place in the physical universe, with stars and galaxies, where that kind of heaven could be. Ancient astronomers called the night sky ‘the heavens’ and this is the origin of the world. But so far, we haven’t spotted thousands of angels up there with the stars, so we’ll leave the idea of heaven to religion!

    • Photo: Catherine Rix

      Catherine Rix answered on 11 Mar 2012:

      I’m going to go for the second question here
      The answer is we don’t know. I don’t believe in alien abductions and things like that, but I think that given how huge the universe is, perhaps there could be life somewhere else as well as on Earth. On Earth life in literally everywhere, it can survive in really extreme environments, so why not on other planets? The distances involved are so huge that we might never know.

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