When we look out into space, we're also looking back into time. Just how far back can we see?Support us at: stories at: us on Twitter: @universetodayFollow us on Tumblr: us on Facebook: + - +universetoday/Instagram - :Fraser Cain - @fcainJason Harmer - @jasoncharmerSusie Murph - @susiemmurphBrian Koberlein - @briankoberleinChad Weber - @ Gill - @kevinmgillCreated by:Fraser Cain and Jason HarmerEdited by: Chad WeberMusic:Left Spine Down - X- Universe is a magic time window, allowing us to peer into the past. The further out we look, the further back in time we see. Despite our brains telling us things we see happen at the instant we view them, light moves at a mere 300,000 kilometers per second, which makes for a really weird time delay at great say that youre talking with a friend whos about a meter away. The light from your friends face took about nanoseconds to reach you. Youre always seeing your loved ones nanoseconds into the past. When you look around you, youre not seeing the world as it is, youre seeing the world as it was, a fraction of a second ago. And the further things are, the further back in time youre distance to the Moon is, on average, about 384,000 km. Light takes about seconds to get from the Moon to the Earth. If there was a large explosion on the Moon of a secret Nazi base, you wouldn't see it for just over a second. Even trying to communicate with someone on the Moon would be frustrating as youd experience a delay each time you go with some larger examples. Our Sun is 8 minutes and 20 seconds away at the speed of light. Youre not seeing the Sun as it is, but how it looked more than 8 minutes ago. On average, Mars is about 14 light minutes away from Earth. When we were watching live coverage of NASAs Curiosity Rover landing on Mars, it wasn't live. Curiosity landed minutes earlier, and we had to wait for the radio signals to reach us, since they travel at the speed of NASAs New Horizons spacecraft reaches Pluto next year, itll be light hours away. If we had a telescope strong enough to watch the close encounter, wed be looking at events that happened hours ago. The closest star, Proxima Centauri, is more than light-years away. This means that the Proxima Centurans dont know who won the last US Election, or that there are going to be new Star Wars movies. They will, however, as of when this video was produced, be watching Toronto make some questionable life choices regarding its mayoral Eagle Nebula with the famous Pillars of Creation, is 7,000 light-years away. Astronomers believe that a supernova has already gone off in this region, blasting them away. Take a picture with a telescope and youll see them, but mostly likely they've been gone for thousands of core of our own Milky Way galaxy is about 25,000 light-years away. When you look at these beautiful pictures of the core of the Milky Way, youre seeing light that may well have left before humans first settled in North dont get me started on Andromeda. That galaxy is more than million light-years away. That light left Andromeda before we had Homo Erectus on Earth. There are galaxies out there, where aliens with powerful enough telescopes could be watching dinosaurs roaming the Earth, right where it gets even more interesting. Some of the brightest objects in the sky are quasars, actively feeding supermassive black holes at the cores of galaxies. The closest is billion light years away, but there are many much further out. Earth formed only billion years ago, so we can see quasars shining where the light had left before the Earth even Cosmic Microwave Background Radiation, the very edge of the observable Universe is about billion light-years away. This light left the Universe when it was only a few hundred thousand years old, and only now has finally reached us. Whats even stranger, the place that emitted that radiation is now 46 billion light-years away from crack out your sonic screwdrivers and enjoy your time machine, Whovians. Your ability to look out into space and peer into the past. Without a finite speed of light, we wouldn't know as much about the Universe we live in and where we came from. What moment in history do you wish you could watch? Express your answer in the form of a distance in light-years.
Credit: project-ufo.blogspot.com
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