Two bright planets dominate the evening sky this fall: One in the west and one in the east, and even though they look quite similar, they could not be more different from one another.
In the west just after the sky begins to darken, but before it is totally black, look for Venus shining brighter than any other object in the sky except the sun or the moon. It orbits the sun closer than we do, so from our perspective it never gets far from the sun. You would never see it overhead.
The reason Venus is so bright is because it is wrapped in a thick layer of clouds that reflect the light of the sun. Those clouds prevent us from seeing the surface of the planet directly so Venus has always been enshrouded in mystery. Early astronomers imagined that they could see Himalayan-sized mountains sticking out of those clouds. Science fiction writers envisioned a steamy jungle world with exotic creatures roaming its surface.
Today we have a very different view of Venus. Forget the steamy jungle world. It is more like Death Valley on steroids. The temperature on the surface of the planet is a searing 900 degrees. Hot enough to melt lead. If we could somehow move the earth to the same orbit as Venus, the temperature would rise 50 degrees on our planet which would be way too hot for us, but 900 degrees? Why is it so hot? Those clouds trap the heat from the sun, producing a runaway greenhouse effect from which Venus will never recover. It is experiencing global warming from hell.
Those clouds which make Venus so bright and beautiful in our evening sky right now are not the friendly water vapor clouds that we have here on earth. They are composed of concentrated battery acid and it actually rains acid in their upper levels. The clouds are so thick and heavy that standing on the surface of Venus would be like standing on the floor of the ocean with 3,000 feet of water above you. They are heavy enough to flatten a car. If you were thinking about a romantic vacation on Venus, maybe you are getting the idea that it would not be a lot of fun.
Jump to Jupiter
Look for another planet, bright but not quite as dazzling as Venus in the east. That is Jupiter, and it could not be any more different from Venus. It is cold, hundreds of degrees below zero. It is a lot farther away from the sun and receives just a fraction of its warmth. Also there is nothing solid to stand on.
It does not just have clouds, it is all clouds. Jupiter is a gas giant as are Saturn, Uranus and Neptune. If you tried to land there, you would sink down into those clouds, and the pressure would build until your space ship would be crushed by the enormous weight of them. Did I tell you about the wind chill? Those clouds are whipping by at 1,000 miles per hour.
If you want to visit Jupiter, I would recommend one of its moons. Last time I checked there were 67 to choose from, each unique. You will have a spectacular view of the planet itself watching the bands of clouds churning and perpetual storms brewing, and you could actually stand on one of those moons.
Hopefully, the smoke will allow us to see these two beautiful planets up there. They are the brightest objects in the sky, so if you cannot see them you cannot see anything. Train a small telescope on Venus and watch it go through its phases like the moon. That telescope will show you four of Jupiter’s moons and, if you look carefully you might spot the cloud bands, little straight lines across the planet. I am looking forward to clearer skies this autumn and being able to see the stars again.