The Significance Of The New Horizons Voyage to Pluto

Science has made it possible for us to discover so many new things not only on our planet, but in our solar system, galaxy and the universe. So many questions have been answered by such explorations and there are still so many questions to be answered. Because of advanced technology, we are discovering things about space that our minds can hardly fathom. As of 2014, NASA has discovered 715 new exoplanets orbiting 305 stars. Most of these planets are between the size of our planet and Neptune. They are tightly packed within the inner regions of their systems and four are said to be in the Goldilocks zone. According to the Kepler home page, the confirmed exoplanet count is at 961 with 3,800 unconfirmed planet candidates. This is just a small percent of the observable universe. We haven’t discovered a large portion of our own galaxy, The Milky Way. The possibilities of discovery are endless.

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Photo of Pluto taken by the New Horizons probe on 14 July 2015 from a distance of 450,000 kilometres. Image credit:

We don’t have to look far for amazing scientific breakthroughs; there is so much happening in our own celestial backyard. We’ve sent men to the moon, we’ve sent robotic land probes to Mars and a number of comets, observed the giant planets through Cassini and now we have reached the very last dwarf planet in our solar system. We’re talking about the New Horizons probe and its flyby the dwarf planet Pluto. If you’re not into science or astronomy, this milestone might not matter too much to you. However, the New Horizons probe was the first spacecraft to fly past Pluto on July 14th, 2015, after a decade and 3.6 billion miles of flying through space. The flyby is very significant because this is probably the furthest planet from Earth that our generation will be able to see and appreciate “up close”. All the other planets will be light years away and it will take centuries for our technology to reach the nearest planet within our galaxy.

4 photo composites were used to make a near true color of Pluto. Image credit:
4 photo composites were used to make a near true colour of Pluto. Image credit:

Pluto’s History

Pluto was discovered in 1930 by Clyde Tombaugh and was originally designated as the 9th planet from the sun. Pluto is a dwarf planet in the Kuiper belt which is a ring of bodies beyond the planet Neptune. Pluto was the first Kuiper belt object to be discovered and it is the largest and the second most massive dwarf planet within our Solar System. Just like other Kuiper belt objects, Pluto is made of rock and ice. After 1992, Pluto’s planetary status was questioned by many astronomers after the discovery of several objects of the same size in the Kuiper belt. Eris was discovered to be fractionally larger than Pluto, exceeding Pluto’s mass by 28%. This led the IAU or the International Astronomical Union to develop a formal definition of a planet. The classification excluded Pluto and so it was reclassified as a dwarf planet. Other astronomers still believe that Pluto and other dwarf planets should be considered planets, however it doesn’t look like the classification will change. Pluto has 5 known moons. Charon is the largest at half the size of Pluto. The other moons are Styx, Nix, Kerberos and Hydra. Pluto has an oval and tilted orbit of the sun and its orbital path has a 17 degree angle above the plane where the other 8 planets in our system orbit.

The picture of Charon and Pluto was taken at a distance of 150,000 miles (250,000 km). Image credit:
The picture of Charon and Pluto was taken at a distance of 150,000 miles (250,000 km). Image credit:

After the probe flyby, scientists were able to determine the exact size of the dwarf planet – 2,370 kilometres or 1,472 miles in diameter with just a potential error of +-20 kilometres or 12 miles. This means Pluto is actually larger than early estimates. We now know that Pluto is less dense with a large proportion of ice layers.

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Pluto discovery image to early Hubble image to later Hubble image to New Horizons early B&W pic to New Horizons colour image. Image credit:

The dwarf planets in our solar system can be found in two places – the main asteroid belt between Mars and Jupiter and in the Kuiper Belt beyond Neptune. Pluto’s orbital distance is 5,874,000,000, with an orbital period of about 248 Earth years compared to Earth’s orbital period of 365 days. The surface temperature is -229 degrees C.

Interesting Facts About Pluto and the New Horizons Probe


The New Horizons probe clocked the fastest launch ever recorded when it blasted off in January 2006. It exceeded 36,000 MPH. The spacecraft passed by the Moon in just 9 hours and reached Jupiter a year later.


Aside from the scientific instruments it carries, it also carries a few interesting mementos including the ashes of Clyde Tombaugh, who discovered the dwarf planet in 1930, CD-ROMs with the names of the 434,000 who signed up, 2 US state quarters and 2 United States flags, and a 1991 stamp that says “Pluto: Not Yet Explored”.

The ashes of Clyde Tombaugh. Image credit.
The ashes of Clyde Tombaugh. Image credit.


Data beamed back to Earth takes about 4 hours and 30 minutes. The signals are so faint that NASA has to use 200 ft wide radio dishes in Australia, Spain and California to pick it up. Data transmission is about 1 KB/Sec which is 50 times slower than a 56k dial up modem from the 90s. So it takes about 42 minutes for the probe to fully transmit an image or pictures with 1024 resolution.


Pluto is just a fraction of the size of Earth, but the dwarf planet has 5 known moons, as mentioned earlier. Pluto and Charon are considered to have a binary system because the barycentre of their orbits does not lie within either of them. It’s like they are dancing with each other in a circular manner while the 4 other smaller moons are pulled up in the pair’s gravitational field resulting in a bizarre and chaotic orbit. It’s controlled chaos. The 2 smallest moons were discovered in 2012 and from the recent flyby the probe has collected lots of data on these moons.

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Charon and Pluto at 15 million miles away from New Horizons. Image credit:
Charon and Pluto at 15 million miles away from New Horizons. Image credit:


New Horizons’ sensors have detected a thin Nitrogen atmosphere that extends far out into space and the surface colouring suggests that there is a patchwork of different concentrations of frozen nitrogen and methane.

Backlit by the sun, Pluto’s atmosphere rings its silhouette like a luminous halo in this image taken by NASA’s New Horizons spacecraft around midnight EDT on July 15. This global portrait of the atmosphere was captured when the spacecraft was about 1.25 million miles (2 million kilometers) from Pluto and shows structures as small as 12 miles across. The image, delivered to Earth on July 23, is displayed with north at the top of the frame. Image Credits: NASA/JHUAPL/SwRI
Backlit by the sun, Pluto’s atmosphere rings its silhouette like a luminous halo in this image taken by NASA’s New Horizons spacecraft. The atmosphere was captured when the spacecraft was about 1.25 million miles (2 million kilometres) from Pluto and shows structures as small as 12 miles across. 
Image Credits: NASA/JHUAPL/SwRI


The NASA mission scientists have started giving unofficial names to some of Pluto’s features. Cthulhu is the name of the dark patch near the south pole while other parts are named Meng-p’o after the Buddhist goddess of forgetfulness and Balrog, the giant, flaming demon of the underworld that is featured in JRR Tolkien’s novel The Lord Of The Rings. For the names to be official, they have to be approved by the IAU.

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The name Pluto was proposed by an 11 year old school girl in Oxford, England. Venetia Burney suggested the name after the god of the underworld. It was officially named on March 24, 1930.


Most spacecrafts and space probes are solar powered, but at 3billion+ miles from the sun, the faint light reaching the spacecraft near Pluto makes it impractical. So the space probe was powered by nuclear fuel, specifically plutonium. The plutonium fuel is designed to last until the late 2020 or possibly beyond.

The Briliant people behind the Pluto Mission. Image credit:
The brilliant people behind the Pluto Mission. Image credit:


The space probe has 3 main cameras named Ralph, Alice and LORRI which can also tell the dwarf planet’s surface  temperature, chemical composition, the density and the temperature of the atmosphere. Other instruments are named PEPSSI (short for Pluto Energetic Particle Spectrometer Science Investigation). It detects particles that are escaping from the planet’s nitrogen atmosphere and tells the scientists what other elements are present. SWAP (Solar Wind Around Pluto) will provide data on how these particles interact with the solar wind. PEPSSI and SWAP will help the scientists understand how the planet’s atmosphere fluctuates over time due to its varying distance to the sun. The Student Dust Counter was designed and built by the students of the University of Colorado, and will give information on the density of the dust in the outer solar system. REX (Radio Science Experiment) will transmit and receive radio signals through the planet’s atmosphere. It will analyse these signals upon reaching Earth and will give many scientists ideas about Pluto’s atmosphere, composition, pressure and temperature.

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The New Horizons probe is powered by and equipped with a MIPS-based Mongoose-V CPU, which is a radiation-hardened space version of the MIPS R3000 used in the original Sony Playstation. The CPU clocked at 12MHz while the Playstation clocked at 33MHz.


New Horizons spotted a volcano eruption on Io, one of Jupiter’s moons when it was utilising a gravity slingshot to reach Pluto. The photos show the Tvashtar volcano erupting on the moon’s surface.


The mission will go beyond Pluto to other Kuiper Belt objects if NASA can get funding. It will probably fly by Eris, Makemake and Haumea.

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This is one of the most important journeys of human history. The teams behind the probe design and the mission planning have allowed us to see these crisp images of a far away dwarf planet for the first time.


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