-------------------------------------^ Techs N Science ^ ----------------------------------

Friday, May 18, 2012

Samsung reveals samsung galaxy s 3

Wednesday, February 29, 2012

Solar Systm

Here we go-

The Solar System^[a] consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass (well over 99%) is in the Sun. Of the many objects that orbit the Sun, most of themass is contained within eight relatively solitary planets^[e] whose orbits are almost circular and lie within a nearly flat disc called the ecliptic plane. The four smaller inner planets, Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and metal. The four outer planets, the gas giants, are substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are composed largely of ices, such as water, ammonia and methane, and are often referred to separately as "ice giants".

The Solar System is also home to a number of regions populated by smaller objects. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc; linked populations of trans-Neptunian objectscomposed mostly of ices such as water, ammonia and methane. Within these populations, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, are recognized to be large enough to have been rounded by their own gravity, and are thus termed dwarf planets.^[e] In addition to thousands of small bodies^[e] in those two regions, various other small body populations, such as comets, centaurs and interplanetary dust, freely travel between regions. Six of the planets and three of the dwarf planets are orbited by natural satellites,^[b] usually termed "moons" after Earth'sMoon. Each of the outer planets is encircled by planetary rings of dust and other particles.

The solar wind, a flow of plasma from the Sun, creates a bubble in the interstellar medium known as the heliosphere, which extends out to the edge of the scattered disc. The hypothetical Oort cloud, which acts as the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of interstellar wind. The Solar System is located within one of the outer arms of Milky Way galaxy, which contains about 200 billion .

Thursday, February 23, 2012

Super Nova

Here we go-

A supernova (abbreviated SN, plural SNe after supernovae) is a stellar explosion that is more energetic than a nova. Supernovae are extremely luminousand cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this short interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span.^[1] The explosion expels much or all of a star's material^[2] at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave^[3] into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called asupernova remnant.Nova (plural novae) means "new" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super-" distinguishes supernovae from ordinary novae, which also involve a star increasing in brightness, though to a lesser extent and through a different mechanism. The word supernova was coined by Swiss astrophysicist and astronomer Fritz Zwicky,^[4]^[5] and was first used in print in 1926.^[6] Several types of supernovae exist. Types I and II can be triggered in one of two ways, either turning off or suddenly turning on the production of energy through nuclear fusion. After the core of an aging massive star ceases generating energy from nuclear fusion, it may undergo sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential energy that heats and expels the star's outer layers. Alternatively a white dwarf star may accumulate sufficient material from a stellar companion (either through accretion or via a merger) to raise its core temperature enough to ignite carbon fusion, at which point it undergoes runaway nuclear fusion, completely disrupting it. Stellar cores whose furnaces have permanently gone out collapse when their masses exceed the Chandrasekhar limit, while accreting white dwarfs ignite as they approach this limit (roughly 1.38^[7] times thesolar mass). White dwarfs are also subject to a different, much smaller type of thermonuclear explosion fueled by hydrogen on their surfaces called a nova. Solitary stars with a mass below approximately 9 solar masses, such as the Sun, evolve into white dwarfs without ever becoming supernovae.

Although no supernova has been observed in the Milky Way since 1604, supernovae remnants indicate on average the event occurs about once every 50 years in the Milky Way.^[8] They play a significant role in enriching the interstellar medium with higher mass elements.^[9] Furthermore, the expanding shock waves from supernova explosions can trigger the formation of new stars.^[10]^[11]^[12]

Sunday, February 19, 2012

SUN

lets see-

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven withmagnetic fields.^[10]^[11] It has a diameter of about 1,392,000 km, about 109 times that of Earth, and its mass (about 2×10³⁰kilograms, 330,000 times that of Earth) accounts for about 99.86% of the total mass of the Solar System.^[12] Chemically, about three quarters of the Sun's mass consists of hydrogen, while the rest is mostly helium. The remainder (1.69%, which nonetheless equals 5,628 times the mass of Earth) consists of heavier elements, including oxygen, carbon, neon, iron, and others.^[13]

The Sun's stellar classification, based on spectral class, is G2V, and is informally designated as a yellow dwarf, because its visible radiation is most intense in the yellow-green portion of the spectrum and although its color is white, from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light.^[14]^[15] In the spectral class label, G2 indicates its surface temperature of approximately 5778 K (5505 °C), and V indicates that the Sun, like most stars, is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 620 million metric tons of hydrogen each second. Once regarded by astronomers as a small and relatively insignificant star, the Sun is now thought to be brighter than about 85% of the stars in the Milky Way galaxy, most of which are red dwarfs.^[16]^[17] The absolute magnitude of the Sun is +4.83; however, as the star closest to Earth, the Sun is the brightest object in the sky with an apparent magnitude of −26.74.^[18]^[19] The Sun's hot corona continuously expands in space creating the solar wind, a stream of charged particles that extends to theheliopause at roughly 100 astronomical units. The bubble in the interstellar medium formed by the solar wind, the heliosphere, is the largest continuous structure in the Solar System.^[20]^[21]

The Sun is currently traveling through the Local Interstellar Cloud in the Local Bubble zone, within the inner rim of the Orion Arm of the Milky Way galaxy. Of the 50 nearest stellar systems within 17 light-years from Earth (the closest being a red dwarf namedProxima Centauri at approximately 4.2 light years away), the Sun ranks fourth in mass.^[22] The Sun orbits the center of the Milky Way at a distance of approximately 24,000–26,000 light years from the galactic center, completing one clockwise orbit, as viewed from the galactic north pole, in about 225–250 million years. Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of the constellation Hydra with a speed of 550 km/s, the Sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.^[23]

The mean distance of the Sun from the Earth is approximately 149.6 million kilometers (1 AU), though the distance varies as the Earth moves from perihelion in January to aphelion in July.^[24] At this average distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The energy of this sunlight supports almost all life on Earth by photosynthesis,^[25] and drives Earth'sclimate and weather. The enormous effect of the Sun on the Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. An accurate scientific understanding of the Sun developed slowly, and as recently as the 19th century prominent scientists had little knowledge of the Sun's physical composition and source of energy. This understanding is still developing; there are a number of present-day anomalies in the Sun's behavior that remain unexplained.