如果航天器装了一箱水到太空中，并且突然把这箱水抛向太空，会发生什么？If a spacecraft were carrying a tank of water in space, and suddenly spewed that water out into space, what would happen?
This was a dump of 150 pounds of water and urine from the Space Shuttle Discovery in 2009. Water ejected into space freezes quickly (due mostly to heat loss caused by rapid evaporation into the vacuum). It then drifts around, glittering in the sunlight, until it sublimates.
Astronaut John Glenn was baffled by what he called “fireflies” orbiting all around his spacecraft, but which were actually urine ice.
Apollo astronauts called their urine dumps “The Constellation Urion” and said it was very beautiful.
为什么机器人不能点击“我不是机器人”这个框呢？Why can’t bots check “I am not a robot” checkboxes?
It would, absolutely. This is a double-check, often used by a system that already believes you are human, but is just making sure a robot hasn’t knocked over your coffee to distract you. The thing is, above is an image, not text. The robot would have to grab every image on screen and perform OCR (Optical Character Recognition) on it, a labor intensive process. Then it would have to click the box. What these ‘not a robot” reCAPTCHAs are mainly looking for is the pattern of mouse movement. Robots tend to be quick and smooth whereas humans tend to be jerky. A robot attempting to OCR the whole screen is going to exhibit a telling processing delay before it kicks into action.
绝对会的。 这是一项双重检查，通常由已经认为您是人类的系统使用，但只是要确保机器人没有敲打您的咖啡来分散您的注意力。 问题是，上面是图像，而不是文本。【译注：例如，找出下面图片中包含自行车的图片】 机器人将不得不抓取屏幕上的所有图像并对其进行OCR（光学字符识别），这是一项劳动密集型的过程。 然后，必须单击该框。 这些验证机制主要寻找的是鼠标移动的模式。 机器人趋向于快速而流畅，而人类则趋于生涩。 试图对整个屏幕进行OCR的机器人在点击某个框之前，会表现出明显的处理延迟。
It works surprisingly well, but if you are pretty smooth with the mouse (as I am) and are expecting the captcha, you can sometimes trip the robot detect even as a human, since it’s biased toward detecting robots. When that happens, you fail and are challenged with a more difficult captcha demanding you understand the context of photographic scenes.
为什么航天飞机着陆时，宇航员需要这么长时间才能离开航天飞机？Why do astronauts take so long to exit the space shuttle when it lands?
The reasons it took so long to egress the crew after a space shuttle landing are:
- The orbiter was hot, having just reentered the atmosphere protected only by a thin skin of insulating tiles.
- The orbiter used extraordinarily toxic bi-propellant fuels for its OMS and manoeuvring thrusters, those thrusters were used during re-entry, and ground crews needed to make sure no residue would come into contact with them or the crew before proceeding.
- The orbiter was extremely complex and rather delicate, and crews needed to inspect it and record any damage before proceeding.
- The orbiter was extremely complex and rather delicate, and the flight crew had a lot of paperwork and closeout procedures to go through before egress. Among other things, they needed to shut down flight systems and vent pressure from tanks that might otherwise rupture or cause damage, or release flammable or toxic materials.
- 轨道飞行器极为复杂且十分精致，飞行机组人员在离开飞机场之前要完成许多文书工作和关闭程序。 除其他事项外，他们还需要关闭飞行系统并释放可能会破裂或造成损坏或释放出易燃或有毒物质的油箱压力。
- The APU and reentry cooling systems had to be shut down and the exterior inspected to keep hypergolics and ammonia away from people.
- After an extended mission, as when retrieving crew from the ISS, those crew members having spent weeks in space needed medical attention and aid on hand before egress, not just to assist them, but to begin several weeks of post-flight data gathering aimed at helping make long-duration space flight safer in the future.
- 延长任务后，例如从国际空间站检索机组人员时，那些在太空呆了几周的机组人员在离开飞机场前需要医疗护理和援助，这不仅是为了协助他们，而且还需要开始几周的飞行后数据收集，以期 有助于使未来的长时间太空飞行更加安全。
- You were supposed to go before you left orbit.
为什么他们在登月后要放置美国国旗而不是地球旗呢？Why did they plant a U.S. flag and not an Earth flag on the moon?
Let me point out something that most people clearly aren’t aware of. In 1963, President Kennedy publicly invited the Soviet Union to join us in our exploration of the moon. This was partly because he was starting to see how expensive it would be and partly because he thought it would be a good way to defuse tensions between our two nations. This was not the first time he made the proposal, and Khrushchev’s son has stated that his father, the Soviet premier at the time, was seriously considering it when Kennedy was killed. That was the end of that—the Russian’s didn’t trust LBJ as far as he could pee on a rose bush—but it was Kennedy’s olive branch that led directly to Apollo-Soyuz and on to the ISS.
让我指出一些大多数人显然不知道的事情。 1963年，肯尼迪总统公开邀请苏联加入我们对月球的探索。 这部分是因为他开始意识到这将是多么昂贵，部分是因为他认为这将是缓解两国之间紧张关系的好方法。 这不是他第一次提出这一建议，赫鲁晓夫的儿子说，他的父亲，当时的苏联总理，在肯尼迪遇害时也仍在认真考虑这一提议。 到此为止（俄罗斯人不相信肯尼迪在玫瑰花丛上撒尿【？？】），但肯尼迪的橄榄枝促成了阿波罗与联盟号火箭的合作飞上国际空间站。
That aside, there are two good reasons were didn’t plant an Earth flag.
#1: There is no Earth flag.
#2: There is no Earth flag.
I realize that’s the same reason twice, but it’s such an important one …
Besides, the entire enterprise was paid for by the American tax payer. There was discussion about this at NASA. Given the political climate and the outer space treaty, it was decided that planting the national flag is just the traditional thing to do and does not, by itself, constitute a claim of sovereignty or ownership.
此外，整个企业由美国纳税人支付。 NASA对此进行了讨论。 考虑到政治气候和外层空间条约，人们决定放置国旗只是传统上要做的事情，本身并不构成对主权或所有权的要求。
We did, however, leave a nice gold-plated plaque clearly stating the we “came in peace for all mankind,” and on a later flight, a plaque and a memorial to all men killed in the exploration of space—from all countries.
Besides, the hardware store in Clear Lake was fresh out of “Earth flags.”
The USA got there, it planted its Flag, and with all the pride in the Universe, they can look at it.
Being Argentine I am proud that our species achieved something that amazing 67 years later that we learned to fly.
The USA Flag there is correct. It was the effort of the United States.
It represented our entire planet, like it or not. Just as Gagarin represents all human kind when he was the first of us to exit our planet.
The Soviet Union and China sent rovers to the Moon, those machines also have their Flags, and its their right too.
Maybe in a future a panglobal Space Organization coordinates all the Space Agencies in the world so we join effots, funding and travel to the cosmos as one Earth Civilization. Then an Earth Flag could be planted, either as a symbol of this Earth Space Coordination Agency or the UN Flag (sorry Switzerland).
Meanwhile, whatever country reachs some place, it can plant its flag and tell We Were Here, FIRST. Is the pride of the pioneers of exploration.
火星上有土壤，为什么我们不在火星上种树？那样不就能产生氧气吗？为什么不可以？Why can’t we plant trees on Mars as it already has soil? Can’t this be done so that they can produce oxygen there? Wouldn’t it be possible? If not, why?
Of known planets excluding Earth, Mars has easily the most habitable surface conditions.
But you know what? I am by far the most qualified nuclear engineer in this house, but if you know what’s good for you, you won’t pay me to design any reactors.
First of all, trees are comparatively slow growing and contribute only a minor fraction of Earth’s oxygen (the bulk comes from the oceans.)
Second, Mars has no air.
Okay, yes, yes I know, it has air. It has a surface pressure of 0.087 psi (6.0 mbar), a little more than half of one percent Earth’s mean sea level pressure of 14.69 psi (1.013 bar). Mars has an atmosphere like Pringles potato chips have nutritional value. No, less than that.
好吧，是的，我知道，它有空气。 它的表面压力为0.087 psi（6.0 mbar），仅比地球平均海平面压力14.69 psi（1.013 bar）的1％多一半。 火星的大气的营养价值和品客薯片，不，比那个还少。
Third—Mars is darker than a Welsh quarry during filming of a Doctor Who episode. It’s darker than what you really think of those buffoons who voted for the other candidate. Mars gets less than half as much sunlight as Earth, and what it does get is virtually unfiltered, so whatever trees you plant can simultaneously turn yellow as lawn turf left under a rug for a week, and become sterilized from the UV radiation (plants like UV, but in moderation).
第三——在《神秘博士》中，火星比威尔士采石场还要暗。 火星比您对那些投票给其他候选人的丑角的想法要黑暗得多。 火星得到的阳光不到地球的一半，而且它得到的几乎没有过滤，因此，无论您种植的任何树木都能同时变黄，就像在地毯下放了一周1的草皮一样，并被过量紫外线辐射消灭了微生物（ 植物喜欢紫外线，但要适度）。
That won’t be a problem though, because as soon as you plant a tree on Mars, its outer surfaces and leaves will flash freeze in the near vacuum. Then the ice will sublimate in the sunlight. Oh, and much, if not all of the soil is toxic.
不过，和接下来的比起来这还不算什么大问题，因为一旦您在火星上种植一棵树，它的外表面和树叶就会在接近真空的状态下瞬间冻结。 然后冰会在阳光下升华。 哦，而且，即使不是全部，土壤也是有毒的。
I write Scifi. I love Mars. Mars is awesome. Elon loves Mars too. Elon wants make big boom rocket go Mars way. Elon may get his way too, but his colonists, if they materialize, will be living under glass, most likely not just for the duration of their lives on Mars, but for the duration of their species on Mars.
我写科幻。 我爱火星。 火星很棒。 Elon也爱火星。 Elon希望让大型火箭去往火星。 Elon也许也可以走自己的路，但是如果他的殖民者实现了，他们将一直生活在玻璃罩里，对于第一批开拓者是如此，人类的后代恐怕也不得不如此。
The reality is, Mars is more habitable than the moon by about as much as I’m more qualified to build a hydrogen bomb than my dog. At least above the clouds of Venus, you don’t need a pressure suit.