John Michell proposed already in 1784 that near compact massive objects gravity would increase so strong that even light cannot escape. At that time Newtonian gravity theory and so called corpuscular (particle) theory of light were dominating, and the idea was that if required escape speed would be exceeding speed of light, then light originating inside or from such distance could escape temporarily but would return. Later, in 1958, David Finkelstein using General Relativity introduced a more strict definition of local black hole event horizon as a boundary beyond which events of any kind cannot affect to any outside observer. This strict definition has lead to information and firewall paradoxes, therefore local event horizon and the notion of black hole is widely re-examined, and several theories has been developed, some with and some without event horizons. Stephen Hawking, one of front line developers of black hole theories, has supposed an apparent horizon to be used instead of event horizon, saying “gravitational collapse produces apparent horizons but no event horizons” and ended up to a conlusion that “The absence of event horizons mean that there are no black holes – in the sense of regimes from which light can’t escape to infinity. ” This does not mean denying the existence of black holes, it merely expresses the distrust towards the conventional strict definition of event horizon.
Some astronomers think that the two gas-giants do not sport solid surfaces secreted beneath their immense and heavy gaseous atmospheres, although others suggest that the jumbo-size duo do, indeed, harbor relatively small cores of rocky-icy stuff. The two other large inhabitants of the outer limits of our Sun's family are Uranus and Neptune, which are both classified as ice-giants, because they harbor large icy cores secreted deep down beneath their heavy, dense gaseous atmospheres which, though very massive, are not nearly as heavy as the gaseous envelopes possessed by Jupiter and Saturn. Phases of the Moon. The moon cycles 13 times a year through phases, each of which influence us just like the pull of the tides. It starts with the New Moon, which carries the energy of new beginnings, this is a great time to focus on stepping into something new. Then the Full Moon, Signifies the time of the completion of a project, and finally returns to the New Moon again. This entire cycle occurs over a period of 28 days, and yes, there is no mistaking it, this is the same as women's menstrual cycles, women tend to be much more connected to the moon than men. The astronomers observed this effect in the upper layer of the lunar crust, termed the megaregolith. This layer is heavily pockmarked by relatively small craters, measuring only 30 kilometers or less in diameter. In contrast, the deeper layers of lunar crust, that are scarred by larger craters, appear not to have been as badly battered, and are, therefore, less porous and fractured.