"Dark Objects" Some objects emit electromagnetic radiation over the entire spectrum, from radio waves to X-rays. Solar flare loops, quasars and, the most amazing are, B. C. Larcertae Objects which display an extremely flat spectrum. This is not just broad band syncrotron radiation. Ball lightning and similar ring like objects have also been reported to emit a pure white light (but not in every case, it might be added). If this weren't strange enough the same types of objects seem to have a "dark" phase. Dark ball lightning and dark solar flare loops have been observed. Here is a thread related to a "dark ring" object. https://www.physicsforums.com/showthread.php?s=&threadid=3748 Dark quasars or B. C. Lacertae objects would be very hard to observe so we can't say that they occur. What mechanism would allow such an object to absorb light over nearly the entire spectrum? Bet there's some ineresting new physics here!