Jimmy Westlake's Celestial News column appears monthly in the Steamboat Today.
Find more columns by Westlake here.
Steamboat Springs What's the brightest star-like object that can shine in our midnight sky? It's the planet Jupiter, the largest of the planets in our solar system. You might have noticed it recently, gleaming over the southern mountaintops late at night. The gap between Earth and Jupiter has been closing throughout the past few months and the two planets will be as close together as possible on the night of July 8. That is the night of Jupiter's opposition to the sun, when the Earth lies directly between the giant planet and the sun. Rising as the Sun goes down, Jupiter will remain in the sky all night long, setting at sunrise. After July 8, Earth and Jupiter will grow farther and farther apart. It then will be a constant companion in our evening sky throughout the remainder of the year, but it will not appear any bigger and brighter than it does for the next few weeks.
This year, Jupiter is nearly as far south in our sky as it can ever be. It slowly is sliding westward from night to night through the stars of Sagittarius, the Archer, near the misty star clouds of the Milky Way.
Do you own a pair of binoculars? If you do, try aiming them at Jupiter, and you might glimpse one or two of Jupiter's four giant moons. A small telescope will show them even better. It's amazing to watch the moons dance around Jupiter, changing their positions from night to night.
Jupiter is a totally different kind of planet than Earth. It is a colossal ball of hydrogen and helium gas, held together by its enormous gravity. Jupiter has no solid surface to stand on. If you tried to land on it, you would just sink down into its deep, deep atmosphere and eventually splash down into an ocean of liquid hydrogen, thousands of miles deep.
With your telescope, you can see alternating light and dark cloud stripes in Jupiter's atmosphere, as well as its famous earth-sized storm, the Great Red Spot. Recently, a smaller red spot has formed, nicknamed Red Junior. Scientists have determined that Red Junior formed as a result of a warming of Jupiter's atmosphere throughout the past few years. Similar warmings have been measured in the atmospheres of Mars, Pluto and even Neptune's large moon Triton. Because there are no SUVs belching CO2 on these worlds, there must be some other cause for the solar system's warming trend. It strongly suggests that "global warming" must originate with the sun, not with anything that we humans are doing. Interesting, isn't it, that by studying Jupiter and the other worlds in our solar system, we learn much about our own planet Earth?
Spot Jupiter for yourself in the southeastern sky this month during the late evening.