Download Science 9 Unit 5: Space Name

Science 9
Unit 5: Space
Name: Danielle Murray
Topic 5 - What Channel Is This?
Radio Telescopes
Radio waves are received from stars, galaxies, nebulae, the Sun and even some
planets. With the development of radio telescopes, astronomers gain an advantage
over optical telescopes, because they are not affected by weather, clouds,
atmosphere or pollution and can be detected day or night. Much information has
been gained about the composition and distribution of matter in space, namely
neutral hydrogen, which makes up a large proportion of matter in our Milky Way
galaxy. Radio telescopes are made of metal mesh and resemble a satellite dish, but
are much larger, curved inward and have a receiver
in the center.
Radio telescope in Arecibo, Puerto Rico.
In 1932 Karl Jansky built a radio antenna that was able to identify radio waves from
space. Grote Reber built a radio dish based on Jansky’s antenna findings, where he
‘listened’ to the sky during the 1930’s. He discovered that the strongest radio waves
came from specific places in space. The static Rober heard became louder when he
tuned into these radio objects. The loudest being our Sun in the Milky Way Galaxy.
Bigger Radio Telescopes
Radio waves have wavelengths that are millions of times longer than light waves,
meaning that these waves give less resolution, but can penetrate dust clouds in the
galaxy, where light waves cannot.
Seeing Radio Waves
Radio telescope waves provide data, which astronomers graph, using computers to
store the data and false color it to produce images of the radio waves, which are
coded to the strength of the waves. Blues for low intensity, and as the signal gets
stronger the colors go through greens, yellows, reds and whites. Radio observations
have provided a whole new outlook on objects we already knew, such as galaxies,
while revealing pulsars and quasars that had been completely
unexpected.
Optical Connections
Radio astronomers wanted to connect their radio waves with visual data obtained
from optical telescopes. Until the resolution of radio telescopes improved making the
connection was difficult. It is now common.
Connecting Radio Telescopes
By combining several small radio telescopes ( just like they do with optical
telescopes ) greater resolving power can be achieved. This is referred to as radio
interferometry, improving the accuracy and performance of the image in making
radio maps. The greater the distance between the radio telescopes the more
accurately they can measure position.
Arrays, like the Very Large Array in Sorocco, New Mexico, which uses 27
telescopes arranged in a Y, can improve accuracy even more.
Radio Telescopes Bigger Than Earth
Telescopes can now be connected without wires, thanks to computers and clocks.
This method is called Very Long Base Interferometry ( VLBI ). With this technique,
images 100 times that of the largest optical telescope can be captured. This is done
by capturing images from any or all radio telescopes in the world. Imagine a
telescope as large as the Earth itself.
Topic 5 Assignment
Vocabulary: (Define in detail each of the words)
Electromagnetic radiation- varying types of energy waves emitted by stars (radio
waves, infrared waves, visible light, ultraviolet waves, X-rays, and gamma rays)
Radio astronomy- Using radio waves to learn about the composition of stars.
Radio objects- objects in space that give off large amounts of radio waves
Interferometry- A technology that electronically connects two (or more) separate
telescopes to combine their images.
Very long base line interferometry (VLBI)- A technology that combines images from
telescopes anywhere on Earth using timing marks but not wires.
1. How do astronomers use radio waves to learn about the composition of
stars?
Astronomers use radio waves to learn about the composition of stars with the
development of radio telescopes, astronomers gain an advantage over optical
telescopes, because they are not affected by weather, clouds, atmosphere or
pollution and can be detected day or night. Much information has been gained about
the composition and distribution of matter in space, namely neutral hydrogen, which
makes up a large proportion of matter in our Milky Way galaxy.
2. Who is Karl Janksy, and why are his contributions important to space
exploration?
Karl Janksy is an engineer worker for Bell Telephone Laboratories, who was given the
job of tracking down the radio emissions that were interfering with these
communications. Karl Janksy’s contributions were important to space because he
built a radio antenna, using the antenna, he learned to identify radio emissions that
rose and set with the Sun, planets, and stars. From this, he concluded that these
radio wave sources came from space.
1. Draw the following on an electromagnetic spectrum below.
(a) microwaves
(b) infrared radiation
(c) Xrays
(d) ultraviolet radiation
(e) radio waves
(f) gamma rays