Come Together

      Where will you be 20 years from now? Not to go all morbid on you but some of us will be in a place without a great view. Or any view at all for that matter.

     That's why I'll be looking to the southwest every clear evening for the rest of the year. As the sky darkens two prominent 'stars' become visible high above the horizon. In truth they are not stars at all but the planets Jupiter and Saturn. Night by night they will be drawing closer together until December 21 when they will almost touch. It's an event that astronomers call a Great Conjunction and due to the physics of their orbits it won't occur again for nearly two decades.

Sky and Telescope image

  

This will be the view thru a small telescope on December 21

Saturn upper right, Jupiter left of center with four of its moons

image from space.com

     Jupiter and Saturn are called gas giants because they are mostly hydrogen and helium, the same as the Sun but without the mass necessary to ignite fusion in their cores. They may be 'failed' stars but they are certainly no slouches, Saturn is 9x and Jupiter 11x larger than Earth. 

NASA image of Jupiter

       While they will appear close together in our sky no social distancing guidelines are being broken. It's strictly a line of sight phenomenon with Saturn being 400 million miles beyond Jupiter in space. A celestial 'Zoom' meeting of sorts, Saturn is orbiting at 21,562 mph, Jupiter picks up the pace at 29,205 mph and Earth zips along at 66,622 mph. Puts to shame those turtles crawling around NASCAR tracks.  

     In mythology Saturn was the father of Jupiter and I see some lingering rivalry between the two. Jupiter is bigger and has a whopping 79 moons, including Ganymede, the largest in the solar system. But Saturn may eventually come out on top with 82 possible moons, some still needing confirmation. And Saturn has Titan, just a little smaller than Ganymede and the only moon known to have an atmosphere. It could harbor life of some sort. Then there are those rings, thin bands of rock and ice fragments that make Saturn such a spellbinding sight.

NASA image of Saturn

     I'm no rocket scientist. Maybe that's why I'm so amazed at what real rocket scientists are capable of. I do go out and gaze at the sky every night before bed. It kind of 'puts me in my place'. But I also like to browse the web for breathtaking images no naked eye will ever see. You can find photos that required 300, maybe 400 hours of exposure time. Ah, the skill and patience needed to let photons dribble in from the farthest reaches of the universe, ever so gradually coalescing into a picture of what lies beyond our wildest imagination. And the spacecraft - Cassini was at Saturn and Juno is now orbiting Jupiter - their views make you feel as if you're swooping by rings and moons and great red spots.

     Our little blue planet has its problems ( a certain poor loser amongst them ), but it's in a fine neighborhood and still a great place to call home. Now, if we could all just come together, it would be even better.

Next door neighbors...

     Mars is visible most of the night. Look for the bright orange dot high in the east as the evening grows dark.

     Venus and Mercury can be seen before dawn. Venus is the brightest object in the sky ( other than the Sun and Moon ). Around 5:30 to 6:00 am is a good time. You may be able to catch much dimmer Mercury, lower and closer to the horizon over the next few mornings. 

Sky and Telescope image