That’s because light moves, at the speed of light. It takes time for the light to reach us. Light can be absorbed, reflected, and re-emitted by gas and dust, giving us a second look. They’re called light echoes, and allow astronomers another way to understand the Universe around us. Audio Podcast version:ITunes: https://itunes.apple.com/us/podcast/universe-today-guide-to-space-audio/id794058155?mt=2RSS: https://www.universetoday.com/audioWhat Fraser's Watching Playlist:https://www.youtube.com/playlist?list=PLbJ42wpShvmkjd428BcHcCEVWOjv7cJ1GWeekly email newsletter:https://www.universetoday.com/newsletterSupport us at: http://www.patreon.com/universetodayMore stories at: http://www.universetoday.com/Twitch: https://twitch.tv/fcainFollow us on Twitter: @universetodayLike us on Facebook: https://www.facebook.com/universetodayInstagram - http://instagram.com/universetodayTeam: Fraser Cain - @fcain / [email protected]Karla Thompson - @karlaii / https://www.youtube.com/channel/UCEItkORQYd4Wf0TpgYI_1fwChad Weber - [email protected]References:https://www.nasa.gov/feature/jpl/arecibo-radar-returns-with-asteroid-phaethon-imageshttps://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20100413-apollo15-LRRR.htmlhttps://www.spacetelescope.org/videos/heic0617a/https://www.nasa.gov/feature/jpl/light-echoes-give-clues-to-protoplanetary-diskhttps://www.nasa.gov/feature/goddard/2019/nasa-s-nicer-mission-maps-light-echoes-of-new-black-holehttps://hubblesite.org/contents/news-releases/2017/news-2017-42.htmlhttps://www.eso.org/public/images/potw1814a/