Cosmic Distances How do we determine the distance to celestial objects? No single method works at...
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![Page 1: Cosmic Distances How do we determine the distance to celestial objects? No single method works at all distances… close, intermediate and far. Astronomers.](https://reader036.fdocuments.net/reader036/viewer/2022082816/56649f3f5503460f94c60112/html5/thumbnails/1.jpg)
Cosmic Distances
How do we determine the distance to celestial objects?
No single method works at all distances… close, intermediate and far.
Astronomers use a “cosmic distance ladder”.
![Page 2: Cosmic Distances How do we determine the distance to celestial objects? No single method works at all distances… close, intermediate and far. Astronomers.](https://reader036.fdocuments.net/reader036/viewer/2022082816/56649f3f5503460f94c60112/html5/thumbnails/2.jpg)
![Page 3: Cosmic Distances How do we determine the distance to celestial objects? No single method works at all distances… close, intermediate and far. Astronomers.](https://reader036.fdocuments.net/reader036/viewer/2022082816/56649f3f5503460f94c60112/html5/thumbnails/3.jpg)
Parallax
How do we determine distances in space?
Simple way is triangulation. If you know two angles and one side, trigonometry does the rest.
Parallax = apparent movement of object when observer’s location moves.
![Page 4: Cosmic Distances How do we determine the distance to celestial objects? No single method works at all distances… close, intermediate and far. Astronomers.](https://reader036.fdocuments.net/reader036/viewer/2022082816/56649f3f5503460f94c60112/html5/thumbnails/4.jpg)
Parallax
![Page 5: Cosmic Distances How do we determine the distance to celestial objects? No single method works at all distances… close, intermediate and far. Astronomers.](https://reader036.fdocuments.net/reader036/viewer/2022082816/56649f3f5503460f94c60112/html5/thumbnails/5.jpg)
Standard Candles
Standard Candle = a celestial object with a known luminosity.
Three problems:
1. calibration - what is the absolute magnitude2. identifying candle - have to be sure you’re using the same object.3. how standard are they?
Ex: Type 1 supernovas, cepheid variables, spectral lines (calcium) directly related to magnitude.