In computer science we often measure time elapsed as very small numbers. It is kind of interesting to think about time in this way. Especially when you consider that science tells us Earth has been in existence for billions of years that means on such a scale of time our lives are really very short. Here's a list of short time measurements that was provided by a student named Kaushik Bukkuri.

There are many measures of time that are less than a second. Here are some from largest to smallest:

1. Decisecond(One tenth of a second)
2. Centisecond(One hundredth of a second)
3. Millisecond(One thousandth of a second)
4. Microsecond(One millionth of a second)
5. Nanosecond(One billionth of a second)
6. Picosecond(One trillionth of a second)
7. Femtosecond(One quadrillionth of a second)
8. Attosecond(One quintilionth of a second)
9. Zeptosecond(One sextillionth of a second)
10. Yoctosecond(One septillionth of a second)
11. Planck time(Shortest theoretically measurable time)

Hope this helps!