In 1905, as part of his Special Theory of Relativity, Albert Einstein published the point that a large amount of energy could be released from a small amount of matter. This was expressed by equation E = me 2(energy = mass times the speed of light squared). But bombs were not what Einstein had in mind when he published this equation.

    In 1929, he publicly declared that if a war broke out he would “refused to do war service, direct or indirect…” His position would change in 1933, as the result of Adolf Hitler's coming into power in Germany.

    Einstein's greatest role in the invention of the atomic bomb was signing a letter to President Franklin Roosevelt urging that the bomb be built because some physicists feared that Germany might be working on an atomic bomb. Among those concerned were physicists Leo Szilard and Eugene Wigner. But Szilard and Wigner had no influence with those in power. So in July 1939 they explained the problem to someone who did: Albert Einstein. After talking with Einstein, in August 1939 Szilard wrote a letter to President Roosevelt with Einstein's signature on it, which was delivered to Roosevelt in October 1939.

    Germany has invaded Poland the previous month; the time was ripe for action. That October research of a-bomb began but proceeded slowly because the invention of the atomic bomb seemed distant and unlikely. In April 1940 an Einstein letter, ghost-written by Szilard, pressed the researchers on the need for “greater speed”.

    As the realization of nuclear weapons grew near, Einstein looked beyond the current war to future problems that such weapons could bring. He wrote to his friend about his fear about the future use of the a-bomb.

    The atomic bombings of Japan occurred three months after Germany gave in.

In November 1954, five months before his death, Einstein summarized his feelings about his role in the creation of the atomic bomb: “I made one great mistake in my life… when I signed a letter to President Roosevelt recommending that atom bombs be made; but there was some justification—- the danger that the Germans would make them”.

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    Are you a social media addict? Are you always checking your smart phone to see how many "likes" you've received for your latest post? Maybe you feel comforted by the sound that someone has sent you a message?

    Don't worry, you're not alone. We check our phones an average of 150 times a day, and around 30% of the total time spent online is devoted to social media. Some experts now fear this habit could be damaging our mental health.

    This is something particularly bothering young adults, according to a study from the University of Pittsburgh. It found the more they used social media, the more likely they were to be depressed. In tests, those people who checked social media frequently were 2.7 times more likely to be depressed compared to those who spent most of their time generally surfing the Internet, who had just 1.7 times the risk.

    Some of us certainly feel sad when we're ignored on social media sites, or when we see someone else having a better time than us. But depression is a more serious condition and clinical psychologist, Abigael San, recently told the BBC that ,"It's a real issue, and it's been getting significantly worse over the last 5﹣6 years. You can get so hooked that it takes you away from your real relationships. "However, Abigael does admit that social media is more likely to worsen pre﹣existing issues than directly cause them.

    Other research by the University of Glasgow found that teenagers are affected by the 24﹣hour demands of their social media accounts. It found that those with higher levels of emotional investment in social media, and who use it at night, were more likely to feel depressed and anxious.

    Despite these warning signs, why do some of us continue to keep clicking? Well, I suppose we all want to be liked and we don't want to miss out on a conversation that's taking place online. But we need to know when to switch off our virtual online world and connect with the real world instead.

    Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

    This finding suggests that taking steps to prevent northern forest to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

    This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

    Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone (臭氧) levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

    "We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere." Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

The wonders of ancient Egypt have drawn visitors for thousands of years. Astonishing temples, pyramids and legendary pharaohs are its timeless legacy. Smithsonian Journeys will be your best choice if you want to visit Ancient Egypt. It would be a great tour as you would be viewing the only remaining structure of the Seven Ancient Wonders of the World. The Pyramids, Temples and Tombs are amazing works that make you wonder just how these magnificent structures were built thousands of years ago! However, there is so much more with Smithsonian Journeys！ Join us on this new tour to discover Egypt's mysteries.

What Is Provided With Your Tour

Pre-tour information, including a reading list;

Luggage handling for one bag per person;

All on-tour transportation, unless otherwise noted;

All accommodations and meals during the tour;

All sightseeing and visits.

A Note about Costs

This journey will cost you about ＄5000. All prices are based on two persons sharing a room. All prices are quoted in U.S. dollars. Tour costs are based upon current airfares, tariffs, currency values. While we will do everything possible to maintain the listed prices, they are subject to change. Due to fluctuations in oil prices, a fuel surcharge may be added to your tour fee (e.g. internal flights, cruises, etc.). Details will be advised prior to departure.

Registration

To submit a reservation request, please use our secure online system at Smithsonian Journeys. Org or contact a Cultural Travel Specialist, at 1-855-330-1542 Mon—Fri 9 am—6 pm. Submitting an online request does not guarantee space on a tour. You will be notified by a Reservation Specialist of your status once your request has been received and processed.

Fans of art believe that its main purpose is to make us look at life from many different angles. When it comes to Cubism(立体主义), however, the artists of this era wanted us to look at life from every angle. 

The father of Cubism, Spanish artist Pablo Picasso, is among the art world's most famous names. Like many other great names before him, he felt restrained by the rules of his teachers and decided to do something: break them. 

Early in his painting career, Picasso realized something important about how people view and remember scenes of beauty. When we look at a subject, we don't just see it from one angle, as many paintings appear. Instead, we study the subject from a number of different angles, heights and viewpoints. This is the aim of Cubism: It portrays(描绘) subjects from a wide range of angles; it doesn't force us to see things as the artist viewed them at the time he or she painted them. To bring his visions to life, Picasso and other Cubists took the most basic components of a subject and rearranged them in a way which let us see it in full detail. 

"By breaking objects and figures down into distinct areas, Picasso aimed to show different viewpoints at the same time and within the same space," in the words of the Tate Institution. Or as Lithuanian—born Cubist Jacques Lipchitz once put it: "Cubism is like standing at a certain point on a mountain and looking around. If you go higher, things will look different; if you go lower, again they will look different."

Cubism stood out as it was an art movement which didn't just rely on the artist to share their vision by painting what they saw. As cubist paintings mainly show their subjects in a deconstructed form, this means that viewers must use their imaginations to find the missing pieces for themselves. As Guardian art critic Johnathan Jones noted, this is part of the beauty of enjoying Picasso's works. "If you can relax your gaze(凝视)enough and just enjoy the painting long enough, something really amazing happens. Your mind produces a solid feeling of the things Picasso was looking at. the world is revealed in its majesty(壮观)," he wrote.