Centered in the middle of the nebula is a pulsar, or the rapidly-spinning, extremely dense remnant of an exploded star.

Does your feature request involve difficulty completing a task? Please describe. I set the home folder in KOReader on my Mac to my Calibre Library. I then found that half of the library is full of the ...

This quantum radar could image buried objects Physicists are exploring a quantum-mechanical approach to making smaller radio wave detectors.