How hard does your science have to be? Because if the answer is "not at all," then there's the ever-popular hand-waving effect:
The deep, in-universe, answer can be something like:
Some millions of years ago, an advanced and unknown alien race required a laboratory with specific pseudo-relativistic conditions. They used an unknown technology to generate a localized time-like metric and tied it to the world (or solar system) at a quantum level, to ensure that the planet (or solar system) didn't travel outside the time-like metric for the duration of the experiment.
When the aliens were done with the experiment, the forgot to switch the effect off, so today we use the world because X.
Or maybe the experiment isn't over yet, and the mice are going to be really hacked when they come back and find out we've skewed their results...
While the answer that the characters know can be:
We don't know why it's like this, but boy it's useful for X!
The difference between the two can be the story in itself.
Ultimately, unless the how is crucial to the story, it's a minor detail and can be hand-waved away. It's not my favorite method as a reader, but it does occasionally help to make the implausible into the plausible.