Flashcards in 3.3 - Using Technology to Interpret Space Deck (12):
How would you use triangulation to determine the distance of an object?
- 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
What is a parallax?
The apparent shift in position of a nearby object, when the object is viewed from 2 different places
Why is a star's parallax useful to astronomers?
Because they can then use the parallax to triangulate the star's distance from Earth. The larger the baseline , the more accurate the result
What is the longest baseline that astronomers can use to triangulate a star's distance from Earth?
The longest baseline that astronomers can use is the diameter of Earth’s orbit (measurements have to be taken 6 months apart)
What is a spectroscope?
An object that refracts light from stars to determine their composition
How can a star's spectrum be used to determine a its composition
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
What is the Doppler effect?
The apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer
When the Doppler effect occurs, what happens when the source moves closer to you?
- As the source moves closer to you, the waves are compressed
- As the source moves away from you, the waves are stretched
What can changes in waves be used to measure?
Changes in waves can be used to measure how fast and in what direction a light-emitting object (such as a star) is moving.
In a red shift, what is occurring?
Star is moving away from you, light waves are being stretched
In a blue shift, what is occurring?
Star is moving towards you, light waves are being compressed