When left alone disks galaxies can rearrange their stars and gas (as a response to instabilities).This process (called secular evolution) is often seen as spiral disks and galactic bars.是什么意思_When left alone disks galaxies can rearrange their stars and gas (as a response to instabilities).This process (called secular evolution) is often seen as spiral disks and galactic bars.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句