Computertech-adviser

WHAT ARE BLACK HOLES (all you need to know about them by nasa)

Don't let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area - think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space.

Although the term was not coined until 1967 by Princeton physicist John Wheeler, the idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.

Scientists can't directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion. A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space. Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.

One Star's End is a Black Hole's Beginning

Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.) If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away. When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object.

Even bigger black holes can result from stellar collisions. Soon after its launch in December 2004, NASA's Swift telescope observed the powerful, fleeting flashes of light known as gamma ray bursts. Chandra and NASA's Hubble Space Telescope later collected data from the event's "afterglow," and together the observations led astronomers to conclude that the powerful explosions can result when a black hole and a neutron star collide, producing another black hole.

Babies and Giants

Although the basic formation process is understood, one perennial mystery in the science of black holes is that they appear to exist on two radically different size scales. On the one end, there are the countless black holes that are the remnants of massive stars. Peppered throughout the Universe, these "stellar mass" black holes are generally 10 to 24 times as massive as the Sun. Astronomers spot them when another star draws near enough for some of the matter surrounding it to be snared by the black hole's gravity, churning out x-rays in the process. Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.

On the other end of the size spectrum are the giants known as "supermassive" black holes, which are millions, if not billions, of times as massive as the Sun. Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.

Observed Mass Ranges of Compact Objects
This chart shows the relative masses of super-dense cosmic objects.

Historically, astronomers have long believed that no mid-sized black holes exist. However, recent evidence from Chandra, XMM-Newton and Hubble strengthens the case that mid-size black holes do exist. One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole.
Areeba Ivan Charles Kalungi Charles Lwanga Ayebesa Shilton Edrisa Edrisa Josephine Tibasabwa Kasule S Timotheus II Gilbert Mwesiga Julie Batenga Amanya Brendah

5 TOP CONSUMER TRENDS TO WATCH 2017
1. VOICE CONTROLS
highlighted is the New Voice of Computing. By that, the user interface for computers keeps changing to suit people as they use computers in new ways. This evolution is similar to what happened when Steve Jobs made the personal computer more accessible and affordable than previous PCs, which helped it take off in the mass market.
2. Artificial Intelligence
The second big trend is the growth of artificial intelligence. Dubravac said AI has started seeping into smaller devices and is being used for things like managing your refrigerator’s cooling level. Household appliances will increasingly monitor things, like how much detergent you have, and reorder when they gets low.
3. The Defining network (5G)
The 5G network will be a wireless data network that allows you to connect to the internet at blazing speeds and communicate with both video and voice at the same time. Lots of big companies, like Ericsson and Verizon and Qualcomm, are all working on defining the standards and capabilities of 5G.This network will determine what kind of gadgets we use in the future, which has inspired an interesting subtrend.
4. TRANSFORMING TRANSPORT
Google’s self-driving cars have driven over 2 million miles. And the result is a lot of aggregated learning about the right way to drive a car.“Self-driving cars is a strong storyline at CES,” Dubravac said. “That is a phenomenal development, as we overlook incremental change that happens every year.”Transportation is being transformed, with vehicle solutions occupying 200,000 square feet of exhibit space at CES, Dubravac said. Chrysler announced the all-electric Portal car today.
5. Digitalizing Consumer Experience
The final trend is digitizing the consumer experience. That includes digitizing everything from the sense of smell to all the other senses. Those advances will be used in devices such as virtual reality hardware.
by Anish Dennis Thinkx Software