Saturday, 28 April 2018

The great scientist sir Stephen Hawking's Biography

Stephen Hawking Biography (1942-2018)
Professor Stephen Hawking speaks about "Why We Should Go into Space" for the NASA Lecture Series, April 21, 2008.
Credit: NASA/Paul Alers

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Stephen Hawking was regarded as one of the most brilliant theoretical physicists in history. His work on the origins and structure of the universe, from the Big Bang to black holes, revolutionized the field, while his best-selling books have appealed to readers who may not have Hawking's scientific background. Hawking died on March 14, 2018.
In this brief biography, we look at Hawking's education and career — ranging from his discoveries to the popular books he's written — and the disease that robbed him of mobility and speech.
British cosmologist Stephen William Hawking was born in England on Jan. 8, 1942 — 300 years to the day after the death of the astronomer Galileo Galilei. He attended University College, Oxford, where he studied physics, despite his father's urging to focus on medicine. Hawking went on to Cambridge to research cosmology, the study of the universe as a whole. 
In early 1963, just shy of his 21st birthday, Hawking was diagnosed with motor neuron disease, more commonly known as Lou Gehrig's disease or amyotrophic lateral sclerosis (ALS). He was not expected to live more than two years. Completing his doctorate did not appear likely. Yet, Hawking defied the odds, not only attaining his Ph.D. but also forging new roads into the understanding of the universe in the decades since.
As the disease spread, Hawking became less mobile and began using a wheelchair. Talking grew more challenging and, in 1985, an emergency tracheotomy caused his total loss of speech. A speech-generating device constructed at Cambridge, combined with a software program, served as his electronic voice, allowing Hawking to select his words by moving the muscles in his cheek.
Just before his diagnosis, Hawking met Jane Wilde, and the two were married in 1965. The couple had three children before separating. Hawking remarried in 1995 but divorced in 2006.

Hawking continued at Cambridge after his graduation, serving as a research fellow and later as a professional fellow. In 1974, he was inducted into the Royal Society, a worldwide fellowship of scientists. In 1979, he was appointed Lucasian Professor of Mathematics at Cambridge, the most famous academic chair in the world (the second holder was Sir Isaac Newton, also a member of the Royal Society).
Over the course of his career, Hawking studied the basic laws governing the universe. He proposed that, since the universe boasts a beginning — the Big Bang — it likely will have an ending. Working with fellow cosmologist Roger Penrose, he demonstrated that Albert Einstein's Theory of General Relativitysuggests that space and time began at the birth of the universe and ends within black holes, which implies that Einstein's theory and quantum theory must be united.
Using the two theories together, Hawking also determined that black holes are not totally dark but instead emit radiation. He predicted that, following the Big Bang, black holes as tiny as protons were created, governed by both general relativity and quantum mechanics. [PHOTOS: Black Holes of the Universe]
Professor Stephen Hawking experiences the freedom of weightlessness during a zero gravity flight.
Professor Stephen Hawking experiences the freedom of weightlessness during a zero gravity flight.
Credit: ZERO-G
In 2014, Hawking revised his theory, even writing that " there are no black holes" — at least, in the way that cosmologists traditionally understand them. His theory removed the existence of an "event horizon," the point where nothing can escape. Instead, he proposed that there would be an "apparent horizon" that would alter according to quantum changes within the black hole. But the theory remains controversial. [Portrait of Genius: Stephen Hawking Exhibit Photos]
Hawking also proposed that the universe itself has no boundary, much like the Earth. Although the planet is finite, one can travel around it (and through the universe) infinitely, never encountering a wall that would be described as the "end." 
Hawking was a popular writer. His first book, "A Brief History of Time" (10th anniversary edition: Bantam, 1998) was first published in 1988 and became an international best seller. In it, Hawking aimed to communicate questions about the birth and death of the universe to the layperson.
Hawking went on to write other nonfiction books aimed at nonscientists. These include "A Briefer History of Time,On the Shoulders of Giants." [Related: 8 Shocking Things We Learned From Stephen Hawking's Book “Grand Design”]
He and his daughter, Lucy Hawking, also created a fictional series of books for middle school children on the creation of the universe, including "George and the Big Bang" (Simon & Schuster, 2012).
Hawking made several television appearances, including a playing hologram of himself on "Star Trek: The Next Generation" and a cameo on the television show "Big Bang Theory." PBS presented an educational miniseries titled "Stephen Hawking's Universe," which probes the theories of the cosmologist.
In 2014, a movie based on Hawking's life was released. Called "The Theory of Everything," the film drew praise from Hawking, who said it made him reflect on his own life. "Although I'm severely disabled, I have been successful in my scientific work," Hawking wrote on Facebook in November 2014. "I travel widely and have been to Antarctica and Easter Island, down in a submarine and up on a zero-gravity flight. One day, I hope to go into space." 
Hawking's quotes range from notable to poetic to controversial. Among them:
  • "Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe? The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing? " 
  • "All of my life, I have been fascinated by the big questions that face us, and have tried to find scientific answers to them. If, like me, you have looked at the stars, and tried to make sense of what you see, you too have started to wonder what makes the universe exist." 
  • "Science predicts that many different kinds of universe will be spontaneously created out of nothing. It is a matter of chance which we are in." 
  • "The whole history of science has been the gradual realization that events do not happen in an arbitrary manner, but that they reflect a certain underlying order, which may or may not be divinely inspired. " 
  • "We should seek the greatest value of our action." 
  • "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." 
  • "Intelligence is the ability to adapt to change." 
  • "It is not clear that intelligence has any long-term survival value. " 
  • "One cannot really argue with a mathematical theorem." 
  • "It is a waste of time to be angry about my disability. One has to get on with life and I haven't done badly. People won't have time for you if you are always angry or complaining." 
  • "I relish the rare opportunity I've been given to live the life of the mind. But I know I need my body and that it will not last forever."
A list of Hawking quotes would be incomplete without mentioning some of his more controversial statements.
He frequently said that humans must leave Earth if we wished to survive. 
"It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million...Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space." — August 2010
"[W]e must … continue to go into space for the future of humanity…I don't think we will survive another 1,000 years without escaping beyond our fragile planet." — November 2016
"We are running out of space and the only places to go to are other worlds. It is time to explore other solar systems. Spreading out may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth." — June 2017
He also said time travel should be possible, and that we should explore space for the romance of it. 
"Time travel used to be thought of as just science fiction, but Einstein's general theory of relativity allows for the possibility that we could warp space-time so much that you could go off in a rocket and return before you set out. I was one of the first to write about the conditions under which this would be possible. I showed it would require matter with negative energy density, which may not be available. Other scientists took courage from my paper and wrote further papers on the subject," he told Parade in 2010.
"Science is not only a disciple of reason, but, also, one of romance and passion."
The theoretical physicist was also concerned that robots could not only have an impact on the economy but also mean doom for humanity.
"The automation of factories has already decimated jobs in traditional manufacturing, and the rise of artificial intelligence is likely to extend this job destruction deep into the middle classes, with only the most caring, creative or supervisory roles remaining," he wrote in a 2016 column in The Guardian.
"The development of full artificial intelligence could spell the end of the human race," he told the BBC in 2014. Hawking added, however, that AI developed to date has been helpful. It's more the self-replication potential that worries him. "It would take off on its own, and re-design itself at an ever-increasing rate. Humans, who are limited by slow biological evolution, couldn't compete, and would be superseded."
"The genie is out of the bottle. I fear that AI may replace humans altogether," Hawking told WIRED in November 2017.
An avowed atheist, Hawking also occasionally waded into the topic of religion.
"Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going." — The Grand Design, by Stephen Hawking and Leonard Mlodinow
"I regard the brain as a computer which will stop working when its components fail…There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark." — 2011 interview with The Guardian
"Before we understand science, it is natural to believe that God created the universe. But now science offers a more convincing explanation. What I meant by 'we would know the mind of God' is, we would know everything that God would know, if there were a God, which there isn't. I'm an atheist." — 2014 interview in El Mundo
Additional reporting by Elizabeth Howell, Contributor
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Friday, 27 April 2018

Why sky is blue color?

Everyone of us see sky is blue color but do you ever thought why it is blue color because its space exists nothing then why does it looks blue.If you got the question did anyone answer your question,ok let me clear it today why sky is blue?

Sun rays take nearly 8 mins 20 sec to reach our earth atmosphere. The sun rays comprises of VIBGYOR.
Here, look at this picture this gives you the answer.
Since Red,Orange,Yellow,Green have higher wave length it reaches the earth surface. Blue has less wave length of above color that can reach only the atmosphere level.
Atmosphere comprises of gases such as Nitrogen, Oxygen, Carbon dioxide etc… so these molecules scatter the blue light that we observe the SKY is BLUE.
Sometimes in evening we can observe sky is ORANGE in colour
This picture makes you clear.
In evening time we observe sky as orange in color because, at the time sun sets, it appear horizontal portion to you. So, the ORANGE which has higher wavelength scatter the air molecules that makes the sky to appear as ORANGE.
In NIGHT time. The sun goes off (bye bye to the sun).
Now there is no rays touches the earth atmosphere this why we it seems dark and we can enjoy the STARS and MOON in the sky. During day time as blue rays disappear the stars.
Hope it’s clear the matter.

Source: quora

Thursday, 26 April 2018

YouTube took down more than 8 million videos in 3 months

Kaya Yurieff

a stop sign© ERIC PIERMONT/AFP/Getty Images

YouTube is once again trying to clean up its platform.
On Monday, the Google-owned company said it took down more than 8 million videos between October and December for violating its community guidelines. The majority of the videos were spam or people trying to upload "adult content."
The information was included in YouTube's first quarterly report on how it's enforcing its community guidelines.
"This regular update will help show the progress we're making in removing violative content from our platform," the video-sharing site said in a blog post.
According to the report, computers detect most of the videos that end up getting taken down. It said 6.7 million videos were first flagged for review by machines, not humans. Of those, 76% were taken down before receiving any views from users.
YouTube has faced complaints from critics and advertisers who say the company has trouble tackling offensive content on its site.
Last week, a CNN investigation found ads from over 300 companies and organizations that ran on YouTube channels promoting white nationalists, Nazis, pedophilia, North Korean propaganda and other controversial or extremist content. In the past, ads have appeared on ISIS videos and other extremist and hateful content.
"I do think it's an underlying issue with [YouTube's] business model," Nicole Perrin, a senior analyst at eMarketer, told CNN last week. "For years [they] encouraged creators to put essentially almost anything on the site. That's led to an explosion of content."
YouTube has over a billion users, and those users watch a billion hours of video every day, making YouTube a difficult place to police.
Daniel Ives, head of technology research at GBH Insights, said the company's new report on its efforts to delete problematic videos is a step in the right direction.
"YouTube and Google are facing increasing pressures to step up their screening and flagging efforts around inappropriate content," he said. "Transparency is key on this hot button issue and these quarterly blog posts are a sign that Google is aggressively focused on this area over the coming years."
Google has pledged to hire 10,000 employees across the company by the end of this year to address "violative" content. YouTube said Monday that it has filled the majority of the additional roles needed to reach its contribution to that goal.
YouTube also said it will add more details to the quarterly reports by the end of the year, such as information about comments, the speed of removal and policy removal reasons.
YouTube also announced a "Reporting History" dashboard where users can check to see the status of videos they've flagged for review.
On Monday, Google's parent company, Alphabet, said profits hit $9.4 billion in the first three months of 2018, a big jump from the $5.4 billion it reported a year ago.

7 Dangers of Plastic

by Dr. Edward Group DC, NP, DACBN, DCBCN, DABFM
Last Updated on 

Recently I talked about the dangers of lead and how, at one time, lead was used as heavily as plastic. Not anymore. Lead was discovered to be highly toxic and the use of it in products like paint, toys, and electronics drastically declined. There is concern now that we’re in a similar position with plastic. Let’s look at a few reasons why you might want to consider going completely plastic free.

The 7 Dangers of Plastic

Plastic is very much a staple in the world today but it’s definitely not a perfect product. There are a slew of toxins within many plastics, including BPA. Here are 7 dangers of plastic and how it’s negatively affecting our health.

Image result for plastic

1. Chemicals in Plastic Disfigure Genitals

Di-isononyl phthalate (DiNP) is a phthalate commonly found in vinyl products. It was actually a chemical chosen to replace a similar toxin, DEHP, which was discovered to hinder genital development in baby boys. While less is known about the reproductive risks of DiNP, a recent study suggests that it can, in fact, affect male genital development. [1] This is worrisome because these problems occur before birth. While many phthalates are banned from children’s products, the pregnant mother can still be exposed.

2. Plastic Increases the Risk of Childhood Asthma

Studies have long suggested a connection between childhood exposure to plasticizers and asthma, but a recent Columbia University report found there is even an increased risk before birth. [2] Scientists studied the phthalate levels of pregnant women over almost a decade and found that children born to mothers with increased levels were over three times more likely to develop asthma symptoms than their counterparts. While no one really knows why the risk is higher, one theory suggests that phthalates increase airway sensitivity, essentially paving the way for asthma symptoms.

3. Chemicals in Plastic Kill Female Libido

Phthalates used in plastic have even been linked to low libido in women, with a recent study even suggesting women with high levels of plasticizers were twice as likely to show less interest in sex than those with low levels. [3] While you may try to limit your exposure, phthalates are often found in everyday items like shower curtains, PVC flooring, car dashboards, and even food. These toxins are endocrine disruptors and can wreak havoc with hormone levels, so limiting your exposure is key.

4. Plastic is Destroying our Waterways

An estimated 13,000 pieces of plastic litters each square kilometer of our oceans, and one huge factor to the problem are microbeads. These tiny plastic beads in many of your personal care products are only one of the environmental contaminants polluting our waters[4] Once in the water supply (by way of your drain), the beads collect toxins. Marine life is exposed to the microplastics and the toxins enter the food chain; but it’s not just our oceans that are affected. In the U.S., the issue of microbeads has become so toxic that many states are looking at banning them.

5. Plastic Has Infiltrated Food

With 6 different phthalates banned from children’s products in the U.S., the last place you’d expect to find these toxins would be in our food. Acrylamide is a fairly common plasticizer that’s been linked to cancer, and other phthalates linked to problems with reproductive development have been appearing at unsafe levels as well. [5] No one really knows how they’re getting into the food, but somehow this is happening before it gets to your home.

6. Plastic Destroys Hormonal Balance

BPA mimics estrogen in the body, so many people try to stay away from the toxin by using BPA-free plastics instead. A recent study suggests, however, that BPA-free plastics could also contain endocrine disruptors. In a test of fourteen resins used in plastic production, four were found to have estrogen-like properties. Not only are things like reusable water bottles and food storage containers at risk, but certain baby products may also contain the unhealthy compound. [6] Phthalates are still a huge concern in plastic packaging, but these plasticizers are also used in personal care products. [7]

7. You Simply Can’t Trust the Plastic Industry

Recently, the Federal Trade Commission (FTC) had to crack down on some plastic bag manufacturers for making uncertain claims. The issue had to do with labeling the bags ‘oxo-degradable,’ a term that implies it’ll biodegrade when exposed to oxygen. [8] Now, it’s likely that many of these bags will, unfortunately, end up in a landfill where little oxygen is present, meaning nothing can break down. At most, the bags might fragment into small pieces, but the pollutants are still there. [9] Essentially, the bags are no more biodegradable than regular ones. Even worse, this is only the latest incident in a string of bogus claims by the plastic industry. There are so many things wrong with using plastic, and I’ve only covered 7 of them here. Do you know of more ways plastic is hurting us all? Leave a comment and share your thoughts.