Perseus is a constellation in the northern sky, named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage. ( Full article...)

Mercury is the first planet from the Sun and the smallest in the Solar System. In English, it is named after the ancient Roman god Mercurius ( Mercury), god of commerce and communication, and the messenger of the gods. Mercury is classified as a terrestrial planet, with roughly the same surface gravity as Mars. The surface of Mercury is heavily cratered, as a result of countless impact events that have accumulated over billions of years. Its largest crater, Caloris Planitia, has a diameter of 1,550 km (960 mi) and one-third the diameter of the planet (4,880 km or 3,030 mi). Similarly to the Earth's Moon, Mercury's surface displays an expansive rupes system generated from thrust faults and bright ray systems formed by impact event remnants. ( Full article...)

The rainbow trout (Oncorhynchus mykiss) is a species of trout native to cold-water tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout) is an anadromous (sea-run) form of the coastal rainbow trout (O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead. ( Full article...)

Osbert Guy Stanhope Crawford CBE FBA FSA (28 October 1886 – 28 November 1957) was a British archaeologist who specialised in the archaeology of prehistoric Britain and Sudan. A keen proponent of aerial archaeology, he spent most of his career as the archaeological officer of the Ordnance Survey (OS) and also wrote a range of books on archaeological subjects. ( Full article...)

The Choiseul pigeon (Microgoura meeki) is an extinct species of bird in the pigeon and dove family, Columbidae. It was endemic to the island of Choiseul in the Solomon Islands, although there are unsubstantiated reports that it may once have lived on several nearby islands. The last confirmed sighting was in 1904. Other common names were Solomons crested pigeon, Solomon Islands crowned-pigeon and Kuvojo. ( Full article...)

Over four weeks in 1954, the United States Atomic Energy Commission (AEC) explored the background, actions, and associations of J. Robert Oppenheimer, the American scientist who directed the Los Alamos Laboratory during World War II as part of the Manhattan Project to develop the atomic bomb. The hearing resulted in Oppenheimer's Q clearance being revoked. This marked the end of his formal relationship with the government of the United States and generated considerable controversy regarding whether the treatment of Oppenheimer was fair, or whether it was an expression of anti-communist McCarthyism. ( Full article...)

The painted turtle (Chrysemys picta) is the most widespread native turtle of North America. It lives in relatively slow-moving fresh waters, from southern Canada to northern Mexico, and from the Atlantic to the Pacific. They have been shown to prefer large wetlands with long periods of inundation and emergent vegetation. This species is one of the few that is specially adapted to tolerate freezing temperatures for extended periods of time due to an antifreeze-like substance in their blood that keeps their cells from freezing. This turtle is a member of the genus Chrysemys, which is part of the pond turtle family Emydidae. Fossils show that the painted turtle existed 15 million years ago. Three regionally based subspecies (the eastern, midland, and western) evolved during the last ice age. The southern painted turtle (C. dorsalis) is alternately considered the only other species in Chrysemys, or another subspecies of C. picta. ( Full article...)

The Galápagos tortoise or Galápagos giant tortoise (Chelonoidis niger) is a very large species of tortoise in the genus Chelonoidis (which also contains three smaller species from mainland South America). The species comprises 15 subspecies (13 extant and 2 extinct). It is the largest living species of tortoise, and can weigh up to 417 kg (919 lb). They are also the largest extant terrestrial cold-blooded animals ( ectotherms). ( Full article...)

The Rodrigues night heron (Nycticorax megacephalus) is an extinct species of heron that was endemic to the Mascarene island of Rodrigues in the Indian Ocean. The species was first mentioned as " bitterns" in two accounts from 1691–1693 and 1725–1726, and these were correlated with subfossil remains found and described in the latter part of the 19th century. The bones showed that the bird was a heron, first named Ardea megacephala in 1873, but moved to the night heron genus Nycticorax in 1879 after more remains were described. The specific name megacephala is Greek for "great-headed". Two related extinct species from the other Mascarene islands have also been identified from accounts and remains: the Mauritius night heron and the Réunion night heron. ( Full article...)

The white-breasted nuthatch (Sitta carolinensis) is a species of bird in the nuthatch family Sittidae. It is a medium-sized nuthatch, measuring approximately 15.5 cm (6.1 in) in length. Coloration varies somewhat along the species' range, but the upperparts are light blue-gray, with a black crown and nape in males, while females have a dark gray crown. The underparts are whitish, with a reddish tinge on the lower abdomen. Despite not being closely related, the white-breasted nuthatch and the white wagtail are very similar in plumage. The white-breasted nuthatch is a noisy bird. It has a nasal voice and often utters little cries or vocalizations, often composed of repetitions of small invariant whistles. In summer, it is an exclusively insectivorous bird, consuming a wide range of arthropods, but in winter its diet consists mainly of seeds. The nest is located in the cavity of a tree. The clutch consists of five to nine eggs, incubated for two weeks by the female, who is fed by the male. The two adults then feed the young until they fledge, and for a few weeks after that. ( Full article...)

Boletus aereus, commonly known as the dark cep, bronze bolete, or queen bolete, is a highly prized and much sought-after edible mushroom in the family Boletaceae. The bolete is widely consumed in Spain ( Basque Country and Navarre), France, Italy, Greece, and generally throughout the Mediterranean. Described in 1789 by French mycologist Pierre Bulliard, it is closely related to several other European boletes, including B. reticulatus, B. pinophilus, and the popular B. edulis. Some populations in North Africa have in the past been classified as a separate species, B. mamorensis, but have been shown to be phylogenetically conspecific to B. aereus and this taxon is now regarded as a synonym. ( Full article...)

The echo parakeet (Psittacula eques) is a species of parrot endemic to the Mascarene Islands of Mauritius and formerly Réunion. It is the only living native parrot of the Mascarene Islands; all others have become extinct due to human activity. Two subspecies have been recognised, the extinct Réunion parakeet (for a long time known only from descriptions and illustrations) and the living echo parakeet, sometimes known as the Mauritius parakeet. The relationship between the two populations was historically unclear, but a 2015 DNA study determined them to be subspecies of the same species by comparing the DNA of echo parakeets with a single skin thought to be from a Réunion parakeet, but it has also been suggested they did not constitute different subspecies. As it was named first, the binomial name of the Réunion parakeet is used for the species; the Réunion subspecies thereby became P. eques eques, while the Mauritius subspecies became P. eques echo. Their closest relative was the extinct Newton's parakeet of Rodrigues, and the three are grouped among the subspecies of the rose-ringed parakeet (from which they diverged) of Asia and Africa. ( Full article...)

Emma Louisa Turner or E L Turner FLS, FZS, HMBOU (9 June 1867 – 13 August 1940) was an English ornithologist and pioneering bird photographer. Turner took up photography at age 34, after meeting the wildlife photographer Richard Kearton. She joined the Royal Photographic Society (RPS) in 1901, and by 1904 she had started to give talks illustrated with her own photographic slides; by 1908, when aged 41, she was established as a professional lecturer. ( Full article...)

Baleen whales ( /bəˈliːn/), also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea ( whales, dolphins and porpoises), which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae ( right and bowhead whales), Balaenopteridae ( rorquals), Eschrichtiidae (the gray whale) and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago. ( Full article...)

Banksia sphaerocarpa, commonly known as the fox banksia or round-fruit banksia, is a species of shrub or tree in the plant genus Banksia (family Proteaceae). It is generally encountered as a 1–2 m (3.3–6.6 ft) high shrub, and is usually smaller in the north of its range. This species has narrow green leaves, and brownish, orange or yellow round flower spikes which may be seen from January to July. It is widely distributed across the southwest of Western Australia, growing exclusively in sandy soils. It is usually the dominant plant in scrubland or low woodland. It is pollinated by, and is a food source for, birds, mammals, and insects. ( Full article...)