[填空题]
A galaxy is moving away from Earth. The "blue" hydrogen linv xipd0g6, u cgw67bjqhfm0o/8 eo.7ve at 4hv7vrf +q 16om34 nm emitted from the galaxy is measured on Em 7r6o1 fvhqv+arth to be 650 nm.
(a) How fast is the galaxy moving? v $\approx$ c
(b) How far is it from Earth? d $\approx $ $ \times 10^9\ \text{y}$
