Tuesday, October 03, 2006

On the Route 10.03.06

If yesterday morning was exceptional, (see previous post below) then this morning was exceptionalER. Wow. The sky was crystal clear in every direction. So at around 5:50 am I got out of my car and did some viewing. Even better sightings of Orion, Hydra, Monoceros and Lepus, easily seen below Orion and shown in diagram to right.

Also, I remember seeing Leo, Little Leo, Ursa Major and Minor going north or left from the first group. Then Cassiopeia, Perseus and Auriga in the north and northeast. Continuing on to Triangulum, Aries and Taurus and then Orion again.

The best viewing in a long time.

As I was thinking about the stars I got to thinking about Light Years. What we see now is what was happening light years ago. Think about it!

"... to measure really long distances, people use a unit called a light year. Light travels at 186,000 miles per second (300,000 kilometers per second). Therefore, a light second is 186,000 miles (300,000 kilometers). A light year is the distance that light can travel in a year, or:

186,000 miles/second * 60 seconds/minute * 60 minutes/hour * 24 hours/day * 365 days/year = 5,865,696,000,000 miles/year

A light year is 5,865,696,000,000 miles (9,460,800,000,000 kilometers). That's a long way!"

Cool Fact
A light nanosecond -- the distance light can travel in a billionth of a second -- is about 1 foot (about 30 cm). Radar uses this fact to measure how far away something like an airplane is. A radar antenna sends out a short radio pulse and then waits for it to echo off an airplane or other target. While it's waiting, it counts the number of nanoseconds that pass. Radio waves travel at the speed of light, so the number of nanoseconds divided by 2 tells the radar unit how far away the object is!

me in the EE


1 comment:

The Fat Lady Sings said...

I remember watching Carl Sagan and Cosmos like it was an addiction. So influential was that series that it was still being shown as part of my degree curriculum in 1989. I know there's been controversy over some of Sagan's conclusions - but no one could say 'billions' quite like that man!