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occrider
Traveladdict
Registered: Oct 2000
Location: New York
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| quote: | Originally posted by Marc Summers
There can't be "Nothing". Even if it looks like there is nothing, there is always something. Space looks empty, but it is full of dark matter, and energy that we can't see with the naked eye. To say that nothing is outside of our universe is shitting all over metaphysics. |
Who said space is nothing? Space isn't nothing which is why it's part of the universe. It's an area that can be defined in spatial/temporal terms and is a medium that matter occupies and affects (e.g. the curvature of spacetime). One can say there is nothing outside the universe if it's analagous to asking the question, what is larger than infinity?
Speaking of those crazy evolutionary scientists ...
| quote: |
T. rex thigh reveals chicken family ties
POSTED: 2152 GMT (0552 HKT), April 12, 2007
Story Highlights• Chickens are distant cousins of the T. Rex, researchers say
• Scientists studied protein from 68 million-year-old bone
• 'First molecular proof' of bird-dinosaur link
Adjust font size:
CHICAGO, Illinois (Reuters) -- Tiny bits of protein extracted from a 68-million-year-old dinosaur bone have given scientists the first genetic proof that the mighty Tyrannosaurus rex is a distant cousin to the modern chicken.
"It's the first molecular evidence of this link between birds and dinosaurs," said John Asara, a Harvard Medical School researcher, whose results were published in Friday's edition of the journal Science.
Scientists have long suspected that birds evolved from dinosaurs based on a study of dinosaur bones, but until recently, no soft tissue had survived to confirm the link.
That all changed in 2005 when Mary Higby Schweitzer of North Carolina State University reported finding soft tissue, including blood vessels and cells, in a T. rex bone dug out of sandstone from the fossil-rich Hell Creek Formation in Montana.
Schweitzer, in another study appearing in this week's issue of Science, found that extracts of T. rex bone reacted with antibodies to chicken collagen, further suggesting the presence of birdlike protein in dinosaur bones.
For his study, Asara used a highly sensitive technology called mass spectrometry to determine the chemical makeup of bone fragments provided by Schweitzer and her team.
He first had to purify the bone extract, which came in the form of a gritty brown powder that remained after minerals were extracted. Asara then broke it down into peptide fragments, little bits of proteins, isolated into the amino acid sequences that make them up.
"It was very tough to get anything," he said in a telephone interview. He wound up with seven separate strands of amino acid, five of which were a particular class of collagen, a fibrous protein found in bone.
Next, Asara had to interpret the sequences. He compared his results to collagen data from living animals. Most matched collagen from chickens, while others matched a newt and frog.
"Based on all of the genomic information we have available today, it appears these sequences are closer to birds or chickens than anything else," Asara said.
Ultimately, scientists had hoped to find genetic material that was unique to the T. rex. That was not possible with the tiny T. rex sample.
"We never found unique T. rex tags," he said.
In a similar study of mastodon bones supplied by Schweitzer, Asara had more luck.
He compared the samples to a database of existing amino acid sequences and against a theoretical set of mastodon sequences and found a total of 78 peptides, including four unique sequences.
Still, Asara said the T. rex protein sequence was useful in providing clues about the evolution of the species.
The researchers said the results may change the way that people think about fossil preservation.
"The fact that we are getting proteins is very exciting," said paleontologist Jack Horner, who dug up the T. rex in 2003 and is co-author of the paper with Schweitzer.
Horner said paleontologists will need to dig deeper for specimens that have not been corrupted by ground water and bacteria.
"I think we are going to find that many specimens are like it. It will be a matter of paleontologists getting into sites that are not necessarily easy," he told reporters in a telephone briefing.
http://edition.cnn.com/2007/TECH/sc...reut/index.html
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Retro ...
Last edited by occrider on Apr-12-2007 at 22:11
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 Apr-12-2007 22:01 
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occrider
Traveladdict
Registered: Oct 2000
Location: New York
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| quote: | Originally posted by Marc Summers
I'm just saying looks can be deceiving, using space as an example, because it was often referred to as a "Void", which is no longer so.
One day we'll come in contact with a species that can bend space and time, then we'll travel to other universes. |
If the universe includes, by definition, everything -- all of space, time, matter, energy, -- than there can be nothing outside of it.
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Retro ...
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Apr-12-2007 22:27
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Marc Summers
I must behave
Registered: Jan 2005
Location: New York, USA
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| quote: | Originally posted by occrider
If the universe includes, by definition, everything -- all of space, time, matter, energy, -- than there can be nothing outside of it. |
Then the definition has to be revised. If our universe can be mapped, and is expanding, then something has to be outside of it for it to expand into. I just can't see the "World is flat and you fall off at the end" explaination of the universe to be reasonable.
___________________
"You won a new refrigerator, great! Where you gonna put it?" - Tony Danza
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Apr-12-2007 22:58 
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MisterOpus1
Grumpy Old Fart
Registered: Dec 2001
Location: Kansas City
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I'll continue to defer to Occ in regards to knowledge on cosmology and astronomy (not by field by a long shot), but I'll stick to the discussion at hand with the Pope and evolution as much as possible:
| quote: | Originally posted by Krypton
Opus:
How can we quantify the supernatural? |
We can't, not in the confines that we currently measure natural phenomena via scientific methodology.
Does that mean the supernatural doesn't exist? Not at all - it just means that scientifically it cannot be demonstrable and verifiable.
Thus the distinct and wonderful separation of faith and science.
| quote: | Just because one believes in the notion that this existence is the result of divine intelligence does not mean one does not believe in science.[QUOTE]
That may very well be true, however the converse is not equivalent. You simply cannot demonstrate divine intervention in scientific inquiry based upon scientific methodology. Again, they need to be kept separate.
[QUOTE]Physicists, even you guys accept that our natural laws have a limit. |
Don't ever tell a physicist that.  .
| quote: | | Light does not travel outside of the universe. Therefore, no information can be exchanged, meaning we could never have contact with anything outside of our universe. Unless something (which would have to be divine/infinately-intellgent) on the other side had the ability to communicate with us. |
And we have demonstrated and verified that latter possibility how again?
| quote: | | Now I'm stepping into the realm of religion and philosophy, but there is no choice. We exist in a container. To question religiously what is outside of it is not madness. |
I think we're speaking similarly here, but arriving at different conclusions. I don't disagree with that last statement at all. Question to your heart's content. Hell, even test those questions. In fact, I challenge you to test those questions. The problem is those tests have come up empty with any verifiable evidence. Again, that doesn't mean those questions of the supernatural cannot be answered. There may very well be supernatural phenomena that we do not currently have the ability to test and verify.
But when was it ever appropriate to insert those unverified and unsupported beliefs into areas of science, i.e. areas that have been verified? This is where the fault of the Pope lies. He's welcome to believe anything he chooses. But what I will not agree to is him inserting those beliefs arbitrarily as he sees fit.
There is no bridge to create between science and faith. There never was. Those that attempt to create such a bridge are attempting in vain. The understanding of faith and science are wholly separate and need to be kept as such.
___________________
Whence September dusk grows crisper still,
with leaves all crimson conquered,
I yearn to shout,
and dance about,
and stick pickles in my honker...
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Apr-12-2007 23:02
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occrider
Traveladdict
Registered: Oct 2000
Location: New York
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| quote: | Originally posted by Marc Summers
Then the definition has to be revised. If our universe can be mapped, and is expanding, then something has to be outside of it for it to expand into. |
Once again, the universe is not "expanding" in the conventional thought that it is a spherical entity that is enlarging and therefore there is an outside and an inside so to speak. The "expansion" of the universe is simply space within the universe stretching.
| quote: |
According to the big bang, space itself is expanding. I don't understand: If space is expanding, into what is it expanding?
Joel R. Primack, a cosmologist at the University of California at Santa Cruz, notes that the big bang involves physical processes quite unlike those of everyday experience. For that reason, people often find it quite difficult to grasp what astronomers mean when they refer to an Rexpanding universe.
One common misconception, Primack says, is "that the big bang is an explosion that occurred at some point in a preexisting static space--which is not a picture in accord with our modern theory of space-time and gravity." He explains why this image of the big bang as an explosion in space, like the detonation of a bomb, is incorrect:
"According to modern cosmological theory, based on Einstein's General Relativity (our modern theory of gravity), the big bang did not occur somewhere in space; it occupied the whole of space. Indeed, it created space. Distant galaxies are not traveling at a high speed through space; instead, just like our own galaxy, they are moving relatively slowly with respect to any of their neighboring galaxies. It is the expansion of space, between the time when the stars in these distant galaxies emitted light and our telescopes receive it, that causes the wavelength of the light to lengthen (redshift). Space is itself infinitely elastic; it is not expanding into anything."
The lengthening, or redshifting, of light that Primack describes was first observed by Edwin Hubble in 1929. This phenomenon is often referred to, incorrectly, as a Doppler shift. A Doppler redshift results from the expansion of light emitted by a receding object. Cosmological redshifts result from the expansion of space (and the light moving through that space) between us and a distant galaxy or quasar. Space is expanding everywhere, so the more distant an object is, the more rapidly it appears to be moving away.
Primack then considers another aspect of the reader's question: What lies beyond our cosmic horizon, the visible "edge" of the universe?
"Every observer in the universe is surrounded by a sphere beyond which nothing can be seen: the observer's cosmic horizon (the point at which the apparent recessional velocity equals the speed of light). Because it is the expansion of space rather than the high velocity of distant galaxies that prevents us from seeing beyond our cosmic horizon, there is no reason to suppose that galaxies outside it are any different from those inside it. Indeed, the extreme isotropy, or smoothness, of the cosmic background radiation (it appears to have the same temperature in all directions, to about one part in 100,000), together with the law of General Relativity and other physical assumptions that seem reasonable, implies that the universe must remain pretty much the same out to a considerable distance beyond our horizon.
"The theory of cosmic inflation, a recent elaboration of the big bang, suggests that at still greater distances, the universe is very different from the way it is locally. Although we cannot check this prediction directly, other predictions of inflation are being tested by new observations, especially those to be made by the astronomy satellites that NASA and the European Space Agency plan to launch in the next five to 10 years. There are many books that discuss current theories of the expansion of the universe and related topics. Of these, my favorite one is Cosmology, by Edward R. Harrison (Cambridge University Press, 1981)."
http://www.sciam.com/askexpert_ques...588F2D7&catID=3
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| quote: |
I just can't see the "World is flat and you fall off at the end" explaination of the universe to be reasonable. |
And as I've been trying to say, that's exactly the type of mentality you're adopting if you continually think of the universe with only 3 spatial dimensions. A hypersphere (the universe appears to be a dodecahedron but we'll use a sphere for simplicity) is a sphere with 4 spatial dimensions. It is impossible to draw, however, movement in 3-dimensions is represented as travelling on the surface of the hypersphere. If you move through space in one direction for an infinite amount of time, much like walking across the surface of the Earth, eventually you end up where you started. As such there is no "edge" or "outside" of the universe as you travel through space as there is no "edge" or "end" of the Earth as you walk around it.
| quote: |
The curvature of space
The first testable predictions about the size and shape of the universe were made by Einstein in 1916 as part of his general theory of relativity. In general relativity massive bodies such as stars change the shape of space-time around them, much as a bowling ball would change the shape of a trampoline. Indeed, it is this local deformation of space-time that is responsible for gravity in Einstein's theory.
The average curvature of space therefore depends on the overall density of matter and energy in the universe. This density is usually expressed in terms of the ratio Ù, which is defined as the actual density of the universe divided by the critical density required for space to be flat or Euclidean. Space can therefore have three possible curvatures: zero curvature (Ù = 1), which means that two parallel lines remain a constant distance apart as they do in the familiar Euclidean space; negative curvature (Ù < 1), with parallel lines diverging as they do on the hyperbolic surface of a saddle; or positive curvature (Ù > 1), which means that parallel lines eventually cross one another as they do on the surface of a sphere.
In the standard model of cosmology, space has been flat and infinite ever since the universe underwent a short period of extremely rapid expansion called inflation shortly after the Big Bang. Moreover, we now know that the expansion of the universe is actually accelerating due to a mysterious repulsive force caused by "dark" energy (see "Dark energy" Physics World May 2004 pp37-42).
In 2003 the Wilkinson Microwave Anisotropy Probe (WMAP) produced a high-resolution map of the cosmic microwave background that provided clues about the expansion rate of the universe and its curvature. Combined with other astronomical observations, the WMAP data suggest that Ù = 1.02 ± 0.02, which favours a spherical universe with positive curvature. The simplest such space is a "hypersphere", which can be thought of as the 3D surface of a 4D ball, just as an ordinary sphere is the 2D surface of a 3D ball. Hyperspherical space is therefore finite but it does not have a problematic boundary (figure 1). However, as we will see, many other spherical spaces can fit the data better than a hypersphere.
Fig. 1.
The topology of space
Curvature is clearly central to the large-scale shape of space, but it is not the only factor. The global topological properties of space are also important because they determine whether the universe is finite or infinite. All spherical spaces are finite, for instance, but not all finite spaces are spherical. Indeed, flat and hyperbolic spaces can have finite or infinite volumes depending on their topologies.
To illustrate this in two dimensions, think of a square and identify opposite sides as being the same, as happens in video games where a spaceship disappearing to the right of the screen reappears on the left. In three dimensions, a spaceship or anything else (such as a particle or a photon) that leaves the "fundamental" cube through one face re-enters it from the opposite face. In this case one can imagine a cubic block of space whose opposite faces have been "glued" together to produce what is effectively a 3D torus.
At first glance all the familiar rules of Euclidean geometry hold in both of these examples, and the spaces look infinite to those who live in them. However, unless the spaceship keeps encountering the same objects on its travels, there is no way that its crew could tell if it is moving through an infinite space or through the same finite space again and again.
Furthermore, general relativity does not distinguish between these possibilities because each of the three plausible cosmic geometries - flat, hyperbolic and spherical - is consistent with many different topologies. For example, a 3D torus and ordinary flat Euclidean space are described by the same equations in general relativity, even though the former is finite and the latter infinite. Determining the topology of the cosmos therefore requires some physical understanding beyond relativity, in particular concerning the way different regions of space-time are connected.
Cosmologists usually assume that the universe is simply connected like a plane, which means there is only one direct path for light to travel from a source to an observer. A simply connected Euclidean or hyperbolic universe would indeed be infinite, but if the universe is multiply connected, like a torus, there would be many different possible paths. This means that an observer would see multiple images of each galaxy and could easily misinterpret them as distinct galaxies in an endless space, much as a visitor to a mirrored room has the illusion of seeing a crowd. Could we, in fact, be living in such a cosmic hall of mirrors?
Topologists have proved that in addition to the ordinary, simply connected Euclidean, spherical and hyperbolic spaces, there are 17 other Euclidean spaces and an infinite number of spherical and hyperbolic spaces - all of which are multiply connected. These spaces differ in the shape of their fundamental blocks, which can take the form of a parallelepiped or a hexagonal prism for a Euclidean space or more complicated polyhedrons for spherical and hyperbolic spaces. The way the faces of these blocks are glued together also differs between each space. The surprise from the WMAP data is that the topology of space seems indeed to be multiply connected and described by a special class of shapes that are called "well proportioned".
Cosmic harmonics
The best way to determine the shape of our universe is to go back to its beginning, just after the Big Bang. The infant universe is thought to have been crossed by acoustic waves that would have caused tiny density fluctuations in the primordial plasma. After about 380,000 years, however, the universe had expanded and cooled enough to allow matter and antimatter to decouple. This meant that photons could travel unhindered through space, carrying with them vital information about the primordial density fluctuations (which are now thought to have been the seeds for galaxies and clusters of galaxies to form). Today, 13.7 billion years after the Big Bang, this radiation has cooled to a temperature of about 2.7 K, which is in the microwave region. And the fluctuations are imprinted as hot and cold spots in this cosmic microwave background.
A good way to understand the connection between acoustics and topology is to sprinkle fine sand uniformly over a drumhead and then make it vibrate. The grains of sand will collect in characteristic areas and patterns that reveal information about the local geometry of the drum and about the elasticity of its membrane. But the distribution of these spots also depends on the global shape - i.e. the topology - of the drum. For example, the waves will be reflected differently according to whether the drumhead is infinite or finite, and whether it is shaped like a circle, an ellipse or some other shape.
Just as the vibration of a drumhead may be expressed as a combination of its harmonics, fluctuations in the temperature of the cosmic background radiation may be expressed as combinations of the vibrational modes of space itself. When the level of fluctuations is plotted as a function of angle, we therefore find a series of peaks that provides a signature of the geometry of space 13.7 billion years ago (figure 2). For example, the position and amplitude of the first peak - i.e. the peak at the largest angle - in this "angular power spectrum" gives the radius of curvature of space.
Fig. 2.
Different cosmological models predict different power spectra, and high-resolution measurements of the cosmic microwave background from instruments such as WMAP now allow us to compare different theories against real data. However, when WMAP released its first data in 2003, advocates of the standard cosmological model were faced with several surprises.
The position of peaks in the angular spectrum is usually described by their wavenumber or mode L = 180°/θ, where θ is the angular distance in the sky. In fact, the lowest mode - the dipole or L = 1 mode - is swamped by the far stronger dipole induced by the motion of the solar system relative to the cosmic background, which means that it cannot be measured. But when researchers determined the first observable mode - the L = 2 or quadrupole mode - they found that it was seven times weaker than the predictions for a flat, infinite universe. Furthermore, the octopole or L = 3 mode was also less than the expected value by a factor of about two-thirds.
For higher modes up to L = 900, which correspond to angular scales of just 0.2°, the WMAP data were fairly consistent with the standard model. But a more careful analysis of the power spectrum also reveals that the distribution of temperature fluctuations is not fully isotropic and that the fluctuations are distributed differently on different angular scales.
All these anomalies contradict the standard picture of the universe, which has led some more conservative cosmologists to claim that they are due to errors in the data analysis. Furthermore, the second round of WMAP data - originally expected in February 2004 - has been delayed for more than a year, which may hint at additional trouble to come! Meanwhile, other cosmologists have taken the problem seriously and proposed new laws to explain the early universe, some of which have exotic names such as "vanilla" and "racetrack" inflation.
Cosmo-topologists, on the other hand, have tried to find a more natural, geometrical explanation for the observed power spectrum. Put simply, the unusually low amplitudes of the quadrupole and octopole modes means that long wavelengths (i.e. temperature fluctuations over large angular scales) are missing, possibly because space is not big enough to sustain them. This can be likened to oscillation of a string fixed at both ends, where the maximum wavelength of an oscillation is twice the string length. The geometrical explanation of the power spectrum thus implies that we live in a finite, multiply connected space that is smaller than the observable universe.
Dodecahedral space
Surprisingly, not all small-volume universes suppress the large-scale fluctuations. In 2003 the present author, Jeff Weeks and co-workers proved that the long-wavelength modes tend to be relatively lowered only in a special family of finite, multiconnected spaces that are called "well-proportioned spaces" because they have a similar extent in all three dimensions. More specifically, we discovered that the best candidate to fit the observed power spectrum is a well-proportioned space called the Poincaré dodecahedral space.
This space may be represented by a polyhedron with 12 pentagonal faces, with opposite faces being "glued" together after a twist of 36° (figure 3). This is the only consistent way to obtain a spherical (i.e. positively curved) space from a dodecahedron: if the twist was 108°, for example, we would end up with a radically different hyperbolic space. The Poincaré dodecahedral space is essentially a multiply connected variant of a simply connected hypersphere, although its volume is 120 times smaller.
Fig. 3.
A rocket leaving the dodecahedron through a given face immediately re-enters through the opposite face, and light propagates such that any observer whose line-of-sight intercepts one face has the illusion of seeing a slightly rotated copy of their own dodecahedron. This means that some photons from the cosmic microwave background, for example, would appear twice in the sky.
The power spectrum associated with the Poincaré dodecahedral space is different from that of a flat space because the fluctuations in the cosmic microwave background will change as a function of their wavelengths. In other words, due to a cut-off in space corresponding to the size of the dodecahedron, one expects fewer fluctuations at large angular scales than in an infinite flat space, but at small angular scales one must recover the same pattern as in the flat infinite space.
In order to calculate the power spectrum we varied the mass-energy density of the dodecahedral universe and computed the quadrupole and the octopole modes relative to the WMAP data. To our delight, we found a small interval of values over which both these modes matched the observations perfectly. Moreover, the best fit occurred in the range 1.01 < Ω < 1.02, which sits comfortably with the observed value.
The Poincaré dodecahedral space therefore accounts for the lack of large-scale fluctuations in the microwave background and also for the slight positive curvature of space inferred from WMAP and other observations. Moreover, given the observed values of the mass-energy densities and of the expansion rate of the universe, the size of the dodecahedral universe can be calculated. We found that the smallest dimension of the Poincaré dodecahedron space is 43 billion light-years, compared with 53 billion light-years for the "horizon radius" of the observable universe. Moreover, the volume of this universe is about 20% smaller than the volume of the observable universe. (There is a common misconception that the horizon radius of a flat universe is 13.7 billion light-years, since that is the age of the universe multiplied by the speed of light. However, the horizon radius is actually much larger because photons from the horizon that are reaching us now have had to cross a much larger distance due to the expansion of the universe.)
If physical space is indeed smaller than the observable universe, some points on the map of the cosmic microwave background will have several copies. As first shown by Neil Cornish of Montana State University and co-workers in 1998, these ghost images would appear as pairs of so-called matched circles in the cosmic microwave background where the temperature fluctuations should be the same (figure 4). This "lensing" effect, which can be precisely calculated, is thus purely attributable to the topology of the universe.
Fig. 4.
Due to its 12-sided regular shape, the Poincaré dodecahedral model actually predicts six pairs of diametrically opposite matched circles with an angular radius of 10-50°, depending on the precise values of cosmological parameters such as the mass-energy density.
http://physicsweb.org/articles/world/18/9/3
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Apr-13-2007 02:00
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