Since we’re all in the democratic mood here today in the U.S., how about another chance to put your vote in on something: names for Pluto’s newest moons!
Today marks the 20th anniversary of the discovery of the first Kuiper Belt Object, 1992QB1. Called KBOs for short, these are distant and mostly tiny worlds made up of ice and rock that orbit the Sun at incredible distances, yet are still very much members of our Solar System. Since 1992 over 1,300 KBOs have been found, and with NASA’s New Horizons spacecraft speeding along to its July 2015 rendezvous with Pluto and Charon (which one could reasonably argue are technically the first KBOs ever found) and then onwards into the Belt, we will soon know much more about these far-flung denizens of deep space. But how has the discovery of the Kuiper Belt — first proposed by Gerard Kuiper in 1951 — changed our understanding of the Solar System?
Acquired in March 2007, this eerie image from Hubble’s Advanced Camera for Surveys’s ultraviolet camera show glowing auroral emissions, always present in Jupiter’s polar regions.
The aurora is hundreds of kilometers wide and about 250 kilometers above the planet. It is caused by electrically charged particles striking atoms in the upper atmosphere from above, the same process involved in Earth’s aurorae (except that Jupiter’s magnetic field is orders of magnitude more powerful than Earth’s!)
NASA’s New Horizons spacecraft is currently speeding through the outer solar system toward its July 2015 date with Pluto, when it will take a good close look at the dwarf planet’s mysterious surface, atmosphere, moons, and… rings?
Less than three-quarters the size of our moon, Pluto nevertheless has no shortage of fascinating features. It has a curiously mottled coloration that seems to change with its seasons, an atmosphere that expands and falls back onto its surface, a system of four moons in orbit around it — the most recent of which, currently called “P4″, was announced just last summer — and, according to Planetary Science Institute senior scientist Henry Throop, possibly even a system of rings.
Hey, at this point… why not?
NASA’s New Horizons spacecraft passed a new milestone today, officially becoming the closest spacecraft ever to the distant dwarf planet Pluto!
As it continues its trip through interplanetary space, clocking an impressive 35,000 mph (more than twice the speed of the ISS in orbit!) New Horizons is currently in hibernation mode, and has already passed the halfway point to Pluto. It will make its closest approach to the Pluto-Charon system on July 14, 2015.
The largest of Jupiter’s 63 known moons and the largest moon in our solar system, Ganymede has twice the mass of our own moon and is even larger than the planet Mercury. Its surface is marked by dark regions which are full of craters and lighter areas lined with ridges.
This image was taken by the New Horizons spacecraft’s Long Range Reconnaissance Imager (LORRI) in February 2007 while on its way to Pluto. New Horizons is scheduled to pass by Pluto in 2015…it is still en route and is currently between the orbits of Saturn and Uranus, over 1.2 billion miles from Earth.
Ganymede has a thin oxygen atmosphere as well as a magnetosphere, and is the only moon currently known to have one. It is likely generated by a molten core made up of heavy conductive metals.
Discovered in 1610, Ganymede is easily visible from Earth as one of the four Galilean moons seen alongside Jupiter. All that’s needed is a small telescope or decent pair of binoculars mounted on a stand and a clear night sky.
Will Pluto be reissued its former status as a full-fledged planet? While it won’t necessarily be a topic of debate at next week’s meeting of the International Astronomical Union – the group in charge of, amongst other things, the official naming of all things extraterrestrial and thus the group responsible for voting Pluto off the planetary island three years ago – it may be the end result of new discoveries in the years ahead…the kinds of discoveries that make the most recent definitions of what signifies a “planet” hard to clarify.
Pluto, discovered in 1930 by Illinois native Clyde Tombaugh, was classified as the ninth planet until the IAU relegated it to dwarf planet status in 2006 due to some new “requirements” of planethood – notably, having enough gravitational influence to clear the path within one’s own orbit. (Illinois, by the way, officially claimed Pluto’s downgraded status as “unfair” and declared March 13, 2009 as “Pluto Day”.) This change was met with mixed reaction by the scientific community and concerned folks everywhere (at least those concerned about such things) and is still hotly debated in some circles.
At least in circles that debate such things hotly.
Anyway, some scientists – namely, Mark Sykes of Tucson’s Planetary Science Institute – think that the results of missions like NASA’s New Horizons spacecraft currently en route to Pluto will challenge the revised qualifications of planethood with their findings, perhaps demanding a re-evaluation. Sykes and others believe if an object directly orbiting a star is big enough for its own gravity to force it into a spherical shape, it should be a planet, regardless of how well it keeps its orbital room clean. Some say that Earth would have a hard time clearing the space around its orbit were it at Pluto’s distance from the sun due to the sheer length of time it takes to make the round trip. (248 years, to be exact.)
Of course, this definition would then have to promote some other worlds to official planetary status too…such as Ceres, an exceptionally large asteroid circling the sun between Mars and Jupiter, as well as many yet-to-be discovered bodies within the Kuiper Belt region even further out than Pluto. But, according to Sykes, the status of “planet” should be given according to our expanding scientific knowledge and not kept out-of-reach purely out of tradition.
“We are shaking off the last vestiges of the mythological view of planets as special objects in the sky – and the idea that there has to be a small number of them because they’re special.” – Mark Sykes, Planetary Science Institute, Tucson, AZ.
Regardless of its classification in science journals and textbooks, the New Horizons mission will be undoubtedly reveal fascinating information about Pluto and its moon, Charon. Even with powerful instruments like the Hubble Space Telescope, at 2.6 billion miles away they only appear as blurry points of light from here. Launched in January 2006, New Horizons will arrive at Pluto in 2015, do a flyby, and then soar into the Kuiper Belt and eventually out of the solar system entirely. The data it sends back will be the most detailed information we will have ever had about this most debated-over member of our solar system.
Planet or not, the results will definitely be exciting.