Unmanned spacecraft from NASA, Europe and other space agencies are exploring the moon, Mars and other destinations across the solar system. (NASA) The solar system that humans call home may be a strange oddity when compared with the incredible diversity of planetary systems researchers are discovering in the Milky Way, astronomers say. Scientists now estimate the Milky Way galaxy contains at least as many planets as it does stars. So far, researchers have detected nearly 900 of these so-called already,...