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Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

The newly renamed object Arrokoth, once known as Ultima Thule, is ultrared, smooth and covered in organic complex molecules, according to new research.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Another look at Ultima Thule reveals the pancake shape many associate it with.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons images revealed that craters on Pluto and Charon were made by small Kuiper Belt objects.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Although this might look more impressive if you put on 3D glasses, this is the first 3D image of Kuiper Belt object Ultima Thule. New Horizons flew by Ultima Thule on January 1.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This is the first color image of Ultima Thule, taken at a distance of 85,000 miles from the object by the New Horizons spacecraft. The "red snowman" replaces the initial "bowling pin" shape it was thought to be. This image reveals that Ultima Thule is actually two objects joined by gravity, making it the first contact binary visited by a spacecraft. The red color is due to it being irradiated in the Kuiper Belt.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons gave us our first "up-close" look at Ultima Thule on January 1. On the left is a composite of two images taken from half a million miles out, indicating the object's size and shape. An artist's impression at right suggests that Ultima Thule is shaped like a bowling pin and spins like a propeller.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

When NASA's New Horizons spacecraft flew past Pluto in July 2015, it captured this image of the major mountain ranges where it meets a vast icy plain called Sputnik Planitia. The ridges in these photos have now been identified as dunes made of solid methane ice grains.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons photographed what scientists are calling "bladed" terrain near the heart-shaped region of the dwarf planet. This 3-D image was created using two images taken about 14 minutes apart on July 14. The first image was snapped about 16,000 miles (25,000 kilometers) from Pluto and the second was taken when the spacecraft was 10,000 miles (about 17,000 kilometers) away. Break out your 3-D glasses for the best view.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

The New Horizons team has discovered a chain of exotic mountains that are covered in methane snow on Pluto. NASA released an image of the snow-capped mountains stretching across the dark expanse of Cthulhu on March 3.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

NASA released a photo on February 4, 2015, of what it suspects is an image of floating hills on Pluto's surface. The hills are made of water ice and are suspended above a sea of nitrogen.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image made in infrared light shows water ice is abundant on Pluto's surface. The image was created using two scans of Pluto made by the New Horizons spacecraft on July 14, when the probe was about 67,000 miles (108,000 kilometers) above Pluto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image shows the layered interior walls of the planet's many craters. According to NASA, "layers in geology usually mean an important change in composition or event." However, NASA says the New Horizons team members do not know if they are seeing local, regional or global layering.

Most of the craters seen here lie within the 155-mile (250-kilometer)-wide Burney Basin. Learn more at NASA's website.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image shows how erosion and faulting has sculpted Pluto's icy crust into rugged badlands. The prominent 1.2-mile-high cliff at the top is part of a great canyon system that stretches for hundreds of miles across Pluto's northern hemisphere, NASA says. Learn more at NASA.gov.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Pluto's largest moon, Charon, in seen in enhanced color in this image taken by NASA's New Horizons spacecraft. The space probe took the image just before it made its closest approach on July 14. The image combines blue, red and infrared images to best highlight the moon's surface features. Charon is 754 miles (1,214 kilometers) across. The image was released on October 1.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Images from two instruments on New Horizons are combined in this photo to show Charon's cratered uplands at the top and a series of canyons. The bottom of the image shows rolling plains.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This composite of enhanced color images shows the striking differences between Pluto, lower right, and its largest moon, Charon. NASA says the color and brightness of the two worlds have been processed identically to allow for direct comparison. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

These photos show Pluto's variety of textures, including what NASA calls "rounded and bizarrely textured mountains." The mountains are informally called the Tartarus Dorsa. This image shows about 330 miles (530 kilometers) of Pluto's terrain. It combines blue, red and infrared images taken by the space probe's Ralph/Multispectral Visual Imaging Camera. The images were taken on July 14, during the probe's flyby. They were released on September 24.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

The photos taken by New Horizons just before its closest approach to Pluto on July 14 are the sharpest images to date of Pluto's varied terrain. This high-resolution image reveals details of two ice mountains. The image spans 75 miles (120 kilometers) of Pluto's surface.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image of the surface of Pluto was taken just 15 minutes after NASA's New Horizon spacecraft made its closest approach to the icy planet on July 14. As it looked toward the Sun, the spacecraft's camera captured more than dozen thin layers of haze in Pluto's atmosphere, at least 60 miles (100 kilometers) above the surface. The photo was downlinked to Earth on September 13.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image of Pluto's icy and mountainous landscapes was taken from a distance of 11,000 miles (17,700 kilometers). "This image really makes you feel you are there, at Pluto, surveying the landscape for yourself," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Colorado.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This picture is a synthesis of new high-resolution images downlinked from New Horizons. The broad icy plains have been nicknamed Sputnik Planum. This image is from a perspective above Pluto's equatorial area. Astronomers began downlinking a data dump from the space craft over Labor Day weekend, September 5 to 7.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Scientists say that what looks like mountains could be huge blocks of frozen water suspended in frozen nitrogen. On the new photos, taken on July 14 and released on September 10, a pixel is 400 meters (440 yards). New Horizons' closest pass by Pluto took it about 50,000 miles from the surface.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Pluto's landscape has lots of variety: plains, mountains, craters and what looks like they might be dunes. The smallest details on the photos are about half a mile wide. The area with the craters is ancient, scientist say. The smooth frozen planes are relatively young.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Just before its closest approach to Pluto on July 14, NASA's New Horizons spacecraft snapped this photo of Charon, Pluto's largest moon. The photo was shot at a distance of 290,000 miles away. Charon's north pole region is markedly dark. This photo was released on September 10.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This new image of Pluto is stunning planetary scientists. It shows the small world's atmosphere, backlit by the sun. NASA says the image reveals layers of haze that are several times higher than predicted. The photo was taken by the New Horizons spacecraft seven hours after its closest approach to Pluto on July 14. New Horizons was about 1.25 million miles from Pluto at the time.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Images taken of Pluto's heart-shaped feature, informally named Tombaugh Regio, reveal a "vast, craterless plain that appears to be no more than 100 million years old," NASA said July 17. The frozen region "is possibly still being shaped by geologic processes." NASA's New Horizons spacecraft was launched in 2006 and traveled 3 billion miles to the dwarf planet.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Close-up images of a region near Pluto's equator revealed a giant surprise: a range of youthful mountains. NASA released the image on July 15.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Remarkable new details of Pluto's largest moon, Charon, are revealed in this image released on July 15.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

The latest spectra analysis from New Horizons' Ralph instrument was released on July 15. It reveals an abundance of methane ice, but with striking differences from place to place across the frozen surface of Pluto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

NASA team members and guests count down to the spacecraft's approach to Pluto on July 14.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image of Pluto was captured by New Horizons on July 13, about 16 hours before the moment of closest approach. The spacecraft was 476,000 miles from Pluto's surface.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

The colors in this image of Pluto and Charon are exaggerated to make it easy to see their different features. (These are not the actual colors of Pluto and Charon, and the two bodies aren't really that close together in space.) This image was created on July 13, one day before New Horizons was to make its closest approach to Pluto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This image of Pluto was captured by New Horizons on July 12. The spacecraft was 1.6 million miles from Pluto at the time.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons snapped this photo of Charon on July 12. It reveals a system of chasms larger than the Grand Canyon. The spacecraft was 1.6 million miles away when the image was taken.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons was about 3.7 million miles from Pluto and Charon when it took this image on July 8.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Do you see a heart on Pluto? This image was taken on July 7 by New Horizons when it was about 5 million miles from the planet. Look to the lower right, and you'll see a large bright area -- about 1,200 miles across -- that resembles a heart.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons took six black-and-white photos of Pluto and Charon between June 23 and 29. The images were combined with color data from another instrument on the space probe to create the images above. The spacecraft was 15 million miles away when it started the sequence and 11 million miles when the last photo was taken.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Pluto is shown here along with Charon in images taken on June 25 and 27. The image on the right shows a series of evenly spaced dark spots near Pluto's equator. Scientists hope to solve the puzzle as New Horizons gets closer to Pluto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons took a series of 13 images of Charon circling Pluto over the span of 6½ days in April. As the images were being taken, the spacecraft moved from about 69 million miles from Pluto to 64 million miles.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Look carefully at the images above: They mark the first time New Horizons has photographed Pluto's smallest and faintest moons, Kerberos and Styx. The images were taken from April 25 to May 1.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons used its color imager to capture this image of Pluto and Charon on April 9. This was the first color image taken by a spacecraft approaching Pluto and Charon, according to NASA. The spacecraft was about 71 million miles away from Pluto when the photo was taken.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

In August 2014, New Horizons crossed the orbit of Neptune, the last planet it would pass on its journey to Pluto. New Horizons took this photo of Neptune and its large moon Triton when it was about 2.45 billion miles from the planet -- more than 26 times the distance between the Earth and our sun.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons captured this image of Jupiter and its volcanic moon Io in early 2007.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

On its way to Pluto, New Horizons snapped these photos of Jupiter's four large "Galilean" moons. From left is Io, Europa, Ganymede and Callisto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

A white arrow points to Pluto in this photo taken in September 2006 from New Horizons. The spacecraft was still about 2.6 billion miles from Pluto.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

Pluto was discovered in 1930 but was only a speck of light in the best telescopes on Earth until February 2010, when NASA released this photo. It was created by combining several images taken by the Hubble Space Telescope -- each only a few pixels wide -- through a technique called dithering. NASA says it took four years and 20 computers operating continuously to create the image.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

This was one of the best views we had of Pluto and its moon Charon before the New Horizons mission. The image was taken by the European Space Agency's Faint Object Camera on the Hubble Space Telescope on February 21, 1994.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

A Hubble Space Telescope image of Pluto and its moons. Charon is the largest moon close to Pluto. The other four bright dots are smaller moons discovered in 2005, 2011 and 2012: Nix, Hydra, Kerberos and Styx.

Our solar system's most distant visited object is covered in 'unidentified organic molecules,' scientists reveal

Photos: New Horizons explores Pluto, Arrokoth

New Horizons launched from Florida's Kennedy Space Center on January 19, 2006. The probe, about the size of a piano, weighed nearly 1,054 pounds at launch. It has seven instruments on board to take images and sample Pluto's atmosphere. After it completes its five-month study of Pluto, the spacecraft will keep going deeper into the Kuiper Belt.

More than a year after NASA's New Horizons mission closely flew by a small, distant Kuiper Belt Object, researchers have been able to sift through the data and learn intriguing new details about this fossil from the formation of the solar system. Located four billion miles beyond Pluto, Arrokoth is the most distant object ever visited by a spacecraft.

Previous studies about Arrokoth were based on a small amount of data sent back by the spacecraft, but the new details were provided by more than ten times as much data. The data enabled researchers to get a more complete picture of the object and determine more about its origin, formation, geology, composition, color and temperature.

And one of the most intriguing discoveries about Arrokoth is that it's covered in methanol ice and unidentified complex organic molecules, according to the researchers.

If the name sounds unfamiliar, it's because the object was renamed in November. Previously, it was known as Ultima Thule, which became controversial after the name was linked to Nazism. Arrokoth is a Native American term that means "sky" in the Powhatan and Algonquian language, according to NASA.

New findings about Arrokoth were presented Thursday at a press conference during the annual meeting of the American Association for the Advancement of Science. Three studies were also published in the journal Science.

"Arrokoth is unlike other small bodies visited by spacecraft," the researchers said in one of the studies.

Studying Arrokoth can shed light on how the building blocks of planets, called planetesimals, formed in our solar system. Arrokoth is largely unchanged after billions of years and acts as a primordial time capsule. The Kuiper Belt, a region of our solar system beyond the orbit of Neptune, is home to these old, cold objects, as well as comets, asteroids and other icy bodies. It's known as the third zone of the solar system.

In one study, researchers were able to use data from New Horizons to simulate the formation of the object, which resembles a peanut or a snowman, depending on how you look at it. It's made of two lobes that gently came together after forming independently.

And while the two lobes have been referred to as pancakes because they appeared flat in some of the first returned images, another new study suggests that they are actually much larger in volume.

Arrokoth's smooth surface is another indicator that the object is largely unchanged even after billions of years. It has a light scattering of small craters, likely caused by small, rapid collisions with other objects. The largest and most well-understood crater, dubbed Maryland, is 4.3 miles across. The others are much smaller. Arrokoth itself is about the size of Seattle, the researchers said.

"Multiple processes, including impacts, have reworked the surfaces of both lobes after their formation, producing the fissures and small dark hills," the researchers wrote in one of the studies.

The third study took a closer look at Arrokoth's unique appearance. It's incredibly cold and the surface is covered in methanol ice. The object's signature red color is likely due to organic molecules also detected on the surface, although their exact composition remains unidentified. It's known as "ultrared matter," a hallmark of Kuiper Belt Objects because it's only thermodynamically stable in this icy region far from the sun.

Methanol could be on the surface of Arrokoth as a result of several possibilities, including a mixture of water and methane ice that was exposed to radiation via the sun's cosmic rays. Water itself has not been detected on the surface of the object.

The researchers believe Arrokoth is about four billion years old. And all three studies provide evidence that the object was formed in a collapsing particle cloud in the local solar nebula -- the cloud of gas and dust from which our sun and planets formed. Its uniform color, smooth surface and how the lobes came together help piece together a picture of how the planetesimal came to be.

As a cloud of particles collapsed, the individual particles condensed to form the two lobes that eventually came together. The gentle bonding of the two lobes happened at about 7 miles per hour, said William McKinnon, New Horizons co-investigator.

This helps solve a debate over how planetesimals formed, both in the Kuiper Belt and across our solar system, said Alan Stern, principal investigator for New Horizons. He calls this discovery a "watershed moment." The other prevailing theory was called hierarchical accretion, where objects from different areas of the solar nebula would collide to form an object.

"We now know as a result of Arrokoth how those first stages of planetesimals formed," Stern said.