A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a streak of light via its rapid motion and sometimes also by shedding glowing material in its wake. Meteors typically occur in the mesosphere at altitudes from 76–100 kilometres (47–62 miles). The root word meteor comes from the Greek μετεωρίτης (meteōrítēs), meaning "high in the air".
Millions of meteors occur in Earth's atmosphere daily. Most meteoroids that cause meteors are about the size of a grain of sand, i.e. they are usually 1 mm (1⁄25 in) or smaller. Meteoroid sizes can be calculated from their mass and density which, in turn, can be estimated from the observed meteor trajectory in the upper atmosphere. Meteors may occur in showers, which arise when Earth passes through a stream of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific stream of space debris. A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the meteoroids producing the meteors have been calculated. The atmospheric velocities of meteors result from the movement of Earth around the Sun at about 30 km/s (67,000 mph; 110,000 km/h), the orbital speeds of meteoroids, and the gravity well of Earth.
Meteors become visible between about 75 to 120 km (47 to 75 mi) above Earth. They usually disintegrate at altitudes of 50 to 95 km (31 to 59 mi). Meteors have roughly a fifty percent chance of a daylight (or near daylight) collision with Earth. Most meteors are, however, observed at night, when darkness allows fainter objects to be recognized. For bodies with a size scale larger than 10 cm (4 in) to several meters meteor visibility is due to the atmospheric ram pressure (not friction) that heats the meteoroid so that it glows and creates a shining trail of gases and melted meteoroid particles. The gases include vaporised meteoroid material and atmospheric gases that heat up when the meteoroid passes through the atmosphere. Most meteors glow for about a second.
Ohio (/oʊˈhaɪ.oʊ/ ⓘ oh-HY-oh) is a state in the Midwestern region of the United States. It borders the Canadian province of Ontario to the north (through Lake Erie), Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the west, and Michigan to the northwest. Of the 50 U.S. states, it is the 34th-largest by area. With a population of nearly 11.9 million, Ohio is the seventh-most populous and tenth-most densely populated state. Its capital and most populous city is Columbus, with other major metropolitan centers including Cleveland and Cincinnati, as well as Dayton, Akron, and Toledo. Ohio is nicknamed the "Buckeye State" after its Ohio buckeye trees, and Ohioans are also known as "Buckeyes".
Ohio derives its name from the Ohio River that forms its southern border, which, in turn, originated from the Seneca word ohiːyo', meaning "good river", "great river", or "large creek". The state was home to several ancient indigenous civilizations, with humans present as early as 10,000 BC. It arose from the lands west of the Appalachian Mountains that were contested by various native tribes and European colonists from the 17th century through the Northwest Indian Wars of the late 18th century. Ohio was partitioned from the Northwest Territory, the first frontier of the new United States, becoming the 17th state admitted to the Union on March 1, 1803, and the first under the Northwest Ordinance. It was the first post-colonial free state admitted to the union and became one of the earliest and most influential industrial powerhouses during the 20th century.
Although Ohio has shifted to a more information and service-based economy in the 21st century, it remains an industrial state, ranking seventh in GDP as of 2019, with the third-largest manufacturing sector and second-largest automobile production. Seven presidents of the United States have come from the state, earning it the moniker "the Mother of Presidents".
Ohio has wide variety of unique animal species. Rare and endangered species include the Eastern Hellbender, which is found in the Southeastern Appalachian region of Ohio and is classified as state endangered. The Eastern Hellbender is the 3rd largest amphibian in the world, and can grow up to 27 inches in length. It is fully aquatic and breathes almost entirely through its skin. Due to this, it is only found in pristine, cool, clear, fast flowing streams and rivers. It is highly threatened by habitat loss, water pollution, and sedimentation due to logging and other human activities.
The hellbender (Cryptobranchus alleganiensis), also known as the hellbender salamander, is a species of aquatic giant salamander endemic to the eastern and central United States. It is the largest salamander in North America. A member of the family Cryptobranchidae, the hellbender is the only extant member of the genus Cryptobranchus. Other closely related salamanders in the same family are in the genus Andrias, which contains the Japanese and Chinese giant salamanders. The hellbender is much larger than any other salamander in its geographic range, and employs an unusual adaption for respiration through cutaneous gas exchange via capillaries found in its lateral skin folds. It fills a particular niche—both as a predator and prey—in its ecosystem, which either it or its ancestors have occupied for around 65 million years. The species is listed as Vulnerable on the IUCN Red List of Threatened Species due to the impacts of disease and widespread habitat loss and degradation throughout much of its range.
Cryptobranchus alleganiensis has a flat body and head, with beady dorsal eyes and slimy skin. Like most salamanders, it has short legs with four toes on the front legs and five on its back limbs, and its tail is keeled for propulsion. Its tail is shaped like a rudder, but it is rarely used for swimming; these salamanders instead use pads on their toes to grip rocks and walk up and down streams instead of swimming. The hellbender has working lungs, but gill slits are often retained, although only immature specimens have true gills; the hellbender absorbs oxygen from the water through capillaries of its side frills. The frills run from their neck down to the base of their tail on each side of their body. The frills' function is to increase the surface area of the hellbender and to help the hellbender breathe. Only occasionally leaving the water, the hellbender makes little use of these lungs and the juveniles lose their external gills after around 18 months or about 125 mm (4.9 in) in length. It is blotchy brown or red-brown in color, with a paler underbelly. Hellbenders can also be described as having a gray, or yellowish-brown, to even black coloration.
Both males and females grow to an adult length of 24 to 40 cm (9.4 to 15.7 in) from snout to vent, with a total length of 30 to 74 cm (12 to 29 in), making them the fourth-largest aquatic salamander species in the world (after the South China giant salamander, the Chinese giant salamander and the Japanese giant salamander, respectively) and the largest amphibian in North America, although this length is rivaled by the reticulated siren of the southeastern United States (although the siren is much leaner in build). While males and females grow at similar rates, the females tend to live longer and therefore grow larger. Adults weigh 1.5 to 2.5 kg (3.3 to 5.5 lb), making them the fifth heaviest living amphibian in the world after their South China, Chinese and Japanese cousins and the goliath frog, while the largest cane toads may also weigh as much as a hellbender. Hellbenders reach sexual maturity at about five years of age, and may live 30 years in captivity.
The hellbender has a few characteristics that make it distinguishable from other native salamanders, including a gigantic, dorsoventrally flattened body with thick folds travelling down the sides, a single open gill slit on each side, and hind feet with five toes each. Easily distinguished from most other endemic salamander species simply by their size, hellbenders average up to 60 cm (2.0 ft) in length; the only species requiring further distinction (due to an overlap in distribution and size range) is the common mudpuppy (Necturus maculosus). This demarcation can be made by noting the presence of external gills in the mudpuppy, which are lacking in the hellbender, as well as the presence of four toes on each hind foot of the mudpuppy (in contrast with the hellbender's five). Furthermore, the average size of C. a. alleganiensis has been reported to be 45–60 cm (18–24 in) (with some reported as reaching up to 74 cm (29 in)), while N. m. maculosus has a reported average size of 28 to 40 cm (11 to 16 in) in length, which means that hellbender adults will still generally be notably larger than even the biggest mudpuppies.
Members of the Pennsylvania State Senate have voted to approve the eastern hellbender as the official state amphibian in an effort to raise awareness about its endangered status. The legislation has been mired in controversy due to a dispute by House members who argue that Wehrle's salamander should be given the honor. The legislation did not pass in 2018, but was reintroduced in 2019. On April 23, 2019, Pennsylvania Governor Tom Wolf signed legislation making the eastern hellbender Pennsylvania's official state amphibian. Youth members of the Chesapeake Bay Foundation's Pennsylvania Student Leadership Council were heavily involved writing and advocating on behalf of this legislation. They hope that the success of the hellbender bill in the Pennsylvania Senate will contribute to clean water efforts and raise awareness for the hellbender's struggling population.
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