"Robi" wrote in message ...
Seamus wrote:
http://www.space.com/scienceastronom..._030710-1.html

You know, I am really amazed how the age of a 'planet'
can be determined through a telescope. 12.7 billion years
(I suppose that's 12.7 milliard years or 12.7 *10^9 years)
I mean, look at the Earth, we're practically sitting on
top of it, and guess the age of it to be what,
4.5 billion[1] years old?
We can take rocks from the surface and from the soil and
analyze them with different methods, but to determine it
through a telescope... at 7.200 lightyears away... mind
boggling.
But now, isn't a planet supposed to turn around a star?
As I understand, this one doesn't... or I didn't get the
meaning out of this report...


[1] using the US billion (milliard or 10^9)

When they say it's "12.7 billion" years old, what they actually
mean (I guess) is that since the universe is currently estimated
to be 13.7 billion years old and since the globular clusters
probably formed 1 billion years after that (at the birth of our
galaxy), then the planet must be 12.7 billion years old. I
doubt the actual scientific paper says that it's 12.7 billion
years old.

Incidentally, a billion is the standard British usage for 10^9
as well. (We dumped the old definition decades ago). Are you
Australian or something?

Richard
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