Cygnus X-1 must have a mass of about 7 solar masses or else it would not exert enough gravitational pull to cause the wobble in the spectral lines of HDE 226868.是什么意思_Cygnus X-1 must have a mass of about 7 solar masses or else it would not exert enough gravitational pull to cause the wobble in the spectral lines of HDE 226868.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句