Cosmologists say a wide range of
evidence is forcing them to consider the possibility that an unknown "dark
energy" exists that is causing the expansion of the universe to accelerate.
"The universe is made mostly of dark matter and dark energy," says the Lab's
Saul Perlmutter, "and we don't know what either of them is." The concept
of dark energy is expanded upon in a May 28 Science article titled, "The Cosmic Triangle: Revealing
the State of the Universe."
Stopping an underground leak can be
costly and difficult. One emerging approach is to inject fluids into the ground that
gel and form a barrier. Unfortunately, controlling the flow of these fluids has been a
problem. Now, researchers are experimenting with ferrofluids that respond to a magnetic
field. Ferrofluid barriers could be steered into place by magnets, sealing
leaking waste tanks, pipes, or landfills with minimum environmental disturbance.