In wireless telecommunications , multipath is the propagation phenomenon that results in radio signals reaching the receiving antenna by two or more paths. Causes of multipath include atmospheric ducting , ionospheric reflection and refraction , and reflection from water bodies and terrestrial objects such as mountains and buildings. The effects of multipath include constructive and destructive interference , and phase shifting of the signal.
The Voyager Golden Record Cover of the Voyager Golden Record The Voyager Golden Records are phonograph records which were included aboard both Voyager spacecraft , which were launched in 1977. They contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them. The Voyager spacecrafts are not heading towards any particular star, but Voyager 1 will be within 1.6 light years of the star Gliese 445 , currently in the constellation Camelopardalis , in about 40,000 years . [ 1 ]
Newcomb's paradox , also referred to as Newcomb's problem , is a thought experiment involving a game between two players, one of whom purports to be able to predict the future. Whether the problem is actually a paradox is disputed. Newcomb's paradox was created by William Newcomb of the University of California 's Lawrence Livermore Laboratory .
Eggs and Their Evolution F emales of all vertebrates produce eggs, but the reptiles "invented" the eggshell -- a device that could keep the egg from drying out and allow reproduction away from water (or, at least, from extremely moist environments). With the exception of the platypus and echidna, mammals provide the developing embryo with a suitable environment within the mother's womb.
Transhumanism , abbreviated as H+ or h+ , is an international intellectual and cultural movement that affirms the possibility and desirability of fundamentally transforming the human condition by developing and making widely available technologies to greatly enhance human intellectual, physical, and psychological capacities. [ 1 ] Transhumanist thinkers study the potential benefits and dangers of emerging technologies that could overcome fundamental human limitations, as well as study the ethical matters involved in developing and using such technologies. They predict that human beings may eventually be able to transform themselves into beings with such greatly expanded abilities as to merit the label " posthuman ". [ 1 ]
Cloud iridescence Cloud iridescence is the occurrence of colors in a cloud similar to those seen in oil films on puddles, and is similar to irisation . It is a fairly uncommon phenomenon, most often observed in altocumulus , [ 1 ] cirrocumulus and lenticular clouds , and very rarely in cirrus clouds . [ 2 ] [ 3 ] [ 4 ] The colors are usually pastel, but can be very vivid.
Moravec's paradox is the discovery by artificial intelligence and robotics researchers that, contrary to traditional assumptions, high-level reasoning requires very little computation, but low-level sensorimotor skills require enormous computational resources. The principle was articulated by Hans Moravec , Rodney Brooks , Marvin Minsky and others in the 1980s. As Moravec writes, "it is comparatively easy to make computers exhibit adult level performance on intelligence tests or playing checkers, and difficult or impossible to give them the skills of a one-year-old when it comes to perception and mobility." Linguist and cognitive scientist Steven Pinker considers this the most significant discovery uncovered by AI researchers.
This video illustrates changes in the shape and intensity of the Van Allen belts. Van Allen radiation belts A Van Allen radiation belt is one of three [ 1 ] layers of energetic charged particles ( plasma ) around the planet Earth, held in place by its magnetic field . The belts extend from an altitude of about 1,000 to 60,000 kilometres above the surface, in which region radiation levels vary. It is thought that most of the particles that form the belts come from solar wind , and other particles by cosmic rays . [ 2 ] It is named after its discoverer, James Van Allen , and is located in the inner region of the Earth's magnetosphere .
Animation of Schumann resonance in Earth's atmosphere. The Schumann resonances (SR) are a set of spectrum peaks in the extremely low frequency (ELF) portion of the Earth 's electromagnetic field spectrum. Schumann resonances are global electromagnetic resonances , excited by lightning discharges in the cavity formed by the Earth's surface and the ionosphere . [ edit ] Description This global electromagnetic resonance phenomenon is named after physicist Winfried Otto Schumann who predicted it mathematically in 1952. Schumann resonances occur because the space between the surface of the Earth and the conductive ionosphere acts as a closed waveguide .
Locations of South Magnetic Pole from direct observation and model prediction. [ 1 ] The South Magnetic Pole is the wandering point on the Earth 's Southern Hemisphere where the geomagnetic field lines are directed vertically upwards. It should not be confused with the lesser known South Geomagnetic Pole described later. For historical reasons, the "end" of a magnet that points (roughly) north is itself called the "north pole" of the magnet, and the other end, pointing south, is called magnet's "south pole". Because opposite poles attract, the Earth's South Magnetic Pole is physically actually a magnetic north pole (see also North Magnetic Pole – Polarity ).
The Naga fireballs ( Thai : บั้งไฟพญานาค ; RTGS : bang fai phaya nak), also known to as Mekong lights , and “bung fai paya nak” by the locals, is a unconfirmed phenomenon often seen in Thailand ’s Mekong river, which is also seen in ( Nong Khai province in Isan ) and in Laos ( Vientiane Province )—in which glowing balls are said to naturally rise from the water high into the air. [ 1 ] The balls are reddish and have diverse size from smaller sparkles up to the size of basketballs; [ 2 ] they quickly rise up to a couple of hundred metres before disappearing. The number of fireballs reported varies between tens and thousands per night. [ 3 ] Objective observers who have witnessed this phenomenon report tracer bullets as probable cause. [ edit ] Timing
By Howard Gardner 1. Naturalist Intelligence (“Nature Smart”) Designates the human ability to discriminate among living things (plants, animals) as well as sensitivity to other features of the natural world (clouds, rock configurations). This ability was clearly of value in our evolutionary past as hunters, gatherers, and farmers; it continues to be central in such roles as botanist or chef.
Genie is the pseudonym of a feral child who was the victim of one of the most severe cases of abuse and neglect ever documented. She spent most of her first thirteen years of life locked inside a bedroom, strapped to a child's toilet or bound inside a crib with her arms and legs immobilized. Genie's abuse came to the attention of Los Angeles child welfare authorities on November 4, 1970. [ 2 ] [ 3 ] In the first several years after Genie's life and circumstances came to light, psychologists , linguists and other scientists focused a great deal of attention on Genie's case, seeing in her near-total social isolation an opportunity to study acquisition of language skills and linguistic development.
Victor of Aveyron (also The Wild Boy of Aveyron ) was a feral child who apparently lived a majority of his childhood naked and alone in the woods before being found wandering the woods near Saint-Sernin-sur-Rance , France, in 1797. He was captured, but soon escaped after being displayed in the town. He was additionally periodically spotted in 1798 and 1799. However, on January 8, 1800, he emerged from the forests on his own. His age was unknown, but citizens of the village estimated he was about twelve years old. His lack of speech, as well as his food preferences and the numerous scars on his body, indicated he had been in the wild for the majority of his life.