February 18, 1930, 24-year old Clyde Tombaugh discovered a faint, remote object on photographic plates he had taken January 23 and 29 from Lowell Observatory in Flagstaff, Arizona. Astronomers credited him with discovering the ninth planet orbiting the Sun, and it was named Pluto.
It was so distant -- further than Neptune -- and so small and faint that for several decades little was learned about Pluto beyond its orbital characteristics.
During the explorations of the 1970s and 1980s, knowledge about our planetary neighbors was greatly expanded when space craft landed on or flew by every other planet, except Pluto. And we've still not visited Pluto, but that's about to change.
January 19, 2006, NASA's New Horizons spacecraft began its 9 1/2 year journey to the planet Pluto and beyond. But ironically before the craft even left the inner solar system, planet Pluto ceased to exist.
In July 2006, the International Astronomical Union, in a highly publicized and controversial decision, redefined "planet," and Pluto was reclassified as a dwarf planet. It is now seen as one of the largest objects in the Kuiper belt, a swarming cluster of small icy objects orbiting the Sun beyond Neptune -- similar to asteroid belt, the swarming cluster of small rocky objects orbiting between Mars and Jupiter.
In July 2015 New Horizons will fly past Pluto and its three moons making them the most remote objects to be studied up-close. It won't land but after zooming within 6,000 miles of Pluto, it should return images to dazzle our imagination and enough data to keep scientists busy for years.
If funding is available, New Horizons will continue its exploratory journey with fly-by visits to one or more other more distant Kuiper Belt objects between 2016 and 2020. To read more about the New Horizons mission, visit www.pluto.jhuapl.edu.
• Sky Calendar.
* Feb. 7 Sun. morning: The crescent Moon is to the upper right of Scorpius' brightest star Antares low in the southeast.
* 11 Thu. morning: The crescent Moon is to the upper right of Mercury very low in the east southeast at dawn, and to the planet's lower left the next morning.
* 13 Sat.: The Moon is new.
* 14 Sun. very early evening: Jupiter is four moonwidths above brighter Venus with an ever-so-thin crescent Moon to their left near the west southwestern horizon; they are visible soon after sunset and set soon thereafter; binoculars will help.
* 16 Tue. early evening: Jupiter is one moonwidth to the right of brighter Venus very low in the west southwest just after sunset.
* 21 Sun.: The Moon is at 1st quarter.
* 25 Thu. evening and all night: Mars is to the left of the bright gibbous Moon; the faint Beehive Cluster is below them but will require binoculars to see.
• Naked-eye Planets. Evening: As twilight ends, Jupiter is setting in the west as Venus begins its stint as the "evening star;" Mars is still prominent in the east. Morning: At dawn Mercury is very low in the southeast, Saturn higher is in the southwest, and Mars is setting in the west northwest.
• Astro Milestones. February15 is the 446th birthday of Galileo Galilei (1564-1642). February 19 is the 537th birthday of Nicolaus Copernicus (1473-1543).
Stargazer appears every other week. Paul Derrick is an amateur astronomer who lives in Waco. Contact him at 918 N. 30th, Waco, 76707, (254) 753-6920 or firstname.lastname@example.org. See the Stargazer Web site at stargazerpaul.com.