Jupiter, king of the planets, rules the night sky during October. The gas giant rises in the east-northeast around 6:30 p.m., reaches its zenith around 60 degrees altitude by 1:30 a.m. and at dawn remains visible near the western horizon.
The best Jupiter photos by a Utah amateur astronomer, that I’ve ever seen, were made by my friend David Rankin on the night of Oct. 22. He took them at Lakeside, Tooele County, and they are stunning.
[Photos of Jupiter by David Rankin. In the second view the Great Red Spot, actually a sort of salmon-colored storm larger than Earth, has rotated into view at the lower left. For more of Rankin’s work, click HERE.]
Rankin, a student at the University of Utah who comes from Big Water, Kane County, wrote the next day, “Seeing last night was fantastic, 9/10. Atmosphere was like looking through glass. When the seeing gets great, the details come out.”
A NASA web site offers this description of the planet: “Jupiter, the most massive planet in our solar system — with dozens of moons and an enormous magnetic field — forms a kind of miniature solar system. Jupiter does resemble a star in composition, but it did not grow big enough to ignite. The planet’s swirling cloud stripes are punctuated by massive storms such as the Great Red Spot, which has raged for hundreds of years.”
How massive is it? With a diameter of around 87,000 miles (compared with Earth’s diameter of a little less than 8,000 miles), it has a circumference of 272,946 miles. Earth’s circumference is only 24,900 miles. Jupiter is so huge that it contains more than 1,300 times Earth’s volume, according to NASA.
The solar system has been called the sun, Jupiter and a few odds and ends that didn’t make it into either.
Hundreds of millions of miles away in the far reaches of the solar system, Jupiter fills an important role as Earth’s protector. Its enormous gravity attracts comets and asteroids that otherwise might loop inward toward our environs. The effect was obvious to all of us who witnessed, through a telescope, the clobbering that Jupiter took from Comet Shoemaker-Levy 9 in July 1994.
On a swing past Jupiter, the comet broke into fragments. After circling the sun, their orbit again took them close to Jupiter. This time they slammed into the King in a string of atmospheric detonations. They hit the planet’s far side but soon the impact sites rotated into view.
Holes punched through the upper cloud layers were big enough to see with moderate-size telescopes.
Although Jupiter consists mostly of hydrogen and helium, its composition isn’t entirely gaseous.
NASA points out, “Deep in the atmosphere, the pressure and temperature increase, compressing the hydrogen gas into a liquid. At depths of about a third of the way down, the hydrogen becomes metallic and electrically conducting. In this metallic layer, Jupiter’s powerful magnetic field is generated by electrical currents driven by Jupiter’s fast rotation. At the center, the immense pressure may support a solid core of rock about the size of Earth.”
The rotation is so fast that centrifugal force gives the planet a big bulge at the equator.
Setting aside size superlatives, Jupiter is a joy to the astronomer because it is large and beautiful, a place where something is always happening. Its four largest moons slide through their orbits, sometimes crossing in front of the planet, sometimes casting a shadow upon it, sometimes strung out to its sides. Starting with the innermost, they are Io, Europa, Ganymede and Callisto.
They are bright enough that an ordinary pair of binoculars can show these satellites.
A useful technique in astrophotography is to take a series of images of the same object and electronically stack them, which reduces noise and renders the view sharper. But there’s a problem with that in imaging Jupiter: it moves fast. The surface makes a complete rotation in less than 10 hours, compared with our own 24-hour day. When you consider Jupiter’s vast girth, that’s incredibly fast, with features traveling around 27,000 mph.
Jupiter rotates so quickly that I’ve had trouble taking photos of it to stack; within 10 or 15 minutes features have moved and no longer line up with their images in earlier pictures. And I have spent hours watching places like the Great Red Spot move across the surface and disappear over the horizon.
Bands of varying darkness and widths, white and salmon-colored and reddish spots that are furiously churning storms, festoons that stretch within bands, brilliant moons, cloud swirls and streaks — Jupiter delights the eye and mind.