标签：行星旅行 相关文章
[00:01.44]我在美国旅行 [00:02.87]Useful Expressions [00:03.81]常用语句 [00:04.75]1.Cheap things are not always good. [00:07.52]便宜的东西不见得都是好货。 [00:10.29]2.It takes a long time to learn English. [00:13.45]学英语要花
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Like a phoenix rising from the ashes, astronomers have found a whole new solar system may be forming in the wake of a star's violent death. This is the Hidden Universe of the Spitzer Space Telescope, exploring the mysteries of infrared astronomy wit
国家地理2008年
Picture a suicide dive into the mysterious depth? Relax, Galileo's already done it for you. We separated the probe from the Galileo mother ship. We were flying in toward Jupiter, basically a ballistic bullet. The Galileo probe went in at an unbelieva
自然百科2012年
This could be the most terrifying sight in the solar system: clear skies above a bottomless pit, an infernal drop into the depth of Jupiters endless sky. You may have raindrops evaporating into the hot interiors of Jupiter, but there is no ocean down
自然百科2012年
Gas escaping into space from the plumes is energized by Jupiters magnetosphere, creating an intense band of ionizing radiation that bombards a surface already soaked in emissions. If you went out relatively unprotected with, like a normal spacesuit f
自然百科2012年
I would like to visit Jupiter one day，I think it would be a good place to take a vacation, but not on July of 1994. That would have been a terrible time. In July, 1994, the fragmented comet Shoemaker-Levy 9 that David helped / discover began its fa
自然百科2012年
When Galileo took a closer look at Europa, the picture changed. Europa is a fascinating object. If you imagine descending onto a world that looks every place like the frozen ways of the Arctic and the Antarctic, youll get a pretty good impression of
自然百科2012年
the processes that hit Io or operating on Europa as well, but on a less dramatic scale. and so was this constant change(s) in Jupiter's gravitational pull that is distorting the surface and that's generating heat in the interior. This is a clue to Eu
自然百科2012年
Steve Squyres Martian odyssey has taken him from pole to pole, visiting those places on earth that share at least some of the same characteristics. They are extremely dry, extremely cold or extremely dead. Death Valley is one of his favorites. This i
自然百科2012年
In the four decades since our robots first arrived, the once fuzzy ball at the end of our telescopes has steadily focused into a red planet we can understand, and it is not a welcoming place. The problem is the atmosphere is so thin and cold that wat
自然百科2012年
Therere some basic things you should know about Mars before leaving home. Most days will be clear, and sunny and cold. The average temperature on Mars is as bitter as midwinter in Antarctica. And about half the diameter of the earth, Mars is a handy
自然百科2012年
Could life have been forged in the same way on both planets? When we sent the first probe to investigate in the 1960s, almost anything was possible. Originally in the popular imagination we thought that Mars might be inhabited by whole civilizations,
自然百科2012年
There is no room to screw up on a trip like this, mental or otherwise. Once on Mars, you are likely to be stuck there for a year or more, waiting for a window of opportunity to ride home. And unlike a robot, the hopes and fears of the whole planet wi
自然百科2012年
If we have been wet, then we want to look for nutrients and food sources that could support microbes. The water ice is proof of a valuable resource for any life forms still clinging(附着) beneath the surface and for future travelers. We now know th
自然百科2012年
It is chemically impossible for methane to survive for long in the Martian atmosphere, so it must have been released recently. Now what makes methane? Cows make methane? Probably not cows. Oh, microbes, various sorts can release methane, there are a
自然百科2012年
You can make estimates of how much water had to have been flowing that carved these things, and you get numbers like 100, 200 Amazon rivers all cut loose at once, big, big amounts of waterfalls / across its surface. The other big attraction on Mars i
自然百科2012年
It was 119 Fahrenheit here yesterday; really, really, really hot day on Mars ever get up to about 30 Fahrenheit and at night it goes to more than 100 below. Martian deserts are both frozen and sun baked. With no Ozone layer, UV levels are so high tha
自然百科2012年
But still be able to use your hands. Not only will you want to move your fingers, you want to move around. NASAs lunar electric rover is a prototype for future missions to the moon and Mars. Its part vehicle and part space suit. I can just picture be
自然百科2012年
Want to step outside to take in the scenery or pick up some rocks? As familiar as it might look beyond the port hole, Mars is dangerously alien. The upside is the low gravity will give you super jumping abilities, the down, the almost complete lack o
自然百科2012年
Before we take this giant leap, we need to be able to carry everything needed for a three-year -round trip with us. This is a much larger effort than getting to the moon. Its the Apollo mission on steroids. At this point we know at least as much as t
自然百科2012年