From "The Big Bang Theory" -- Neil deGrasse Tyson plays himself, confronted by Sheldon Cooper over the "demotion" of Pluto
Link goes to YouTube — embedding of this was disabled, unfortunately.
Don't Forget the Dwarf Planets....
The whole Pluto/Eris flap a few years back ended with the creation of a new category: the dwarf planet. This blog is dedicated to these interesting solar system objects.
Astronomers find ice and possibly methane on Snow White, a distant dwarf planet
Astronomers at the California Institute of Technology (Caltech) have discovered that the dwarf planet 2007 OR10—nicknamed Snow White—is an icy world, with about half its surface covered in water ice that once flowed from ancient, slush-spewing volcanoes. The new findings also suggest that the red-tinged dwarf planet may be covered in a thin layer of methane, the remnants of an atmosphere that’s slowly being lost into space.
“You get to see this nice picture of what once was an active little world with water volcanoes and an atmosphere, and it’s now just frozen, dead, with an atmosphere that’s slowly slipping away,” says Mike Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy, who is the lead author on a paper to be published in the Astrophysical Journal Letters describing the findings. The paper is now in press.
Snow White—which was discovered in 2007 as part of the PhD thesis of Brown’s former graduate student Meg Schwamb—orbits the sun at the edge of the solar system and is about half the size of Pluto, making it the fifth largest dwarf planet. At the time, Brown had guessed incorrectly that it was an icy body that had broken off from another dwarf planet named Haumea; he nicknamed it Snow White for its presumed white color.
Soon, however, follow-up observations revealed that Snow White is actually one of the reddest objects in the solar system. A few other dwarf planets at the edge of the solar system are also red. These distant dwarf planets are themselves part of a larger group of icy bodies called Kuiper Belt Objects (KBOs). As far as the researchers could tell, Snow White, though relatively large, was unremarkable—just one out of more than 400 potential dwarf planets that are among hundreds of thousands of KBOs.
(via PhysOrg.com)
How could you NOT love National Geographic??
An illustration of a planet-like body in the Kuiper belt.
Published August 11, 2011
Three relatively bright space rocks recently found in Pluto’s neighborhood may be new members of the dwarf planet family, astronomers say.
The objects were discovered in a little studied section of the Kuiper belt, a region of the solar system that starts beyond the orbit of Neptune and extends 5.1 billion miles (8.2 billion kilometers) from the sun.
Astronomer Scott Sheppard, of the Carnegie Institute of Washington, and colleagues found the bodies using the 1.3-meter Warsaw University Telescope at Las Campanas in Chile.
The region of the Kuiper belt visible from Earth’s Northern Hemisphere has been fairly well studied. But until recently, a lack of instruments prohibited searches from the Southern Hemisphere.
The latest survey turned up 14 new Kuiper belt objects, three of which are probably big enough to join Pluto, Eris, Ceres, Haumea, and Makemake in dwarf-planet status, the study authors say. (Related: “Pluto Gets 14 New Neighbors.”)
“I’m glad someone finally did it. It needed to happen,” Mike Brown, a Caltech astronomer who was not involved in the study, said of the southern-sky survey.
New Bodies Are Planetary Pipsqueaks
The International Astronomical Union defines a dwarf planet as something orbiting the sun that’s so massive its own gravity molds the object into a rough sphere. Such worlds also haven’t cleared their neighborhoods of other small, planet-like bodies.
(Related: “New Moon Discovered Orbiting Pluto.”)
By estimating the objects’ reflectivity, Sheppard and colleagues could derive their sizes: The largest object is likely 384 miles (620 kilometers) across. The worlds are massive enough to be round, but they’re still pipsqueaks, even by dwarf-planet standards.
By contrast, Pluto and Eris are both 1,450 miles (2,333 kilometers) or so wide. Ceres, the smallest of the confirmed dwarfs, is about 303 miles (487 kilometers) across.
(Related: “NASA’s Dawn Spacecraft to Reach Asteroid This Weekend.”)
Because the newfound objects are so small and so far away, astronomers can’t yet say for sure whether they are in fact spherical and therefore worthy of being named dwarf planets.
Pluto Has No Southern Twins?
The Kuiper belt is full of objects about the size—or at least the brightness—of the three new bodies, Brown added. In fact, there are 37 other objects in the Kuiper belt at least as bright as the newly discovered candidate dwarfs.
Still, the new work does help fill in gaps in the known population of the solar system.
“By determining how many large objects are in the Kuiper belt, we now know how much stuff is there,” study leader Sheppard said. “The point was to complete [our knowledge of] the Kuiper belt.”
For instance, the study closes the possibility of finding a larger, Pluto-size object in the southern skies.
But it’s always possible that “we will find more objects out in the next region [beyond the Kuiper belt], where Sedna is,” Caltech’s Brown said, referring to another candidate dwarf planet, which orbits at an average of 8.9 billion miles (14.3 billion kilometers) from the sun.
The paper describing the three possible new dwarfs has been accepted for publication in the Astronomical Journal.
No number of Moons qualifies Pluto as a Planet………. Pluto is still and always will be a dwarf Planet.
Last week, news broke that a team of astronomers using the Hubble Space Telescope had discovered a new moon in orbit around Pluto.
They were actually looking for signs of a ring system when they stumbled across another tiny object — now imaginatively called “P4” — bringing Pluto’s moon count to four.
This is quite a nice little news story in its own right, and covered by my Discovery News colleague Irene Klotz (see the July 20 article: “Hubble Discovers New Pluto Moon”). However, what I hadn’t anticipated was a deluge of messages asking me if this means Pluto is now a planet again.
Well, the answer is a resounding no. It is still, and always will be, a dwarf planet.
BIG PIC: A Complex and Changing World
But what rules have we applied to Pluto to forever condemn it to the back seats of the solar system rankings?
Before we look at the well established rules of planetary terminology, it’s worth remembering why we even need such a definition.
Like many of you, I was taught as a school kid that there were nine planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto along with thousands and thousands of tiny objects called asteroids. For a long time, Pluto was believed to larger than Mercury but after the discovery of Charon (Pluto’s largest moon) in 1978, the foundations of its planetary status started to wobble.
By studying Charon, astronomers could accurately determine the mass of Pluto and surprisingly found it to be much smaller than Mercury and even our own moon.
During the late 20th century, more objects started to be discovered at comparable distances to Pluto’s orbit and beyond; one of which, Eris, was even thought to be larger than the ninth planet in our solar system. Eris was discovered by Mike Brown and his Palomar Observatory-based team in 2005.
INTERVIEW: Where Are You Hiding Planet X, Dr. Brown?
These discoveries led the International Astronomical Union (IAU) to setup a committee in 2005 to consider an official definition of a planet. There were a number of different definitions that were considered, but in 2006 a final, all-encompassing set of criteria was identified that, once and for all, knocked Pluto off its planetary pedestal.
For a celestial body to be considered a planet, it must;
1) be in orbit around the sun.
Clearly, Pluto is in orbit around the sun, but so do thousands of asteroids. As far as this criterion is concerned, Pluto is still hanging on by the skin of its teeth.
2) have sufficient mass to assume hydrostatic equilibrium.
This is just a posh way to say it is pretty much spherical in shape. Note the careful use of the phrase ‘pretty much’; no planet is a perfect sphere. Due to their rotation, often they are a little squashed along the polar axis.
ANALYSIS: Eris and Pluto Find Common Ground
This criterion is just saying they that they must have sufficient gravity to have overcome other forces and mould a more-or-less sphere-shaped body. Pluto maintains hydrostatic equilibrium, whereas many of the asteroids and other minor planets are quite oddly shaped.
3) have cleared the neighborhood around its orbit.
BOOM! That’s the nail in the coffin for Pluto.
DNEWS VIDEO: PLUTO GETS DEMOTEDThis final criterion requires that it must have cleared its orbit of all other objects of comparable size, other than its own satellites. This means “a planet” must be gravitationally dominant in its orbit and this is where Pluto fails. Pluto not only shares its orbit with a number of other Kuiper Belt objects, but it also flies inside the orbit of ice giant Neptune!
The small print here says that if it fails on this point alone, then it must be classified as a dwarf planet. And so the case against Pluto finally got laid to rest in 2006 when the IAU voted to “demote” Pluto to the status of dwarf planet.
The recent discovery of another moon in orbit around the tiny distant world doesn’t change anything, sadly.
I think in the hearts of thousands of people, Pluto will still always be the ninth planet in our solar system; we just won’t talk about it (much).
Article: Discovery News
Seeker Cranny: Astronomer Mike Brown nicknamed his newly discovered dwarf planet...
Astronomer Mike Brown nicknamed his newly discovered dwarf planet “Xena” - finding this name more convenient to use than the then-official designation, 2003 UB313. When this object was determined to be larger than Pluto, it gained international attention and forced a year-long debate…
