This will require a time machine and a Simbot, which you must have a level 10 in the Invention skill to create. Once you reach level 10 in Inventing, you will eventually receive a series of invention skill opportunities. They will involve bringing 1 unit of palladium, 10 life fruit or life fruit seeds, a heart-shaped cut pink diamond, and 100 pieces of scrap to the Science Facility. With the exception of the scrap, all of these materials can be found by a dog with a level 10 Digging skill. The Science Facility will then give you an item you can take to the Invention Bench in order to make a Simbot. NOTE: You will also need room in your household as a Simbot is a playable Sim.
Once you have constructed a time machine and a Simbot, control the Simbot, click on the time machine and select Travel To The --> Past.