If the ocean floor is rocky, the loud pulses fi red by seismic air guns — to generate waves that can be used to image the ocean floor — can travel immense distances. (scientificamerican.com)
Exploding stars seen across immense distances show that the cosmic expansion may be accelerating — a sign that the universe may be driven apart by an exotic new form of energy (scientificamerican.com)
Loeb and his co-author Manasvi Lingam (Harvard University) examined the feasibility of creating a radio transmitter strong enough for it to be detectable across such immense distances. (sciencedaily.com)