Pluto Acts Like a Cosmic Lava Lamp
Like a cosmic lava lamp, a large section of Pluto’s icy surface is renewed by a process called convection that replace older ices with fresher material. Giant convective cells continually refresh dwarf planet’s icy heart.
Combining computer models with topographic and compositional data gathered by NASA’s New Horizons spacecraft last summer, New Horizons team members have been able to determine the depth of this layer of solid nitrogen ice within Pluto’s distinctive “heart” feature — a large plain informally known as Sputnik Planum — and how fast that ice is flowing. The study is published in the June 2, 2016 issue of the journal Nature.
Global view of Pluto reconstructed from images made during the July 14, 2015 flyby of the dwarf planet. The pristine “heart,” to the lower right, so unlike the features of other icy planets, begs for explanation.
“For the first time, we can really determine what these strange welts of the icy surface of Pluto really are,” said William B. McKinnon, professor of earth an planetary sciences in Arts & Sciences at Washington University in St. Louis, who led the study. “We found evidence that even on a distant cold planet billions of miles from Earth, there is sufficient energy for vigorous geological activity, as long as you have something as soft and pliable as nitrogen ice.” McKinnon is also deputy lead for geology, geophysics and imaging for New Horizons.
McKinnon and colleagues believe the pattern of these cells stems from the slow thermal convection of the nitrogen-dominated ices that fill Sputnik Planum. A reservoir that’s likely several miles deep in some places, the solid nitrogen is warmed by Pluto’s modest internal heat, becomes buoyant and rises up in great blobs — think of a lava lamp — before cooling off and sinking again to renew the cycle.
The computer models show that ice need only be a few miles deep for this process to occur, and that the convection cells are very broad. The models also show that these blobs of overturning solid nitrogen can slowly evolve and merge over millions of years. Ridges that mark where cooled nitrogen ice sinks back down can be pinched off and abandoned, resulting in Y- or X-shaped features in junctions where three or four convection cells once met.
Close-up of Sputnik Planum shows the slowly overturning cells of nitrogen ice. Boulders of water ice and methane debris (red) that have broken off hills surrounding the heart have collected at the boundaries of the cells.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
These convective surface motions average only a few centimeters a year — about as fast as your fingernails grow — which means cells recycle their surfaces every 500,000 years or so. Slow on human clocks, but a rapid clip on geological timescales.
Computer simulations show that Pluto’s Sputnik Planum is covered with icy, churning, convective “cells” 10-30 miles across, and less than a million years old. The scene above, which is about 100 miles (165 kilometers) across, is part of the highest resolution scan taken by the New Horizons spacecraft. The picture below shows a depth cross-section of what the convection pattern in the nitrogen ice layer might look like, with warmer nitrogen ice (in red) rising to the surface and spreading out, then cooling (in blue) and descending back to the bottom of the layer.
Credit: NASA/JHUAPL/Southwest Research Institute/Washington University
New Horizons also could potentially take a close-up look at a smaller, more ancient object much farther out in the Kuiper Belt: the disk-shaped region beyond the orbit of Neptune believed to contain comets, asteroids and other small, icy bodies. New Horizons flew through the Pluto system on July 14, 2015, making the first close observations of Pluto and its family of five moons.
The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on Jan. 1, 2019, should NASA approve funding for an extended mission.
Diana Lutz
Citation: Convection in a volatile nitrogen-ice-rich layer drives Pluto’s geological vigour
William B. McKinnon, Francis Nimmo, Teresa Wong, Paul M. Schenk, Oliver L. White, J. H. Roberts, J. M. Moore, J. R. Spencer, A. D. Howard, O. M. Umurhan, S. A. Stern, H. A. Weaver,
C. B. Olkin, L. A. Young, K. E. Smith & the New Horizons Geology, Geophysics and Imaging Theme Team Nature 534, 82–85 (02 June 2016) doi:10.1038/nature18289 http://dx.doi.org/10.1038/nature18289
Source:
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world. Anyone can join. Anyone can contribute. Anyone can become informed about their world. "United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
LION'S MANE PRODUCT
Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules
Mushrooms are having a moment. One fabulous fungus in particular, lion’s mane, may help improve memory, depression and anxiety symptoms. They are also an excellent source of nutrients that show promise as a therapy for dementia, and other neurodegenerative diseases. If you’re living with anxiety or depression, you may be curious about all the therapy options out there — including the natural ones.Our Lion’s Mane WHOLE MIND Nootropic Blend has been formulated to utilize the potency of Lion’s mane but also include the benefits of four other Highly Beneficial Mushrooms. Synergistically, they work together to Build your health through improving cognitive function and immunity regardless of your age. Our Nootropic not only improves your Cognitive Function and Activates your Immune System, but it benefits growth of Essential Gut Flora, further enhancing your Vitality.
Our Formula includes: Lion’s Mane Mushrooms which Increase Brain Power through nerve growth, lessen anxiety, reduce depression, and improve concentration. Its an excellent adaptogen, promotes sleep and improves immunity. Shiitake Mushrooms which Fight cancer cells and infectious disease, boost the immune system, promotes brain function, and serves as a source of B vitamins. Maitake Mushrooms which regulate blood sugar levels of diabetics, reduce hypertension and boosts the immune system. Reishi Mushrooms which Fight inflammation, liver disease, fatigue, tumor growth and cancer. They Improve skin disorders and soothes digestive problems, stomach ulcers and leaky gut syndrome. Chaga Mushrooms which have anti-aging effects, boost immune function, improve stamina and athletic performance, even act as a natural aphrodisiac, fighting diabetes and improving liver function. Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules Today. Be 100% Satisfied or Receive a Full Money Back Guarantee. Order Yours Today by Following This Link.
| Visits: | 1,707,055,070 |
| Stories: | 8,447,112 |
Whistler Blowers, Insiders
