Gazing up at the night sky, it is easy to be struck by a sense of awe and wonder. We can see galaxies trillions of miles away, the closest of which is our own Milky Way. But what about galaxies that lie beyond our own? One such galaxy is ESO 300-16, a ghostly assemblage of stars 28.7 million light-years from Earth in the constellation Eridanus.
The NASA/ESA Hubble Space Telescope has captured an image of this distant galaxy, which resembles a sparkling cloud. Included in the image are other distant galaxies and foreground stars making this an astronomical portrait of the cosmos.
This picture is part of a series of observations aimed at getting to know our galactic neighbors. Hubble has been able to observe around three-quarters of the known galaxies within 10 megaparsecs (or 30.9 trillion kilometers) from Earth, enough to detect the brightest stars and measure the distance of these galaxies. A team of astronomers has even proposed using gaps in Hubble’s schedule to observe the remaining quarter of these nearby galaxies.
The unit used by astronomers to measure these colossal distances is the megaparsec (one million parsecs). A parsec is equal to 3.26 light-years or 30.9 trillion kilometers (19.2 trillion miles). As Earth orbits around the Sun, stars appear to shift slightly against very distant stars over time; this effect is called parallax and is measured in angular units such as degrees, minutes and seconds.
In other words, when observing stars from different angles, they appear to move relative to each other and this movement is referred to as parallax. One parsec is equivalent to the distance creating a parallax of one-arcsecond. The closest star to our Sun is Proxima Centauri, which lies 1.3 parsecs away.
Being able to observe galaxies such as ESO 300-16 still leaves us in awe and wonder about our place in the universe. Knowing that there are millions upon millions of galaxies out there makes us reflect on our own insignificance in the grand scheme of things—but also on our importance as conscious, intelligent beings. This makes it all the more meaningful when we look up at night at ESO 300-16 and other distant galaxies, knowing that each one has its own story to tell.