Question

Why do scientists use light-years to represent distances in outer space. Describe how you could create a model of various aspects of the solar system using distances in light-years?

Explain how astronomers gain information about the universe using different wavelengths of the electromagnetic spectrum? Explain how radio astronomy changed the way scientists study the universe?

I can't find anything on these!

Answer 1

The short answer is because it's mostly for convenience. When you start measuring stuff like the distance between stars and galaxies, scientists use light years in the same way miles are used instead of inches to tell us how far the next town is. You could do the math and find out how many inches are in x number of miles, but it's not as practical.

As for radio astronomy, it's a little more complicated. I guess a roundabout way of describing it is that because telescopes can only see so far, scientists examine radio emissions objects put out to get a better idea of what they are like -- such as a star or a planet. Instead of just relying on what visual data telescopes can tell them, scientists use these radio emissions to get a better idea of what the universe is doing. That's where giant, radio telescopes are used which look like titanic satellite dishes.

For example, if your car is making a weird sound, there's something wrong with it. If you just rely on your eyes, your car may look normal. But because you can hear something else going on, that tells you more than what your eyes do.

Here's a link from NASA that provides more info on radio astronomy along with some neat pics, including one of a radio telescope:

http://dsnra.jpl.nasa.gov/radio_astronomy/index.html