3.3 - Using Technology to Interpret Space

Question 1

How would you use triangulation to determine the distance of an object?

Answer 1

• Measure the length of the baseline
• Measure the angles created between the ends of the baseline and the sides of the triangle
• Make a scale drawing of the triangle using the length of the baseline and the two angles
• Make a perpendicular line from the baseline to the object. Measure this line and use the scale to convert it to it’s actual length

Question 2

What is a parallax?

Answer 2

The apparent shift in position of a nearby object, when the object is viewed from 2 different places

Question 3

Why is a star’s parallax useful to astronomers?

Answer 3

Because they can then use the parallax to triangulate the star’s distance from Earth. The larger the baseline , the more accurate the result

Question 4

What is the longest baseline that astronomers can use to triangulate a star’s distance from Earth?

Answer 4

The longest baseline that astronomers can use is the diameter of Earth’s orbit (measurements have to be taken 6 months apart)

Question 5

What is a spectroscope?

Answer 5

An object that refracts light from stars to determine their composition

Question 6

How can a star’s spectrum be used to determine a its composition

Answer 6

On their spectra, stars have a series of dark bands in distinct sequences and thicknesses. Because each element in a star creates it’s own black-line “fingerprint”, a star’s spectrum can be used to determine its composition

Question 7

What is the Doppler effect?

Answer 7

The apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer

Question 8

When the Doppler effect occurs, what happens when the source moves closer to you?

Answer 8

• As the source moves closer to you, the waves are compressed
• As the source moves away from you, the waves are stretched

Question 9

What can changes in waves be used to measure?

Answer 9

Changes in waves can be used to measure how fast and in what direction a light-emitting object (such as a star) is moving.

Question 10

In a red shift, what is occurring?

Answer 10

Star is moving away from you, light waves are being stretched

Question 11

In a blue shift, what is occurring?

Answer 11

Star is moving towards you, light waves are being compressed

Question 12

What does the amount of shift in a star indicate?

Answer 12

The amount of shift indicates speed