2019
灞婇珮鑰冭嫳璇叏鐪熸ā鎷熷瘑鍗峰強绛旀
(
鍚嶅笀鎶奸棰勬祴
+
瀹炴垬璁粌锛屽缓璁笅杞界粌涔?/p>
)
1
銆?/p>
The oddness (
鍙嶅父
) of life in space never quite goes away. Here are some examples.
First consider something as simple as sleep. Its position presents its own challenges. The
main question is whether you want your arms inside or outside the sleeping bag. If you leave
your arms out, they float free in zero gravity, often giving a sleeping astronaut the look of a
funny balled (
鑺暰
) dancer. 鈥淚鈥檓 an inside guy,鈥?nbsp;Mike Hopkins says, who returned from a
six-month tour on the
International Space Station. 鈥淚 like to be wrapped up.鈥?/p>
On the station, the ordinary becomes strange. The exercise bike for the American
astronauts has no handlebars. It also has no seat. With no gravity, it鈥檚 just as easy to pedal
violently. You can watch a movie while you pedal by floating a microcomputer anywhere you
want. But station residents have to be careful about staying in one place too long. Without
gravity to help circulate air, the carbon dioxide you exhale (
鍛兼皵
) has a tendency to form an
invisible (
闅愬舰鐨?/p>
) cloud around you head. You can end up with what astronauts call a
carbon-dioxide headache.
Leroy Chiao, 54, an American retired astronaut after four flights, describes what happens
even before you float out of your seat, 鈥淵our inner ear thinks you鈥檙e falling. Meanwhile your
eyes are telling you you鈥檙e standing straight. That can be annoying鈥攖hat鈥檚 why some people
feel sick.鈥?nbsp;Within a couple days鈥?/p>
truly terrible days for some
鈥?/p>
astronauts, brains learn to
ignore the panicky signals from the inner ear, and space sickness disappears.
Space travel can be so delightful but at the same time invisibly dangerous. For instance,
astronauts lose bone mass. That鈥檚 why exercise is considered so vital that National
Aeronautics and Space Administration (NASA) puts it right on the workday schedule. The
focus on fitness is as much about science and the future as it is about keeping any individual
astronauts return home, and, more importantly, how to maintain strength and fitness for the
two and a half years or more that it would take to make a round-trip to Mars.