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How many galaxies are in the Universe?       Astronomers think that there are at least several billion galaxies in the Universe. The exact number is not known. The estimate of how many galaxies there are in the Universe is done by counting how many galaxies we can see in a small area of the sky. This number is then used to guess how many galaxies there are in the entire sky. Research released in 2016 revised the number of galaxies in the observable universe from a previous estimate of 200 billion (2×1011)[7] to a suggested two trillion (2×1012) or more[8][9] and, overall, as many as an estimated 1×1024 stars[10][11] (more stars than all the grains of sand on planet Earth).[12] Most of the galaxies are 1,000 to 100,000 parsecs in diameter (approximately 3,000 to 300,000 light years) and separated by distances on the order of millions of parsecs (or megaparsecs). For comparison, the Milky Way has a diameter of at least 30,000 parsecs (100,000 ly) and is separated from the And

  HOW OLD IS THE UNIVERSE?   The universe is looking younger every day, it seems. New calculations suggest the  universe  could be a couple billion years younger than scientists now estimate, and even younger than suggested by two other calculations published this year that trimmed hundreds of millions of years from the age of the cosmos.                                Fortunately, the launch of NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) in 2001 and the European Space Agency’s Planck satellite in 2009 changed all that. Still, astronomers’ attempts during the previous century to narrow the age estimates makes for a fascinating detective story.  Before WMAP and Planck, the best approach for determining the universe’s age relied on the much-debated Hubble constant, a figure that describes the rate at which the universe is expanding. The generally accepted age of the universe is 13.7 billion years, based on a Hubble Constant of 70 . To find the Hubble constant, astronom