Some Introductory Q&A

Continue the tour to the Precambrian

How long is "long?"

The earth is old. And the universe is even older. The kind of "old" that's hard for us to imagine in human terms. A century is a long time in human, historical terms, but it's hardly measurable in geologic terms. Except for the most recent epoch, the holocene, all of the durations we deal with are measurable in millions of years, or at least very substantial fractions of a million years. And before multicellular life becomes commonplace, the precambrian, and before the earth exists at all, we're dealing with billions of years.

To provide some sort of context for this, here are some legths of time to orient you:
Average age of a freshman at Dartmouth 18 years
Approximate life-expectancy of a freshman at Dartmouth ~75 years
Age of Dartmouth College 230 years
Age of England, since the Norman conquest 933 years
Approximate time since the discovery of agriculture ~10,000 years
Number of modern lifetimes in 10,000 years 133.333
Approximate age of our species (Homo sapiens sapiens) if the RAO people are right 100,000 years
Approximate age of the oldest species of our genus (Homo habilis) 2-2.5 million years

How old is the Universe?

The best estimates these days (as given in class) are that the universe is about 11 billion years old.

How old is the Earth?

The earth is about 4.5 billion years old, and only slightly younger than the rest of the solar system.

How can I remember all the bleeping names?

Dr. Bob's Geologic Time Page has some cool mnemonics which can help you remember them. One which helped me remember the Paleozoic periods, which were giving me trouble was "Come Over So Dan Can Play" (Cambrian, Ordovician, etc) which I got from that page.
Continue the tour to the Precambrian