Getting there and today's the Day

Just about as close as it is going to get.

Pluto nearly fills the frame in this image from the Long Range Reconnaissance Imager (LORRI) aboard NASA’s New Horizons spacecraft, taken on July 13, 2015 when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. This is the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14. The color image has been combined with lower-resolution color information from the Ralph instrument that was acquired earlier on July 13. This view is dominated by the large, bright feature informally named the “heart,” which measures approximately 1,000 miles (1,600 kilometers) across. The heart borders darker equatorial terrains, and the mottled terrain to its east (right) are complex. However, even at this resolution, much of the heart’s interior appears remarkably featureless—possibly a sign of ongoing geologic processes.

Credits: NASA/APL/SwRI

  About 0ne million miles off the closest approach
Image Credit: NASA/JHUAPL/SWRI

So excited by the fabulous images coming back this week from the New Horizons spacecraft. Well done NASA and the many academic and manufacturing collaborators that have made this amazing technological acheivement possible. All Americans should be very proud!

The spacecraft is currently zooming past Pluto and its retinue of moons at 30,800 miles per hour and will be gathering a range of data before and after closest approach.  Because of the vast distance between Pluto and the Earth, 3 billion miles, and the relatively slow data transfer speeds, this data will take a number of weeks to be received. Analysis will take even longer, so we can expect the release of more fascinating information and  images over the coming months.

A portrait from the final approach. Pluto and Charon display striking color and brightness contrast in this composite image from July 11, showing high-resolution black-and-white LORRI images colorized with Ralph data collected from the last rotation of Pluto. Color data being returned by the spacecraft now will update these images, bringing color contrast into sharper focus.

Credits: NASA-JHUAPL-SWRI

 Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were used to make this determination. This result confirms what was already suspected: Pluto is larger than all other known solar system objects beyond the orbit of Neptune.  Will this re-evaluation of Pluto's dimensions mean a possible reclassification of Pluto as a proper planet?

Image credits: NASA-JHUAPL-SWRI

UPDATE 16/07/2015
Latest image of Pluto's suface from New Horizons closest pass.

New close-up images of a region near Pluto’s equator reveal a giant surprise -- a range of youthful mountains rising as high as 11,000 feet (3,500 meters) above the surface of the icy body.

Credits: NASA/JHU APL/SwRI

Scientists were surprised at the lack of surface craters. The implication of this paucity of impact scars is that there is some ongoing geological activity that hides or obliterates ancient craters. On earth this is accomplished by plate tectonics  and on Jupiter's moon Io by volcanism. Both these processes require internal heat. The Earth's primary internal heat source is provided by radioactive decay and on Io internal heat is created by tidal stresses and strains as Io interacts with Jupiter's gravity. Neither radioactivity or gravitational force can be associated with whatever is going on on Pluto - so watch this space!

I was impressed by the similarities between the surface of Pluto as shown by this closeup image and the surface of the comet 67P/Churyumov–Gerasimenko which is currently being photographed by ESA's Rosetta spacecraft.  Perhaps all the planetoids, icy bodies and comets that formed out in the Kuiper Belt have similar surface characteristics?

UPDATE 18/07/2015

The images from New Horizons are very strange. This latest image shows an area within the 'Heart' now named after Pluto's discovere Clyde Tombaugh.

In the center left of Pluto’s vast heart-shaped feature – informally named “Tombaugh Regio” - lies a vast, craterless plain that appears to be no more than 100 million years old, and is possibly still being shaped by geologic processes. This frozen region is north of Pluto’s icy mountains and has been informally named Sputnik Planum (Sputnik Plain), after Earth’s first artificial satellite. The surface appears to be divided into irregularly-shaped segments that are ringed by narrow troughs. Features that appear to be groups of mounds and fields of small pits are also visible. This image was acquired by the Long Range Reconnaissance Imager (LORRI) on July 14 from a distance of 48,000 miles (77,000 kilometers). Features as small as one-half mile (1 kilometer) across are visible. The blocky appearance of some features is due to compression of the image.

Credits: NASA/JHUAPL/SWRI

 “This terrain is not easy to explain,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team (GGI) at NASA’s Ames Research Center in Moffett Field, California. “The discovery of vast, craterless, very young plains on Pluto exceeds all pre-flyby expectations.”

" Scientists have two working theories as to how these segments were formed. The irregular shapes may be the result of the contraction of surface materials, similar to what happens when mud dries. Alternatively, they may be a product of convection, similar to wax rising in a lava lamp. On Pluto, convection would occur within a surface layer of frozen carbon monoxide, methane and nitrogen, driven by the scant warmth of Pluto’s interior".

Wow!

UPDATE 23/07/2015

A newly discovered mountain range lies near the southwestern margin of Pluto’s Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015 from a distance of 48,000 miles (77,000 kilometers) and received on Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible.

Credits: NASA/JHUAPL/SWRI

  Credit: NASA