- published: 20 Jan 2015
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In physics, mass is a property of a physical body. It is generally a measure of an object's resistance to changing its state of motion when a force is applied. It is determined by the strength of its mutual gravitational attraction to other bodies, its resistance to being accelerated by a force, and in the theory of relativity gives the mass–energy content of a system. The SI unit of mass is the kilogram (kg).
Mass is not the same as weight, even though we often calculate an object's mass by measuring its weight with a spring scale instead of comparing it to known masses. An object on the Moon would weigh less than it would on Earth because of the lower gravity, but it would still have the same mass.
For everyday objects and energies well-described by Newtonian physics, mass describes the amount of matter in an object. However, at very high speeds or for subatomic particles, special relativity shows that energy is an additional source of mass. Thus, any stationary body having mass has an equivalent amount of energy, and all forms of energy resist acceleration by a force and have gravitational attraction.
A short teaser of The Freetown 50, a challenging but not impossible mountain bike race held in Freetown, MA in September. This race features 50, 25, and 11 mile races in Freetown-Fall River State Forest, The Watuppa Reservation, and Copicut Woods which are all part of the Southeastern Massachusetts BioReserve. This rare course mixture of fire roads, tight single-track, rock gardens, and fast double-track. This type of course does not favor any particular type of rider, but it's supposed to be hard. http://www.freetown50.com/
Everett Castro of Green Futures, along with Roger Garant, led a group of nine hikers on October 13, 2012 along Copicut Road in the Southeastern Massachusetts Bioreserve and then around the Copicut Reservoir. The hikers left from one of the many fishermen's parking areas along Copicut Road and hike the roughly five miles around the Reservoir. "The area around the Reservoir is normally closed to hikers," noted Castro, "but we got special permission for the walk from the Water Authority." The Reservoir was constructed in the early 1970s by damming the Copicut River to provide an additional water supply for the City of Fall River as well as Freetown, Westport and Tiverton. It has been open to fishing from the shore since 2009. Much of the Reservoir can be seen by walking along Copicut Road. Fo...
The Maya Biosphere Reserve is a nature reserve in Guatemala managed by Guatemala's National Council of Protected Areas (CONAP). The Maya Biosphere Reserve covers a total area of 21,602 km², which is considerably larger than Yellowstone National Park. The park is home to a large number of species of fauna including the Jaguar, the Puma, the Ocelot, the Margay, spider monkeys, howler monkeys, tapirs, crocodiles, the Red Brocket and the White-tail deers, the Harpy Eagle, several hawk species, the Scarlet Macaw, fresh water turtles, etc. It is also rich in flora including mahogany, Ceiba, cedar, etc. The area ranges from wetlands, to low mountain ranges, and has several bodies of water, including lakes, rivers, streams and cenotes. The Reserve was created in 1990 to protect the largest area of...
A floating paradised Loktak Lake covered with floating Phumdis. Phumdis are a series of floating islands, exclusive to the Loktak Lake in Manipur state, in northeastern India. They cover a substantial part of the lake area and are heterogeneous masses of vegetation, soil and organic matter, in different stages of decay. The largest single mass of phumdi is in the southeastern part of the lake, covering an area of 40 km2 (15.4 sq mi). This mass constitutes the world's largest floating park, named Keibul Lamjao National Park. The park was formed to preserve the endangered Eld's Deer subspecies, called Sangai in the Manipuri language, indigenous to this area. Phumdis are used by the local people for constructing their huts for fishing and other livelihood uses, and are inhabited by about 40...
au nord du pays, se trouvent ses deux monastères tous deux situés dans un environnement bucolique, Haghbat fut le premier monument classé par l'Unesco "Patrimoine de l'Humanité", Sanahin a suivi, ce sont deux beaux exemples d'art religieux médiéval.
Ecuador's Yasuni National Park, a UNESCO world biosphere reserve, is also home to some 846 million barrels of untapped crude. To avoid drilling in the fragile region, President Rafael Correa is asking the international community to pay his country half of the amount they estimate the country would have earned on the oil, some 3.6 billion dollars. With one of the world's most biodiverse places at stake, the project's supporters insist the sum represents a worthwhile investment in the global environmental future. Duration: 02:03
Thousands of miles of ocean separate the islands that shape the Polynesian Triangle — anchored by New Zealand (Aotearoa) in the west, Easter Island (Rapa Nui) to the southeast, and Hawaii to the north. In April 2013, representatives from Easter Island and French Polynesia traveled to New Zealand to celebrate their cultural ties and mutual desire for ocean conservation. Along their journey across Aotearoa's North Island, they met with Maori leaders, scientists, government officials, tour operators and conservationists. They discussed the challenges toward creating marine reserves and protected areas, as well as the benefits that can follow. Global Ocean Legacy is a project of The Pew Charitable Trusts and its partners. Target link: www.pewenvironment.org/globaloceanlegacy
Mexico's dissident teachers' movement held a one-day national strike and took to the streets in mass protests yesterday against the government's educational reform. The teachers charge that the reform will erode labor rights and promote an educational model geared to satisfying corporate and business interests. In the face of threats by top government officials to fire teachers participating in the protests, the turnout was lower than expected. Clayton Conn reports from Mexico City. teleSUR http://multimedia.telesurtv.net/v/mexico-dissident-teachers-hold-strike/
The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel. The peninsula lies east of the Isthmus of Tehuantepec, a northwestern geographic partition separating the region of Central America from the rest of North America. The peninsula comprises the Mexican states of Yucatán, Campeche, and Quintana Roo; the northern part of the nation of Belize; and Guatemala's northern department of El Petén. The peninsula is the exposed portion of the larger Yucatán Platform, all of which is composed of carbonate and soluble rocks, being mostly limestone although dolomite and evaporites are also present at various depths. The whole of the Yucatán peninsula is an unconfined flat lying karst landscape. Sinkholes...