Theoretically you could, but don't go shopping for giant mirrors any time soon. You might be thinking that if we place a large enough mirror far enough away that we could somehow see into our own past-- that is, the past relative to the people placing the mirror. In order for us to see our own past in the mirror, the mirror must already have been put in place at an enormous distance long, long ago, so that the light we see reflected in the mirror will have had its origin on earth at the distant past time that we would like to observe. Not doable. However, theoretical physicists and other scientists are already outlining not-totally-outlandish scenarios where travel through time may be possible in some circumstances. The outlining and the necessary engineering are probably going to be separated by many generations before there is any practical demonstration. Much more useful is the reality that the light we now observe from distant stars started its journey from the star as long ago as millions or even billions of years. Interestingly, from the point of view of the photons themselves, the trip is instantaneous.