It is designed merely to ensure that we 'do' something with life within the space of time. Jim from Alabama is sure it is all in the mind. Since weekends fly and weekdays drag on, but years continue to go faster, then time travel must be a mental phenomenon. Just as it's safer and easier to send probes to the outer limits of the solar system, we will be able to send probes to the future and to the past. Another Jim sums it up - at the speed of light.
Light is composed of particles that have mass, etc.
If it can do it, so can other things that have mass. Juanita reckons we are but figments of God's imagination - and He set us in motion with a Big Bang. I like that idea about time travel being a mental thing because I don't believe matter really exists except in the mind of God. I think Einstein believed that. I'm not sure.