An Earthlike Planet In January 2006, astronomers reported the discovery of a planet comparable in size to the earth orbiting another star and having a mass of about 5.5 times the earth's mass. It is believed to consist of a mixture of rock and ice, similar to Neptune. If this planet has the same density as Neptune (1.76 g/cm'), what is its radius expressed
(a) In kilometers and
(b) As a multiple of earth's radius? Consult Appendix F for astronomical data.