Facebook founder Mark Zuckerberg took out full-page ads in British and American newspapers on Sunday to apologize for the Cambridge Analytica scandal（丑闻）, admitting the quiz app built by a university researcher that leaked（泄漏）Facebook data of millions of people was a “betrayal of trust”.

    Since the scandal broke, the public has become more aware and concerned about how their online behavior may be used for purposes to which they have not agreed. It emphasizes the urgent need for better protection of personal information.

    To better protect personal data privacy（隐私）, targeted laws are needed. More effective cooperation should be carried out to protect people's privacy online as soon as possible.

    Countries, such as the United States and China in particular, which are global leaders in the use of big data should accelerate legislation（立法）on how it can be collected and for what purposes it can be used.

    At the same time, a closer watch should be kept on the world's major internet companies, such as Apple, Facebook, Amazon, Google, Microsoft, Alibaba, Tencent and Baidu to ensure they do not acquire unnecessary personal information or misuse the information they obtain. Despite the huge challenge such personal data protection may pose to their established profit-making models, these companies should know that the more powerful they are, the bigger responsibilities they shoulder.

    Strengthened efforts for personal privacy protection do not mean that big data must not be used, but that it is used appropriately. Big data is like a mountain or gold, and overemphasis on its security at the expense of its use will undoubtedly waste a valuable resource. The key problem is how to promote its use while guaranteeing people's privacy to be protected.

    Newspapers in Great Britain vary greatly in their ways of carrying the news. There are serious papers for those who want to know about important happenings everywhere, both at home and abroad. There are popular newspapers for those who prefer entertainment to information.

    The London newspaper that is best known outside Great Britain is probably the Times. It began in 1785, and has a high reputation for believable news and serious opinions on the news. It calls itself an independent paper, which means that it does not give its support to a particular political party. Its leading articles give the opinions of the editors, not those of the owners of the paper.

    Letters to the editor are printed in the newspaper. These parts of the Times are always interesting. Most of the letters are serious subjects. But from time to time there will be long letters on the subject which is not at all serious, perhaps on a new fashion of dress, or the bad manners of the young people, compared with manners of thirty years ago.

    The Great Fire of London started in the very early hours of 2 September 1666. In four days it destroyed more than three-quarters of the old city, where most of the houses were wooden and close together. One hundred thousand people became homeless, but only a few lost their lives.

    The fire started on Sunday morning in the house of the King's baker(面包师)in Pudding Lane. The baker, with his wife and family, was able to get out through a window in the roof. A strong wind blew the fire from the bakery(面包房)into a small hotel next door. Then it spread quickly into Thames Street. That was the beginning.

    By eight o'clock three hundred houses were on fire. On Monday nearly a kilometer of the city was burning along the River Thames. Tuesday was the worst day. The fire destroyed many well-known buildings, old St Paul's and the Guildhall among them.

    Samuel Pepys, the famous writer, wrote about the fire. People threw their things into the river. Many poor people stayed in their houses until the last moment. Birds fell out of the air because of the heat.

    The fire stopped only when the King finally ordered people to destroy hundreds of buildings in the path of the fire. With nothing left to burn, the fire became weak and finally died out.

    After the fire, Christopher Wren, the architect(建筑师), wanted a city with wider streets and fine new houses of stone. In fact, the streets are still narrow; but he did build more than fifty churches, among them new St Paul's.

    The fire caused great pain and loss, but after it London was a better place: a city for the future and not just of the past.

    Fashions have a lot of rules. Most of them, however, are just wrong. But there's one rule that goes beyond tradition and into the field of scientific study of the brain: Black clothes are slimming. It all comes down to how your visual system processes the light. The below holes in each square are the same in size, yet the white hole looks bigger than the black hole.

    In the 1500s, Galileo Galilei noticed that some of the planets looked larger when viewed with the naked eye than they did when viewed through a telescope, making the white light of Venus appear eight to ten times larger than Jupiter in the night sky. He knew something strange must be going on with his vision to cause this illusion, but he wasn't sure what it was. Luckily, scientists never stopped wondering, and in 2014, they figured it out.

    Our visual system operates via two main channels: "on" neurons (神经元) that are sensitive to light things and "off" neurons that are sensitive to dark things. When it came to the dark "off" neurons, the researchers found that they responded predictably to dark shapes on a light background the greater the contrast between the two, the more active these neurons were. But the light on" neurons behaved unpredictably. Even with the same amount of contrast, light objects on a dark background caused a greater response in these neurons.

    This phenomenon makes some sense, evolutionarily speaking. In the dark of night, you'd want to be able to take in every bit of light you can get, so a visual system that enlarges light objects on a dark background could be very useful. However, it's not that hard to see dark objects in the light of day. It has some effects in the colors of your clothes and in the appearance of the planets—the brighter appearance of Venus in the night sky makes it look bigger than the darker Jupiter.

    NASA has a new job listing, and it's no joke. The US space agency is looking for a "joker" to join their planned mission to Mars.

    A mission to Mars is no laughing matter. On average, the red planet is 140 million miles (225 million kilometers) away from Earth. A trip there would take around eight months in a small spacecraft. And Mars has a communications delay of 20 minutes. This means that astronauts will have to wait 20 minutes for a reply, when an emergency happens.

    "When you're living with others in a confined space for a long period of time, such as on a mission to Mars, problems are likely to occur," Jeffrey Johnson, a scientist at the University of Florida, told The Guardian.

    This is probably why NASA wants an astronaut with a sense of humor. "These are people that have the ability to pull everyone together," Johnson said.

    In stressful situations, perhaps humor is a way to know we aren't alone. By laughing together, we share our stress. Then we can focus on our jobs instead of just worrying.

    There are other examples of team "clowns". One example is the journey to the South Pole led by Norwegian explorer Roald Amundsen. It was a difficult journey full of danger. Adolf Lindstrom, a cook at Amundsen's team, was a "clown". He made people laugh through the whole journey. Amundsen later wrote that Lindstrom was the most valuable member of the team.

    But if you're hoping that your favorite TV comedian will fly to Mars, that probably won't happen.

    "Being funny won't be enough to land somebody the job," Johnson said. "They also need to be an excellent engineer."

    Besides, they must be in top physical condition.

    Nine years ago, when the closest and largest full moon fell on March 19, 2011, many people used the term, "supermoon", which we had never heard before. In 2012, we heard this term again to describe the year's closest full moon on May 6, 2012. Supermoons also appeared in 2013, 2014, 2015, 2017 and 2019.

    What does "supermoon" mean exactly? And how special was the March 19, 2011 supermoon?

    The word "supermoon" didn't come from astronomy. Instead, it came from astrology (占星学). In 1979, astrologer Richard Nolle defined it as a new or full moon which occurs at or near its closest point to the earth in its orbit. In short, the earth, moon and sun are all in a line, with the moon at its nearest point to the earth.

And the full moon of March 19, 2011 was the largest moon of that year. This "supermoon" was at perigee (近地点) — its closest point to the earth in its orbit. It was bigger and brighter than other full moons of 2011. Astronomers call this sort of close full moon a perigee full moon.

    That doesn't sound very special, does it? In fact, the March 2011 full moon lined up much more closely with perigee than Nolle's original definition. But were you able to notice with your eyes alone that this full moon was bigger or brighter than usual? Astronomers said no. But it was fun to stand outside under this full moon and know that the moon was closer than ever.

    In 2019, there were three supermoons. The first supermoon of 2019 was the Super Blood Wolf Moon on January 21, which occurred with a total lunar eclipse (月全食) at the same time, also known as a "blood moon". The second supermoon of 2019 was on February 19, also called the Snow Moon, which was the closest full moon of the year. The third and final supermoon of 2019, known by Native Americans as the Worm Moon, occurred on March 21. It fell on the day of the vernal equinox (春分), which signals the end of winter and the beginning of spring.