Outer space 外太空.docx

外太空（outer space）：外太空指的是地球稠密大气层之外的空间区域，并没有明确的界线分野。又称为宇宙空间，指的是相对于地球天空中大气层之外的虚空区域，外太空通常用来和领空（领土）划分区别；虽然称为空，却也并非虚无缥缈。外太空也简称太空，一般定义为大约距离地球表面1000千米之外的空间。国际航空联合会定义在100公里的高度为卡门线，为现行大气层和太空的界线定义。美国认定到达海拔80公里的人为太空人，在太空船重返地球的过程中，120公里是空气阻力开始发生作用的边界。
外太空的环境：
一、低温，极低的温度，约为 -273摄氏度。已非常接近极限低温了。
二、真空，极好的真空，比人类在实验室中制造的最好的真空还要“空”几个数量级。
三、强辐射，对我们人类现在的科技水平来说，这强辐射主要来自我们的太阳。因为恒星都是巨大的热核反应堆，所以伴随着光和热向四周发散的就是强辐射。
四、失重，就是所有物体在外太空都是可以随意漂浮的，当然前提是周围没有大的天体，不会有引力来干扰这失重。
五、空，极空。可能老祖宗早都知道这一点，所以居然用了“太空”这么一个词。外太空天体间的距离很大，以光年计也要成十上百的。
失重：The condition of apparent weightlessness occurring when the centrifugal force on a body exactly counterbalances the gravitational attraction on it.
真空：Vacuum is space that is devoid of matter. The word stems from the Latin adjective vacuus for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure.[1] Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum.

The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%.[2] Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm3.[3] Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average.[4] According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transiting gamma- and cosmic rays, neutrinos, along with other phenomena in quantum physics. In modern particle physics, the vacuum state is considered as the ground state of matter.
Vacuum has been a frequent topic of philosophical debate since ancient Greek times, but was not studied empirically until the 17th century. Evangelista Torricelli produced the first laboratory vacuum in 1643, and other experimental techniques were developed as a result of his theories of atmospheric pressure. A torricellian vacuum is created by filling with mercury a tall glass container closed at one end and then inverting the container into a bowl to contain the mercury.[5]
Vacuum became a valuable industrial tool in the 20th century with the introduction of incandescent light bulbs and vacuum tubes, and a wide array of vacuum technology has since become available. The recent development of human spaceflight has raised interest in the impact of vacuum on human health, and on life forms in general

Outer space is just what its name implies. It is the void that lies beyond the uppermost reaches of the atmosphere of Earth and between all other objects in the universe. Although it is a void, outer space may be thought of as an environment. Radiation and objects pass through it freely. An unprotected human or other living being placed in the outer space environment would perish in a few brief, agonizing moments.
The principal environmental characteristic of outer space is the vacuum, or nearly total absence of gas molecules. The gravitational attraction of large bodies in space, such as planets and stars, pulls gas molecules close to their surfaces leaving the space between virtually empty. Some stray gas molecules are found between these bodies, but their density is so low that they can be thought of as practically nonexistent.
On Earth, the atmosphere exerts pressure in all directions. At sea level, that pressure is 101 kilopascals. In space, the pressure is nearly zero. With virtually no pressure from the outside, air inside an unprotected human's lungs would immediately rush out in the vacuum of space. Dissolved gases in body fluids would expand, pushing solids and liquids apart. The skin would expand much like an inflating balloon. Bubbles would form in the bloodstream and render blood ineffective as a transporter of oxygen and nutrients to the body's cells. Furthermore, the sudden absence of external pressure balancing the internal pressure of body fluids and gases would rupture fragile tissues such as eardrums and capillaries. The net effect on the body would be swelling, tissue damage, and a deprivation of oxygen to the brain that would result in unconsciousness in less than 15 seconds. 
The temperature range found in outer space provides a second major obstacle. The sunlit side of objects in space at Earth's distance from the Sun can climb to over 120 degrees Celsius while the shaded side can plummet to lower than minus 100 degrees Celsius. Maintaining a comfortable temperature range becomes a significant problem.
Other environmental factors encountered in outer space include: microgravity, radiation of electrically charged particles from the Sun, ultraviolet radiation, and meteoroids. Meteoroids are very small bits of rock and metal left over from the formation of the solar system and from the collisions of comets and asteroids. Though usually small in mass, these particles travel at very high velocities and can easily penetrate human skin and thin metal. Equally dangerous is debris from previous space missions. A tiny paint chip traveling at thousands of kilometers per hour can do substantial damage.

Gravity is a 2013 science fiction thriller film directed, co-written, co-produced and co-edited by Alfonso Cuarón. It stars Sandra Bullock and George Clooney as astronauts, and sees them stranded in space after the mid-orbit destruction of their space shuttle and their subsequent attempt to return to Earth.
Cuarón wrote the screenplay with his son Jonás and attempted to develop the film at Universal Pictures. The rights were sold to Warner Bros. Pictures, where the project eventually found traction. David Heyman, who previously worked with Cuarón on Harry Potter and the Prisoner of Azkaban (2004), produced the film with him. Gravity was produced entirely in the UK, where the British visual effects company Framestore spent more than three years creating most of the film's visual effects, which comprise over 80 of its 91 minutes.
Gravity opened the 70th Venice International Film Festival in August 2013 and had its North American premiere three days later at the Telluride Film Festival. It was released to cinemas in the United States and Canada on October 4, 2013. The film was met with near-universal acclaim from critics, who praised Emmanuel Lubezki's cinematography, Steven Price's musical score, Cuarón's direction, Bullock's performance and Framestore's visual effects. It has grossed more than US$716 million worldwide, making it the eighth highest-grossing film of 2013.
At the 86th Academy Awards, Gravity received a leading ten nominations—tying with American Hustle (2013)—and won seven, the most for the ceremony, including Best Director for Cuarón, Best Cinematography for Lubezki, Best Visual Effects, and Best Original Score for Price. The film was also awarded six BAFTA Awards, including Outstanding British Film and Best Director, the Golden Globe Award for Best Director, and seven Critics Choice Awards.

情节：
Dr. Ryan Stone is a biomedical engineer aboard the NASA space shuttle Explorer for her first space mission, the STS-157 program. Veteran astronaut Matt Kowalski is commanding his final expedition. During a spacewalk to service the Hubble Space Telescope and Stone's upgrades to the Telescope, Mission Control in Houston warns the team about a Russian missile strike on a defunct satellite, which has inadvertently caused a chain reaction forming a cloud of debris in space. Mission Control orders that the mission be aborted and the shuttle begin re-entry immediately to leave because the debris is speeding towards the telescope. Communication with Mission Control is lost shortly after.
High-speed debris from the Russian satellite strikes the Explorer and Hubble, detaching Stone from the shuttle and leaving her tumbling through space. Kowalski, using a manned maneuvering unit (MMU), soon recovers Stone and they return to the Explorer. They discover that it has suffered catastrophic damage and the rest of the crew is dead. They use the MMU to reach the International Space Station (ISS), which is in orbit about 1,450 km (900 mi) away. Kowalski estimates they have 90 minutes before the debris field completes an orbit and threatens them again.
En route to the ISS, the two discuss Stone's home life and the death of her young daughter. As they approach the substantially damaged but still operational ISS, they see its crew has evacuated in one of its two Soyuz modules. The parachute of the remaining Soyuz has deployed, rendering the capsule useless for returning to Earth. Kowalski suggests using it to travel to the nearby Chinese space station Tiangong, 100 km (60 mi) away, in order to board a Chinese module to return safely to Earth. Out of air and maneuvering power, the two try to grab onto the ISS as they fly by. Stone's leg gets entangled in Soyuz's parachute cords and she grabs a strap on Kowalski's suit. Despite Stone's protests, Kowalski detaches himself from the tether to save her from drifting away with him, and she is pulled back towards the ISS while Kowalski floats away to a certain death. He continues to support her until he is out of communications reach.
Stone enters the ISS via an airlock. She cannot re-establish communication with Kowalski and concludes that she is the sole survivor. A fire breaks out, forcing her to rush to the Soyuz. As she maneuvers the capsule away from the ISS, the tangled parachute tethers prevent it from separating from the station. She spacewalks to release the cables, succeeding just as the debris field completes its orbit and destroys the station. Stone aligns the Soyuz with Tiangong but discovers that its engine has no fuel.
After a poignant radio communication with a foreign-speaking fisherman on Earth, Stone resigns herself to being stranded and shuts down the cabin's oxygen supply to commit suicide. As she begins to lose consciousness, Kowalski enters the capsule. Scolding her for giving up, he tells her to rig the Soyuz's landing rockets to propel the capsule toward Tiangong. Stone then realizes that Kowalski's reappearance was not real, but has nonetheless given her the strength of will to continue. She restores the flow of oxygen and uses the landing rockets to navigate toward Tiangong, which is rapidly deorbiting.
Unable to maneuver the Soyuz to dock with the station, Stone ejects herself via explosive decompression and uses a fire extinguisher as a makeshift thruster to travel the final metres to Tiangong. Stone enters the Shenzhou capsule just as Tiangong starts to break up on the upper edge of the atmosphere. Stone radios in the blind that she is ready to head back to Earth. After re-entering the atmosphere, Stone hears Mission Control, which is tracking the capsule.
After speeding through the orbit, the capsule lands in a lake, but dense smoke from an electrical fire inside the capsule forces Stone to evacuate immediately as it starts sinking. She opens the capsule hatch, allowing water to enter and sink it, forcing Stone to shed her spacesuit and swim ashore. She watches the remains of the Tiangong re-enter the atmosphere and takes her first shaky steps on land.

Themes：
Although Gravity is often cited in the media as a science fiction film,[29] Cuarón told BBC that he sees the film rather as "a drama of a woman in space".[30]
Despite being set in space, the film uses motifs from shipwreck and wilderness survival stories about psychological change and resilience in the aftermath of catastrophe.[31][32][33][34] Cuarón uses the character, Stone, to illustrate clarity of mind, persistence, training, and improvisation in the face of isolation and the consequences of a relentless Murphy's law.[29] The film incorporates spiritual or existential themes, in the facts of Stone's daughter's accidental and meaningless death, and in the necessity of summoning the will to survive in the face of overwhelming odds, without future certainties, and with the impossibility of rescue from personal dissolution without finding this willpower.[32] Calamities occur but only the surviving astronauts see them.[35]
The impact of scenes is heightened by alternating between objective and subjective perspectives, the warm face of the Earth and the depths of dark space, the chaos and predictability of the debris field, and silence of the vacuum of space with the background score giving the desired effect.[34][36] The film uses very long, uninterrupted shots throughout to draw the audience into the action but contrasts these with claustrophobic shots within space suits and capsules.[32][37]
Some commentators have noted religious themes in the film.[38][39][40][41] For instance, Fr. Robert Barron in The Catholic Register summarizes the tension between Gravity's technology and religious symbolism. He said, "The technology which this film legitimately celebrates... can't save us, and it can't provide the means by which we establish real contact with each other. The Ganges in the sun, the St. Christopher icon, the statue of Budai, and above all, a visit from a denizen of heaven, signal that there is a dimension of reality that lies beyond what technology can master or access ... the reality of God".[41]
The film also suggests themes of humanity's ubiquitous strategy of existential resilience; that, across cultures, individuals must postulate meaning, beyond material existence, wherever none can be perceived. Human evolution and the resilience of life may also be seen as key themes of Gravity.[42][43][44][45] The film opens with the exploration of space—the climax of human civilization, and ends with an allegory of the dawn of mankind when Dr. Ryan Stone fights her way out of the water after the crash-landing, passing an amphibian, grabs the soil and slowly regains her capacity to stand upright and walk. Director Cuarón said, "She’s in these murky waters almost like an amniotic fluid or a primordial soup. In which you see amphibians swimming. She crawls out of the water, not unlike early creatures in evolution. And then she goes on all fours. And after going on all fours she’s a bit curved until she is completely erect. It was the evolution of life in one, quick shot".[43] Other imagery depicting the formation of life includes a scene in which Stone rests in an embryonic position, surrounded by a rope strongly resembling an umbilical cord. Stone's return from space,