Precession has an immediate impact on astronomers but a much
slower one on the seasons. Right now, the Earth’s north axis points
toward the Sun in June. But due to precession, 13,000 years from
now—half a precession cycle—the Earth’s north pole will be pointed
away from the Sun in June and toward it in December. Seasons
will be reversed relative to our current calendar.
Remember, too, that we are closest to the Sun on our elliptical
orbit in January. So half a cycle from now the northern hemisphere
of the Earth will experience summer when the Earth is closest to
56 FROM THE EARTH TO THE MOON
the Sun, amplifying the heat. It’ll also be winter when we’re farther
from the Sun, amplifying the cold. Seasons will be more severe. In
the southern hemisphere, the seasons will be even milder than they
are now, since they’ll have summer when we are farther from the
Sun and winter when we are closer.
This works the other way, too: 13,000 years in the past, the seasons
were reversed. Summers were hotter and winters were colder
in the northern hemisphere. Climatologists have used that fact to
show that things might have been profoundly different back then.
The slow change in the direction of the Earth’s axis might have
even been the cause of the Sahara becoming a desert! On a yearby-
year basis precession is barely noticeable, but over centuries
and millennia even small changes add up. Nature is usually brutal
and swift, but it can also display remarkable subtlety. It just depends
on your slant.
Sunday, November 8, 2009
Tuesday, November 3, 2009
Saturday, October 31, 2009
coriolis effect - water spins n vs s of equator ??
as we already saw, the Coriolis effect
only produces a measurable effect over huge distances and long
periods of time. Even the most decadent of bathtubs is thousands
of times too small and drains way too quickly to ever be affected
by it. It can be shown mathematically that random motions in
your water are thousands of times stronger than the Coriolis effect,
FLUSHED WITH EMBARRASSMENT 25
which means that any random eddy or swirl in the water will completely
swamp it. If the water always drains one way from your
bathtub, then it has far more to do with the detailed shape of your
drain than from the rotating Earth.
Obsessive would-be physicists have actually performed experiments
using household sinks. They have found that the sink needs
to sit still for over three weeks so that random currents die off
enough to see an appreciable Coriolis effect. Not only that, they
have to let the sink drain one drip at a time to give the effect time
to take hold. You’re not likely to see this after hand-washing your
delicates in the sink.
The same is true for your toilet. This one always makes me
laugh: toilets are designed to spin the water. It helps remove, well,
stubborn things that don’t want to be removed so easily. The water
is injected into the bowl through tubes that are angled, so it always
flushes the same way! If I were to rip my toilet out of the wall and
Equator
low
pressure
system
low
pressure
system
The Coriolis effect is only significant over large
distances. A hurricane is born when a low-pressure
patch of air draws air in from higher and lower
latitudes. Because of the Coriolis effect, in the
northern hemisphere the air from the south moves
east, and the air from the north moves west,
causing a clockwise rotation.
26 BAD ASTRONOMY BEGINS AT HOME
fly it down to Australia, it would flush in the same direction it
does now.
The idea that the Coriolis effect works on such small scales is
a pernicious myth. I have seen it in countless television shows and
magazine articles; it was once even reported in the Sports Illustrated
swimsuit issue. Oddly, they describe walking across the
equator from the Central American country of Costa Rica, which
is hundreds of kilometers from the equator. Some writer on staff
did the figures incorrectly, but then, those aren’t the kind of figures
the magazine is usually trying to sell. On the other hand, maybe all
that walking is how the models stay so slim.
So, if the Coriolis effect doesn’t work on something as small as
a sink or a pan, how did Peter McLeary pull it off? After all, as
Michael Palin commented, it worked for him.
Actually, McLeary cheated. If you watch him do it on Pole to
Pole, you can catch the swindle. He stands on his equator line and
fills the basin. Then he walks a few meters or so north, and rapidly
turns to his right to face his audience. He opens a hole in the
bottom of the pan and the water obligingly rotates clockwise as it
drains out. Next, he refills it, walks a few meters south of the
equator, then rapidly turns to his left to face the audience. Draining,
the water spins counterclockwise.
Do you see how this works? By spinning rapidly in opposite
directions, he can make the water rotate any way he wants! The
squarish shape of the pan helps, too; the corners help push on the
water as the pan rotates, making it flow better.
Meteorology professor Alistair Fraser has used this demonstration
in his own class. He draws a line down the middle of the
classroom and declares it to be the equator (he teaches in Pennsylvania).
He then does just what McLeary does and gets the same
results.
Still don’t believe me? Then think about it: the Coriolis effect
should make draining water spin counterclockwise in the northern
hemisphere and clockwise in the southern. In the northern hemisphere,
water moving north deflects east, moving it counterclockwise.
Water coming south from the north deflects west, but that’s
FLUSHED WITH EMBARRASSMENT 27
still counterclockwise. The opposite is true again for the southern
hemisphere; the water will spin clockwise.
But this is precisely the opposite of what McLeary demonstrates.
He’s a fraud!
Your honor, I rest my case.
Well, not really. I have one more tale to tell. While searching
for information about Nanyuki, I found one tourist’s travelogue
that describes three sinks sitting roughly ten meters apart, just outside
of town. One is south of the equator, the second is directly on
it, and the third is north of it. Perhaps someone else is horning in
on McLeary’s act. Anyway, the tourist who wrote the travelogue
claimed that the northern sink drained clockwise, the southern
sink drained counterclockwise, and the one in the middle drained
straight down. Evidently the drain holes have been cut in such a
way as to force the water to drain the way the designer wanted.
Note once again that they drain the wrong way!
It’s pretty funny, actually. They go through all that trouble to
make a few bucks, and they don’t even get the scam right. Somehow,
though, I don’t think those con artists are starving. Con artists
rarely do. They can always put the right spin on their subjects
only produces a measurable effect over huge distances and long
periods of time. Even the most decadent of bathtubs is thousands
of times too small and drains way too quickly to ever be affected
by it. It can be shown mathematically that random motions in
your water are thousands of times stronger than the Coriolis effect,
FLUSHED WITH EMBARRASSMENT 25
which means that any random eddy or swirl in the water will completely
swamp it. If the water always drains one way from your
bathtub, then it has far more to do with the detailed shape of your
drain than from the rotating Earth.
Obsessive would-be physicists have actually performed experiments
using household sinks. They have found that the sink needs
to sit still for over three weeks so that random currents die off
enough to see an appreciable Coriolis effect. Not only that, they
have to let the sink drain one drip at a time to give the effect time
to take hold. You’re not likely to see this after hand-washing your
delicates in the sink.
The same is true for your toilet. This one always makes me
laugh: toilets are designed to spin the water. It helps remove, well,
stubborn things that don’t want to be removed so easily. The water
is injected into the bowl through tubes that are angled, so it always
flushes the same way! If I were to rip my toilet out of the wall and
Equator
low
pressure
system
low
pressure
system
The Coriolis effect is only significant over large
distances. A hurricane is born when a low-pressure
patch of air draws air in from higher and lower
latitudes. Because of the Coriolis effect, in the
northern hemisphere the air from the south moves
east, and the air from the north moves west,
causing a clockwise rotation.
26 BAD ASTRONOMY BEGINS AT HOME
fly it down to Australia, it would flush in the same direction it
does now.
The idea that the Coriolis effect works on such small scales is
a pernicious myth. I have seen it in countless television shows and
magazine articles; it was once even reported in the Sports Illustrated
swimsuit issue. Oddly, they describe walking across the
equator from the Central American country of Costa Rica, which
is hundreds of kilometers from the equator. Some writer on staff
did the figures incorrectly, but then, those aren’t the kind of figures
the magazine is usually trying to sell. On the other hand, maybe all
that walking is how the models stay so slim.
So, if the Coriolis effect doesn’t work on something as small as
a sink or a pan, how did Peter McLeary pull it off? After all, as
Michael Palin commented, it worked for him.
Actually, McLeary cheated. If you watch him do it on Pole to
Pole, you can catch the swindle. He stands on his equator line and
fills the basin. Then he walks a few meters or so north, and rapidly
turns to his right to face his audience. He opens a hole in the
bottom of the pan and the water obligingly rotates clockwise as it
drains out. Next, he refills it, walks a few meters south of the
equator, then rapidly turns to his left to face the audience. Draining,
the water spins counterclockwise.
Do you see how this works? By spinning rapidly in opposite
directions, he can make the water rotate any way he wants! The
squarish shape of the pan helps, too; the corners help push on the
water as the pan rotates, making it flow better.
Meteorology professor Alistair Fraser has used this demonstration
in his own class. He draws a line down the middle of the
classroom and declares it to be the equator (he teaches in Pennsylvania).
He then does just what McLeary does and gets the same
results.
Still don’t believe me? Then think about it: the Coriolis effect
should make draining water spin counterclockwise in the northern
hemisphere and clockwise in the southern. In the northern hemisphere,
water moving north deflects east, moving it counterclockwise.
Water coming south from the north deflects west, but that’s
FLUSHED WITH EMBARRASSMENT 27
still counterclockwise. The opposite is true again for the southern
hemisphere; the water will spin clockwise.
But this is precisely the opposite of what McLeary demonstrates.
He’s a fraud!
Your honor, I rest my case.
Well, not really. I have one more tale to tell. While searching
for information about Nanyuki, I found one tourist’s travelogue
that describes three sinks sitting roughly ten meters apart, just outside
of town. One is south of the equator, the second is directly on
it, and the third is north of it. Perhaps someone else is horning in
on McLeary’s act. Anyway, the tourist who wrote the travelogue
claimed that the northern sink drained clockwise, the southern
sink drained counterclockwise, and the one in the middle drained
straight down. Evidently the drain holes have been cut in such a
way as to force the water to drain the way the designer wanted.
Note once again that they drain the wrong way!
It’s pretty funny, actually. They go through all that trouble to
make a few bucks, and they don’t even get the scam right. Somehow,
though, I don’t think those con artists are starving. Con artists
rarely do. They can always put the right spin on their subjects
Wednesday, October 21, 2009
Tuesday, October 20, 2009
Blinking Planetary Nebula - NGC 6826
NGC 6826 is a wonderful example of a planetary nebula due to the amount of detail it presents. First of all, the name refers to the nature of human vision and not that of the nebula at all! The nebula appears to "blink" because it is dim. Human eyeballs have their least sensitive cells in the center of the fovea. Thus, staring at this object makes it appear to dim (or even disappear) whereas using "averted vision" makes the nebula look brighter. In a telescope this nebula glows a neon green with bright central star.
I personally observed this one and it's a great object!! sort of reminds me of the ghost of jupiter and saturn nebulas... it's bluish appearance oustanding in a telescope. I did not observe the blinking effect, however, not the central star in my 13.1"...but i didn't observe it for any definite period of time, hoping to go back later...unfortunately, i was off by myself in an environment where wild dogs, coyotes, etc...were coming in in packs close to me, so i headed out as fast as i could...lol
really, i'm being humourous here...but wild animals are something to think about when observing alone... i used to do it alot, but now, i prefer to observe with friends.
much safer!!!
Monday, October 5, 2009
Standard vs Steady State vs Oscillating Universe
The term “Big Bang,” originally a derisive expression coined by Fred Hoyle to
characterize the beginning of the universe predicted by the Friedman-Lemaître
model, is thus potentially misleading, since the expansion cannot be visualized
from the outside (there being no “outside,” just as there is no “before” with respect
to the Big Bang).60
The standard Big Bang model, as the Friedman-Lemaître model came to be
called, thus describes a universe which is not eternal in the past, but which came
into being a finite time ago. Moreover—and this deserves underscoring—the
origin it posits is an absolute origin out of nothing. For not only all matter and
energy, but space and time themselves come into being at the initial cosmological
singularity. As physicists John Barrow and Frank Tipler emphasize, “At this
singularity, space and time came into existence; literally nothing existed before
the singularity, so, if the Universe originated at such a singularity, we would truly
have a creation ex nihilo.”61 Thus, we may graphically represent spacetime as a
cone (Fig. 3.2).
Time
Space
Initial
cosmological
singularity
Fig. 3.2: Conical representation of Standard Model spacetime. Space and time begin at the initial
cosmological singularity, before which literally nothing exists.
60. As Gott, Gunn, Schramm, and Tinsley write: “The universe began from a state of infinite density
about one Hubble time ago. Space and time were created in that event and so was all the matter in the
universe. It is not meaningful to ask what happened before the big bang; it is somewhat like asking what
is north of the North Pole. Similarly, it is not sensible to ask where the big bang took place. The pointuniverse
was not an object isolated in space; it was the entire universe, and so the only answer can be that
the big bang happened everywhere.” J. Richard Gott III, James E. Gunn, David N. Schramm, and Beatrice
M. Tinsley, “Will the Universe Expand Forever?” Scientific American, March 1976, 65.
The Hubble time is the time since the singularity if the rate of expansion has been constant. The singularity
is a point only in the sense that the distance between any two points in the singularity is zero. Anyone
who thinks that there must be a place in the universe where the Big Bang occurred still has not grasped
that it is space itself which is expanding; it is the two-dimensional surface of an inflating balloon which is
analogous to three-dimensional space. The spherical surface has no center and so no location where the
expansion begins. The analogy of the North Pole with the beginning of time should not be pressed, since
the North Pole is not an edge to the surface of the globe; the beginning of time is more like the apex of a
cone. But the idea is that just as one cannot go further north than the North Pole, so one cannot go earlier
than the initial singularity.
61. John Barrow and Frank Tipler, The Anthropic Cosmological Principle (Oxford: Clarendon, 1986),
442.
128 De Deo
On such a model the universe originates ex nihilo in the sense that at the initial
singularity it is true that there is no earlier spacetime point or it is false that something
existed prior to the singularity.
Now such a conclusion is profoundly disturbing for anyone who ponders it.
For the question cannot be suppressed: why did the universe come into being? Sir
Arthur Eddington, contemplating the beginning of the universe, opined that the
expansion of the universe was so preposterous and incredible that “I feel almost
an indignation that anyone should believe in it—except myself.”62 He finally felt
forced to conclude, “The beginning seems to present insuperable difficulties unless
we agree to look on it as frankly supernatural.”63 The problem of the origin
of the universe, in the words of one astrophysical team, thus “involves a certain
metaphysical aspect which may be either appealing or revolting.”64
The Steady State Model
Revolted by the stark metaphysical alternatives presented by an absolute beginning
of the universe, certain theorists have been understandably eager to subvert the
Standard Model and restore an eternal universe. The first such attempt came in
1948 with the first competitor to the Standard Model, namely, the Steady State
Model of the universe. According to this theory, the universe is in a state of cosmic
expansion, but as the galaxies recede, new matter is drawn into being ex nihilo in
the voids created by the galactic recession (Fig. 3.3).
Fig. 3.3: Steady State Model. As the galaxies mutually recede, new matter comes into existence to
replace them. The universe thus constantly renews itself and so never began to exist.
62. Arthur Eddington, The Expanding Universe (New York: Macmillan, 1933), 124.
63. Ibid., 178.
64. Hubert Reeves, Jean Audouze, William A. Fowler, and David N. Schramm, “On the Origin of
Light Elements,” Astrophysical Journal 179 (1973): 912.
The Existence of God (1) 129
If one extrapolates the expansion of the universe back in time, the density of
the universe never increases because the matter and energy simply vanish as the
galaxies mutually approach!
The Steady State theory never secured a single piece of experimental verification;
its appeal was purely metaphysical. Instead, observational astronomy made it
increasingly evident that the universe had an evolutionary history. But the decisive
refutation of the Steady State Model came with two discoveries which constituted,
in addition to the galactic red-shift, the most significant evidence for the Big Bang
theory: the primordial nucleosynthesis of the light elements and the microwave
background radiation. Although the heavy elements were synthesized in the stars,
stellar nucleosynthesis could not manufacture the abundant light elements such as
helium and deuterium. These could only have been created in the extreme conditions
present in the first moment of the Big Bang. In 1965 a serendipitous discovery
revealed the existence of a cosmic background radiation predicted in the 1940s by
George Gamow on the basis of the Standard Model. This radiation, now shifted
into the microwave region of the spectrum, consists of photons emitted during a
very hot and dense phase of the universe. In the minds of most cosmologists, the
cosmic background radiation decisively discredited the Steady State Model.
Oscillating Models
The Standard Model was based on the assumption that the universe is largely the
same in every direction. In the 1960s and 1970s some cosmologists suggested
that by denying that assumption, one might be able to craft an Oscillating Model
of the universe and thus avert the absolute beginning predicted by the Standard
Model. If the internal gravitational pull of the mass of the universe were able to
overcome the force of its expansion, then the expansion could be reversed into a
cosmic contraction, a Big Crunch. If the matter of the universe were not evenly
distributed, then the collapsing universe might not coalesce at a point, but quantities
of matter might pass by one another, so that the universe would appear to
bounce back from the contraction into a new expansion phase. If this process
could be repeated indefinitely, then an absolute beginning of the universe might
be avoided (Fig. 3.4).
Radius of the universe
Time
Fig. 3.4: Oscillating Model. Each expansion phase is preceded and succeeded by a contraction phase,
so that the universe in concertina-like fashion exists beginninglessly and endlessly.
Such a theory is extraordinarily speculative, but again there were metaphysical
motivations for adopting this model. The prospects of the Oscillating Model were
130 De Deo
severely dimmed in 1970, however, by Roger Penrose and Stephen Hawking’s
formulation of the Singularity Theorems which bear their names. The theorems
disclosed that under very generalized conditions an initial cosmological singularity
is inevitable, even for inhomogeneous universes. Reflecting on the impact of this
discovery, Hawking notes that the Hawking-Penrose Singularity Theorems “led
to the abandonment of attempts (mainly by the Russians) to argue that there was
a previous contracting phase and a non-singular bounce into expansion. Instead
almost everyone now believes that the universe, and time itself, had a beginning
at the big bang.”65
Despite the fact that no spacetime trajectory can be extended through a singularity,
the Oscillating Model exhibited a stubborn persistence. Two further strikes
were lodged against it. First, there are no known physics which would cause a collapsing
universe to bounce back to a new expansion. If, in defiance of the Hawking-
Penrose Singularity Theorems, the universe rebounds, this is predicated upon
a physics which is as yet unknown. Second, attempts by observational astronomers
to discover the mass density sufficient to generate the gravitational attraction required
to halt and reverse the expansion continually came up short. In January of
1998 astronomical teams from Princeton, Yale, the Lawrence Berkeley National
Laboratory, and the Harvard-Smithsonian Astrophysics Institute reported at the
American Astronomical Society meeting that their various tests all showed that
“the universe will expand forever.”66 A spokesman for the Harvard-Smithsonian
team stated that they were now at least 95 percent certain that “the density of
matter is insufficient to halt the expansion of the universe.”67
At the same time, observations of the red-shifts of supernovae yielded unexpected
results that have thrown the discussion of the universe’s fate into a wholly
new arena and served to render questions of its density irrelevant. The red-shift
data gathered from the distant supernovae indicate that, far from decelerating,
the cosmic expansion is actually accelerating! There is some sort of mysterious
“dark energy” in the form of either a variable energy field (called “quintessence”)
or, more probably, a positive cosmological constant or vacuum energy which at a
certain point in the evolution of the cosmos kicks the expansion into a higher gear,
causing the expansion to proceed more rapidly. Consequently, even high density
universes may expand forever; a potentially infinite future is no longer the privileged
prerogative of low density universes. Highly accurate recent measurements
of the cosmic microwave background radiation by the Wilkinson Microwave Anisotropy
Probe (WMAP) indicate, “For the theory that fits our data, the Universe
will expand forever.”68
65. Stephen Hawking and Roger Penrose, The Nature of Space and Time, The Isaac Newton Institute
Series of Lectures (Princeton, N. J.: Princeton University Press, 1996), 20.
66. Associated Press News Release, January 9, 1998.
67. Ibid.
68. See http://map.gsfc.nasa.gov/m_mm/mr_limits.html.
characterize the beginning of the universe predicted by the Friedman-Lemaître
model, is thus potentially misleading, since the expansion cannot be visualized
from the outside (there being no “outside,” just as there is no “before” with respect
to the Big Bang).60
The standard Big Bang model, as the Friedman-Lemaître model came to be
called, thus describes a universe which is not eternal in the past, but which came
into being a finite time ago. Moreover—and this deserves underscoring—the
origin it posits is an absolute origin out of nothing. For not only all matter and
energy, but space and time themselves come into being at the initial cosmological
singularity. As physicists John Barrow and Frank Tipler emphasize, “At this
singularity, space and time came into existence; literally nothing existed before
the singularity, so, if the Universe originated at such a singularity, we would truly
have a creation ex nihilo.”61 Thus, we may graphically represent spacetime as a
cone (Fig. 3.2).
Time
Space
Initial
cosmological
singularity
Fig. 3.2: Conical representation of Standard Model spacetime. Space and time begin at the initial
cosmological singularity, before which literally nothing exists.
60. As Gott, Gunn, Schramm, and Tinsley write: “The universe began from a state of infinite density
about one Hubble time ago. Space and time were created in that event and so was all the matter in the
universe. It is not meaningful to ask what happened before the big bang; it is somewhat like asking what
is north of the North Pole. Similarly, it is not sensible to ask where the big bang took place. The pointuniverse
was not an object isolated in space; it was the entire universe, and so the only answer can be that
the big bang happened everywhere.” J. Richard Gott III, James E. Gunn, David N. Schramm, and Beatrice
M. Tinsley, “Will the Universe Expand Forever?” Scientific American, March 1976, 65.
The Hubble time is the time since the singularity if the rate of expansion has been constant. The singularity
is a point only in the sense that the distance between any two points in the singularity is zero. Anyone
who thinks that there must be a place in the universe where the Big Bang occurred still has not grasped
that it is space itself which is expanding; it is the two-dimensional surface of an inflating balloon which is
analogous to three-dimensional space. The spherical surface has no center and so no location where the
expansion begins. The analogy of the North Pole with the beginning of time should not be pressed, since
the North Pole is not an edge to the surface of the globe; the beginning of time is more like the apex of a
cone. But the idea is that just as one cannot go further north than the North Pole, so one cannot go earlier
than the initial singularity.
61. John Barrow and Frank Tipler, The Anthropic Cosmological Principle (Oxford: Clarendon, 1986),
442.
128 De Deo
On such a model the universe originates ex nihilo in the sense that at the initial
singularity it is true that there is no earlier spacetime point or it is false that something
existed prior to the singularity.
Now such a conclusion is profoundly disturbing for anyone who ponders it.
For the question cannot be suppressed: why did the universe come into being? Sir
Arthur Eddington, contemplating the beginning of the universe, opined that the
expansion of the universe was so preposterous and incredible that “I feel almost
an indignation that anyone should believe in it—except myself.”62 He finally felt
forced to conclude, “The beginning seems to present insuperable difficulties unless
we agree to look on it as frankly supernatural.”63 The problem of the origin
of the universe, in the words of one astrophysical team, thus “involves a certain
metaphysical aspect which may be either appealing or revolting.”64
The Steady State Model
Revolted by the stark metaphysical alternatives presented by an absolute beginning
of the universe, certain theorists have been understandably eager to subvert the
Standard Model and restore an eternal universe. The first such attempt came in
1948 with the first competitor to the Standard Model, namely, the Steady State
Model of the universe. According to this theory, the universe is in a state of cosmic
expansion, but as the galaxies recede, new matter is drawn into being ex nihilo in
the voids created by the galactic recession (Fig. 3.3).
Fig. 3.3: Steady State Model. As the galaxies mutually recede, new matter comes into existence to
replace them. The universe thus constantly renews itself and so never began to exist.
62. Arthur Eddington, The Expanding Universe (New York: Macmillan, 1933), 124.
63. Ibid., 178.
64. Hubert Reeves, Jean Audouze, William A. Fowler, and David N. Schramm, “On the Origin of
Light Elements,” Astrophysical Journal 179 (1973): 912.
The Existence of God (1) 129
If one extrapolates the expansion of the universe back in time, the density of
the universe never increases because the matter and energy simply vanish as the
galaxies mutually approach!
The Steady State theory never secured a single piece of experimental verification;
its appeal was purely metaphysical. Instead, observational astronomy made it
increasingly evident that the universe had an evolutionary history. But the decisive
refutation of the Steady State Model came with two discoveries which constituted,
in addition to the galactic red-shift, the most significant evidence for the Big Bang
theory: the primordial nucleosynthesis of the light elements and the microwave
background radiation. Although the heavy elements were synthesized in the stars,
stellar nucleosynthesis could not manufacture the abundant light elements such as
helium and deuterium. These could only have been created in the extreme conditions
present in the first moment of the Big Bang. In 1965 a serendipitous discovery
revealed the existence of a cosmic background radiation predicted in the 1940s by
George Gamow on the basis of the Standard Model. This radiation, now shifted
into the microwave region of the spectrum, consists of photons emitted during a
very hot and dense phase of the universe. In the minds of most cosmologists, the
cosmic background radiation decisively discredited the Steady State Model.
Oscillating Models
The Standard Model was based on the assumption that the universe is largely the
same in every direction. In the 1960s and 1970s some cosmologists suggested
that by denying that assumption, one might be able to craft an Oscillating Model
of the universe and thus avert the absolute beginning predicted by the Standard
Model. If the internal gravitational pull of the mass of the universe were able to
overcome the force of its expansion, then the expansion could be reversed into a
cosmic contraction, a Big Crunch. If the matter of the universe were not evenly
distributed, then the collapsing universe might not coalesce at a point, but quantities
of matter might pass by one another, so that the universe would appear to
bounce back from the contraction into a new expansion phase. If this process
could be repeated indefinitely, then an absolute beginning of the universe might
be avoided (Fig. 3.4).
Radius of the universe
Time
Fig. 3.4: Oscillating Model. Each expansion phase is preceded and succeeded by a contraction phase,
so that the universe in concertina-like fashion exists beginninglessly and endlessly.
Such a theory is extraordinarily speculative, but again there were metaphysical
motivations for adopting this model. The prospects of the Oscillating Model were
130 De Deo
severely dimmed in 1970, however, by Roger Penrose and Stephen Hawking’s
formulation of the Singularity Theorems which bear their names. The theorems
disclosed that under very generalized conditions an initial cosmological singularity
is inevitable, even for inhomogeneous universes. Reflecting on the impact of this
discovery, Hawking notes that the Hawking-Penrose Singularity Theorems “led
to the abandonment of attempts (mainly by the Russians) to argue that there was
a previous contracting phase and a non-singular bounce into expansion. Instead
almost everyone now believes that the universe, and time itself, had a beginning
at the big bang.”65
Despite the fact that no spacetime trajectory can be extended through a singularity,
the Oscillating Model exhibited a stubborn persistence. Two further strikes
were lodged against it. First, there are no known physics which would cause a collapsing
universe to bounce back to a new expansion. If, in defiance of the Hawking-
Penrose Singularity Theorems, the universe rebounds, this is predicated upon
a physics which is as yet unknown. Second, attempts by observational astronomers
to discover the mass density sufficient to generate the gravitational attraction required
to halt and reverse the expansion continually came up short. In January of
1998 astronomical teams from Princeton, Yale, the Lawrence Berkeley National
Laboratory, and the Harvard-Smithsonian Astrophysics Institute reported at the
American Astronomical Society meeting that their various tests all showed that
“the universe will expand forever.”66 A spokesman for the Harvard-Smithsonian
team stated that they were now at least 95 percent certain that “the density of
matter is insufficient to halt the expansion of the universe.”67
At the same time, observations of the red-shifts of supernovae yielded unexpected
results that have thrown the discussion of the universe’s fate into a wholly
new arena and served to render questions of its density irrelevant. The red-shift
data gathered from the distant supernovae indicate that, far from decelerating,
the cosmic expansion is actually accelerating! There is some sort of mysterious
“dark energy” in the form of either a variable energy field (called “quintessence”)
or, more probably, a positive cosmological constant or vacuum energy which at a
certain point in the evolution of the cosmos kicks the expansion into a higher gear,
causing the expansion to proceed more rapidly. Consequently, even high density
universes may expand forever; a potentially infinite future is no longer the privileged
prerogative of low density universes. Highly accurate recent measurements
of the cosmic microwave background radiation by the Wilkinson Microwave Anisotropy
Probe (WMAP) indicate, “For the theory that fits our data, the Universe
will expand forever.”68
65. Stephen Hawking and Roger Penrose, The Nature of Space and Time, The Isaac Newton Institute
Series of Lectures (Princeton, N. J.: Princeton University Press, 1996), 20.
66. Associated Press News Release, January 9, 1998.
67. Ibid.
68. See http://map.gsfc.nasa.gov/m_mm/mr_limits.html.
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