The universe looks like a pretty quiet place to live. But the universe is filled with dangerous things, all struggling to be the one to wipe us off the planet. Happily for us, they're all pretty unlikely, but if you wait long enough, one of them is certain to get us. But which one?

1). Death by Asteroid (小行星)

    Of all the ways we might meet our untimely death, getting wiped out by an asteroid is the most likely. Why? Because we sit in a universal shooting gallery, with 100 tons of material hitting us every day. The problem, though, occurs every few centuries when something big this way comes. If you could ask a dinosaur, I'd imagine they would tell you to take this seriously.

2). Death by Exploding Star

    When a huge star ends its life, it does so with a bang, which sends death spreading across space in the form of high-energy radiation. Many studies show that the bang would have to be closer than about 75 light years to do us any harm. The good news: no stars so close are able to do the deed.

3). Death by Dying Sun

    The sun is important to us; without it, we'd freeze. But the sun is also middle-aged, already halfway to running out of fuel, expanding into a red giant, and cooking us to a fine crisp. Even long before then, it'll warm up enough to raise our average temperature and cause a runaway greenhouse effect, boiling our oceans. Happily, that's a long time from now.

4). Death by Black Hole

    Black holes are misunderstood. They don't wander the galaxy looking for tasty snacks in the form of planets and stars; they turn around the Milky Way just like the hundreds of billions of other stars do. But it's possible that one could wander too close to us. If it did, planetary paths would be disturbed, causing the Earth to drop into the sun or be thrown out into deep space.

    Given that it could be trillions of years or more before even that happens, we don't have to worry too much about black holes.

    My advice? Go outside, look up, enjoy the sun, the moon, and the stars. They may be there forever as far as any one of us is concerned...and forever is a long, long time.

    Polar bears are one of the most popular animals for people. Polar bears are different from every other bear in the world. This is because polar bears have white fur. However, there are many facts about polar bears that people might not be aware of .

    The skin of polar bears is black, which according to thinkquest.org allows them to absorb more heat from the sun. Polar bear fur is transparent , because it is made up of hollow guard hairs. Loc.gov explains that the reason polar bears display white fur is that when the sun hits the fur ,the hollow spaces in the hair scatter the light. Since none of the light is absorbed, the light reflected back appears white to human eyes.

    Polar bears' conservation status is considered close to extinction. Global warming is considered the main cause of the decline in polar population. Polar bears use ice floats to hunt for their food. However, these ice floats are melting so polar bears are starting to drown in the search for food, and the food is becoming more difficult to get. Contrary to popular belief, polar bears do not eat penguins, because polar bears are not found in the Antarctic region of the world. Polar bears are only found around the Arctic Circle. Polar bears do not drink water. They get all the water they need from the prey they eat.

    FES. Gov specifies that polar bears are considered the largest land carnivores(食肉动物) in the world. The polar bear weight ranges between 700--1,500 pounds. Since the polar bear habitat is melting away, their main evolutionary advantages are fading. Polar bears are not able to use their camouflage(伪装) to find prey in habitats not covered with snow. Polar bears do not hibernate(冬眠). However, when the weather gets uncomfortable, or mothers give birth, polar bears will dig themselves a hidden home.

    What can we do to help save the polar bears? We can donate to organizations like the World Wildlife Fund, reduce our carbon footprint, and send letters to politicians explaining to them that we need to set up more preserves to help save the polar bear habitat.

    The Broadcom MASTERS competition aims to find a balance between celebrating individual accomplishments and acknowledging that science seldom happens alone. The competition takes off when students from around the country are teamed up and have to solve a series of hands—on challenges in the spotlight.

    Nowadays, kids are fed with “the myth of the lone scientist”, so placing such challenges in the middle school period has a huge potential for impact. The focus on teambuilding skills gets students excited before more fears and stereotypes(成见)set in.

    The initial pool of qualified students comes from the participants in nation-wide science fairs. Those who score in the top 10％(about 10, 000 kids)have the qualification to apply. The judges select the top 300 young scientists, and that group is finally narrowed to 30 finalists.

    Selection at this stage is clearly an honor in itself, but it counts as step one for the finalists. They are then flown to Washington, D. C. and placed into teams of five for the hands-on part of the competition. Each team is made up of students with different talents and skills, including academic focus and experience.

    Unlike the science fairs, where most of the work takes place behind the scenes and students share a polished outcome, the hands-on challenges create a space where the work is the competition itself. The students take up a range of challenges in science, technology, engineering, math and so on. Each of the challenges will need the insight and skills of multiple team members.

    Judges observing the challenges aren't just looking for outcomes but also for leadership, teamwork and problem solving.

    The Broadcom MASTERS attracts increasing numbers of passionate and talented young people who are eager to take part in a program that helps them grow as scientists, engineers and inventors. It lets the students experience a sense of coming together with true peers. More importantly, it provides them with new skills to tackle future challenges.

    Christmas is a time for eating great food, giving and receiving presents, and most importantly spending time with your family watching some classic Christmas movies.

    The Grinch (2000)

    This is a Christmas must­watch and one of Jim Carrey's best performances. It was also originally a nursery tale book written by Dr Seuss. It's the story of a green monster who wants to ruin Christmas but who in the end discovers the power of love and generosity. I promise it's a great film with plenty of laughs along the way.

    Love Actually (2003)

    While this is not a personal favourite of mine, people in the UK absolutely love this film. It has many featuring actors and actresses. It might be a little difficult to follow as there are complex plots, so I recommend watching a translated version or enabling subtitles (字幕) in your native language. However, the heart­warming elements of the film make it worth watching.

    Home Alone (1990)

    This amusing masterwork is one of my favourite films of all time. It tells the story of a boy, Kevin, who is left alone in his house when his large family forgets to take him on vacation with them. While the families are away, burglars try to rob the house and Kevin must protect his home by setting traps. The trips, falls and traps will have you laughing out loud as you watch a 10­year­old boy beat two grown men.

    Miracle on 34th Street (1994)

You can't have Christmas in an English­speaking country without watching this movie. It's not funny like Home Alone or The Grinch, but it is incredibly touching. It's about a man who claims to be Santa, but nobody believes him except a lawyer and a little girl. The story­line may seem a little childish but you can enjoy it at any age.