RR Lyrae variable
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RR Lyrae variables are periodic variable stars, commonly found in globular clusters and other old stellar populations in galaxies. They are used as standard candles to measure galactic distances, assi
RR Lyrae-type variable stars close to the galactic center from the VVV ESO public survey
Cosmic distance ladder
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The cosmic distance ladder is the succession of methods by which astronomers determine the distances to celestial objects. A direct distance measurement of an astronomical object is possible only for
RR Lyrae variable
…RR Lyrae variables are periodic variable stars, commonly found in globular clusters and other old stellar populations in galaxies. They are used as standard candles to measure (extra) galactic distances, assisting with the cosmic distance ladder. This class is named after the prototype and brightest example, RR…
The sculpture The Astronomer shows the use of parallax to measure distance. It is made from parts of the Yale–Columbia Refractor telescope (1924) damaged when the 2003 Canberra bushfires burned out the Mount Stromlo Observatory; at Questacon, Canberra.
SN 1994D (bright spot on the lower left) in the NGC 4526 galaxy. Image by NASA, ESA, The Hubble Key Project Team, and The High-Z Supernova Search Team
Galaxy cluster