Transcript:

So, continuing this theme of infinity across parallel mirrors, take a look at this photo. If the resolution of the eye was perfect, how far back in time could we see on Earth? Now, why is it important to be on Earth? Because if it was flat space, you could see theoretically infinite back in time. But Earth is curved. It has a diameter of 12,750 kilometers. The mirrors are, let's say, five feet apart, and the height of the mirror is five feet.

With these constraints—five feet high mirror, five feet apart parallel mirrors, diameter of the Earth is 12,750 kilometers, speed of light is 3 × 10^8 meters per second—how far back in time can you see on Earth when two mirrors are kept parallel to each other?

Figure it out. If you know the answer, let me know in the comments. Bye!