So, you want to travel back in time? Here’s the solution. But first forget the tricked-out DeLorean and H.G. Wells’ victorian time machine. What you need is a Tipler Cylinder. Let’s begin with the ingredients if you are inclined to construct your very own cylinder.

1. Take a mass of about 10 times that of the Sun.
2. Compress and fashion the mass into an infinitely long, spaghetti-like cylinder.
3. Spin the cylinder, along its longitudinal axis, at least up to several billion revolutions per minute.

Once you’ve  done this all you need in a craft able to spiral around the cylinder — without getting crushed by gravity — to make use of its frame-dragging of spacetime. Voila! Do this correctly, and you might well emerge billions of years from where you began. But, you’ll be in the past, of course.

Read more about the Tipler Cylinder here.