Claim CH200:
The universe is relatively young, only 6,000 to 10,000 years old.
Response:
- The age of the earth is 4.5 billion years.
- The universe is shown to be old by several independent types of
measurements:
- We can measure the distances to some types of stars from their
apparent brightness. (We know their absolute brightness from nearby
stars of the same type whose distances can be measured
geometrically.) We find distances more than fifty million
light-years away, which means the universe must be at least 50
million years old for the light to reach us. Measurements based on
the brightness of supernovae and galaxies, although less accurate,
give distances up to billions of light years.
- The Large Magellanic Cloud is 153,000 light years away, as measured
by an eclipsing binary star (Cole 2000). This method gives a
relatively direct measurement from simple observations. A star's
absolute brightness is determined from its temperature and diameter,
which can be determined from its spectrum and length of eclipse.
Distance is then determined from the apparent brightness.
- The orbits of thirteen of the Koronis family of asteroids were
traced back and found to match 5.8 million years ago, suggesting
that they formed then from a collision of larger asteroids (Nesvorny
et al. 2002)
- The ages of stars in the oldest globular clusters puts a lower limit
on the age of the universe at 12.07 billion years (Chaboyer et
al. 1996).
- There are white dwarf stars found to be twelve to thirteen billion
years old, based on their cooling rate.
Links:
Fraknoi, Andrew, George Greenstein, Bruce Partridge, and John Percy, 2004.
An ancient universe: How astronomers know the vast scale of cosmic time.
http://education.aas.org/publications/ancientuniverse.html
or
http://education.aas.org/publications/AncientUniverseWeb.pdf
References:
- Chaboyer, Brian, Pierre Demarque, Peter J. Kernan, and Lawrence M.
Krauss. 1996. A lower limit on the age of the universe. Science
271: 957-961.
- Cole, Andrew A., 2000. The distance to the Large Magellanic Cloud.
Science 289: 1149-1150.
- Nesvorny, D., W. F. Bottke Jr., L. Dones and H. F. Levison, 2002. The
recent breakup of an asteroid in the main-belt region. Nature 417:
720-722.
Further Reading:
Ferris, Timothy, 1997. The Whole Shebang. New York: Simon &
Schuster.
created 2001-2-17, modified 2005-2-24