Eureka! The Universe is an Infinite
Cappuccino
New Evidence for an Infinite Future
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Media Release - School of Physics
The University of New South Wales
Tuesday 29th September 1998
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A University of New South
Wales astronomer examining fossil light from the Big Bang has found
new evidence that our Universe will last forever.
Astronomers spend their lives looking
up at the heavens trying to figure out what kind of Universe we
live in. So far they've told us that the Sun will blow up in 5 billion
years and that the whole Universe is expanding. But will it continue
to expand forever? Or will the Universe stop expanding, recollapse
and end in a Big Crunch in which all life forms die and all matter
evaporates, disassociates, ionises, and turns into a very hot plasma
like the centre of a nuclear explosion or the centre of the Sun.
Cosmologists are the astronomers who
try to answer this question. Recently they have found a new tool:
the fossil light from the Big Bang itself. This light is known as
the cosmic microwave background radiation and it is the oldest light
we can see. It is as old as the Universe itself. By scrutinising
the variations in this light (there are hot spots and cold spots)
cosmologists can tell us what will become of our Universe.
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Image Above :
A full-sky map of the fossil light from the Big Bang. The
red and blue spots are hot and cold spots in the cosmic
microwave background. Dr. Lineweaver combined measurements
of these temperature fluctuations with data from supernovae
and several other data sets. The result is the most accurate
determination of the acceleration of the Universe.
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In a research paper to be published
October 1st cosmologist Dr. Charles Lineweaver of the
University of New South Wales reports new evidence that our Universe
is destined to expand forever.
How did he arrive at that conclusion?
In the Big Bang Model the fate of the Universe is determined by
two numbers: the density of the universe, Omega_m, and the cosmological
constant Omega_Lambda.
"I combined the most recent
measurements of the cosmic microwave background with the most recent
supernovae results and other cosmological data. Separately these
data sets cannot determine unambiguously what the destiny of the
Universe will be. But together they form a powerful interlocking
network of constraints yielding the most precise estimates of Omega_m
and Omega_Lambda. The result is strong evidence and the best evidence
to date that the Universe will expand forever."
Dr. Charles
Lineweaver
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Image Right :
The acceleration of the Universe is obtained from two parameters:
the density of the Universe Omega_m and the cosmological constant,
Omega_Lambda. This contour plot shows the region preferred
by the combination of the data. The star marks the best-fit:
Omega_m = 0.24 +/- 0.10 and Omega_Lambda = 0.62 +/- 0.16.
Any model without a cosmological constant is strongly excluded.
This result is surprising because for the past 15 years the
standard model was in the lower right (Omega_m = 1, Omega_Lambda
=0).
For more details see
Dr. Lineweaver's paper in the Astrophysical Journal Letter,
Oct. 1, 1998,505, L69.
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The strength of this new result is not
only that it gives the best evidence that the Universe will expand
forever, it also yields the best evidence that the rate of expansion
is increasing, that is, the Universe is accelerating. We seem to
be in an epoch of slow inflation that will speed up as time goes
by. It's a little like Han Solo in Star Wars when he goes into hyperspace
by jumping to light speed. The stars recede in every direction with
ever increasing speeds. A more sobering consequence of this result
is that as the Universe gets older we will be able to see less and
less of it.
Even more surprising is that Dr. Lineweaver's
results indicate that most of the energy of the Universe is in a
weird form of energy known as vacuum energy. (The vacuum of modern
physics is not empty. It is seething with virtual particles coming
in and out of existence. All this seething produces a vacuum energy
which has a negative pressure. Unlike normal mass which slows down
the expansion of the Universe, vacuum energy speeds up the expansion.
It's a bit like discovering compressed springs everywhere in the
vacuum of space. These springs make the Universe expand.
The Universe contains very strange stuff.
Compare the Universe to a cappuccino. The weird vacuum energy is
the coffee. Equally mysterious dark matter is the milk. The planets,
stars, galaxies and everything else we know about is just the chocolate
powder and froth.
What does it all mean? Well for one
thing, the future is infinite. If we can get off the Earth before
the Sun explodes we won't need to worry about the Universe collapsing
in on us. But our closest neighbours will recede in the distance
as we huddle around cooling stars, nomads gradually running out
of firewood as night falls.
This new picture will soon be confirmed
or invalidated. New data is coming in quickly from supernovae searches,
gravitational lensing, ground-based cosmic microwave background
measurements and two new satellites.
Stay tuned.
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Further Information
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