{"id":16152,"date":"2015-07-26T21:04:29","date_gmt":"2015-07-26T13:04:29","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/nasa-probe-finds-intriguing-ice-flows-under-hazy-skies-on-pluto\/"},"modified":"2015-07-26T21:04:29","modified_gmt":"2015-07-26T13:04:29","slug":"nasa-probe-finds-intriguing-ice-flows-under-hazy-skies-on-pluto","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/nasa-probe-finds-intriguing-ice-flows-under-hazy-skies-on-pluto\/","title":{"rendered":"NASA probe finds intriguing ice flows under hazy skies on Pluto"},"content":{"rendered":"
\"This
This new global mosaic of Pluto was created by combining four black-and-white images from New Horizons\u2019 Long Range Reconnaissance Imager and color data from the probe\u2019s Ralph instrument. The LORRI images were taken July 14, when New Horizons was approximately 280,000 miles (450,000 kilometers) from Pluto. Features as small as 1.4 miles (2.2 kilometers) are resolved in this image. Credit: NASA\/JHUAPL\/SWRI<\/figcaption><\/figure>\n

Images obtained during the New Horizons spacecraft\u2019s July 14 encounter with Pluto show apparent glacial ice flows wrapping around barrier islands and towering mountain ranges, all under a newly-discovered haze layer suspended up to 100 miles above the distant world\u2019s frozen surface, scientists said Friday.<\/p>\n

The latest views of an icy heart-shaped feature on Pluto, informally dubbed Tombaugh Regio after the dwarf planet\u2019s discoverer, reveal complicated boundaries between relatively flat ice fields and rugged mountains primarily composed of water ice, which at Pluto\u2019s frigid temperatures has the consistency of rock on Earth.<\/p>\n

At the northern fringe of the frozen icy plain, which has been tentatively named Sputnik Planum, fingers of ice jut into mountainous topography like the fjords of Norway.<\/p>\n

\u201cWe interpret them to be just like glacial flow on the Earth,\u201d said William McKinnon, co-investigator on the New Horizons mission from Washington University in St. Louis. \u201cI don\u2019t have to remind you that glaciers on Earth are made of ice, like in Antarctica or in Greenland, but water ice at Pluto\u2019s temperatures won\u2019t move anywhere. It\u2019s immobile and brittle.\u201d<\/p>\n

Temperature at the surface of Sputnik Planum hover around 38 Kelvin, or about minus 390 degrees Fahrenheit, according to Michael Summers, New Horizons co-investigator from George Mason University in Fairfax, Virginia.<\/p>\n

\u201cBut on Pluto, the kind of ices we think make up the (Sputnik) Planum \u2014 nitrogen ice, carbon monoxide ice, methane ice \u2014 these ices are geologically soft and malleable, even at Pluto conditions, and they will flow in the same way that glaciers do on the Earth. So we have actual evidence for basically recent geological activity.\u201d<\/p>\n

That is a surprise to many planetary geologists, who figured Pluto might be geologically dead with an icy surface frozen in place for billions of years.<\/p>\n

But the smoothness of Sputnik Planum tells another story.<\/p>\n

Researchers use crater counts to get rough estimates for the age of a geologic unit.<\/p>\n

\u201cWhen I say recent (geologic activity), I don\u2019t necessarily mean yesterday,\u201d McKinnon said. \u201cI mean geologically recent. But the appearance of this terrain, the utter lack of impact craters on the Sputnik Planum, tells us that this is really a young unit.\u201d<\/p>\n

\"Apparent
Apparent nitrogen ice flows are found on the northern edge of Pluto\u2019s Sputnik Planum. Credit: NASA\/JHUAPL\/SWRI\/William McKinnon<\/figcaption><\/figure>\n

While Sputnik Planum may still be resurfacing today, McKinnon put an upper bound on the age of the geologic unit at a few tens of millions of years, a blink of the eye compared to the four-and-a-half billion-year age of the solar system.<\/p>\n

Exactly what drives the geologic activity refreshing Pluto\u2019s surface is still unclear, but McKinnon said the leading theory is remnant heat deep inside Pluto could generate slow, bubbling convection to produce the ice blocks and flows observed in Sputnik Planum.<\/p>\n

Maybe the cataclysmic collision between Pluto and another massive object thought to produce the Texas-sized moon Charon may have occurred more recently than originally suspected, leaving Pluto\u2019s deep interior still rumbling, some scientists believe.<\/p>\n

New Horizons discovered a pair of mountain ranges closer to Pluto\u2019s equator, near the southern flank of Sputnik Planum. The ranges are unofficially named Norgay Montes and Hillary Montes after the first two people known to reach the summit of Mount Everest.<\/p>\n

The first close-up of Pluto from New Horizons\u2019 long-range telescopic camera revealed Norgay Montes, which rise more than 2 miles over their surrounding terrain. Hillary Montes came into focus in another image released earlier this week.<\/p>\n

\u201cThe scientifically interesting and fascinating thing about this picture to me is that the Sputnik Planum ice \u2014 these mobile ices \u2014 seem to have moved, surrounded and embayed the Hillary Montes,\u201d McKinnon said.<\/p>\n

The blocks of ice in Sputnik Planum get smaller south of Hillary Montes, indicating a much thinner layer of ice there, according to McKinnon.<\/p>\n

Beyond Hillary Montes, the ice tapers into Cthulhu Regio, part of a much darker band of surface material stretching around Pluto\u2019s equator. The area\u2019s asphalt-colored crust is marked by craters, leading geologists to believe it is relatively ancient.<\/p>\n

\"The
The Hillary Montes mountain range, seen here in the upper right, is surrounded by an ice sheet, which tapers into much darker, older terrain at left in a region called Cthulhu Regio. Credit: NASA\/JHUAPL\/SWRI<\/figcaption><\/figure>\n

Scientists are trying to sort out the heart-shaped Tombaugh Regio\u2019s role in Pluto\u2019s climate cycle. The western and eastern halves of the heart have different spectral signatures and are likely made of slightly different material, said Cathy Olkin, deputy project scientist on the New Horizons mission from the Southwest Research Institute.<\/p>\n

Alan Stern, the New Horizons mission\u2019s principal investigator, said the western lobe of the Tombaugh Regio heart appears to be the source for a thin layer covering the region\u2019s eastern part.<\/p>\n

\u201cBright material, probably nitrogen snow, is being transported off the source region off the western lobe, perhaps by winds and aeolian transport, perhaps by sublimation and winds and then re-condensation, or perhaps by a process we haven\u2019t thought about,\u201d Stern said.<\/p>\n

Pluto takes 248 years to orbit the sun, and seasons last for many decades. The icy world\u2019s northern hemisphere, which New Horizons flew past, is currently in basking in sunny summertime.<\/p>\n

Before New Horizons visited Pluto, researchers knew Pluto was rich in nitrogen, methane and carbon monoxide ices that likely sublimated \u2014 turned directly from a solid to a gaseous phase \u2014 under solar heating and rained back down as tiny snow particles.<\/p>\n

\u201cWe\u2019re seeing methane, nitrogen and carbon monoxide ices there,\u201d Olkin said. \u201cThis is telling us something that we need to understand. On the northern part of Pluto, we see methane and nitrogen, but not carbon monoxide, so maybe what we\u2019re seeing in Tombaugh Regio is a source region for some of these specific ices. That complicates the story of this seasonal transport.\u201d<\/p>\n

Measurements show Tombaugh Regio is richer in carbon monoxide than any other part of Pluto.<\/p>\n

\u201cWe have a vast region that seems to be truly a reservoir,\u201d McKinnon said. \u201cWe describe this poetically as the beating heart of Pluto. It may be the supply zone, the supply hut, of the entire atmosphere.\u201d<\/p>\n

One thing scientists are eager to find, if it is there, is evidence of a deep underground ocean.<\/p>\n

\u201cWe don\u2019t have any direct evidence for an interior liquid water ocean from these images,\u201d McKinnon said.<\/p>\n

But based on Pluto\u2019s low density and surface appearance, there is a good chance an ocean of liquid nitrogen, or another mixture, lurks below the world\u2019s icy shell.<\/p>\n

\u201cAll other things being equal, it increases the probability that there may still be an ocean way down underneath a very thick layer of ice,\u201d McKinnon said. \u201cThat\u2019s a theoretical inference right now, but it\u2019s something that we\u2019re keeping in mind as we explore Pluto.\u201d<\/p>\n

\"This
This global mosaic of Pluto uses exaggerated colors to illustrate contrasts between different geologic units. The differences in the two lobes of the heart, or Tombaugh Regio, are obvious in this image. Credit: NASA\/JHUAPL\/SWRI<\/figcaption><\/figure>\n

Only a handful of images from the July 14 Pluto flyby have reached Earth. Hundreds more are due to come down beginning in September and stretching into 2016.<\/p>\n

But one photo recorded just after the encounter has resolved Pluto\u2019s atmospheric haze for the first time, revealing layers of particles reaching up to 100 miles above its surface illuminated by sunlight, five times higher than models predicted.<\/p>\n

\u201cThis is the image that stunned the encounter team,\u201d said Summers, an atmospheric scientist on the New Horizons mission. \u201cFor 25 years, we\u2019ve known that Pluto has an atmosphere, but it\u2019s been known by numbers. This is the first picture, this is the first time we\u2019ve really seen it. This was the image that almost brought tears to the eyes to the atmospheric scientists on the team.\u201d<\/p>\n

Now scientists are trying couple the geologic and atmospheric data to unravel how the Pluto system works.<\/p>\n

\u201cThe haze is pretty,\u201d Summers said. \u201cIt\u2019s a way to see the atmosphere, but it\u2019s a piece of a big story that we\u2019re trying to understand at Pluto, and that is how the atmosphere and the surfaces are connected.\u201d<\/p>\n

Methane particles lofted from Pluto\u2019s surface are irradiated high up in Pluto\u2019s atmosphere, creating ethylene, acetylene and other varieties of particles named tholins detected by New Horizons.<\/p>\n

The particles then fall back to Pluto to create the icy dwarf\u2019s red veneer.<\/p>\n

\u201cAt some point in this cycle, those haze particles are chemically processed to produce what we call tholins, which are chemically altered hydrocarbons that have a red color,\u201d Summers said. \u201cWe think that is how Pluto\u2019s surface got its reddish hue.\u201d<\/p>\n

\u201cOn Pluto, we have a much more intimate and intricate interaction between geology, volatile transport and the seasonal climate cycles \u2014 those kinds of things \u2014 that are foricng one another, and feeding one another, and creating a very complicated and layered story about the planet\u2019s history,\u201d Stern said. \u201cIt\u2019s rare in the pantheon of objects in the solar system that we have seen this kind of an intricate and complicated story. I\u2019m reminded in some ways of (Saturn\u2019s moon) Titan, but few other examples that are so dramatic. It\u2019s brand new.\u201d<\/p>\n

New Horizons also spotted a dark, reddish deposit on Charon\u2019s north pole, potentially created by similar tholins from Pluto\u2019s atmosphere ending up there.<\/p>\n

Charon does not appear to have its own atmosphere, according to new results from New Horizons\u2019 Alice spectrometer. If it does, it is much thinner than Pluto\u2019s.<\/p>\n

\u201cFor now, all we can say is it\u2019s a much more rarefied atmosphere and that confirms our pre-flight notions, and we\u2019re really looking forward to seeing just how rarefied that is,\u201d Stern said. \u201cIt may be that there is a thin nitrogen layer in the atmosphere, or methane, or some other constituent, but it must be very tenuous compared to Pluto, again, emphasizing just how different these two objects are despite their close association in space.\u201d<\/p>\n

\"Alan
Alan Stern, New Horizons\u2019 principal investigator, during a media briefing Friday. Credit: NASA\/Joel Kowsky<\/figcaption><\/figure>\n

Another science shocker from New Horizons came from the first direct measurement of Pluto\u2019s surface pressure.<\/p>\n

It turns out the Pluto\u2019s atmosphere has a surface pressure of no more than 10 microbars, about one hundred thousandth the thickness of Earth\u2019s at sea level. That\u2019s substantially less than a measurement made from Earth two years ago, Summers said.<\/p>\n

\u201cThe mass of Pluto\u2019s atmosphere has decreased by factor of two in about two years,\u201d Summers said. \u201cThat\u2019s pretty astonishing, at least to an atmospheric scientist. That tells us something is happening.\u201d<\/p>\n

Using radio signals beamed up from Earth to a receiver aboard New Horizons, scientists measured Pluto\u2019s surface pressure by studying how the signals traveled through its atmosphere. The radio science experiment, or REX, relied on high-power signals broadcast by NASA\u2019s Deep Space Network.<\/p>\n

New Horizons may have caught the early stages of a hypothesized collapse and freezing of Pluto\u2019s atmosphere as it opens its distance from the sun. Pluto\u2019s egg-shaped orbit brought the faraway world closest to the sun in 1989, and it is now about 3 billion miles away.<\/p>\n

But Pluto\u2019s atmospheric pressure continued rising after 1989, perhaps due to a climate lag, similar to how the hottest part of summer comes weeks after the summer equinox.<\/p>\n

\u201cAfter we saw pressure rising from occulation data, some thought maybe there\u2019s not going to be a Pluto atmospheric collapse,\u201d Stern said. \u201cWhat REX seems to have detected is the potential for the first stages of that collapse, just as New Horizons arrived. It would be an amazing coincidence, but there are some on our team who would say \u2018I told you so.’\u201d<\/p>\n

Less than 5 percent of the mission\u2019s total data haul had reached the ground as of Friday, according to Stern.<\/p>\n

\u201cWe\u2019ve now finished the first phase of downlink,\u201d Stern said. \u201cThat was an intensive 10-day period in which we sent down images, spectra and other datasets just to whet our appetites and tell us the basics about the Pluto system.\u201d<\/p>\n

More pieces of the Pluto puzzle will come down in future data downlinks, which will focus on plasma and dust measurements over the next couple of months. In September, scientists say a wider pipeline of images will come back to Earth.<\/p>\n

\u201cFor the next couple of months, until we reach mid-September, it\u2019ll only be occasionally that we have new images on the ground and available to release,\u201d Stern said. \u201cStarting in September, the spigot opens again, and then for about a year \u2014 maybe a little bit more \u2014 the sky will be raining presents with data from the Pluto system. It\u2019s going to be quite a ride.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

This new global mosaic of Pluto was created by combining four black-and-white images from New Horizons\u2019 Long Range Reconnaissance Imager and color data from the probe\u2019s Ralph instrument. The LORRI images were taken July 14, when New Horizons was approximately 280,000 miles (450,000 kilometers) from Pluto. Features as small as 1.4 miles (2.2 kilometers) are […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1861,2174,2848,2612],"class_list":["post-16152","post","type-post","status-publish","format-standard","hentry","category-news","tag-jhuapl","tag-new-horizons","tag-pluto","tag-swri"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16152"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=16152"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16152\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=16152"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=16152"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=16152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}