A black hole is a region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe.
"Ganymede's ocean might be organized like a Dagwood sandwich," commented Dr. Steve Vance in a May 1, 2014 statement. Dr. Vance, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, went on to explain the weird moon's resemblance to the Blondie cartoon character's famous multi-layered sandwiches. The study, headed by Dr. Vance, provides new theoretical indications for the team's "club sandwich" model, originally proposed in 2013. The research appears in the journal Planetary and Space Science. So here you have two definitions of a blue moon but the one for a calendar blue moon does not describe the true meaning of a blue moon. Here's why: Earth's Moon is the largest and brightest object suspended in the darkness of the starry night sky. It is both lovely and enchanting, and it has, since ancient times, inspired curiosity and wonder in human beings who gaze up at the mysterious sky after the Sun has set. As such, Earth's Moon has long served as the inspiration for imaginative, wild and marvelous tales--it is the stuff of mythology and folklore. The "Man in the Moon" refers to several fantastic images of a human face that certain traditions see outlined in the gleaming disk of the full Moon. In November 2013, astronomers using data from the lunar-orbiting twins composing NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, announced that they have been acquiring new and fascinating insight into how this bewitching "face," etched on our Moon's disk, received its captivating and enchanting good looks!