Without getting into too much detail, a time machine like a Tipler cylinder could create a closed timelike curve.
简单来说，像提普勒柱体这样的时间机器可以创造出一个封闭的时间型曲线。
假如有如果
That is, if you have access to a big enough black hole, or to a time machine like a Tipler cylinder.
也就是说，只要你能进入到一个足够大的黑洞，或者像提普勒柱体这样的时间机器的话。
英语百科
Tipler cylinder
A Tipler cylinder, also called a Tipler time machine, is a hypothetical object theorized to be a potential mode of time travel—although results have shown that a Tipler cylinder could only allow time travel if its length were infinite or with the existence of negative energy (see the discussion of Hawking's proof below).