7. Basic Relativity
So now you've got this far, I thought I might introduce something a little more challenging. Relativity is the theory that time travel is possible. Becuase this is a bit tricky, I suggest reading the time travel section on my website, https://sites.google.com/site/theplanetscom for more information if you get stuck. It is also recommended that you draw a scetch of this as we go along. Any bits I think are worth drawing, I have but in bold print.
Space cannot work without time and vice versa, so draw a diagram with two lines in a cross shape, the x labelled 'space' and the y labelled 'time'. Then draw a small circle where the two lines meet and label it 'Here and now'. This circle represents this location, at this time exactly. This is important as the diagram you have just drawn is a map of the entire universe! This next bit could be quite hard, so pay attention. I want you to draw four seperate lines at 45 degree angles through each of the lines you drew before. Label the one at the top 'Future Light Cone' and the bottom one 'Past Light Cone'.
Now you've done that, (and a big well done if you managed it!) let me tell you about these 'light cones'. When Einstein made this theory, he knew you could only travel a certain length of time. The 'light cones' are the barriers of what you can travel. They are there because of the USL or Universal Speed Limit. This is also known as the speed of light, which is approximately 300,000 KM/s (kilometers per second).
You can find out about making it your future to go to the past on my website (https://sites.google.com/site/theplanetscom). Thanks for sticking with me through this tough chapter!