HubbleSite
NGC 3021
Scientist Pick: Whatever dark energy is, explanations for it have less wiggle room following a Hubble Space Telescope observation that refined the measurement of the universe's present expansion rate. The new value for the expansion rate, known as the Hubble Constant, is 74.2 kilometers per second per megaparsec. Hubble observations of pulsating stars called Cepheid variables in a nearby cosmic mile marker, the galaxy NGC 4258, and in the host galaxies of recent supernovae, directly link these distance indicators. Learn more
NGC 3021
Scientist Pick: Whatever dark energy is, explanations for it have less wiggle room following a Hubble Space Telescope observation that refined the measurement of the universe's present expansion rate. The new value for the expansion rate, known as the Hubble Constant, is 74.2 kilometers per second per megaparsec. Hubble observations of pulsating stars called Cepheid variables in a nearby cosmic mile marker, the galaxy NGC 4258, and in the host galaxies of recent supernovae, directly link these distance indicators. Learn more