[Marxism] In Praise of Lumpy Gravy From the Cosmic Kitchen

Louis Proyect lnp3 at panix.com
Tue Nov 26 09:57:00 MST 2019


NY Times, Nov. 26, 2019
In Praise of Lumpy Gravy From the Cosmic Kitchen
By Dennis Overbye

As Thanksgiving approaches, would-be chefs and hosts, including 
apparently my editors, are perfecting their techniques for making the 
all-important gravy for the turkey and potatoes.

I have my moments as a cook — come over for my stardust waffles some 
Sunday morning — but I have never had the patience or skill to master 
gravy, so it usually comes out lumpy. This is a problem at the dinner 
table. On the grandest possible scale, however, lumps are a good thing.

During the Big Bang 14 billion years ago, a fizzy stew of energy and gas 
emerged that became, and still suffuses, the universe. Astronomers 
initially thought this cosmic gravy was perfectly uniform, like 
something Julia Child might have whipped up. But not even Einstein’s 
“Old One” can make a perfect gravy, apparently, and in 1992 astronomers 
discovered that the cosmic gravy is, like mine, lumpy. And that’s a 
reason to be thankful this year, or any year, because without those 
lumps there would be no us.

“If you’re religious, it’s like seeing God,” George Smoot, an astronomer 
at the University of California’s Lawrence Berkeley National Laboratory 
who won a Nobel Prize for the 1992 discovery, said at the time.

That fizzy energy stew of the Big Bang manifests itself today as a bath 
of microwave radiation that fills the sky. In effect, we live amid the 
fading remnant of the primordial fireball; astronomers call it the 
cosmic microwave background.

This cosmic gravy has been the subject of three Nobel Prizes: one to 
Arno Penzias and Robert Wilson, the Bell Labs astronomers who discovered 
the radiation by accident back in 1964; one to Dr. Smoot and his 
collaborator, John Mather, in 2006, and the third to James Peebles of 
Princeton, for his early work on the properties of this fireball.

The discovery of the cosmic microwave background cemented the case for 
the Big Bang origin of the universe. But there was a problem. In every 
direction that radio astronomers looked, the temperature of the cosmic 
gravy was exactly the same: 2.725 degrees Celsius above absolute zero, 
even in places so far apart that, according to a conventional rewinding 
of the expansion of the universe, the regions could not ever have 
touched. It was as if Christopher Columbus had sailed all over the world 
and found that, wherever he went, the local inhabitants spoke perfect 
Italian.

How could this be? Alan Guth, a theoretical physicist at M.I.T., 
proposed an answer in 1980: in its early moments the universe was under 
the sway of an exotic force that caused a brief, violent moment of 
hyper-expansion, called inflation. In that instant, what is now the 
whole observable universe grew from a single submicroscopic point to the 
size of a grapefruit, and then proceeded to expand at the more leisurely 
rate seen today. In the process, any primordial nonuniformities, or 
lumps, were swept forever out of view.

Inflation drastically altered how cosmologists believed the Big Bang 
occurred; Dr. Guth is regularly mentioned as a Nobel candidate.

But in the whack-a-mole world of cosmology, this solution only raised 
another problem. The universe today is quite obviously not uniform — it 
is full of giant lumps called stars and galaxies. How did they arise?

Inflation offered an answer for that too: Whatever force drove inflation 
would have been subjected to the randomness of quantum mechanics, the 
weird rules that govern subatomic physics. The result would be 
submicroscopic irregularities or fluctuations, teeny-tiny lumps of hot 
and cold. Over cosmic time these would grow, as gravity drew them into 
the majestic clouds of stars we call home. The theory, if true, offered 
a stunning unification of the very large and the very small — of the 
random subatomic realm and the galumphing, space-bending world of Einstein.

But a decade of more and more sensitive observations failed to find any 
hot spots or lumps; the cosmic gravy had been very finely stirred, and 
the elegant notion of inflation seemed doomed. Then, in 1992, Dr. Smoot 
reported that data from a satellite experiment called the Cosmic 
Background Explorer, or COBE, revealed a pattern of minuscule 
temperature variations in the gravy, amounting to 500 millionths of a 
degree Celsius, in the range of what inflation had predicted. The gravy 
had lumps after all!

Subsequent experiments with balloons, radio telescopes and space 
missions, such as NASA’s Wilkinson Microwave Anisotropy Project, or 
WMAP, and the European Space Agency’s Planck telescope, have sifted and 
studied those lumps and the surrounding gravy of energy sufficiently to 
sketch a detailed portrait of the infant cosmos roughly 380,000 years 
after the Big Bang.

Using this data, astronomers have been able to come up with a complete 
recipe for how the universe came to be. The so-called Standard Model 
answers all the questions that scientists have traditionally argued 
about: how big and old the universe is, how fast it is expanding, how 
the stars and galaxies evolved and grew, and how the cosmos will 
eventually end.

Lately, however, cracks have developed in this model and some 
astronomers have complained that maybe some ingredients have been left 
out of the recipe. For instance, their increasingly precise measurements 
of the cosmic expansion rate, or Hubble constant, using different 
techniques, don’t quite agree.

Moreover, a trio of astronomers recently suggested that the universe is 
even lumpier and denser than the standard recipe prescribes, based on a 
recent analysis of the Planck data. The cosmic gravy is thicker than was 
thought. This would have a dramatic effect on the shape and fate of the 
cosmos.

According to Einstein’s theory of general relativity, the extra mass in 
the gravy would warp the geometry of the universe. Most cosmologists 
have long preferred, on mathematical grounds, to think of space-time as 
flat, like a sheet of paper, and infinite; added mass instead would make 
it curved, like the surface of a sphere, and finite. If you traveled 
long enough in any direction in an extra-lumpy cosmos, you would 
eventually return to Earth (or to whatever Earth became in the trillions 
of years the journey would take).

But adjusting the cosmic recipe to allow for more density would throw 
everything else seriously out of whack. A handful of cosmologists I 
consulted recently in a quick email seminar weren’t ready to change the 
recipe just yet, even though they all agree that there are mysteries in 
the Planck data. There is still an excellent chance that these new 
results are a statistical fluke.

Indeed, the change would be so radical that Joseph Silk, an 
astrophysicist at Oxford and one of three authors of the paper that 
presented the new analysis, declined to bring it up in October at a 
major cosmology conference in Chicago.

So I asked Dr. Silk directly: How would he account for all the 
“fine-tuned” features, like the extreme flatness and uniformity of the 
universe, that the standard inflation recipe so neatly explains. A good 
cook is always willing to experiment with new tastes and spices, and Dr. 
Silk was unperturbed. “I don’t think it’s any more of a tuning issue 
than the various others being discussed,” he said in an email.

There is an art to making gravy. You’ll make mistakes, and you’ll take 
some lumps, on the stove and in the seminar room. If you can’t stand the 
heat stay out of the cosmic kitchen.



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