I hope you enjoyed the recent planetary conjunction in the western sky. From our perspective, Venus and Jupiter are now slowly separating from each other after their closest approach June 30. Although they appeared very close in the sky, Jupiter is more than 10 times farther away than Venus.
If that distance sounds incredible, it is. But Pluto is almost 10 times farther away than Jupiter. It is so distant, that even Hubble telescope photos show an object only a few pixels across.
The ninth planet was discovered in 1930, but even by this century not much had been learned about it – except that it wasn’t a planet. Beginning in the 1990s, many objects of a similar distance to the sun were discovered, and it was evident that Pluto was one of these Kuiper belt objects. The Kuiper belt is the solar system’s reservoir of short period comets.
In 2006, Pluto received what many of the public feel to be a demotion to dwarf planet status. I have seen petitions attempting to restore it to its previous designation, but I doubt that any will be successful. The most compelling argument for me is that if Pluto were somehow to travel to our part of the solar system, it would most likely develop a tail like a comet. That would be a most un-planet-like trait.
Nine years after leaving Earth, the New Horizons spacecraft is now approaching Pluto and will begin nine days of intensive scientific observations next week. As with all voyages of discovery, no one is quite sure what to expect.
The visible light photographic images might end up being the most memorable, but other instruments on New Horizons include spectrometers in various wavelength bands, instruments to measure the solar wind, and the Student Dust Counter, or SDC. The SDC has a Colorado connection. It was designed, built and is being operated by students at the University of Colorado Boulder Laboratory for Atmospheric and Space Physics.
Venus and Jupiter are still the two brightest things in the sky besides the sun and the moon. They are both in the western sky right after sunset, and will make good telescope targets for the next few weeks. Venus shows a nice crescent shape right now that is visible even under very low magnification.
Saturn, now in the constellation Libra, is getting into a prime viewing position high in the sky during the early evening. The tilt of the rings this year is greater than it has been in a decade, and we can look forward to some amazing views.
If the weather holds, there will tentatively be stargazing events Saturday at Mancos State Park, Wednesday at Durango Nature Studies and July 17 at Chimney Rock.
I hope to see some of you at one of these events.
Charles Hakes is an assistant professor in the physics and engineering department at Fort Lewis College and is director of the Fort Lewis Observatory. Reach him at firstname.lastname@example.org.