The key discovery about Cepheid variable stars that led in the 1920s to the resolution of the question of whether spiral "nebulae" were separate and distant galaxies or part of the Milky Way Galaxy was the direct relationship between the pulsation period and the absolute brightness or luminosity of the Cepheid variables. A measurement of brightness of a variable star could then be used to determine the distance to the "nebula" containing it.
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Physics, 21.06.2019 20:00, izabellehannah7165
Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?
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Physics, 22.06.2019 10:50, madiiiiiii69
If jerome is swinging on a rope and transferring energy from gravitational potential energy to kinetic energy, is being done.
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Physics, 22.06.2019 12:00, stephanieboyd
Explain why electric current cannot exist if a current doesn't have a voltage source.
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Physics, 22.06.2019 16:40, Mikey5818
On your wedding day your lover gives you a gold ring of mass 3.67 g. 48 years later its mass is 3.44 g. on the average how many atoms were abrated from the ring during each second of your marriage? the atomic mass of gold is 197 u. don't enter units
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The key discovery about Cepheid variable stars that led in the 1920s to the resolution of the questi...
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