[vsnet-chat 693] Will universe expand forever?

[Rudolf Novak <rudolfn@physics.muni.cz>]

> PHYSICS NEWS UPDATE                         
> The American Institute of Physics Bulletin of Physics News
> Number 355 January 20, 1998   by Phillip F. Schewe and Ben Stein
> 
> THE UNIVERSE WILL EXPAND FOREVER. This prediction is
> based on new studies of distant supernovas. Because Type Ia
> supernovas (supernovas in which material falling onto a white dwarf
> from a companion object ignites violently) brighten and fade in such
> a predictable way, their intrinsic brightness (and their distances
> from Earth) can be determined by carefully watching light emission
> over time. Combining these distances with the velocities of the host
> galaxies (determined from redshifts) allows one to calculate the
> expansion of the universe with some confidence.  And the result
> appears to suggest that the universe does not have enough matter
> (visible or dark) to halt the current expansion. This view emerged
> two weeks ago at the meeting of the American Astronomical Society
> in Washington, where optical  data for many new supernovas
> (including the most distant supernova ever observed, one with a
> redshift of 0.97) were reported by a group from LBL (led by Saul
> Perlmutter) and one from Harvard-Smithsonian (Peter Garnavich).
> The new findings are consistent with an age estimate for the
> universe of 15 billion years.

 Dear Colleagues,
do you think that we can say this if we have just a few observations?
I think that observations of Ia supernovae in very big distances can say
somethink about age and speed of expanding. But can we say that this is
real solution for so important question?

Have a nice day

Rudolf


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* Rudolf Novak                              Private:         Rudolf Novak *
* Nicholas Copernicus Observatory                    Bohuslava Martinu 50 *
* Kravi Hora 2                                                BRNO 602 00 *
* BRNO 616 00                                              Czech Republic *
* Czech Republic                                                          *
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*                    e-mail: rudolfn@physics.muni.cz                      *
*                    h-page: http://vsnet.sci.muni.cz/~rudolfn              *
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