Category Archives: charon

astronomy, ceres, charon, dawn mission, New Horizons mission, planetary science, Pluto

Pluto and Ceres: Solar System Gifts that Keep on Giving

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Exploring the Deeps of the Solar System

I gotta say: we live in a time of fascinating scientific discoveries in our solar system. We’ve been in a “golden age” of in situ planetary exploration that began in the 1960s. Now, well into the 21st century, space agencies around the world continue to dish out juicy findings. Every week I see news from the outer solar system in the form of Pluto and Charon system results from the New Horizons mission. We’re also getting frequent updates from the Dawn mission currently circling Ceres, a dwarf planet out beyond the orbit of Mars in the Asteroid Belt. I find it amazing that we can know so much about these distant places, all through the efforts of a two small spacecraft and the science teams that built and continue to manage them.

Visiting Ceres

Haulani Crater on Ceres
Ceres’ Haulani Crater, with a diameter of 21 miles (34 kilometers), shows evidence of landslides from its crater rim.
Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

For example, Dawn has been in “deep orbit” around Ceres. Since 2015, it has been snapping up high-resolution images and data of the surface. The team just released an image of Haulani crater, a 21 mile-wide impact feature that seems to show evidence of landslides from its crater walls. This enhanced-color image shows the younger features in blue and older ones in gray. The rays extending out around the crater (and colored blue) are made of material ejected as something slammed into the Cerean surface. It also looks like whatever smacked Ceres hit this world right in a region that was already stressed and fractured. Hence the odd shape of the crater.

The Dawn mission is continuing to explore Ceres in minute detail, giving us new insight into this frozen, cracked, and cratered world.

Pluto’s Latest and Greatest

This image of Pluto's spider terrain was obtained by New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC). It was obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
This image of Pluto’s spider terrain was obtained by New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC). It was obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

While New Horizons is no longer at Pluto, it continues to radio back data  across the solar system from its momentous 2015 encounter. Pluto continues to amaze everybody with a wide range of interesting features in its icy crust. The latest up-close image shows a region of cracked terrain nicknamed the “Ice Spider” of Pluto. Nothing quite like it has been seen on other bodies in the outer solar system.

This crack in the crust is a set of fractures. The longest one is about 580 km (360 miles) long and appears to lie roughly north-south. The shorter cracks run east-west. They’re only about 100 km (60 miles) long. There’s also a hint of some kind of reddish material in some of the spider’s legs.

The fractures that make up the spider are probablye due to a global extension and shrinking of Pluto’s water-ice crust. However, they could also be telling us there’s some local activity occurring, too.

Award-Winning Science

Both the New Horizons and Dawn Mission teams have been winning prestigious awards for their work exploring these distant worlds. On March 8, the Dawn project team was chosen for the prestigious National Aeronautic Association Robert J. Collier Trophy “for the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year.” Established in 1911, the 8-foot tall trophy resides at the Smithsonian National Air and Space Museum in Washington and is engraved with the names of recipients. Dawn competed with a field of nine finalists to win this year’s award. The award will be presented on June 9.

On March 11, the team was also honored with the National Space Club and Foundation’s Nelson P. Jackson Award, presented annually for “a significant contribution to the missile, aircraft or space field.” The Dawn team accepted the award at the organization’s 59th Annual Robert H. Goddard Memorial Dinner in Washington.

New Horizons team members are also basking in the glory of their achievements. PI Alan Stern, who was just named one of Time magazine’s list of 100 most influential people in the world, accepted the Carl Sagan award earlier this year, and gave a Kavli Prize Lecture at the American Astronomical Society meeting about his team’s exploration of the outer solar system. The team itself has earned the John L. “Jack” Swigert, Jr. Award for Space Exploration from the Space Foundation, the National Space Society Space Pioneer Award, and many others. The Smithsonian Institution also gave the New Horizons team a Current Achievement award.

As these two missions continue on their voyages of discovery, I’m sure we’ll ALL be awarded with more great views and data of distant worlds.

charon, New Horizons mission, Pluto

Serenity Chasma: A Window to Charon and its Past

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Charon Valley May Tell a Tale of Primordial Oceans

The side of Charon viewed by the passing New Horizons spacecraft in July 2015 shows a system of “pull apart” tectonic faults, which look like ridges, scarps and valleys—the latter sometimes reaching more than 4 miles (6.5 kilometers) deep. Courtesy New Horizons mission/JHU/APL.
The side of Charon viewed by the passing New Horizons spacecraft in July 2015 shows a system of “pull apart” tectonic faults, which look like ridges, scarps and valleys—the latter sometimes reaching more than 4 miles (6.5 kilometers) deep. Courtesy New Horizons mission/JHU/APL.

I have to say, the New Horizons mission is really the planetary exploration gift that keeps on giving! Every week the mission team drops some more amazing science on us.  This week, the scientists are sharing an image with us that may be evidence of an ancient ocean on Pluto’s largest moon (and orbital companion) Charon. It’s a valley on the icy surface called Serenity Chasma.

Serenity appears to be a tectonic fault that was formed when something pulled the surface apart. You see similar places on Earth, where the crust cracked open and formed a valley or a scarp. On Charon, these formed when the surface cracked as the subsurface part of the moon expanded as it froze. To understand this, take a look at Charon’s structure. Its upper layer is mostly water ice. When this moon was a young’un, it was still being heated from within by the heat that built up as it formed. Also, radioactive elements inside this moon supplied heat as they decayed. This is called radiogenic heating and is a well-known heat source for many places in the solar system. Inside of Charon, this heat could have kept the interior ices slushy and even liquid for quite a while.

However, all good things must come to an end. And, as happens with worlds as they cool down, Charon’s heat dissipated and that caused the interior ocean and the surface to freeze. When water ice freezes, it expands. That must have pushed the surface outward. Since water ice is pretty brittle, it cracked, forming the valleys we see today. That’s the best geological explanation for the valleys that seem to cross the surface of Charon, giving us more fascinating peeks into the ancient past of the most distant worlds in the solar system explored to date.  The spacecraft, which is on its way to an encounter with another Kuiper Belt object in a few years, is slowly sending back all the data it collected when it swept past the Pluto system in July 2015.