For humans throughout history, the sky has evoked thoughts of a vast emptiness, of a great vacant dome punctuated during the day by the sun, and at night by numerous tiny spots of light (and periodically by the moon). As we have ventured into space, both physically, with spacecraft, and optically, with a range of telescopic technologies, we now know that there is quite a lot of stuff up there. For humans throughout history, the sky has evoked thoughts of a vast emptiness, of a great vacant dome punctuated during the day by the sun, and at night by numerous tiny spots of light (and periodically by the moon). As we have ventured into space, both physically, with spacecraft, and optically, with a range of telescopic technologies, we now know that there is quite a lot of stuff up there. Space Exploration Phys.org – latest science and technology news stories