If you only observe by absorbing particles, but not emitting them, you can be far enough away so that the light cone of your observation only intersects with the Earth later than the original departure point. That would only change the past of presumably uninhabited areas of space-time.
If you only observe by absorbing particles, but not emitting them, you can be far enough away so that the light cone of your observation only intersects with the Earth later than the original departure point. That would only change the past of presumably uninhabited areas of space-time.