It may appear to be an illusion, but really it is an interesting way for an observer to notice how the mind interacts with time. On their site there an animated clock to use in your attempt at this.
From the link:
Einstein demonstrated that time is relative.
But the rabbit-hole goes much deeper. Quantum physics discovered that consciousness is entangled in matter in some inexplicable ways; but other than the very fast, or very small, or very large, we tend to assume our “ordinary” reality conforms more to the laws of Newton. Simple cause and effect unfolding with clockwork constancy — well, it’s time to shatter this assumption. Let’s stop time.
Find a clock with a smooth sweeping second hand. The one on this page might work, but depending on how much is running on your computer, it may or may not be completely smooth. If it appears relatively smooth, it will still work, you’ll be able to factor out what you are controlling.
After watching the second hand for a bit, look off to the side of the clock, outside of the box, and about 15 to 20 minutes ahead of the second hand. You should still be able to see the second hand, but you won’t be looking directly at it. Now just relax and see if you can stop the second hand. If it starts catching up to the point you are looking at, jump ahead to another spot about 20 minutes ahead. With very little practice you are extremely likely to make a most remarkable discovery. You can stop time. Perhaps at first for only a second or two, but with practice, you’ll be able to freeze it for longer. If you can’t get it right away, try playing with your focus point, move it further away or closer to the frame of the clock. Or look at one of the hour markers on the clock about 20 to 30 minutes ahead. After you get it, try counting internally. The count you reach is the number of discrete thought processes you performed in zero clock time.
Once you’ve accomplished this amazing feat, what does it mean? Some people think it’s just a simple optical illusion, that they merely stopped seeing the second hand which was actually still moving (which gets entertaining with banishing incantations of blind spots, foveal vision, saccades and such.) But if they ask themselves why it started moving again from the point it stopped (and most won’t), their explanation doesn’t quite pan out. Some will just dismiss it as a curious blip that doesn’t really fit into their radar about “reality” and it won’t be cause for further concern. But a few of us will notice the crack between experience and beliefs and want to play. Does it stop sound at the same time? For some people, for others not, which is curiosier still.
Maybe consciousness can be more than a passive observer of this “constant” called time?
UPDATE — A new post on Grasshopper Enterprises, which is a worthy read (especially if you followed the above link and found that you, too, could alter your involvement with time):
Milton Erickson, the father of American medical hypnosis, performed a series of fascinating experiments in 1948-1954 documented in the book Time Distortion and Hypnosis. He used a metronome with subjects imagining themselves doing various tasks under hypnosis, at a normal pace, like counting beans or picking cotton (hey, this was the 40s and 50s :-) ) One subject counted 862 cotton bolls, taking her time, brushing the leaves aside to insure she hadn’t missed any, in a period of 3 seconds in external clock time. Others had similarly remarkable experiences.
Erickson also worked with author Aldous Huxley who could enter into a light trance and develop writing themes; Huxley could subjectively experience 6-7 hours in the period of a few minutes, an ability he explored and further refined with Erickson.
Ultimately the clock doesn’t “measure” time in any objective sense in the way a thermometer measures temperature, rather it creates something we can synchronize experience to. This synchronization is a learned, cultural and social conditioning that is largely unconscious.