Parallel Worlds by Michio Kaku

any
matter; in fact, it consisted only of energy contained in the vacuum, the
cosmological constant. This pure antigravity force was sufficient to drive a
rapid, exponential expansion of the universe. Even without matter, this dark
energy could create an expanding universe.
    Physicists were
now faced with a dilemma. Einstein's universe had matter, but no motion. De Sitter's
universe had motion, but no matter. In Einstein's universe, the cosmological
constant was necessary to neutralize the attraction of gravity and create a
static universe. In de Sitter's universe, the cosmological constant alone was
sufficient to create an expanding universe.
    Finally, in
1919, when Europe was trying to dig its way out of the rubble and carnage of
World War I, teams of astronomers were sent around the world to test Einstein's
new theory. Einstein had earlier proposed that the curvature of space-time by
the Sun would be suf-
    In
1919, two groups confirmed Einstein's prediction that light from a distant star
would bend when passing by the Sun. Thus, the position of the star would appear
to move from its normal position in the presence of the Sun. This is because
the Sun has warped the space-time surrounding it. Thus, gravity does not
"pull." Rather, space "pushes." ficient to bend starlight that is
passing in its vicinity. Starlight should bend around the Sun in a precise,
calculable way, similar to the way glass bends light. But since the brilliance
of Sun's light masks any stars during the day, scientists would have to wait
for an eclipse of the Sun to make the decisive experiment.
    A group led by
British astrophysicist Arthur Eddington sailed to the island of Principe in the
Gulf of Guinea off the coast of West Africa to record the bending of starlight
around the Sun during the next solar eclipse. Another team, led by Andrew
Crommelin, set sail to Sobral in northern Brazil. The data they gathered
indicated an average deviation of starlight to be 1.79 arc seconds, which
confirmed Einstein's prediction of 1.74 arc seconds (to within experimental error).
In other words, light did bend near the Sun. Eddington later claimed that
verifying Einstein's theory was the greatest moment in his life.
    On November 6,
1919, at a joint meeting of the Royal Society and the Royal Astronomical
Society in London, Nobel laureate and Royal Society president J. J. Thompson
said solemnly that this was "one of the greatest achievements in the
history of human thought. It is not the discovery of an outlying island but of
a whole continent of new scientific ideas. It is the greatest discovery in
connection with gravitation since Newton enunciated his principles."
    (According to
legend, Eddington was later asked by a reporter, "There's a rumor that
only three people in the entire world understand Einstein's theory. You must
be one of them." Eddington stood in silence, so the reporter said,
"Don't be modest, Eddington." Eddington shrugged, and said, "Not
at all. I was wondering who the third might be.")
    The next day,
the London Times splashed the
headline: "Revolution in Science—New Theory of the Universe—Newton's Ideas
Overthrown." The headline marked the moment when Einstein became a
world-renowned figure, a messenger from the stars.
    So great was
this announcement, and so radical was Einstein's departure from Newton, that it
also caused a backlash, as distinguished physicists and astronomers denounced
the theory. At Columbia University, Charles Lane Poor, a professor of celestial
mechanics, led the criticism of relativity, saying, "I feel as if I had
been wandering with Alice in Wonderland and had tea with the Mad Hatter."
    The reason that
relativity violates our common sense is not that relativity is wrong, but that
our common sense does not represent reality. We are the oddballs of the universe. We inhabit an unusual piece of real estate,
where temperatures, densities, and velocities are quite mild. However, in the "real
universe," temperatures can be