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Astronomical distance measurement begins with geometry.
supportedAstronomical distance measurement begins with geometry. Geometric distances calibrate the first rung of the cosmic distance ladder and anchor luminosities, stellar radii, standard candles, and the Hubble constant.
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Astronomical distance measurement begins with geometry.
supportedA nearby star viewed from opposite sides of Earth's orbit appears to shift against much more distant background stars.
supportedRadar echoes from planets establish precise Solar-System scales, while ground and space astrometry measure parallaxes for nearby stars.