My Blog List


Alifye Meaning A to Z Full Online Encyclopedia of Knowledge, Entertainment, Articles, Essay Writing, Science, Economy, Islamic Study, History, Education, World Knowledge, Sports, News, Literature, Personality, Question Answer, Asia, Europe, Middle East, America, Africa, World Sea,

Friday, 20 April 2018


Sound is produced by the vibrations of an object or mechanism and transmitted in the form of waves—alternating increase and decrease in pressures. It radiates outward through a material medium of molecules, more or less like the ripples spreading out on water after some he7vy object has been thrown into it. The frequency of sound is determined by the number of times the vibrating waves undulate per second. The Slower the cycle, the lower the pitch.
Alifye - Theory of Space - Sound

Ultra Sonics

The human ear cannot generally hear sounds frequencies higher than 20,000 vibrations per second or 20,000 1-1Z., Sounds of frequencies higher than 20.000 HZ which are inaudible are called ultra – sonic. Bats produce very high sound when they fly they are at ultra – sonic frequencies from 20 000 to 100.000 cannot hear them.

Speed of Sound

The speed of sound varies according to the nature of the carrier media. The speed of sound is around 1088 feet per second. In water, sound travels about 5 times faster than in air. In iron and steel, it is even faster, about 3 times faster than the speed in water.

Speed of sound through some media is:
Ice — cold water        4938 ft per second
Brick                          11960 ft per second
Granite                      1296 ft. per second
Hardwood                 12620 ft. per second
Glass                         16410 to 19690 ft per second

Super - Sonic

Super — sonic speed is greater than the speed of sound i.e 760 miles per hour. This is a unit, worked out by Ernst Mach and therefore named after him. Mach is the ratio of the speed of flight to the speed of sound under the same conditions of pressure and density. When a plane moves at the speed of sound, it is Mach I. When a plane move at twice the speed of sound (supersonic), it is Mach2. When it is less than the speed of sound it is sub — sonic and therefore lesser than Mach I. At half the speed of sound it is Mach '/2.

Sound Barrier

It is the point at which the speed of the flight equals the speed of sound. When a plane flies faster than sound. it is said to cross the sound barrier.

Sonic Booms

When a plane passes the sound barrier, speed produces shock waves in the atmosphere which produce booms like thunder clips. These are called sonic booms. They trouble the ears of the people of the areas over which the aircraft is flying at supersonic speed. But these do not trouble the passengers inside the aircraft because it is flying faster than the shock waves learning them behind.


The loudness of the. sound. reflects the pressure of the sound waves. This pressure is expressed in decibels. A decibel may be regarded as the smallest difference between sounds detectable by the human ear. Th. e human ear can safely respond to pressures up to 120 decibels. Any intensity higher than this is painful, and can conceivably damage the delicate nerves of the ear.

Friday, 13 April 2018


Alifye - Satellites - Space & Astronomy

Artificial Satellite

It is a man-made object orbiting a planet or the Su the Earth's first artificial satellite, Sputnik 1. was. launched by the USSR on Oct. 4, 1957. The first U.S satellite was Explorer I launched on January 31, 1958. Artificial satellites have also been launched to move round the Moon, Mars, Venus and the Sun.

Communications Satellite  

It is a satellite that relays E.Mail, Fa,x, Internet. telephone, telex and T.V. transmission between ground stations on Earth. The first active communications satellite was Telstar launched in 1962. These satellites eliminate the need for expensive cables or chains of radio relay stations. These are more flexible than long distance can ventional communication links because a satellite can link any two points on Earth that are visible from the satellite. Each communications satellite or comsat) is placed in orbit above Earth's equator at the height of 35680 km. and takes 24 hours to circle the Earth - the same time as is taken by the Earth to spin round its own axis once. Therefore in relation to the Earth it seems stationary and is called synchronous orbit orgeostationary, They receive transmission from ground stations, amplify them and rebroadcast them back to Earth.

Cosmos Satellites

These are a series of Russian unmanned Earth satellite. which were successors to the sputniks. used for scientific tests. The first was launched on March 16, 1962. 

Discoverer Satellites

These were an early series of U.S satellites, launched between 1959 and 1962. These showed that manned spacecraft could safely return from orbit. These satellites were also used to test a prototype of modern rnilitam `spysatellites', which eject capsules containing film for recovery on Earth.


Ecliptic is the Earth's path round the Sun. On the celestial sphere. the Sun appears to move along the ecliptic during the year, this is the effect of the Earth moving in orbit round the Sun. 

Escape Velocity

Escape Velocity is the speed that an object like rocket. must reach to escape permanently from the body of a planet. The escape velocity from the surface of the Earth is nearly 11 km., per second or 40.000 km, per hour.

Explorer Satellites

Explorer Satellites A series of U.S scientific satellites designed to study the Earth, its surroundings in space, and astronomical objects such as the Sun and Stars. The first Explorer was launched on January 31, 1958.


Satellites Natural satellites, also termed moons, are small planets which revolve round the larger once. In the solar system, moons orbit six of the nine known planets.


Skylab was a U.S space station in which astronauts set up duration records for living and working in space. The skylab space station was launched in May 1973. Three separate three — men crews boarded the station for periods of up to three months each; fell back to Earth near Australia about two years back. 


Weightlessness is the condition encountered in space in which the ,astronaut, his craft. and object inside it seem to hang without weight. The term Zero gravity is incorrect because the craft is still within the gravitational pull of the Earth and Sun,


Zodiac is a band of 12 constellations through which the Sun passes Zodiac do not coincide \Nri th the constellations named after the each .ear- These signs of Zodiac used by the astrologers. 


Pulsars are fast rotating neutron stars. They send out radio Pulsars - gaff frequency, at the remarkably short radio period of 0.033 Waves in re second. 


Quasars or Quasi Stellar Radio sources are part star and part radio objects. They combine the characteristics of stars and radio galaxies. Many of the Quasars are radio quiet. These are compact blue objects that emitted radiation strongly in the ultra – violet as well as the radio portion of the spectrum. They exhibit many peculiarities like fluctuating brightness and large red shifts. Quasars are small objects compared to galaxies but all of them emit radiation for in excess of their size or brightness. Some are believed to emit energy which is greater than the combined energy emitted by a hundred galaxies like the Milky way. They fluctuate in brightness at intervals. Since they emit enormous energy, their life times are son. Many of them die out in less than a billion years. All of them are removed from Earth by distances of billions of light years.

Contact Form


Email *

Message *