When you consider just how far away the cosmos is, the numbers can get so mind boggling that when you try to wrap your brain around them your head could explode! That’s really a bad scene!

To avoid making a mess of your mind, you can make use of some handy units of measurements designed for astronomy that ease your brain.

First off, let me start with a unit we all know and love, the mile. Just to give you some perspective, the diameter of the Earth is about 8,000 miles and the circumference of the Earth at the equator is just less than 25,000 miles.

The closest celestial object in the heavens, be it human made, is the International Space Station that circles our world once every 90 minutes at a height of around 250 miles.

If it happens to be passing above Butler you can’t miss it. It’s so easy to see, no binoculars or telescopes needed. I think a lot of folks mistake it for a high-flying aircraft. It resembles a super bright star generally pushing from the west to east at various heights across the celestial dome.

The best website to keep up with space station’s comings and goings is www.heavensabove.com. Just set your location with the database provided and you’re good to go.

The next closest celestial body is the moon with an average distance of about 238,000 miles.

Now, I can deal with hundreds of thousands of miles but when it comes to millions of miles, the distance of the planets in our solar system, that’s when I need help!

For example, the brightest planet in the night sky right now is Venus. It resembles a super bright star shining like a bright beacon in the low early evening western sky. In fact, it pops out well before the end of evening twilight.

Venus is about 130 million miles away right now. An easier way to express distances in our solar system is in astronomical units and they’re really simple. One astronomical unit (A.U.) equals 93 million miles, the average distance between the Earth and the sun. That would put Venus at about 1.4 A.U. away, which is fairly close by as planets go.

Venus’s brilliance is not only due to its proximity to the Earth but the fact that the planet, about the same size as our Earth, is completely swamped in a heavy atmosphere that’s very reflective of the sun’s light.

By the way, if you’re considering travel to Venus anytime soon, I would reconsider. That thick atmosphere contains lovely things like carbon monoxide gas laced with acid rain.

Even If you got by all that and reached the surface, you’d be subjected to crushing atmospheric pressure exceeding 90 times that of Earth. You’d also be well baked with surface temperatures as high as 900 degrees. Talk about a pressure cooker!

Another planet available in the early evening sky is Saturn in the southwestern sky, just a little above and to the left of Venus. It’s not as bright as Venus but is the next brightest starlike object in that part of the sky. It shines at us from 893 million miles in our collective backyards.

I don’t know about you, but that kind of distance is tough to visualize. If you use astronomical units that would put the ringed wonder of our solar system at 9.6 A.U. away, which is a little easier to intellectually digest.

Even as far away as Saturn is it’s so gigantic that even with a small telescope you can see the ring system and maybe even some of its moons. As you can see on the diagram, you can use the waxing gibbous moon Tuesday evening to find Saturn.

For stellar distances it would be absolutely silly to talk about them in the miles. The next closest star to our sun is Proxima Centauri. That star is nearly 25 trillion miles away.

As humongous of a number as that is, that’s celestial chicken feed compared to distances of other stars, many of which we can see every night with just our naked eyes. That’s why it’s best to express stellar distance in light years.

A light-year is defined as the distance a beam of light travels in one year’s time. Using the speed of light, which is 186,300 miles per second, one light-year computes out to be 5.8 trillion miles. That would put Proxima Centauri at about 4.3 light years away.

For example, the next brightest star closest to Saturn in the southwest sky is Spica, just to the lower right of Saturn. Spica is 263 light years away. You certainly wouldn’t want to express that in miles.

Actually, there are some stars you can easily see just with your eyes that are thousands of light years away. In fact, there are whole other galaxies of stars that over 10 billion light years away!

Light years are also cool because not only do they express distance but they also express time.

Because a light-year is the distance light travels in one year, the light you see from a star that’s 10 light years away takes 10 years to reach your eyes. The light you see from a star 100 light years away would take a century to reach you. If a star is a 1,000 light years away, it would take a millennium for the light to reach you.

So when you’re stargazing on these warm summer nights, keep in mind that when you look into the heavens, not only are you looking into incredibly far away places but you’re peering way back in time. Don’t let your head explode!

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications available at bookstores at www.adventurepublications.net.