1、The mystery arises when one considers how a spiral galaxy rotates.
當(dāng)人們考慮旋渦星系是如何轉(zhuǎn)動的時候難題就來了。

2、The mystery arises when one considers how a spiral galaxy rotates
當(dāng)人們考慮旋渦星系是如何轉(zhuǎn)動的時候難題就來了。

3、Barred spiral galaxy NGC 4731 lies some 65 million light-years away.
棒旋星系ngc 4731約在6500光年以外。

4、On the right, surrounded by blue spiral arms, is spiral galaxy M81.
右邊被藍色旋臂環(huán)繞的是旋渦星系m 81。