exaannum, usual symbol Ea, is a unit of time equal to (1018) years (one quintillion on the short scale, one trillion on the long scale). It is an extremely long unit of time. The half-life of tungsten-180 is 1.8 Ea.
According to Wikipedia
(http://www.reference.com/browse/wiki/Annum) megaannum, usual
symbol Ma, is a unit of time equal to one million (106) years. It
is commonly used in scientific disciplines such as geology,
Paleontology, and celestial mechanics to signify very long time
periods in the past. For example, the dinosaur species
Tyrannosaurus rex was abundant approximately 65 Ma (65 million
years) ago (ago may not always be mentioned; if the quantity is
specified while not explicitly discussing a duration, one can
assume that "ago" is implied; "mya" includes "ago" explicitly.). In
astronomical applications, the year used is the Julian year of
precisely 365.25 days.
* gigaannum, usual symbol Ga, is a unit of time equal to one
(short scale) billion (109) years. It is commonly used in
scientific disciplines such as cosmology and geology to signify
extremely long time periods in the past. For example, the formation
of the Earth occurred approximately 4.57 Ga (4.57 billion years)
ago. * exaannum, usual symbol Ea, is a unit of time equal to (1018)
years (one quintillion on the short scale, one trillion on the long
scale). It is an extremely long unit of time. The half-life of
tungsten-180 is 1.8 Ea.
The Thunder Rolls !!
Yeeee Haaaaaw !!
chilidog
SBR Posting Legend
04-05-09
10305
#2
But does the Lightning strike?
Comment
Shafted69
SBR Hall of Famer
07-04-08
6412
#3
Originally posted by chilidog
But does the Lightning strike?
The thunder rolls
And the lightnin' strikes.
Another love grows cold
On a sleepless night,
As the storm blows on
Out of control
Deep in her heart
The thunder rolls.
