If you could travel in time, when would you want to visit? While time travel as we know it from science fiction isn’t possible, there are other ways of looking into the past. Observing the night sky, we can see light finally reaching us after traveling large distances and spans of time, letting us step back in the history of Earth and the universe.
The easiest example to start with is Sol, our sun. Light takes about 8 minutes to travel from the sun to Earth. Now, a lot can happen in 8 minutes, but what about traveling even farther back in time?
Arcing west of Ursa Major’s tail we arrive at the constellation Boötes. In Boötes is the galaxy 3C 295. If you were light traveling from that galaxy, you would have covered about 5 billion light-years. When your journey started, there would still be about 500 million years before the Earth formed.
Continuing the arc west from Boötes, you reach the constellation Virgo. In her right hand is a palm frond or bundle of grain or corn, which contains the Virgo Cluster. Within that cluster is a group of galaxies referred to as Markarian’s Chain. The closest of these galaxies is still 50 million light-years away. The light left these galaxies near the end of the uplift of the Rocky Mountains.
Sitting low on the northern horizon sits the W-shaped constellation Cassiopeia. Below Schedar, in the pointier part of the W, lies a Local Group galaxy that is 2 million light-years away. If something in that galaxy, called NGC 185, was viewing Earth and could see Colorado, they would see it before the Black Canyon of the Gunnison had formed. Schedar, on the other hand, is a mere 230 light-years away. Light left that star 3 years after the US Constitution was written.
Vega, part of both the constellation Lyra and the Summer Triangle asterism, can be found above Polaris, the North Star. Vega is only 25 light-years away. Perhaps you can remember something that happened to you in 1997, as that light left.
Returning to Ursa Major, in the north-west, is one of the current oldest and furthest confirmed galaxies in the universe, GN-z11. This galaxy was observed just above the cup of the Big Dipper by NASA’s Spitzer Space Telescope in 2015. We see this galaxy as it existed a staggering 13.4 billion years ago. Its light has been traveling since just after the birth of the universe.
As we learn more about deep-space objects such as these, we better understand what our universe was like in its infancy. The more we learn about the universe, the better we understand our relatively brief chapter in its history.
Western Slope Skies is produced by the Black Canyon Astronomical Society and KVNF Community Radio. This feature was written and voiced by Jaron Boerner-Mercier, Park Ranger at Black Canyon of the Gunnison National Park.