The first ghost imaging experiment was demonstrated in 1995 at UMBC by taking advantage of the nonlocal behavior of an entangled photon pair.  10 years later, in 2005, based on the quantum theory of light, we found that the nonlocal interference of a random pair of photons of thermal light, such as that of the sunlight, is also able to produce ghost image.  Recently, inspired by ghost imaging, we discovered and developed a new type of camera that produces image of a target object from the quantum noises scattered from the object, namely a 'ghost' camera.  This ghost camera has the following advantages over the classical imaging technology: (1) the image of the ghost camera is insensitive to any atmospheric turbulence; (2) the imaging resolution of the ghost camera is mainly determined by the angular diameter of the light source.  These properties are particularly attractive for sunlight long distance imaging, such as satellite imaging: the angular diameter of the sun is ~0.53 degree, providing in principle a turbulence-free resolution of 200um for any object on earth at any distance without the need of huge lenses. How does a random pair of photons produce such turbulence-free image with nonclassical imaging resolution? Where does the quantum noise come from? How does quantum noise cause a point-to-point spatial correlation at distance? This talk will address these fundamentally interesting and practically useful physics.