In fact, it's a lot more squishy. Our calendars are imperfect. We need a leap day to keep them in line with the seasons, and even so, time will eventually get away from us.
"If you feel there aren't enough hours in a day, just wait," says Max Tegmark, a cosmologist at the Massachusetts Institute of Technology. "In a few hundred million years, tidal friction will have slowed Earth's rotation to make the day 25 hours long."
If that doesn't make your head spin, consider that in physics, motion alters time; in psychology, different stimuli alter our perception of time; and in philosophy, there's disagreement on whether time is even real. "In terms of our inner lives, no time exists except for what is happening in the present moment," says Joan Halifax Roshi, a Zen Buddhist teacher.
In order to get a better understanding of time, we consulted physicists, philosophers and religious scholars. We talked to doctors who study aging, a watch-company executive, and a man building a clock designed to last 10,000 years.
We talked to time-management and productivity experts, including one who has built a lifestyle around working only four hours a week. And we talked to spiritual guide and alternative medicine expert Deepak Chopra, who warned of the dangers of a hectic lifestyle.
"People who feel that they are 'running out of time' have speeded up their biological clocks," says Chopra. "They have faster heart rates and jittery platelets with high levels of adrenaline. When they drop dead from a premature heart attack, they have literally 'run out of time.'"