Unknown Facts About Pluto

 

Unknown Facts About Pluto

Pluto, once considered the ninth planet in the solar system, is now classified as a dwarf planet. Despite its reclassification in 2006 by the International Astronomical Union (IAU), Pluto remains a subject of fascination due to its unique characteristics and the mysteries surrounding its distant location.  

Pluto’s Orbit Is Highly Eccentric  

Pluto’s orbit is elliptical and tilted, causing it to sometimes come closer to the Sun than Neptune. For about 20 years of its 248-Earth-year orbit, Pluto is closer to the Sun than Neptune. This last occurred from 1979 to 1999 (Stern et al., 2015).  

Pluto Has Five Known Moons  

Pluto has five known moons: Charon, Nix, Hydra, Kerberos, and Styx. Charon, the largest, is so massive relative to Pluto that they form a binary system, with the center of their shared orbit lying outside of Pluto (Weaver et al., 2006).  

Pluto’s Surface Is Covered in Ice and Methane  

Pluto's surface consists mainly of nitrogen ice, with traces of methane and carbon monoxide. Its surface temperature is estimated to be around -229 degrees Celsius, making it one of the coldest known objects in the solar system (Grundy et al., 2016).  

Pluto Has a Blue Sky  

Despite its icy surface, Pluto’s thin atmosphere scatters sunlight, creating a blue sky similar to Earth’s. This was observed during the New Horizons mission, which detected layers of haze in its atmosphere (Gladstone et al., 2016).  

Pluto Is Smaller Than Some Moons  

Pluto is smaller than several moons in the solar system, including Earth’s Moon, Jupiter’s Ganymede, and Saturn’s Titan. Its diameter is about 2,377 kilometers, roughly two-thirds the size of Earth's Moon (Stern et al., 2015).  

Pluto Was Named by an 11-Year-Old Girl  

The name "Pluto" was suggested by Venetia Burney, an 11-year-old girl from England, in 1930. She proposed the name after the Roman god of the underworld, aligning with the naming convention of mythological figures for celestial objects (Tombaugh & Moore, 2009).  

Pluto’s Heart-Shaped Glacier Is Fascinating  

Pluto's most iconic feature is the large, heart-shaped glacier called Sputnik Planitia. It is composed of nitrogen and carbon monoxide ice and exhibits active glacial flow, suggesting geologic activity despite Pluto's small size and distance from the Sun (Moore et al., 2016).  

Pluto’s Atmosphere Expands and Collapses  

Pluto’s thin atmosphere, primarily composed of nitrogen, methane, and carbon monoxide, expands when it is closer to the Sun and freezes onto the surface as frost when it moves farther away. This dynamic cycle is unique among solar system bodies (Young et al., 1997).  

Pluto Was Downgraded to a Dwarf Planet  

In 2006, Pluto was reclassified as a dwarf planet because it does not meet all the criteria for a planet. Specifically, it has not "cleared its orbit" of other debris, a key requirement established by the IAU (IAU, 2006).  

New Horizons Revolutionized Pluto’s Study  

NASA’s New Horizons spacecraft, which flew by Pluto in 2015, provided unprecedented data about the dwarf planet. It revealed detailed images of its surface, discovered atmospheric hazes, and mapped Pluto's moons in high resolution (Stern et al., 2015).  

Pluto Exists in the Kuiper Belt  

Pluto is a member of the Kuiper Belt, a region beyond Neptune filled with icy bodies and remnants from the solar system’s formation. Its study provides insights into the early solar system (Jewitt & Luu, 2000).  

Charon Has a Red Pole  

Charon, Pluto's largest moon, has a reddish cap at its north pole caused by tholins—complex organic molecules formed when methane from Pluto’s atmosphere interacts with ultraviolet light (Grundy et al., 2016).  

Pluto’s Day Is Longer Than Its Year  

Pluto rotates very slowly, taking about 6.4 Earth days to complete one rotation. Its year, or one orbit around the Sun, lasts 248 Earth years, making its day relatively long compared to its year (Buie et al., 1997).  

Pluto Is Geologically Active  

Despite its size and distance from the Sun, Pluto displays signs of geological activity, including flowing glaciers, shifting tectonic plates, and potential cryovolcanism, challenging assumptions about small icy worlds (Moore et al., 2016).  

Pluto Has Exotic Weather  

Pluto’s thin atmosphere supports unique weather patterns, including nitrogen frost cycles. These patterns are influenced by its extreme axial tilt of 120 degrees, which causes dramatic seasonal changes (Young et al., 1997).  

References  

Buie, M. W., Tholen, D. J., & Horne, K. (1997). Albedo maps of Pluto and Charon: Initial mutual event results. *Icarus*, *125*(2), 233-244.  

Gladstone, G. R., et al. (2016). The atmosphere of Pluto as observed by New Horizons. *Science*, *351*(6279), aad8866.  

Grundy, W. M., et al. (2016). Surface compositions across Pluto and Charon. *Science*, *351*(6279), aad9189.  

IAU. (2006). Definition of a planet in the solar system. International Astronomical Union General Assembly, Resolution B5.  

Jewitt, D., & Luu, J. (2000). The Kuiper Belt and the solar system’s formation. *Nature*, *432*(7020), 731-733.  

Moore, J. M., et al. (2016). The geology of Pluto and Charon through New Horizons. *Science*, *351*(6279), 1284-1293.  

Stern, S. A., et al. (2015). The Pluto system: Initial results from its exploration by New Horizons. *Science*, *350*(6258), aad1815.  

Tombaugh, C. W., & Moore, P. (2009). Out of the darkness: The planet Pluto. *Cambridge University Press*.  

Weaver, H. A., et al. (2006). Discovery of two new satellites of Pluto. *Nature*, *439*(7079), 943-945.  

Young, L. A., et al. (1997). Vertical structure of Pluto’s atmosphere from stellar occultations. *Icarus*, *127*(2), 258-287.