  The new millennium will see the upcoming of several ground-based
interferometric gravitational wave antennas. Within the next decade a
space-based antenna may also begin to observe the distant Universe. These
gravitational wave detectors will together operate as a network taking data
continuously for several years, watching the transient and continuous phenomena
occurring in the deep cores of astronomical objects and dense environs of the
early Universe where gravity was extremely strong and highly non-linear. The
network will listen to the waves from rapidly spinning non-axisymmetric neutron
stars, normal modes of black holes, binary black hole inspiral and merger,
phase transitions in the early Universe, quantum fluctuations resulting in a
characteristic background in the early Universe. The gravitational wave
antennas will open a new window to observe the dark Universe unreachable via
other channels of astronomical observations.
