Space is dark, we all know that. But how dark? Astronomers have tried to answer this big question with the New Horizons spacecraft. The NASA probe has finally helped experts shed more light on the topic by making the most precise and direct measurements ever of the total amount of light generated by the universe.&nbsp;

Launched 18 years ago, the spacecraft is now more than 5.4 billion miles from Earth, far away from the planets in our solar system. It is in the darkest possible place in space where the glow of background dust in our system does not affect it in any way.&nbsp;

Being present in the darkest skies available to any existing telescope, the probe has the best viewpoint to measure the overall brightness, or darkness, of the distant universe.

The new research has been published in The Astrophysical Journal.

"If you hold up your hand in deep space, how much light does the universe shine on it?” asks Marc Postman, an astronomer at the Space Telescope Science Institute in Baltimore and lead author of the paper.

The researchers found that the glow coming from different background galaxies alone fills the universe. Nothing else was found to generate light.

“We now have a good idea of just how dark space really is. The results show that the great majority of visible light we receive from the universe is generated in galaxies. Importantly, we also found that there is no evidence for significant levels of light produced by sources not presently known to astronomers.”

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In the 1960s, astronomers Arno Penzias and Robert Wilson discovered that space is filled with strong microwave radiation, which was likely left over from the creation of the universe itself. Later, astronomers also found evidence for the existence of X-rays, gamma rays and infrared radiation.

They needed to&nbsp;add up all the light generated by galaxies over the lifetime of the universe.&nbsp;Detecting the background of "ordinary" (or visible) light, also known as cosmic optical background, or COB, was one way.&nbsp;

Once Hubble and James Webb came, astronomers measured the COB to detect light that might come from sources other than these known galaxies.&nbsp;But, there was a problem.

<h2>Measuring total light produced by the universe</h2>

It is not possible to measure the total light generated by the universe from Earth or anywhere in the inner solar system, Tod Lauer, a New Horizons co-investigator, said.&nbsp;

"There’s just too much sunlight and reflected interplanetary dust that scatters the light around into a hazy fog that obscures the faint light from the distant universe,” he said.&nbsp;

Once New Horizons was billions of miles away, it scanned the universe with its Long Range Reconnaissance Imager (LORRI), collecting two dozen separate imaging fields from a distance of 57 times farther from the Sun than Earth.

The data, combined with previous information, showed that after taking into account all known sources of light, like background stars and light scattered by thin clouds of dust within the Milky Way, the remaining level of visible light matched the intensity of light generated by all galaxies over the past 12.6 billion years.

"The simplest interpretation is that the COB is completely due to galaxies," Lauer said. "Looking outside the galaxies, we find darkness there and nothing more."

Space is dark, we all know that. But how dark? Astronomers have tried to answer this big question with the New Horizons spacecraft. The NASA probe has finally helped experts shed more light on the topic by making the most precise and direct measurements ever of the total amount of light generated by the universe.

Space is dark, we all know that. But how dark? Astronomers have tried to answer this big question with the New Horizons spacecraft. The NASA probe has finally helped experts shed more light on the topic by making the most precise and direct measurements ever of the total amount of light generated by the universe. Launched 18 years ago, the spacecraft is now more than 5.4 billion miles from Earth, far away from the planets in our solar system. It is in the darkest possible place in space where the glow of background dust in our system does not affect it in any way. Being present in the darkest skies available to any existing telescope, the probe has the best viewpoint to measure the overall brightness, or darkness, of the distant universe. The new research has been published in The Astrophysical Journal. "If you hold up your hand in deep space, how much light does the universe shine on it?” asks Marc Postman, an astronomer at the Space Telescope Science Institute in Baltimore and lead author of the paper. The researchers found that the glow coming from different background galaxies alone fills the universe. Nothing else was found to generate light. “We now have a good idea of just how dark space really is. The results show that the great majority of visible light we receive from the universe is generated in galaxies. Importantly, we also found that there is no evidence for significant levels of light produced by sources not presently known to astronomers.” Also Read: Nearly 1,700 ancient viruses spanning 41,000 years unearthed from Himalayas In the 1960s, astronomers Arno Penzias and Robert Wilson discovered that space is filled with strong microwave radiation, which was likely left over from the creation of the universe itself. Later, astronomers also found evidence for the existence of X-rays, gamma rays and infrared radiation. They needed to add up all the light generated by galaxies over the lifetime of the universe. Detecting the background of "ordinary" (or visible) light, also known as cosmic optical background, or COB, was one way. Once Hubble and James Webb came, astronomers measured the COB to detect light that might come from sources other than these known galaxies. But, there was a problem. Measuring total light produced by the universe It is not possible to measure the total light generated by the universe from Earth or anywhere in the inner solar system, Tod Lauer, a New Horizons co-investigator, said. "There’s just too much sunlight and reflected interplanetary dust that scatters the light around into a hazy fog that obscures the faint light from the distant universe,” he said. Once New Horizons was billions of miles away, it scanned the universe with its Long Range Reconnaissance Imager (LORRI), collecting two dozen separate imaging fields from a distance of 57 times farther from the Sun than Earth. The data, combined with previous information, showed that after taking into account all known sources of light, like background stars and light scattered by thin clouds of dust within the Milky Way, the remaining level of visible light matched the intensity of light generated by all galaxies over the past 12.6 billion years. "The simplest interpretation is that the COB is completely due to galaxies," Lauer said. "Looking outside the galaxies, we find darkness there and nothing more."

IT IS DARK! In space, all the light comes from only one type of source

Four billion miles from the sun floats Ultima Thule, an icy celestial body that NASA scientists announced Wednesday is aptly shaped like a giant snowman.&nbsp;

The first detailed images beamed back from the US agency's New Horizons mission allowed scientists to confidently determine the body was formed when two spheres, or "lobes," slowly gravitated towards each other until they stuck together -- a major scientific discovery.

The New Horizons spacecraft on Tuesday flew past Ultima Thule, which was discovered via telescope in 2014 and is the farthest and potentially oldest cosmic body ever observed by a spacecraft.

Before that flyby, the only image scientists had was a blurry one showing Ultima Thule's oblong shape, resembling something like a bowling pin or a peanut.

"That image is so 2018... Meet Ultima Thule!" said lead investigator Alan Stern, doing little to hide his joy as he revealed a new sharper image of the cosmic body, taken at a distance as close as 17,000 miles (about 27,000 kilometers) with a resolution of 140 meters per pixel.

"That bowling pin is gone -- it's a snowman if anything at all," Stern said during a NASA briefing.

"What this spacecraft and this team accomplished is unprecedented."

Ultima Thule's surface reflects light about as much as "garden variety dirt," he said, as the sun's rays are 1,600 times fainter there than on Earth.

The body is roughly 19 miles long and completes its own rotation in about 15 hours. NASA dubbed the larger lobe Ultima, and the other, which is about three times smaller, Thule.

"This is the first object that we can clearly tell was born this way" Stern said, instead of evolving as a sort of "bi-lobe."

"This really puts the nail on the coffin now. We know that this is how these kinds of objects in many cases form."

'A time machine'

Some 4.5 billion years ago a cloud of frozen pebbles began to join forces, gradually forming two bodies -- Ultima and Thule.

Slowing turning, they eventually touched at each other at what mission geology manager Jeff Moore called an "extremely slow speed" -- maybe just one to a few miles per hour.

If such a meeting occurred between two cars in a parking lot, he said, no driver would bother writing it up. The lobes, according to Moore, are really just "resting on each other."

"New Horizons is like a time machine, taking us back to the birth of the solar system," Moore said. "We are seeing a physical representation of the beginning of planetary formation, frozen in time."

Carly Howett, another researcher of the mission, noted that "we can definitely say that Ultima Thule is red," perhaps due to irradiation of ice.

NASA researchers promised fresh announcements would drop Thursday, including on the composition and atmosphere of Ultima Thule, as new images with even more precise resolution have come through.&nbsp;

&nbsp;

Four billion miles from the sun floats Ultima Thule, an icy celestial body that NASA scientists announced Wednesday is aptly shaped like a giant snowman. The first detailed images beamed back from the US agency's New Horizons mission allowed scientists to confidently determine the body was formed when two spheres, or "lobes," slowly gravitated towards each other until they stuck together -- a major scientific discovery.

Four billion miles from the sun floats Ultima Thule, an icy celestial body that NASA scientists announced Wednesday is aptly shaped like a giant snowman. The first detailed images beamed back from the US agency's New Horizons mission allowed scientists to confidently determine the body was formed when two spheres, or "lobes," slowly gravitated towards each other until they stuck together -- a major scientific discovery. The New Horizons spacecraft on Tuesday flew past Ultima Thule, which was discovered via telescope in 2014 and is the farthest and potentially oldest cosmic body ever observed by a spacecraft. Before that flyby, the only image scientists had was a blurry one showing Ultima Thule's oblong shape, resembling something like a bowling pin or a peanut. "That image is so 2018... Meet Ultima Thule!" said lead investigator Alan Stern, doing little to hide his joy as he revealed a new sharper image of the cosmic body, taken at a distance as close as 17,000 miles (about 27,000 kilometers) with a resolution of 140 meters per pixel. "That bowling pin is gone -- it's a snowman if anything at all," Stern said during a NASA briefing. "What this spacecraft and this team accomplished is unprecedented." Ultima Thule's surface reflects light about as much as "garden variety dirt," he said, as the sun's rays are 1,600 times fainter there than on Earth. The body is roughly 19 miles long and completes its own rotation in about 15 hours. NASA dubbed the larger lobe Ultima, and the other, which is about three times smaller, Thule. "This is the first object that we can clearly tell was born this way" Stern said, instead of evolving as a sort of "bi-lobe." "This really puts the nail on the coffin now. We know that this is how these kinds of objects in many cases form." 'A time machine' Some 4.5 billion years ago a cloud of frozen pebbles began to join forces, gradually forming two bodies -- Ultima and Thule. Slowing turning, they eventually touched at each other at what mission geology manager Jeff Moore called an "extremely slow speed" -- maybe just one to a few miles per hour. If such a meeting occurred between two cars in a parking lot, he said, no driver would bother writing it up. The lobes, according to Moore, are really just "resting on each other." "New Horizons is like a time machine, taking us back to the birth of the solar system," Moore said. "We are seeing a physical representation of the beginning of planetary formation, frozen in time." Carly Howett, another researcher of the mission, noted that "we can definitely say that Ultima Thule is red," perhaps due to irradiation of ice. NASA researchers promised fresh announcements would drop Thursday, including on the composition and atmosphere of Ultima Thule, as new images with even more precise resolution have come through.

NASA says faraway world Ultima Thule shaped like 'snowman'

<a href="http://www.wionews.com/world/nasa-spacecraft-makes-historic-flyby-of-ultima-thule-distant-world-ever-studied-187648">NASA's New Horizons explorer</a> successfully "phoned home" on Tuesday after a journey to the most distant world ever explored by humankind, a frozen rock at the edge of the solar system that scientists hope will uncover secrets to its creation.

<a href="http://www.wionews.com/world/nasa-spacecraft-breaks-record-for-smallest-space-object-ever-orbited-187693">The nuclear-powered space probe</a> has travelled 4 billion miles (6.4 billion km) to come within 2,200 miles (3,540 km) of Ultima Thule, an apparently peanut-shaped, 20-mile-long (32-km-long) space rock in the uncharted heart of the Kuiper Belt. The belt is a ring of icy celestial bodies just outside Neptune's orbit.

Engineers at Johns Hopkins Applied Physics Laboratory in Maryland cheered when the spacecraft's first signals came through the National Aeronautic and Space Agency's Deep Space Network at 10:28 am EST (1528 GMT).

"We have a healthy spacecraft," Mission Operations Manager Alice Bowman declared.

The spacecraft will ping back more detailed images and data from Thule in the coming days, NASA said. &nbsp;

Launched in January 2006, New Horizons embarked on its 4 billion-mile journey toward the solar system’s edge to study the dwarf planet Pluto and its five moons.

"Last night, overnight, the United States spacecraft New Horizons conducted the farthest exploration in the history of humankind, and did so spectacularly," New Horizons principal investigator Alan Stern told a news conference at the Johns Hopkins facility in Laurel, Maryland.

An image of Thule, sent overnight and barely more detailed than previous images, deepens the mystery of whether Thule is a single rock shaped like an asymmetrical peanut or actually two rocks orbiting each other, "blurred together because of their proximity," Stern said.

During a 2015 fly-by, the probe found Pluto to be slightly larger than previously thought. In March, it revealed methane-rich dunes on the icy dwarf planet’s surface.

Now 1 billion miles (1.6 billion km) beyond Pluto for its second mission into the Kuiper Belt, New Horizons will study the makeup of Ultima Thule's atmosphere and terrain in a months-long study to seek clues about the formation of the solar system and its planets.

Scientists had not discovered Ultima Thule when the probe was launched, according to NASA, making the mission unique in that respect. In 2014, astronomers found Thule using the Hubble Space Telescope and the following year selected it for New Horizon's extended mission.&nbsp;

As the probe flies 2,200 miles (3,540 km) above Thule's surface, scientists hope it will detect the chemical composition of its atmosphere and terrain in what NASA says will be the closest observation of a body so remote.&nbsp;

"We are straining the capabilities of this spacecraft, and by tomorrow we'll know how we did," Stern told reporters on Monday. "There are no second chances for New Horizons."

While the mission marks the farthest close encounter of an object within our solar system, NASA's Voyager 1 and 2, a pair of deep-space probes launched in 1977, have reached greater distances on a mission to survey extrasolar bodies. Both probes are still operational.

Launched in January 2006, New Horizons embarked on its 4 billion-mile journey toward the solar system’s edge to study the dwarf planet Pluto and its five moons.

NASA's New Horizons explorer successfully "phoned home" on Tuesday after a journey to the most distant world ever explored by humankind, a frozen rock at the edge of the solar system that scientists hope will uncover secrets to its creation. The nuclear-powered space probe has travelled 4 billion miles (6.4 billion km) to come within 2,200 miles (3,540 km) of Ultima Thule, an apparently peanut-shaped, 20-mile-long (32-km-long) space rock in the uncharted heart of the Kuiper Belt. The belt is a ring of icy celestial bodies just outside Neptune's orbit. Engineers at Johns Hopkins Applied Physics Laboratory in Maryland cheered when the spacecraft's first signals came through the National Aeronautic and Space Agency's Deep Space Network at 10:28 am EST (1528 GMT). "We have a healthy spacecraft," Mission Operations Manager Alice Bowman declared. The spacecraft will ping back more detailed images and data from Thule in the coming days, NASA said. Launched in January 2006, New Horizons embarked on its 4 billion-mile journey toward the solar system’s edge to study the dwarf planet Pluto and its five moons. "Last night, overnight, the United States spacecraft New Horizons conducted the farthest exploration in the history of humankind, and did so spectacularly," New Horizons principal investigator Alan Stern told a news conference at the Johns Hopkins facility in Laurel, Maryland. An image of Thule, sent overnight and barely more detailed than previous images, deepens the mystery of whether Thule is a single rock shaped like an asymmetrical peanut or actually two rocks orbiting each other, "blurred together because of their proximity," Stern said. During a 2015 fly-by, the probe found Pluto to be slightly larger than previously thought. In March, it revealed methane-rich dunes on the icy dwarf planet’s surface. Now 1 billion miles (1.6 billion km) beyond Pluto for its second mission into the Kuiper Belt, New Horizons will study the makeup of Ultima Thule's atmosphere and terrain in a months-long study to seek clues about the formation of the solar system and its planets. Scientists had not discovered Ultima Thule when the probe was launched, according to NASA, making the mission unique in that respect. In 2014, astronomers found Thule using the Hubble Space Telescope and the following year selected it for New Horizon's extended mission. As the probe flies 2,200 miles (3,540 km) above Thule's surface, scientists hope it will detect the chemical composition of its atmosphere and terrain in what NASA says will be the closest observation of a body so remote. "We are straining the capabilities of this spacecraft, and by tomorrow we'll know how we did," Stern told reporters on Monday. "There are no second chances for New Horizons." While the mission marks the farthest close encounter of an object within our solar system, NASA's Voyager 1 and 2, a pair of deep-space probes launched in 1977, have reached greater distances on a mission to survey extrasolar bodies. Both probes are still operational.

NASA space probe 'phones home' in landmark mission to solar system's edge

<a href="http://www.wionews.com/world/nasas-intrepid-voyager-2-probe-crosses-into-interstellar-space-183047">NASA'</a>s unmanned New Horizons spacecraft is closing in on its historic New Year's flyby target, the most distant world ever studied, a frozen relic of the solar system some four billion miles (6.4 billion kilometres) away.

The cosmic object, known as Ultima Thule, is about the size of the US capital, Washington, and orbits in the dark and frigid Kuiper Belt about a billion miles beyond the dwarf planet, Pluto.

The spacecraft's closest approach to this primitive space rock comes January 1 at 12:33 am ET (0533 GMT).&nbsp;

Until then, what it looks like, and what it is made of, remain a mystery.

"This is a time capsule that is going to take us back four and a half billion years to the birth of the solar system," said Alan Stern, the principal investigator on the project at the Southwest Research Institute, during a press briefing Friday.

A camera on board the New Horizons spacecraft is currently zooming in on Ultima Thule, so scientists can get a better sense of its shape and configuration — whether it is one object or several.

"We've never been to a type of object like this before," said Kelsi Singer, New Horizons co-investigator at the Southwest Research Institute.&nbsp;

About a day prior, "we will start to see what the actual shape of the object is," she said.

The spacecraft entered "encounter mode" on December 26, and is "very healthy," added Stern.

Communicating with a spacecraft that is so far away takes six hours and eight minutes each way — or about 12 hours and 15 minutes round trip.

New Horizons' eagerly awaited "phone home" command, indicating if it survived the close pass — at a distance of just 2,200 miles (3,500 kilometres) — is expected January 1 at 10:29 am (1529 GMT).

Until then, the New Horizons spacecraft continues speeding through space at 32,000 miles (51,500 kilometres) per hour, travelling almost a million miles per day.

And <a href="http://www.wionews.com/entertainment/nasa-offers-advice-to-marvel-after-anguished-fans-seek-help-to-bring-back-tony-stark-from-space-182864">NASA scientists</a> are eagerly awaiting the first images.

"Because this is a flyby mission, we only have one chance to get it right," said Alice Bowman, missions operations manager for New Horizons.&nbsp;

The spacecraft, which launched in 2006, captured stunning images of Pluto when it flew by the dwarf planet in 2015. 
&nbsp;

NASA's unmanned New Horizons spacecraft is closing in on its historic New Year's flyby target, the most distant world ever studied, a frozen relic of the solar system some four billion miles (6.

NASA's unmanned New Horizons spacecraft is closing in on its historic New Year's flyby target, the most distant world ever studied, a frozen relic of the solar system some four billion miles (6.4 billion kilometres) away. The cosmic object, known as Ultima Thule, is about the size of the US capital, Washington, and orbits in the dark and frigid Kuiper Belt about a billion miles beyond the dwarf planet, Pluto. The spacecraft's closest approach to this primitive space rock comes January 1 at 12:33 am ET (0533 GMT). Until then, what it looks like, and what it is made of, remain a mystery. "This is a time capsule that is going to take us back four and a half billion years to the birth of the solar system," said Alan Stern, the principal investigator on the project at the Southwest Research Institute, during a press briefing Friday. A camera on board the New Horizons spacecraft is currently zooming in on Ultima Thule, so scientists can get a better sense of its shape and configuration — whether it is one object or several. "We've never been to a type of object like this before," said Kelsi Singer, New Horizons co-investigator at the Southwest Research Institute. About a day prior, "we will start to see what the actual shape of the object is," she said. The spacecraft entered "encounter mode" on December 26, and is "very healthy," added Stern. Communicating with a spacecraft that is so far away takes six hours and eight minutes each way — or about 12 hours and 15 minutes round trip. New Horizons' eagerly awaited "phone home" command, indicating if it survived the close pass — at a distance of just 2,200 miles (3,500 kilometres) — is expected January 1 at 10:29 am (1529 GMT). Until then, the New Horizons spacecraft continues speeding through space at 32,000 miles (51,500 kilometres) per hour, travelling almost a million miles per day. And NASA scientists are eagerly awaiting the first images. "Because this is a flyby mission, we only have one chance to get it right," said Alice Bowman, missions operations manager for New Horizons. The spacecraft, which launched in 2006, captured stunning images of Pluto when it flew by the dwarf planet in 2015.

NASA's unmanned spaceship closes in on most distant world ever studied

Present day Pluto may have a liquid ocean sloshing around under its icy crust, according to to a new analysis of data from NASA&rsquo;s New Horizons spacecraft. 
 
When New Horizons buzzed by Pluto last year, it unveiled clues that the dwarf planet might have &ndash; or had at one time &ndash; a sub-surface liquid ocean. 
 
Scientists from Brown University in the US, who used a thermal evolution model for Pluto updated with data from New Horizons, found that if its ocean had frozen, it would have caused the entire planet to shrink. 
 
However, there are no signs of a global contraction to be found on Pluto&rsquo;s surface, researchers said. On the contrary, New Horizons showed signs that Pluto has been expanding. 
 
The pictures New Horizons sent back from its close encounter with the Kuiper Belt&rsquo;s most famous denizen showed that Pluto was much more than a simple snowball in space. 
 
It has an exotic surface made from different types of ices &ndash; water, nitrogen and methane.&nbsp;It has mountains hundreds of meters high and a vast heart-shaped plain.&nbsp;It also has giant tectonic features &ndash; sinuous faults hundreds of kilometres long as deep as 4 kilometres.&nbsp;It was those tectonic features that got scientists thinking that a subsurface ocean was a real possibility for Pluto. 
 
&ldquo;What New Horizons showed was that there are extensional tectonic features, which indicate that Pluto underwent a period of global expansion,&rdquo; said Noah Hammond, a graduate student in Brown University. 
 
&ldquo;A subsurface ocean that was slowly freezing over would cause this kind of expansion,&rdquo; Hammond said. 
 
Scientists think that there may have been enough heat-producing radioactive elements within Pluto&rsquo;s rocky core to melt part of the planet&rsquo;s ice shell. 
 
Over time in the frigid Kuiper belt, that melted portion would eventually start to refreeze. Ice is less dense than water, so when it freezes, it expands. 
 
If Pluto had an ocean that was frozen or in the process of freezing, extensional tectonics on the surface would result, and that is what New Horizons saw. 
 
The thermal evolution model showed that because of the low temperatures and high pressure within Pluto, an ocean that had completely frozen over would quickly convert from the normal ice we all know to a different phase called ice II. 
 
Ice II has a more compact crystalline structure than standard ice, so an ocean frozen to ice II would occupy a smaller volume and lead to a global contraction on Pluto, rather than an expansion. 
 
&ldquo;We don&rsquo;t see the things on the surface we&rsquo;d expect if there had been a global contraction,&rdquo; Hammond said. 
 
&ldquo;So we conclude that ice II has not formed, and therefore that the ocean hasn&rsquo;t completely frozen,&rdquo; she said. 
 
The new model bolsters the case for an ocean environment in the furthest reaches of the solar system. 
 
The study was published in the journal Geophysical Research Letters. 
 
(PTI)

Scientists think that there may have been enough heat-producing elements within Pluto?s rocky core to melt part of the planet?s ice shell

Present day Pluto may have a liquid ocean sloshing around under its icy crust, according to to a new analysis of data from NASA’s New Horizons spacecraft. When New Horizons buzzed by Pluto last year, it unveiled clues that the dwarf planet might have – or had at one time – a sub-surface liquid ocean. Scientists from Brown University in the US, who used a thermal evolution model for Pluto updated with data from New Horizons, found that if its ocean had frozen, it would have caused the entire planet to shrink. However, there are no signs of a global contraction to be found on Pluto’s surface, researchers said. On the contrary, New Horizons showed signs that Pluto has been expanding. The pictures New Horizons sent back from its close encounter with the Kuiper Belt’s most famous denizen showed that Pluto was much more than a simple snowball in space. It has an exotic surface made from different types of ices – water, nitrogen and methane. It has mountains hundreds of meters high and a vast heart-shaped plain. It also has giant tectonic features – sinuous faults hundreds of kilometres long as deep as 4 kilometres. It was those tectonic features that got scientists thinking that a subsurface ocean was a real possibility for Pluto. “What New Horizons showed was that there are extensional tectonic features, which indicate that Pluto underwent a period of global expansion,” said Noah Hammond, a graduate student in Brown University. “A subsurface ocean that was slowly freezing over would cause this kind of expansion,” Hammond said. Scientists think that there may have been enough heat-producing radioactive elements within Pluto’s rocky core to melt part of the planet’s ice shell. Over time in the frigid Kuiper belt, that melted portion would eventually start to refreeze. Ice is less dense than water, so when it freezes, it expands. If Pluto had an ocean that was frozen or in the process of freezing, extensional tectonics on the surface would result, and that is what New Horizons saw. The thermal evolution model showed that because of the low temperatures and high pressure within Pluto, an ocean that had completely frozen over would quickly convert from the normal ice we all know to a different phase called ice II. Ice II has a more compact crystalline structure than standard ice, so an ocean frozen to ice II would occupy a smaller volume and lead to a global contraction on Pluto, rather than an expansion. “We don’t see the things on the surface we’d expect if there had been a global contraction,” Hammond said. “So we conclude that ice II has not formed, and therefore that the ocean hasn’t completely frozen,” she said. The new model bolsters the case for an ocean environment in the furthest reaches of the solar system. The study was published in the journal Geophysical Research Letters. (PTI)

Pluto may have liquid ocean under ice shell

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IT IS DARK! In space, all the light comes from only one type of source

NASA says faraway world Ultima Thule shaped like 'snowman'

NASA space probe 'phones home' in landmark mission to solar system's edge

NASA's unmanned spaceship closes in on most distant world ever studied

Pluto may have liquid ocean under ice shell