The “Age Paradox”
How can the stars be older than the Universe????
In
1994 Dr. Wendy L. Freedman, using the Hubble Space Telescope, observed
individual Cepheid Variable stars in spiral galaxy M-100.
Seeing these “standard candles” allowed her to estimate a distance to M-100
(seen at right, and the entire Virgo group) of 51 million light years. This
was much less than the previous estimate of 60+ million light years, and
created great controversy in that it also led Dr. Freedman to estimate that
the Universe was only 8 billion years old. For many years theories of star
evolution based on particle physics and star distance estimates predicted
that the oldest stars were 12 to 15 billion years old. There is an obvious
paradox here!! One can’t have stars older than the universe they are in!
Other Astronomers strongly disagreed with Dr. Freedman’s results, but
they were good enough to send many astronomers, physicists, and
cosmologists, “back to the drawing board” to examine both the Big Bang
Theory and stellar evolution. Some even said that there might be errors in
particle physics theories.
More recently(1997), data from the Hipparcos satellite gives better distance
and brightness estimates for a few close Cepheid Variables. Direct
measurements by Hipparcos imply that the Cepheids are more luminous and more
distant than previously imagined. This adjustment to the “standard candles”
means that M-100 and the other galaxies are about 10% further, and that the
Universe is about 13 billion years old. Other Hipparcos results which give
better data on another type of variable, revised the distances and ages of
Globular Cluster stars. These oldest stars are now estimated to be 9 to 12
billion years old, younger than the new 13 billion year estimated age of the
Universe.
So, the “Age Paradox” is solved!!! Well, maybe not!
Even the nearest Cepheid Variables are at the outer limits of Hipparcos’
measurement abilities. Some scientists now claim that there is still a large
margin of error in the Hipparcos data and that certain statistical quirks
could cause an over-estimate of Cepheid distances. While other results
support the new distances and ages, the “Age Paradox” could return to
challenge scientists to further refine their theories. Of course that is the
way science has always worked.
For more on the “Age Paradox”, Check out these links:
-
NASA Press Release & HST M-100 observations and the “Age Paradox”
-
ESA Press Release on the Hipparcos satellite data that may solve the “Age Paradox”
George Normandin, KAS
July 7th, 1998
