String theorists had looked at the idea of confining all forces
to a brane and having gravity leak, but they had not worked out
the mechanism, says physicist Joseph Lykken of Fermilab in
Batavia, Ill. Randall and Sundrum, he remarks, "changed people's
thinking about this stuff entirely." As Randall and Sundrum
refined their idea, they realized that if the extra dimension of
spacetime were warped in anti-De Sitter fashion, it could be
infinitely large and what we observe about gravity could still
be true. This model came to be known as RS-2. "Working that out
was mind-blowing," Sundrum recalls. "We had reason to be dead
scared. In each of these cases, there was a distinct fear of
making complete fools of ourselves." "It was counterintuitive,"
notes theorist Michael J. Duff of Imperial College London. "It
came as a surprise even to those working in extra dimensions
that even though the extra dimension is very large, we wouldn't
be aware of it. Newton's law would still be an inverse square
law, not an inverse cu