How time travel works

1. The wormholes involved are tiny, sarcely bigger than most human cells and smaller than some such as nerve cells. That means you need lots of wormholes to allow a human to pass through.
2. Creating wormholes requires energy; lots of energy. Carrying with you a great enough power source to supply this energy is impractible. It's easier to use a natural power source such as lightning. It seems 'Back to the Future' got it right.
3. It's no good simply changing the time.You must also take into account location because the earth turns, moves around the sun, the sun spins around the galaxy centre and the galaxy moves through space. Calculating the change of location and syncronizing the action of the wormholes demands tremendous processing power.

The answer to these problems is to use nanotechnology. The time traveller's body is filled with tiny machines called timebots networked together. The timebots together have the processing power needed to calculate a move through time and space. They can draw power from a lightning strike to create the myriad of wormholes needed. When not doing that they can use their processing power to provide the time traveller with some very special abilities.

• Timebots give the timetraveller instant access to a very powerful computer which means they can perform calculations and feats of memory.
• Timebots protect from lightning strikes.
• Timebots generate a 'skin' surrounding the timetraveller which protects the traveller from weapons, heat and cold.
• Timebots can store a certain amount of surplus energy and make this available to the body. Properly configured, this helps in cases of extreme cold. It also allows for 'minor' location changes. Where 'minor' means teleporting a few thousand miles without changing the time.

Of course there are downsides for the time traveller.

• Timebots have mass. This makes the timetraveller about 50% heavier than they should be. That allows the timetraveller to be detected.
• Because the wormholes used are smaller than nerve cell axon some memories are not retained. However they are stored in the timebots and restored from these. This leads to the time traveller being in a confused state after each time travel for a short period.