Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 1 decade ago

Why do most stars show no parallax angle?

Why do most stars show no parallax angle?

a. There are not sufficient background stars to measure the shift.

b. Most stars show a blue shift which blurs the parallax measurement.

c. The atmosphere blurs the measurements. This creates inaccuracies.

d. They are so far away that we ca not measure the apparent shift against the background stars.

e. The rotation of the earth distorts the angle measurement.

6 Answers

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  • Anonymous
    1 decade ago
    Favorite Answer

    d. They are so far away that we ca not measure the apparent shift against the background stars.

    You need a significant distance between the two lower points of the triangle to be able to triangulate properly. But Earth´s orbit provides only about 15 light-minutes, and the nearest - the very nearest - star is almost 4 light years away. You understand how that would make accurate measurements difficult over even bigger distances.

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  • Anonymous
    1 decade ago

    d. They are so far away that we ca not measure the apparent shift against the background stars.

    "...In astronomy, parallax is the only direct method by which distances to objects (typically stars) beyond the Solar System can be measured. The Hipparcos satellite has used the technique for over 100,000 nearby stars. This provides the basis for all other distance measurements in astronomy, the cosmic distance ladder. Here, the term "parallax" is the angle or semi-angle of inclination between two sightlines to the star. ..."

    http://en.wikipedia.org/wiki/Parallax

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  • 1 decade ago

    The answer they are looking for is probably d. However the Hipparcos satellite measured the parallax of more than 2.5 million stars. This is far more than are visible to the naked eye, although obviously only a tiny proportion of the total stars in the Universe.

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  • 1 decade ago

    d. They are so far away that we ca not measure the apparent shift against the background stars.

    Source(s): The Universe on the history channel
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  • Anonymous
    1 decade ago

    D is the correct answer.

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  • Araina
    Lv 4
    1 decade ago

    D.

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