Friday, April 8, 2016

Today's SCIENCE Blog: How Big Is Pluto?

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, Contributor

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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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
Under this criteria, Pluto's low mass does not directly keep it from full planetary status, but the fact that it fails to sweep clean the area surrounding it. Of course, 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
Editor's note: This article was updated on March 18, 2016, to correct Pluto's mass, volume and density.
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Gift/Memorial Suggestions

Several of our friends have lost loved ones (human and pets) and we found that one of the best ways to honor their memory is to give to an animal charity.
What better way to recognize a life of love, than by giving another life a chance for love?
We donate to many animal rescues, but because we volunteer with
DC Weimaraner Rescue and Coast-to-Coast Dachshund Rescue, those are our 2 favorites.
Consider giving the chance of life to a dog or cat.

About us

We're two married guys who enjoy the simple things in life, especially our dogs. We volunteer for dog rescues, enjoy splitting dinners, exercising, blogging, helping friends and neighbors, ghost investigations, coffee and tea, Tudor history, weather, superheroes, comic books, mystery novels, traveling, 70s and 80s music, classic country, piano, gardening, writing books on ghosts and spirits, architecture, keeping a clean house, cooking simply, and keeping in shape. You'll find tidbits of all of these things on this blog and more.

Tom and Rob Thinking Hard!

Tom and Rob Thinking Hard!
Wondering what home project to do next