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More Big Bang

How Old is the Universe?

       In a report that came out today, it has been announced that the Hubble Space Telescope has calculated the age of the universe within a 10% accurracy variance.  After observing 18 galaxies as far away as 850 million light years, they found 800 Cepheid variable stars. These are the most accurate indicators known to astronomers for measuring vast distances. The team of 27 astronomers from 13 U.S. and international institutions used four  different methods to calculate the Hubble Constant (or rate of universe expansion). All four methods produced the same age range of between 12 and 13.5 billion years old.  Another scientist even more recently has revised it further much as 15% lower, placing the age even closer to the lowest age of 10 billion. This measurement provides the most reliable measurement yet of the age of the universe where before, astronomers guessed anywhere between a low of 10 billion to a max of 20 billion. (see elsewhere in my Big Bang page)
       However, there is some dispute among a particular group of scientists who have pondered this problem as far back as the 1960's.  They claim to put the universe age at 14 to 18 billion years after 30 years of ground based study, but ground telescopes cannot get the clarity of measurements that the Hubble Space Telescope can due to the destortion caused by the atmosphere.
        The problem with these findings for science is that there have been observations and measurements of stars as old as 15 to 20 billion years....effectively older than the universe. The lower the age gets for the universe, the more theorists sweat since it gives them less and less time to explain how things happened the way they did.


The Findings of the Hipparcos Satellite

       The Hipparcos satellite was launched in 1997 with the mission to measure the actual distances to stars with an accuracy not available from Earth. They measure the distances by using the parallax of the star as we move about the Sun every year.....much like when you drive in a car down the interstate and the trees visible a mile away off to your left appear to stand still, while the mile-marker signs right up against the road wiz past unbelievably fast. They use this apparant shift in position to form a trigometric triangle and then use math to figure the distance.
       Before Hipparcos, star distances were based on indirect methods on often uncertain assumptions. Therefore, the 3-D arrangement of stars beyond just a few light years from Earth was a mystery. Now however, this satellite has given us the direct evidence needed to get a precise measurement never before available, extending the number of stars whose distance was reliably known from 1,000 to 22,396 to an average of a 10% accuracy.
       Another finding of the satellite is that there is no significant amount of "dark matter" in our area of the universe. However there has to be a massive amount of this "dark matter" in halo which surrounds and penetrates the outer arms of the Milky Way to account for the faster-than-should-be speed of their rotation around the galactic center. So for a universe that is supposed to be awash in a bath of "dark matter", our part of the universe is particularly bare.
       Then another result of the Hipparcos satellite's observations has been a precise placing of the distance to the Pleiades Star Cluster. The cluster has now been measured to be 375 light years away, or 115 parsecs. This is a problem because this places the cluster 15% closer to us than previously thought. Since they are closer to us, then they are therefore younger than expected. If they are younger than expected than the whole model of star formation and development is in question since the aging process of these young stars are now off the Hertzsprung - Russell diagram......the diagram of accepted and expected star development.
       "How old is the universe?" , is another key question pondered by the satellite. Based on the data produced, it aged nearby globular clusters to a range of 12 to 14 billion years old. (see previous story at top of this page) If the universe is the same age as these clusters, then they must have apparantly formed at the same time.

On to some alternate theories

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