Download Radio Astronomy

Name _________________________ Period _____
_____ / 25
Radio Astronomy
Background
Astronomy began as people viewed the night sky with their
naked eyes. When the optical telescope was invented in the 17th
century, optical astronomy made great advances. Early errors, such
as the assumption that the universe rotated around the earth, were
discarded. Radio astronomy began by accident. In 1931, Karl
Jansky was looking for the source of radio interference at Bell
Labs. He discovered a source of noise that moved across the sky
with the stars. Although it was not known then, the source of the radio waves was the
center of our galaxy, where a large black hole resides. Radio waves are emitted because
the black hole ingests hydrogen gas, along with anything else that comes near it, and the
captured material is accelerated and ionized on approach and in the presence of a
magnetic field produces radiation at radio frequencies. When astronomers realized that a
radio telescope could observe radio waves from the center of the galaxy, which was
blocked to their optical instruments by clouds of dust, the building of the great radio
telescopes began.
What comes out of a radio telescope is not a picture, as we cannot see radio
waves. Some astronomers listen to the radio signals in search of audible patterns. Other
astronomers wish to view the information. To study the information from a radio
telescope visually, we must convert the data into “false color” images. This allows us to
see the data from a radio telescope. Computers take each radio wave signal and break it
into tiny segments called pixels. Each pixel is assigned a number based on the intensity
of the radio waves. This data is stored as a stream of numbers representing changing
intensities as the telescope scans the night sky. To view the image we assign a color to
each signal strength and assemble the picture one pixel at a time.
Purpose
To examine how scientists interpret radio signals from space by creating an image using a
stream of data from a radio telescope.
Materials
 Pen/pencil
 Colored pencils
 Blank star map
Procedure
1. Examine the string of numbers in the radio telescope data. This represent
a radio signal received by a radio telescope from deep space. Each digit
represents the signal strength (intensity) from a section of space the
telescope was listening to.
2. Use the data from figure one to fill in the star map. The first digit in the
data stream (0) does in the upper left hand box. The second digit (0) goes
in the box to the right, and so on. When you get to the end of a row, go
back to the left side and start in the next row down.
3. When you have finished numbering use the color code and fill in the map.
4. Answer the questions.
Radio Astronomy -Enrichment
Answer Sheet
0
black
1
violet
Signal Strength Color Code
2
3
4
green
yellow
orange
Star Map
5
red
Questions
1. What early misconception about the structure of the solar system was
disproved by optical telescopes?
2. What are two advantages that radio telescopes have over optical
telescopes?
1.__________________________________________________________
2.__________________________________________________________
3. What is one disadvantage of using a radio telescope?
4. Why are star maps created by radio telescopes considered “false color
images”?
5. How many definite radio sources appear on your map?
6. Look at the map and determine which source is the largest. Circle the
largest source. How did you arrive at your answer?
7. Circle the rest of the radio sources and rank them from largest (#1) to
smallest.
8. After completing the star map, do you agree or disagree with the following
statement; “If we didn’t have computers our recent astronomy studies
would not have gone as well.”
Agree or Disagree (circle one)
Why?__________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________