So, if we say something is 1 billion years old, is that (365 spins on earth’s axis x 1 billion)? Is it (1 trip around the sun x 1 billion), or a different measurement? The answers to those change depending on how it’s calculated.
In other words, if I say I lived one year, that means 24 hr/day for 365 days/year in todays terms. Over time the earth’s orbit of the sun becomes faster and slower changing the meaning of a year. Also, as the earth spins faster and slower on its axis, a day in terms of hours is different relative to today. It breaks my brain.
What about the needs for adjustments for leap years? How does this influence radiometric dating? If a molecule degrades by 1 measurement every 300,000 years, the first 150,000 years are going to be different than the last half. If you want to pinpoint the halfway mark, where is it?
In: Planetary Science
It’s one trip around the Sun times one billion.
If you want a good unit of time to standardize on, use the second. We can base that off of some physical process that we can assume is constant over geologic time.
Today, a (solar) day is 86400 sec. A long time ago, it was some smaller number of seconds. The year (measured in seconds) has been more stable than the day. Radiometric processes will be the same today as they always have been.
Latest Answers