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Cosmology II: Link from today's NYTimes(11 posts)

Cosmology II: Link from today's NYTimesOldEdScott
Mar 11, 2003 6:04 AM
one of those sign up thingsDougSloan
Mar 11, 2003 7:52 AM
Can you post part of the article? I don't do those sign up internet things, for it usually means more spam. Thanks.

NY TimesMJ
Mar 11, 2003 8:04 AM
doesn't spam - been signed up for years and have never received any - they do annoying screen popups - it's free to sign up
Here's the text, butOldEdScott
Mar 11, 2003 8:15 AM
NYTimes doesn't spam, it's a good thing to subscribe to, and you may want to see the pictures ...

Universe as Doughnut: New Data, New Debate

March 11, 2003

Long ago in the dawn of the computer age, college students
often whiled away the nights playing a computer game called
Spacewar. It consisted of two rocket ships attempting to
blast each other out of the sky with torpedoes while trying
to avoid falling into a star at the center of the screen.

Although cartoonish in appearance, the game was amazingly
faithful to the laws of physics, complete with a
gravitational field that affected both the torpedoes and
the rockets. Only one feature seemed outlandish: a ship
that drifted off the edge of the screen would reappear on
the opposite side.

Real space couldn't work that way.

Or could it?

Imagine that the Spacewar screen is wrapped
around to form a cylinder or a section of a doughnut so
that the two edges meet.

That is the picture of space, some cosmologists say, that
has been suggested by a new detailed map of the early
universe. Their analysis of this map has now provided a
series of hints - though only hints - that the universe may
have a more complicated shape than astronomers presumed.

Rather than being infinite in all directions, as the most
fashionable theory suggests, the universe could be
radically smaller in one direction than the others. As a
result it may be even be shaped like a doughnut.

"There's a hint in the data that if you traveled far and
fast in the direction of the constellation Virgo, you'd
return to Earth from the opposite direction," said Dr. Max
Tegmark, a cosmologist at the University of Pennsylvania.

The new data have generated both buzz and skepticism among
cosmologists in recent weeks. Dr. Tegmark and other
astronomers agree that the measurements are far from
conclusive, or even persuasive about the shape of the

But if true, the doughnut universe would force cosmologists
to reconsider their theories about what happened in the
earliest moments after the universe was born in the Big
Bang; those theories predict an infinite cosmos.

The new findings have brought to center stage the hope that
astronomers may be able to test speculations about the
shape, or topology, of the universe that until recently
have been relegated to the abstract mathematical margins of

The results are part of the bounty of data produced by a
NASA satellite known as the Wilkinson Microwave Anisotropy
Probe, built and operated by an international collaboration
led by Dr. Charles L. Bennett of the Goddard Space Flight
Center in Greenbelt, Md. The satellite recorded the pattern
of heat, in the form of faint microwave radiation, that
fills the sky.

This radiation is believed to be the afterglow of the Big
Bang itself, and thus constitutes a portrait of the
universe when it was only 380,000 years old.

As the COBE satellite first confirmed in 1992, the
microwave cloud is laced with ripples and splotches - lumps
in the cosmic gravy - from which galaxies and other cosmic
structures would ultimately form.

According to theory, these lumps are born as microscopic
fluctuations during the first instant of time and then
amplified into sound waves as the universe expands and
matter and energy slosh around.

Now the new satellite has illuminated the findings of COBE
(pronounced KOE-bee, for Cosmic Background Explorer) in
exquisite detail.

By analyzing these waves cosmologists can determine many of
the characteristics of the universe, which scientists have
long debated, like its age and density. To their delight,
the first results from the Wilkinson satellite, released
last month, confirmed many of the strange ideas that
cosmologists entertained in the last decade, including the
notion that most
ahh, donutsDougSloan
Mar 11, 2003 8:34 AM
Interesting. Seems like about once a year there is a new theory. Problem is, they come up with theories that are basically extrapolated from relatively teeny, tiny bits of information; any slightest error in measurement or assumption is enough to change the entire theory (and shape, age, or composition of the universe).

I think our minds keep trying to create some sort of finite universe, as the concept of infinity is really hard to get a handle on.


the donut universe!Fredrico
Mar 12, 2003 11:21 AM
Y'know, the Washington Post,, and every other discussion site I've visited doesn't have the degree of intelligent contributors that this humble cycling site has. Is there a connection with bicycling here? Does one activity influence the other?

First is the string theory and now a donut universe. Suppose the big bang was in a plane, like dropping a stone in a pool of water. That would produce a donut shaped universe.

Or if the big bang were in all directions, the universe would be in the shape of a ball, wouldn't it? Perhaps all the galaxies, all the matter, would be on the skin of the ball, and just as if you took off across the Atlantic from New York and went far enough, eventually you'd get back to New York, so if you took off from the Milky Way, eventually you'd get back to it from the opposite direction.
the donut universe!DougSloan
Mar 12, 2003 2:19 PM
But then again, there could have been strange things happening that have no relationship to how we experience things in our world, like explosions in a plane or sphere, ripples on a pond, etc.

The big bang could have been very irregular, with masses bouncing off each other, really weird gravity interactions, secondary explosions, implosions, and things we can't even imagine. Space/time/matter/energy was so different then, I understand, that we may never understand what happened, and therefore be able to deduce the shape of the resulting universe.

It's sure interesting to speculate, though.

What's outside the doughnut?Me Dot Org
Mar 11, 2003 10:49 AM
It's funny, but I probably have more of a problem imagining a finite universe. So you get to one end and it flips around to the other end...what's outside the doughnut? Doesn't the construct of a doughnut imply a shape, with an inside and an outside? What is outside?
A moebus strip has only one side and edge, even though youOldEdScott
Mar 11, 2003 11:19 AM
can 'see' two sides and edges. I think it's that kind of apparent paradox.
you still have 3 dimensions, thoughDougSloan
Mar 11, 2003 11:23 AM
Even with a strip turned back on itself, you still could look up and see forever, supposedly.

I think the "answer" is more like "we just can't know that." The universe is "programmed" so that the infinite is unknowable. With physical limitations like speed of light and great distances, the evidence, if any, will always be out of reach. Well, it's my pet theory du jure.

Guess what I was trying to say isOldEdScott
Mar 11, 2003 11:30 AM
just as there's no 'this side/that side' to a moebius strip, there would be no inside/outside to a finite universe. There would just be a universe we would come to the 'end' of -- only to be at the beginning! Our brains won't wrap around that notion, obviously. Mine just spits the idea out like alum.