Is there a means to determine our frame of reference on past events in space-time? How do I know my current reference (today) is the same as it was two days ago for the rate at which time is perceived? A satellite sits in space and has an atomic clock while another is on Earth there will be a perceivable change over time between the two clocks. If we could, somehow, view past events in the same way would we see a constant change over time or would that change be faster or slower from our current, changing frame of reference?
How do I know the day two days ago was as long as the day today, from my current frame of reference?