Pluto sweats, and 5 other things you didn't know about the dwarf planet

Pluto sweats, and 5 other things you didn’t know about the dwarf planet
Credit: Tim Wetherell And Charles Lineweaver Australian National University, Artist's Conception

After nine years and six billion kilometres, the New Horizons space probe will fly past Pluto July 14.

The probe, moving at a speed of 50,000 km/h, will provide astronomers with loads of information and the first clear photos of the , and will come within 12,500 km of its surface.

Needless to say, astronomers – including McMaster's Rob Cockcroft – are very excited.

"We will never have another opportunity to freshly explore an object that was once considered a planet – not until we figure out how to get to , anyway," he says. "The data New Horizons gathers won't just help us understand how Pluto was formed, but how the Solar System itself was formed."

Clearly there's lots we don't know about Pluto – so what do we know? Cockcroft provides a Pluto primer below.

  • Day length: Pluto takes much longer to complete a full rotation than Earth does, making a day there equal to nearly six and half Earth days. A Pluto year is about 248 Earth years.
  • Composition: Basically, Pluto is a huge chunk of rock covered in a relatively thin layer of ice, with nitrogen ice on the surface - and very possibly, water ice between that and the rock.
  • Atmosphere: Pluto doesn't have an atmosphere like ours. It's about 100,000 times less dense than ours, because the planet is "sweating". It's mostly nitrogen, with traces of methane and , that sublimate – or move from solids directly to gases – off the surface to produce this thin "atmosphere".
  • Distance: On average, Pluto is about 40 times further from the Sun than the Earth (it varies between 39 times and 50 times because its orbit is elliptical). That's between 4.4 and 7.4B km from the Sun.
  • Seasons: Pluto's seasons are extreme and long. Earth's seasons are caused by its tilt (23.5 degrees). To give you some perspective, Pluto's tilt is 120 degrees!
  • Orbit: Pluto and its largest moon, Charon, orbit in such a way that the same moon face is always seen from Pluto's surface – just like Earth and its Moon. But Charon is also always in the same spot in Pluto's sky, meaning that if you're on the wrong side of Pluto, you'd never see the .

Explore further

NASA missions have their eyes peeled on Pluto

Citation: Pluto sweats, and 5 other things you didn't know about the dwarf planet (2015, July 10) retrieved 18 October 2019 from https://phys.org/news/2015-07-pluto-didnt-dwarf-planet.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
51 shares

Feedback to editors

User comments

Jul 10, 2015
Something doesn't jive here: Below are two excerpts, one from this article and one from another Physorg article published 2/18/15

"Distance: On average, Pluto is about 40 times further from the Sun than the Earth (it varies between 39 times and 50 times because its orbit is elliptical). That's between 4.4 and 7.4B km from the Sun."

Read more at: http://phys.org/n...html#jCp

"According to NASA, its average distance from the Sun is 39.5 astronomical units (Earth-Sun distances), but it can come as close as 29.7 AU and as far away as 49.7 AU. It was last "inside" Neptune's orbit between 1979 and 1999."

Read more at: http://phys.org/n...html#jCp

Jul 10, 2015
Caltech site states:

"Pluto's average distance from the Sun is 3,670,050,000 miles (5,906,380,000 kilometers). Because Pluto has an orbit that is very elliptical, there is a big difference between its closest distance to the sun and its farthest distance from the Sun. The closest Pluto gets to the Sun is 2,756,902,000 miles or 4,436,820,000 kilometers. The farthest Pluto gets from the Sun is 4,583,190,000 miles or about 7,375,930,000 kilometers. At its closest, it is inside the orbit of Neptune."

I find it interesting there is so much variation on a google search results for Pluto's distance from the sun. I would think they could get the most accurate distance data from New Horizons

Jul 10, 2015
I would think they could get the most accurate distance data from New Horizons
And how would that be accomplished?

Jul 10, 2015
*a freakin laser beam attached to its freakin mount?
*measuring using known redshifting to get a distance
*they must have a distance as the thing is not flying by damn sight lol

Jul 11, 2015
How can they say the tilt is 120 degrees?

By asking 'Through what angle would the planet's axis have to be rotated to get it parallel to the axis of its orbit and rotating in the same sense?'

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more