09 triangulation
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Triangulation is a method used to measure vast distances like between Earth and Alpha Centauri. It involves using two observers located a few kilometers apart who measure the base angles to an object. By knowing the baseline distance between the observers and using trigonometry, the distance to the object can be calculated from a scaled drawing. However, for very distant stars the angles appear the same from both points, and with too short a baseline the method is limited.
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09 triangulation
- 2. How can we measure vast distances, like the distance between earth and Alpha Centauri? Triangulation ? ? ?
- 3. Triangulation ? To do this, two observers are located at 'A' and 'B' separated by a few kilometers (baseline) A B baseline
- 4. Triangulation ? A B The base angles at A and B can be measured with a protractor or theodolite. baseline x y
- 6. Triangulation ? By knowing the baseline distance, the distance D can be worked out with a simple scaled drawing A B baseline D x y
- 7. Triangulation ? For example: A B 5 m D 50 55 How do you make a scaled drawing?
- 8. Triangulation ? For example: How do you make a scaled drawing? 5 cm 1) Draw the bottom line to scale (ex. 1 cm = 1 m)
- 9. Triangulation ? For example: How do you make a scaled drawing? 5 cm 50 55 2) Draw the two angled lines
- 10. Triangulation ? For example: How do you make a scaled drawing? 5 cm D 50 55 3) Measure distance D
- 11. Triangulation ? ? Limitations: 1 km Stars are so far away that the angles appear to be 90 , as if the star is straight up for both observers
- 12. Triangulation ? Limitations: 1 m D Similar problem exists when two observers stand too close (baseline is too short)
- 13. Triangulation ? Solution: To solve this problem, astronomers use trigonometric parallax, where they use photography to measure the vertex angle of the triangle
- 14. Triangulation ? Solution: D You can solve this problem by standing farther apart.
Editor's Notes
- #2: http://spacemath.gsfc.nasa.gov/transits/TRACEvenus.html (helpful resource)Page 442-443 Nelson Science 9