?Getting around the sun in 2017 was a memorable trip.繞日而行可以說是2017年里一段難忘的旅程了。
? 撰文\播音:史蒂夫·米爾斯基(Steve Mirsky) 翻譯:陳美娟 審校:張清越 Happy New Year!?And if you’ve been away from work for a few days,?you deserve some time off. After all, you’ve traveled far.?Even if you just stayed at home. According to NASA, just by being on the planet Earth in the last year, you’ve zipped about 584 million miles around the sun.?At an average speed of about 67,000 miles per hour.?[Siren sound.]?Hey, I wasn’t speeding—in my inertial reference frame. 如果你已經(jīng)甩開工作好幾天了的話,我只能說你確實該緩緩身子了。畢竟,今年你已經(jīng)“轉(zhuǎn)”了這么遠。就算你只是待在家里也算。NASA(美國國家航空航天局)的報告顯示,光是去年一年,身在地球上的你就已經(jīng)以平均每小時六萬七千米的速度繞著太陽轉(zhuǎn)了五億八千四百多萬米了。【警笛響起——】嗐,我可是一直照著慣性參照系算的,一點沒超速。 Of course, the trip was not a perfect circle.?As Kepler showed, the Earth’s orbit is an ellipse, with the sun at one of the two focal points.?He also figured out the planet goes faster when it’s at perihelion, nearer the sun, than when it’s at aphelion, its farthest distance.?Which would explain why summer seems to zip by, except that the seasons are a function of the tilt of the Earth’s axis, not its different distances from the sun.?And the Earth rotated 365 and a quarter times during its sweep around the sun.?The trip took 8,766 hours.?Or 525,960 minutes. Or 31,557,600 seconds.?Tick tock. 當然啦,這趟旅程沒按著完美的正圓形軌道在走。開普勒證明過,地球的繞日軌道是個橢圓形,太陽剛好位于其中一個焦點上。他還指出,地球在位于接近太陽的近日點處的速度比在離太陽最遠的的遠日點的速度更快。這就可以解釋除了季節(jié)的變化對地軸傾斜程度有影響外,為什么夏天的日子看起來飛逝而過,而這卻不是由地球離太陽的遠近決定的。地球繞日一周要365又四分之一天。這是8766個小時。也就是31,557,600秒。嘀嗒一下,秒奔千里。