It can seem quite challenging for stargazers to comprehend the structure of the universe, but it's really not that difficult.
Just think of it as being assembled in a hierarchical structure not unlike the folders and files in your computer.
Let's start at the beginning ... with stars.
They're everywhere, and we believe that orbiting nearly every star is a planetary system. Get enough stars close enough, and their mutual gravitation can hold them in orbit around a common center of mass.
These are what we know as star clusters.
Now gather a few hundred billion stars and star clusters together, and you've got an immense structure known as a galaxy.
The galaxy in which our star -- the sun -- resides is the Milky Way, so named because its central plane appears as a milky band of light arching across the summertime evening sky.
As immense as it is, ours is not the only galaxy there is.
And, just like stars, galaxies can gather into what we call galaxy clusters and superclusters that extend as far as the largest telescopes can see.
We suspect there may be a trillion or more such galaxies that make up the visible universe. With this many, it's not surprising that some would be visible with even a moderately sized backyard telescope.
And this time of year is a perfect time to do so, since the thickest part of our own Milky Way is below the horizon and does not block our view of the universe beyond.
We can find one of the richest galactic regions of the heavens in the area between the Big Dipper and the stars Arcturus and Spica, high in the eastern sky after dark.
This area of the springtime sky is known to astronomers as the Realm of the Galaxies, and it's definitely worth putting on your bucket list of celestial sights to check out.
If you have a small telescope and a clear night away from bright city lights, scan it slowly through this celestial area and you'll be stunned by what you see.
Even a telescope of 4 or 6 inches in diameter will reveal patch after patch of fuzzy light among the sharper stars.
These are not just smudges but dozens of individual galaxies whose light has been traveling to our eyes since the time that dinosaurs roamed the Earth.
In the vicinity of the bright star Spica, for example, we find the famous Virgo cluster of galaxies, a system of several thousand galaxies bound together by gravitation and located some 60 million or 70 million lightyears from the Milky Way.
To a small telescope, they appear only as tiny smudges of light, but most are gargantuan spiral and elliptically shaped structures.
To the west of Arcturus, we can find the more distant Coma cluster of galaxies. Lying some 400 million light years away, this cluster is home to a thousand galaxies embedded in a region filled with hot gas.
It's truly remarkable what lies in the darkness above our heads on spring evenings. On your next clear, dark night, I hope you'll aim a telescope skyward for a remarkable journey among the galaxies.