|
Nanotube loudspeakers
Researchers from Tsinghua University
and
Beijing
Normal
University
have demonstrated a radically
simpler loudspeaker design based
on nanotubes
Shocking start for the solar
system
In the 1970s, the hypothesis
arose that our solar system was
formed by a passing shock wave
from a supernova, which
triggered the collapse of an
interstellar cloud into a dense
region of gas and dust that
further contracted to become the
Sun and its orbiting planets.
Signs of Dark Matter?
Two groups of cosmic-ray
observers have reported
unexpectedly large fluxes of
high-energy electrons and
positrons. Those excesses
suggest either that there are
undiscovered astrophysical
sources such as radio-quiet
pulsars surprisingly nearby or
that the positrons and electrons
are annihilation products of
WIMPs-weakly interacting
dark-matter particles hundreds
of times more massive than the
proton.
Vortices spontaneously arise as
a Bose-Einstein condensate forms
In an emptying bathtub, water
forms a whirlpool around the
drain. But circular flow can't
persist to the very center of
the vortex; there must be a
water-free funnel. In 1985
Wojciech Zurek, following on
work of Tom Kibble, suggested
that "topological defects"
analogous to the whirlpool could
be generated spontaneously in a
system undergoing a second-order
phase transition.
|
