Telescopes
Electromagnetic Spectrum
Characteristics of Stars
Distance in Space
H-R Diagram
100
an instrument that collects and focuses a specific form of electromagnetic radiation
What is a telescope?
100
Any form of energy that can travel through space as waves
What is electromagnetic radiation?
100
List at least three characteristics which can be used to classify stars.
Size, color, temperature, brightness, composition
100
What is the speed of light equal to?
300,000 km/s (186,000 miles/s)
100
What two factors does the H-R Diagram compare?
Absolute brightness (on the y-axis) and surface temperature (on the x-axis).
200
Italian astronomer, physicist, and mathematician who was among the first to develop and use the telescope.
Who is Galileo Galilei?
200
The most common form of electromagnetic radiation (EM).
What is visible light?
200
Aldebaran is orange, while the Sun is yellow. Which star is hotter?
Stars proceed from cool to hot according to the visible light spectrum, ROYGBV. Since yellow light has higher energy than orange, the Sun is hotter than Aldebaran.
200
Explain how a light year is determined.
A light year is equal to the distance traveled by light (moving at 300,000 m/s) in one year.
200
Using the H-R Diagram, which is hotter: Betelgeuse or the Sun? Explain your answer.
The Sun is hotter because it is a yellow star, while Betelgeuse is a red star. Also, the sun is further to the left, and surface temp increases from r-->l on the H-R Diagram.
300
Name at least three different types of telescopes, AND identify the type of electromagnetic radiation that they use.
AWV, but could include optical (visible light), radio (radiowaves), X-ray (x-rays), etc.
300
Name two forms of electromagnetic radiation with LESS energy than visible light.
Answers will vary (AWV) among; radio, micro, infrared.
300
List the elements that make up the average star, as well as their percentages.
H-73%; He-25%; other-2%
300
How far would light travel in 3 seconds?
Traveling at 300,000 m/s, light would travel 300,000 x 3 = 900,000 m in 3 seconds.
300
Which is bright; Sirius A or Sirius B? Explain your answer.
Sirius A is brighter than Sirius B. We know this because it is higher on the y-axis, and absolute brightness increases from bottom to top on the H-R diagram.
400
Compare and contrast refraction and reflection. You must: explain what happens to light in each case, and describe which could see more deeply into space AND why.
Reflection-light rays bounce off an object. Refraction-light rays bend through a material Reflecting telescope can see more deeply b/c it can have larger MIRRORS than a refracting telescope can have LENSES.
400
Betelgeuse is a red star, while the Sun is yellow. Which star has a lower surface temperature?
What is Betelguese?
400
Explain how a spectrograph can be used to determine the elements that make up a distant star.
Spectrographs are devices that break up light into its component colors. The spectrograph for each element is unique. Therefore, by comparing the spectrograph produced by a distant star against reference samples (for hydrogen, helium, etc.), we can determine the elements that make it up.
400
Explain the relationship between the distance to an object (like a star) and its parallax.
The closer an object is, the greater its parallax (sideways motion); the further away an object is, the lesser its parallax.
400
Which is larger: the sun or Polaris? Explain your answer.
The sun is a main sequence star, while Polaris is a supergiant. It stands to reason that Polaris is much larger than the sun.
500
Explain the difference between a concave and convex surface, AND identify which type of lenses are used in a refracting telescope.
Concave is a surface curved inward (like a cave) while convex is a surface curved outward (like your eyeball). Refracting telescopes use CONVEX lenses, because they cause light rays to converge (come together) so that an image can form.
500
Light travels at a speed of 300,000 km/s. How far would light travel in 5 seconds?
What is 1,500,000 km?
500
Compare and contrast absolute brightness and apparent brightness.
Absolute brightness refers to the actual amount of light which a star produces. It is dependent upon the size and temperature of the star. Apparent brightness refers to the brightness of a star AS SEEN FROM EARTH. This DOES NOT take into account whether the star is very close or very far from Earth. For this reason, it is a less accurate estimate of brightness. For example, a dim, but close star could look brighter than a bright, but distant star (think of the flashlight demo).
500
Star A is 30 l-y away, while Star B is 60 l-y away. Which star will demonstrate the greater parallax? Explain your answer.
Star A will experience a greater parallax (apparent change of position) because it is closer to us. Star B would appear to move less because it is further away.
500
Estimate the surface temperatures of Aldebaran, the sun, and Rigel. Explain how you determined these responses.
To estimate surface temperature, drop a vertical line to the x-axis from each star. Aldebaran is approximately 4,400 C, the sun is about 5,300 C, and Rigel is about 17,000 C.
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