Todd Trierweiler, age 14, ofPortland, Mich., for his question:
HOW LONG DOES IT TAKE FOR STARLIGHT TO REACH EARTH?
The sun is the star nearest the earth. The distance between the two is 93 million miles. The distance from the sun to the star that is second nearest it is called
Proxima Centauri is a total distance of 25 trillion miles. That's the number 25 followed by 12 zeros.
Measuring the distances between one star and another, the usual units of miles are far too small. So in order to keep the number of zeros in the measurement of these distances to a reasonable amount, the velocity of light is employed.
We call the measurement a light year, and it is that total distance light will travel in one year.
The velocity oflight is about 186,000 miles per second. In one year,the light will travel a total of 5 trillion, 730 billionmiles. Here's how that cardinal number looks with all of itszeros: 5,730,000,000,000.
The distance from earth to the second nearest star, Proxima Centauri, is about 4.2 light years from the sun. Remember, that translates to 25 trillion miles.
Now for some really big numbers:
The most distant star group that can be seen with the naked eye is the Great Spiral Nebula in Andromeda. It is a total of about 1.5 million light years away from the earth.
You'll need the 200 inch reflector at Mount Palomar in California to see what is the furtherest visible sparkle it's a galaxy that is located about 2 billion light years out in space.
The star Alpha Centauri, located in the constellation Centaurus, is 4.3 light years away. Translated into miles, this distance is about 26 trillion miles.
Comets are called hairy stars. And in nine years you'll see the most famous one: it's Haley's Comet and it visits earth's sky every 76 years. It was here last in 1910 and will return in 1986. We have records, with only a few gaps, that trace this hairy star back to 170 B.C.
Numbers get large when you are reaching for the stars. How many times would your wristwatch tick in a thousand years? The number of ticks is still too small to compare to the number of miles we are from the stars. If every tick were a mile, your watch would have to run for a million years to tick out the distance to some of the brightest stars.