Expert: Ed - 2/15/2006

Question
Is it possible to use the stars to calculate your position on Earth, like a GPS system? Even if its off by 100 miles, it wouldn't matter, just if it would work. I was thinking about this with regards to ancient civilizations.

Answer
Juan,
This is an interesting question.  Thank you for asking it.

The answer is -- sort of.  The ancients could use the stars to calculate latitude, but no one figured out how to calculate longitude until the 18th century.

Here is a nice link created by NOVA, about calculating latitude with the North Star:
http://www.pbs.org/wgbh/nova/shackleton/classroom/w3northstar.html

If you want to learn about how an amazing genius figured out how to calculate longitude, try asking your local librarian to help you find a copy of "Longitude," by Dava (not Dana, DAVA) Sobel.
http://www.amazon.com/gp/product/0140258795/qid=1140119428/sr=2-1/ref=pd_bbs_b_2...

I have also enjoyed a book by Brian Cunliffe about Pytheas, an ancient Greek explorer who navigated through the coast of Europe using astronomical information.
http://www.amazon.com/gp/product/0142002542/qid=1140119743/sr=1-2/ref=sr_1_2/103...

Keep Looking Up!
--Ed