[填空题]
The nearest star to Eac6pur )-:6gvt2vy j hzrth is Proxima Cw -tybsy/ o:o) ) uwsib m*lznq-d66ywawt91 .entauri, 4.3 light-years away.
(a) At what constant velocity must a spacecraft travel from Earth if it is to reach the star in 4.0 years, as measured by travelers on the spacecraft? c
(b) How long does the trip take according to Earth observers?$t_{Earth}$ = yr
