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There's
good old Mother Earth.
Say, did you ever wonder
about all of the things that have ever happened on Earth and how
old it really is? As it turns out, Mother Earth was a bit reluctant
to let out her true age. It took us a long time to figure it out,
but as near as we can tell, Mother Earth is four thousand, six hundred
million years old (4,600 million = 4.6 billion), give or take a
few hundred million years.
How old is that, really?
It's older than your parents, or your grandparents, or even you
great grandparents! It is older than anything you can see around
you, like trees, buildings, or roads. It is even older than the
hills, valleys, and rivers around where you live. It is so old that
the world's mountains have been built up and worn down many times,
the continents have wandered across the face of Earth like tumbleweeds,
and plants and animals have changed many times, from amoebas to
dinosaurs to people. The age of Earth is so long compared to all
periods of time that we humans are familiar with, it has been given
a special name: Geologic time.
The age of Earth is as
vast in time as the universe is vast in space. It is not easy to
really get a "feel" for 4,600 million years! One way to
try to get a "feel" for how big it is, is to break the
number down into smaller pieces that perhaps we can understand.
Just for fun you might try the activity, "What
is a Million?" Then try to think about 4,600 million!
Another way we try to
understand the enormous age of Earth is to make simple comparisons.
One comparison you can use is to compare the length of Earth's history
to the length of a football field in the geologic
time activity.
Here we use another comparison
to help show the span of time since the formation of Earth: "The
Stairway of Time."
The bottom of the Stairway
represents the formation of Earth 4.6 billion years ago. The top
represents the present or today. The different steps represent different
segments of time in Earth's history. Something different was happening
during each segment.
Many exciting changes
have happened on Earth since it formed. To find out a little about
the changes that occurred during the different time segments, click
on the names on the Staircase or on the list below:
- Cenozoic
Era
- Mesozoic
Era
- Paleozoic
Era
- Precambrian
Eon
Are you curious about
where the strange names on the Staircase of
Time come from? Do you want to know "How
old is that rock?" and how geologic time periods were determined?
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