Perfect time to witness solar system in action


The current health crisis forces us to “shelter in place.” Our universe has become inevitably constricted to our homes, our yards if we have one, and perhaps a walk around our neighborhoods.

Still, we may get a glimpse of the larger universe and our location in it simply by going out into our own backyards in evening and morning twilight.

We are in the midst of a grand planetary conjunction. In the evening, Venus, the brightest of all the planets, is visible in the west as an attention-grabbing point of pure white light, but it isn’t part of the conjunction.

In the morning, Jupiter, Saturn, and Mars are all easily visible to the unaided eye in the southeast. They are clustered together in the same section of the sky. Of course, they only appear to be close together, which is the sole criterion for a conjunction of the planets.

In addition, Pluto is over there near Jupiter, but unless you have an observatory-sized telescope in your backyard, a detailed set of star charts, and infinite patience, I wouldn’t spend much time looking for Pluto. I’ve seen it twice in my observing life, and despite having all those advantages, it still took me a minimum of two hours to find it.

Still, add Pluto to the morning mix, and you have yourself a recipe for a brand of the Internet silliness that we have come to call “fake news.” Others call it astrology.

Our ancient forebears made much of such close approaches. When they saw the planets line up, they saw portends of great good or great evil.

Sad to say, the old superstitions have not disappeared entirely. I have recently perused many astrological interpretations of our grand morning conjunction. Some of them say — after the fact, mostly — that the conjunction predicted the current COVID-19 crisis. Others say that the conjunction — particularly the conjunction of Jupiter and Pluto — predicts the length and severity of the coronavirus crisis.

The logic is hard to fathom, but it’s there. Jupiter was the king of the gods. He had some control of nature. When he was in a bad mood, disaster often followed on Earth.

Nothing ruined Jupiter’s mood more than having to spend time with his morose brother, Pluto. He was the god who ruled the Underworld, where the spirits of the dead aimlessly wandered. Given his dark domain of death, Pluto was not the most jocular of fellows.

Of course, the ancients had no knowledge of the planet Pluto. Unfortunately, when Clyde Tombaugh discovered the tiny ice dwarf in 1930, astronomers quite naturally chose to name it Pluto. They were continuing the tradition of naming planets after Roman gods even if nobody believed in them anymore.

Also, Pluto is way out there in the coldness and darkness of space. Pluto seemed like the perfect name for the tiny, isolated object. The members of the naming committee could hardly have predicted the astrological silliness that was to follow.

Besides, the apparent closeness of the planets in the morning conjunction is simply a line-of-sight illusion caused by our Earthly vantage point. The planets are lined up, but enormous distances separate them.

Earth is the third planet from the sun. Mars is the fourth. Right now, Mars is a rather distant (for Mars) 140 million miles away.

Jupiter is the next planet out at over 490 million miles away. Distant Saturn is almost 960 million miles away.

That’s nearly a billion miles, folks. If numbers that big make absolutely no sense to you, join the club. But a billion miles is still next door, cosmically speaking, compared to Pluto, which takes the conjunctive prize at over three billion miles away.

One way of thinking about those incomprehensible distances is to think about how far the planets are away from us if we measure them in light minutes.

Light from the sun bounces off the planets, and a tiny portion of it heads toward planet Earth and your eyeballs. Light takes time to get from there to here, and that time is also a measure of distance.

Thus, Mars is a scant 12 light-minutes away. You are seeing it the way it looked 12 minutes ago. Jupiter is about 44 minutes away by light beam. Saturn is 85 light-minutes away, almost an hour and a half. Pluto is 285 light minutes away, about 4 ¾ hours.

To at long-last return to astrology, it’s difficult to figure how those distant planets could be influencing your life on Earth, but I’ll leave it to the astrologists to explain if they want to.

With those enormous distances in mind, I hope you’ll go outside into your backyard and find them. Let’s start with the easy ones. It’s hard to miss extraordinarily bright Venus high in the northwestern sky during evening twilight. Venus gets its brilliance partly from its proximity. We live on the third planet from the sun. Venus is the second.

Mostly, Venus is simply very reflective. Its layer of white sulfuric-acid clouds makes for a very shiny mirror of the sun’s light. Sulfuric acid aside, it’s hard to match Venus’s pure-white splendor. It’s easy to see why the ancients thought she was the goddess of love and beauty.

We now switch to the morning sky. Jupiter is not so bright or so close as Venus, but it’s still pretty obvious in deep morning twilight. Look southeast for a slightly yellow point of light. I have been starting at 5 a.m. and waiting for Jupiter to rise above the houses in that direction.

Jupiter is the largest of the planets at almost 90,000 miles wide. At 8,000 miles wide, Earth would fit inside of it over 1,400 times.

But Jupiter, as we have seen, is also very far away. Thus, it takes at least a small telescope to resolve it into a tiny disk. Binoculars won’t help you much here.

But grab your binoculars anyway and check out Jupiter’s four brightest moons, the Galilean satellites. Depending on the quality of your binos, at least two of them should be visible lined up closely around the planet.

If you see them, consider the great distance that the light had to travel to get to your eyes. The moons were in the positions you see them 44 minutes ago. As they rapidly orbit Jupiter, they have moved to new locations. In the “now” that you are seeing them, they are actually someplace else.

Down and to the left from Jupiter is yellowish Saturn, which should stand out even if it is not nearly so bright as Jupiter.

Binoculars won’t help you much here. It is twice the distance as Jupiter right now, and the planet is even smaller than Jupiter at 75,000 miles wide. Its fabulous rings stretch over 200,000 miles from side to side, however. If you have even a small telescope and you or your children have never seen the rings, I envy you the life-changing experience of seeing them for the first time.

Down and to the left from Saturn is tiny Mars, which shines right now with about the same brightness as Saturn. At only 4,000 miles wide, Mars is only twice the diameter of Earth’s moon. Mars may be, on average, the closest planet to Earth, but its small size makes it a poor object for even a large telescope.

Instead, marvel at its reddish hue, which the ancients associated with blood. Is it any wonder why our ancient forebears associated the planet with bloody Mars, the god of war?

As you face the morning planets, take a moment to orient yourself in space. You are gravitationally bound to a tiny, 8,000-mile wide ball of rock called Earth. As you stare at the morning planets, so far away, your planet is spinning in their general direction — the direction you are facing — at 680 miles per hour.

Venus is 53 million miles behind you. Because its orbital speed is faster than Earth’s, the goddess of love is, for a while at least, moving ever closer to you.

To your left is the soon-to-rise sun, around which you and your planet are orbiting at 67,000 miles per hour, again in the direction you are facing.

Your neighborhood, which in these days of imposed isolation seems so small, has just expanded to include the vastness of space.

Clear mornings are hard to come by this time of year, and your cosmic neighborhood is all lined up and waiting for you. So set your alarm for 4:45 a.m., and stick your head out the window. If you see stars, I hope you will briefly escape the confines of your temporarily restricted world by going outside and witnessing the solar system, your larger neighborhood.

By Tom Burns


Tom Burns is the former director of the Perkins Observatory in Delaware.

No posts to display