A dialogue between Mr. Big Bang and Mr. Steady State
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(Please read first the NASA press release and summary of results at the
end of the dialogue.)
Mr. Bang:
In an eternal, steady state universe there is no evolution. Galaxies would
be infinitely evolved, so would life. Big Bang or not we have abundant
observational evidence that the universe is changing over time, evolving
from chaos to structure. the build up of large scale structure of galaxy
superclusters, the origin of the heavier elements, the assembly of galaxies
are all consistent with direct observational evidence for this conclusion.
To prove otherwise one would have to throw out at lease three decades worth of
astronomical observations by the world's most powerful telescopes, and find
alternative interpretations for thousands of peer-reviewed scientific papers
on cosmology.
NASA's W-MAP satellite builds upon this robust and consistent evidence to
independently verify the universe is expanding and evolving from state where
it was once dense and hot. this does not "prove" there was a big bang, but
the expansion of space, and the evolution of galaxies is incontrovertible
and based on direct observations, not just theory.
This doesn't mean everything is absolutely right. And, if evidence comes up
that contradicts the big bang cosmology, astronomers will embrace it as an
exciting new intellectual challenge to theory.
Mr. State:
A great number of spiral galaxies should have halos with globular
clusters as old as M4 (12 to 13 billion years). A galaxy situated at,
for instance, 8 billion light-years from us is seen at it was 8 billion years
ago. Thus, stars from its halo are theoretically 20-21 billion years
old. How can this be compatible with an universe which is only
13.7 +/- 0.2 billion years old, according to the BB theory?
Doesn't the discrepancy between the age of an expanding universe and that
of stars it contains constitute an irrefutable evidence?
It is difficult to abandon a 80 year's old paradigm, but this should not
prevent the NASA specialists from analysing their wonderful findings
in terms of the expanding *and* the "static" universe theories.
Mr. Bang:
Globulars formed 13 GY ago and the galactic disk about 7 GY ago as part
of the hierchical growth of galaxies So? Also, oldest stars are measured
to be 13 GY old, no more.
There simply is no discrepency whasoever, everything is consistent chronologically.
Cosmic expansion aside, the universe looked fundamentally different
in the past than it does today. this cannot happen in a steady state cosmology.
Mr. State:
You are right about M4, which is very close to the Earth.
But if a galaxy is situated at, for instance, 8 billion light-years away, its
light takes about 8 GY to reach us. In other words, we see that galaxy as
it was 8 billion years ago.
Its globular clusters, if present, thus formed 8+13 = 21 GY ago.
Mr. Bang:
The age of the globular clusters in a 8 billion-year distant galaxy would be
13GY - 8GY = 5 GY.
Mr. State:
Imagine that you find to-day in your attic a photo of your grand grand
father, taken 40 years ago.
Iow, you see to-day, on the photo, your grand grand father as he was
40 years ago.
On the photo, he is 50 years old. Are you claiming that he was born
50Y - 40Y = 10Y ago?
Of course, he was born 50 + 40 = 90 years ago!
Now let's go back to the galaxy. You see it to-day as it was 8 GY ago.
You know that 8 GY ago, it was 13 GY old.
Thus, the galaxy was born 13GY + 8Gy = 21 GY ago.
Mr. Bang:
The information about how my grandfather looked at age 10, was delayed
by 40 years until I found the scrapbook. Information from the distant
universe is similarly delayed.
50y (grandfather age) - 40yr (information delay time) = 10yr (age in picture)
Distance has nothing to do with this. If M4 were halfway across
the universe it would still be the same age.
A globular cluster 13 billion years away would be seen as a newborn object.
The age of the universe is very solid. There are no paradoxes.
The local globular cluster are the age of the universe, and anyone
living in another galaxy would reach the same conclusion about their
own globular clusters.
The age of the universe is well-established and supported by numerous
lines of observational evidence.
Mr. State:
You don't see a newborn globular cluster, you take to-day the photo of
a galaxy, which is supposed to be surrounded by globular clusters.
If the galaxy is 8G light-years away from you, its light took 8 GY to reach you.
You know that its globular clusters are 13GY old. Hence, they were born
21 GY ago. This is not a paradox, it is simply logic.
I said that you found a photo, taken 40 years ago, of your grand grand
father who was 50 when the photo was taken. Iow, his age in picture is 50 yr,
not 10 yr.
The only valid conclusion is that he was born 90 years ago.
If you arrive at another conclusion, you don't think logically.
You should use a mental trick to determine when galaxies were born:
Instead of saying "This galaxy is e.g. 8 G light-years away", imagine
that its photo was taken 8 GY ago (without bothering about the redshift,
it could be due to some ageing of the picture).
If the galaxy looks on the photo as if it were likely to be surrounded
by a halo of globular clusters having an age of 13 GY, you should infer that
the galaxy was born 21 GY ago.
Mr. Bang:
The clusters in that galaxy would have an age of 5 GY, they co-evolve
with the galaxy. Very simple, no paradox.
This simply is not an issue in cosmology at all. the age of the universe
is well-established and suported by numerous lines of observational evidence.
If the universe were steady-state we would have no evidence for
the origin of structure, the periodic table, or the hierchical grown of
galaxies. the past would look exactly the same as the present, and that
would be true for the infinite future too.
Mr. State:
Don't you realize that a galaxy situated at 8 GLY is seen as it was
8 GY ago? Iow, 8 GY ago, such galaxy was already (supposedly) as old
as our own galaxy. Or you are claiming that its clusters would have
an age of only 5 GY. Iow, the galaxy would be older than its clusters,
in plain contradiction with what was rightly claimed in the NASA
press release of April 24, 2002:
"Globular clusters are the first pioneer settlers of the Milky Way.
Many coalesced to build the hub of our galaxy and formed billions
of years before the appearance of the Milky Way's magnificent pinwheel
disk (as further confirmed by Richer's observations)."
Since globular clusters are "the first pioneer settlers of our galaxy",
they should be the first settlers of all other comparable galaxies, and also
formed billion of years before their appearance.
Your position is really untenable. Simple arithmetic and logic should
tell you a galaxy already existing 8 GY ago was likely born (or rather
its clusters) 21 GY ago.
Mr. Bang:
Please read the press release. It explains why globular clusters set the age of
the universe at 13 GY, if the universe were infinitely old there would
be "black dwarf" stars. which simply don't exist.
Mr. State:
How do you know that "black", or rather very very faint, dwarf stars don't exist?
According to the press release,
"The ancient white dwarf stars, as seen by Hubble, turn out to be
12 to 13 billion years old.
As white dwarfs cool they grow fainter, and this required that Hubble
take many snapshots of the ancient globular star cluster M4. The observations
amounted to nearly eight days of exposure time over a 67-day period.
This allowed for even fainter dwarfs to become visible, until at last
the coolest and oldest dwarfs were seen. These stars are so feeble
(at 30th magnitude which is considerably fainter than originally anticipated
for any Hubble telescope imaging with the original cameras), they are less
than one-billionth the apparent brightness of the faintest stars that can be
seen by the naked eye."
Hubble could hopefully "see" dwarfs of magnitude greater than 30 by increasing
the observation period.
Anyhow, logic tells that a galaxy comparable to our spiral galaxy,
whose dwarf stars supposedly "formed 12 to 13 GY ago", should be older
that the BB universe, born 13.7 +/- 0.2 GY ago, if its distance from us were
greater than about 2 billion light-years.
******
A question to everybody:
_______________________
Who is likely to be right, Mr. Bang or Mr. State?
Thanks,
Marcel Luttgens
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Hubble Uncovers Oldest "Clocks" in Space to Read Age of Universe
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Full press release text:
Pushing the limits of its powerful vision, NASA's Hubble Space Telescope
has uncovered the oldest burned-out stars in our Milky Way Galaxy.
These extremely old, dim "clockwork stars" provide a completely independent
reading on the age of the universe without relying on measurements of the
expansion of the universe.
The ancient white dwarf stars, as seen by Hubble, turn out to be 12 to 13 billion
years old. Because earlier Hubble observations show that the first stars
formed less than 1 billion years after the universe's birth in the big bang,
finding the oldest stars puts astronomers well within arm's reach of calculating
the absolute age of the universe.
Though previous Hubble research sets the age of the universe at 13 to 14 billion
years based on the rate of expansion of space, the universe's birthday is such
a fundamental and profound value that astronomers have long sought other
age-dating techniques to cross-check their conclusions. "This new observation
short-circuits getting to the age question, and offers a completely independent
way of pinning down that value," says Harvey Richer of the University of
British Columbia, Canada.
The new age-dating observations were done by Richer and colleagues by using
Hubble to go hunting for elusive ancient stars hidden inside a globular star
cluster located 5,600 light-years away in the constellation Scorpius.
The results are to be published in the Astrophysical Journal Letters.
Conceptually, the new age-dating observation is as elegantly simple as
estimating how long ago a campfire was burning by measuring the temperature
of the smoldering coals. For Hubble, the "coals" are white dwarf stars,
the burned out remnants of the earliest stars that formed in our galaxy.
Hot, dense spheres of carbon "ash" left behind by the long-dead star's
nuclear furnace, white dwarfs cool down at a predictable rate the older
the dwarf, the cooler it is, making it a perfect "clock" that has been
ticking for almost as long as the universe has existed.
This approach has been recognized as more reliable than age-dating the
oldest stars still burning by nuclear fusion, which relies on complex models
and calculations about how a star burns its nuclear fuel and ages.
White dwarfs are easier to age-date because they are simply cooling,
but the trick has always been finding the dimmest and hence longest-running
"clocks."
As white dwarfs cool they grow fainter, and this required that Hubble
take many snapshots of the ancient globular star cluster M4. The observations
amounted to nearly eight days of exposure time over a 67-day period.
This allowed for even fainter dwarfs to become visible, until at last
the coolest and oldest dwarfs were seen. These stars are so feeble
(at 30th magnitude which is considerably fainter than originally anticipated
for any Hubble telescope imaging with the original cameras), they are less
than one-billionth the apparent brightness of the faintest stars that can be
seen by the naked eye.
Globular clusters are the first pioneer settlers of the Milky Way.
Many coalesced to build the hub of our galaxy and formed billions of years
before the appearance of the Milky Way's magnificent pinwheel disk (as further
confirmed by Richer's observations). Today 150 globular clusters survive in the
galactic halo. The globular cluster M4 was selected because it is the nearest
to Earth, so the intrinsically feeblest white dwarfs are still apparently bright
enough to be picked out by Hubble.
In 1928, Edwin Hubble's measurements of galaxies made him realize that the
universe was uniformly expanding, which meant the universe had a finite age
that could be estimated by mathematically "running the expansion backward."
Edwin Hubble first estimated the universe was only 2 billion years old.
Uncertainties over the true expansion rate led to a spirited debate
in the late 1970s, with estimates ranging from 8 billion to 18 billion years.
Estimates of the ages of the oldest normal "main-sequence" stars were at odds
with the lower value, since stars could not be older than the universe itself.
In 1997 Hubble astronomers broke this impasse by triumphantly announcing
a reliable age for the universe, calculated from a very precise measurement
of the expansion rate. The picture soon got more complicated when astronomers
using Hubble and ground-based observatories discovered the universe was not
expanding at a constant rate, but accelerating due to an unknown repulsive
force termed "dark energy." When dark energy is factored into the universe's
expansion history, astronomers arrive at an age for the universe of
13-14 billion years. This age is now independently verified by the ages
of the "clockwork" white dwarfs measured by Hubble.
Release Date: 1:00PM (EDT) April 24, 2002
Release Number: STScI-2002-10
Find more Releases at
http://hubblesite.org/newscenter/archive/2002/10/
About Star Cluster Globular
About Star White Dwarf
About Cosmology Universe: Age/Size
Summary of results:
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The universe is dominated by dark energy (73%). The dark matter is most of
the rest (22.4%), and the ordinary stuff we know (all the elements on the
periodic table) comprises only 4.4%.
About 96% of the universe is unknown stuff.
Also, the results indicate an epoch of ionizing radiation around redshift 20
(about 180 million years after the big bang). This ionizing radiation
presumably comes from the first stars in the universe, which previously were
thought to come from about 800 million years after the big bang. So star
formation is earlier than expected, Hubble will not be able to see it (too
far into the infrared), and NGST has a new observational motivation.
A new map of the cosmic microwave background covering the entire sky
confirms COBE results and provides 30 times more resolution.
And provides detailed power spectrum of fluctuations in CMB in five different
wavelengths.
The power spectrum of the CMB fluctutations combined with
other results yields a precise 'best fit' cosmology.
Age of universe = 13.7 +/- 0.2 billion years
Hubble parameter = 71 +/- 4 km/s/Mpc
Total mass-energy density parameter, Omega_total = 1.02 +/- 0.02
Dark energy density parameter, Omega_lambda = 0.73 +/- 0.04
Dark matter density parameter, Omega_dark = 0.224 +/- 0.009
Baryon density parameter, Omega_baryon = 0.044 +/- 0.004
Redshift at decoupling (CMB release) = 1089 +/- 1
Age of universe at decoupling = 379,000 +/- 8000 years
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