Here's an article that gives you a great idea of just how big of a planet Pluto really is. We found this fascinating. What do you think?
Rob and Tom
How Big Is
Pluto?
By Nola
Taylor Redd, Space.com Contributor
SOURCE: http://www.space.com/18568-how-big-is-pluto.html#sthash.bcXZ4vdn.dpuf
After 76
years of classification as a planet, Pluto was demoted in 2006 to a dwarf
planet, in part because of its size but also because of its minor gravitational
effects on the bodies around it.
When NASA's
New Horizons mission visited in 2015, it took the most accurate measurement of
the world, revealing it to be larger than previously thought, but still not
large enough to be qualified as full-grown planet. Pluto remains one of the
most well-known non-planetary bodies in the solar system.
Radius,
diameter and circumference
When New
Horizons arrived at Pluto, it measured the diameter of the world to be 1,473
miles (2,370 kilometers) across, about two-thirds the diameter of Earth's moon.
This makes it larger than the dwarf planet Eris, once thought to be larger than
Pluto. Eris is 1,445 miles (2,326 km) in diameter.
"This
settles the debate about the largest object in the solar system [beyond
Neptune]," New Horizons principal investigator Alan Stern of the Southwest
Research Institute in Boulder, Colorado, said during a NASA press briefing
reviewing the mission flyby.
 |
|
This graphic presents a
view of Pluto and Charon as they would appear if placed slightly above Earth's
surface and viewed from a great distance. Credit: NASA
|
Unlike many
of the planets in the solar system, such as Earth, Pluto does not bulge at its
center; its radius — 1,185 km (737 miles) — is the same at its poles and at its
equator.
Circumference: If you were to take a walk around the
equator of Pluto, you would travel
about 4,627 miles (7,445 km). That is just a bit less than the distance from
Denver to London (4,683 miles).
Pluto is
thought to have a rocky core covered
by ice, which would mean that its surface features would change with temperature as it travels closer to and farther from the sun. In fact, as the ice melts, the atmosphere of the
tiny body expands outward.
Although all
of the planets beyond Mars are gas giants, Pluto is small and rocky. The tiny
body has a mass of only 1.31 x 1022 kilograms, about two-tenths of a
percent of Earth's. It has a volume of 1.5 billion cubic miles (6.4 billion
cubic km).
Pluto's
small size and low mass mean that it has a density of 1.86 grams per cubic
centimeter according to recent measurements by New Horizons,
about 40 percent of Earth's density.
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Demoted from planetary status
Since its discovery in 1930, Pluto's status as a planet has been debated. It is less massive than seven of the moons in the solar system — Earth's moon, the four Galilean moons of Jupiter, Neptune's moon Triton, and Saturn's moon Titan. [Infographic: Pluto's 5 Moons Explained]In 2003, the icy body of Eris was found far beyond the Kuiper Belt. Originally, it appeared to be larger than Pluto. The discovery sparked a debate about what it meant to be a planet.
In 2006, the International Astronomical Union came up with four criteria that cause an object to be classified as a dwarf planet. A dwarf planet:
- Orbits the sun
- Has enough mass to assume a nearly round shape
- Is not a moon
- Has not cleared the neighborhood around its orbit
,
the reason it can't clear out the Kuiper Belt it orbits through is
because it lacks the gravitational force to do so, a fact related to its
mass.Follow Nola Taylor Redd on Twitter @NolaTRedd or Google+. Follow us at @Spacedotcom, Facebook or Google+. Originally published on Space.com.
Editor's note: This article was updated on March 18, 2016, to correct Pluto's mass, volume and density.
- See more at: http://www.space.com/18568-how-big-is-pluto.html#sthash.bcXZ4vdn.dpuf
