I was lounging with some friends and fellow-practitioners from Boston and New York, on a sunny day at our beautiful, green retreat land in upstate New York. The conversation started when I mentioned that a photon doesn’t experience the passage of time in transit from the sun to our retina, or wherever its destination may be on earth. This is despite the fact that in our frame of reference it takes 20 seconds for the photon to arrive.
Participants of the conversation included a Harvard astrophysics postdoc, an entrepreneur trained as an aerospace engineer, and a Buddhist teacher/IT professional, which might explain why we couldn’t just relax and enjoy the weather. The Buddhist teacher’s perspective was that the only thing he knows which is beyond time is enlightenment, the timeless state. We couldn’t disagree with this and spent some time thereafter reconciling these two things.
Put simply, a photon isn’t beyond time, because with the passage of time it is emitted and absorbed. However, there’s a cool analogy with the nature of mind, which is what a Buddhist fully recognizes when he or she attains enlightenment: you cannot deny it exists but from the time it is emitted to the time it is absorbed, no time passes because nothing about it changes. Since it doesn’t exist for any length of time, you can hardly say it exists. So it seems to have in common with mind that it is beyond existence or non-existence. All kinds of things play around in it yet mind itself cannot said to have any color, shape, form, and so forth. If you would like to know more about the nature of mind from a Buddhist perspective I recommend the 3rd Karmapa's Mahamudra Wishes (Karmapa is a realized teacher and meditator well-known in Tibet and now also in the west), which is the text I'm most familiar with on the topic. A fantastic commentary on this work is The Great Seal by Lama Ole Nydahl.
You might say, as the astrophysicist did, “But it is changing in transit when you take into account the expansion of the universe. The photon is red-shifted by the expansion of space.” We thought, “Is this a limitation of Einstein’s Relativity?” and ultimately concluded that there is an analogy which reconciles the idea that no time passes for the photon and the red-shift caused by the expansion of the universe. It’s like if you had a 10 pound note in your pocket. Then the Brexit happened (The Brexit is a nickname for the British Exit from the European Union if you are reading this after the hype has passed). From your frame of reference, nothing has happened. There is still a 10 pound note in your pocket. But from the perspective of the economy it has less of an effect. You can’t buy as much with it. When you look at the photon solely from its frame of reference, the frame of reference expands with the photon because that’s the only place we’re looking. But due to the expansion of the universe it has less of an effect when it gets to its destination.
It’s not until it reaches its destination that the change in its width becomes relevant. It’s upon this realization that my friend, a joyful muscular individual who we refer to as Thor because of their similar appearance, said, “A photon is enlightened, it doesn’t exist, it has no past and no future, just the present moment!” So perhaps a photon is a good example for us. It exists only exactly in that moment with no separation between where it is coming from and where it is going.