On July 14, 2015 the New Horizons space probe made its closest approach to the dwarf planet Pluto. Passing 7,800 miles above Pluto’s surface, it became the first spacecraft to explore Pluto. Humanity’s view of Pluto went from a fuzzy,
On July 14, 2015 the New Horizons space probe made its closest approach to the dwarf planet Pluto. Passing 7,800 miles above Pluto’s surface, it became the first spacecraft to explore Pluto. Humanity’s view of Pluto went from a fuzzy, indistinct blob to a high resolution, fascinating body almost overnight.
Because of Pluto’s distance from the Earth (almost 3 billion miles) and the very, very slow connection between New Horizons and mission control (1 kilobit/second), the data taken during the flyby will not be fully downloaded until this September, almost 16 months after New Horizon’s closest approach. Despite the delay in receiving all of the data, the New Horizon team has made numerous discoveries over the past year.
One of the most famous surface features on Pluto is now the heart shaped planes region informally named Sputnik Planum. While Sputnik Planum appears smooth from a distance, high-resolution images show the area is covered with irregular-shaped polygons ranging in size from 10-30 miles in diameter. The centers of these polygons are higher than the edges, forming strange, icy humps on the surface of Pluto.
In early June, a team of scientists announced that they found that the humps are caused by convection under the nitrogen ice surface of Pluto. The convention is similar to what one sees when water boils: bubbles of nitrogen are warmed by Pluto’s internal heat and rise to the surface. The lower edges form when the cooler nitrogen sinks back towards Pluto’s center, renewing the cycle. The convection is slow, only about 1.5 centimeters a year. While slow, the team estimates the surface of Sputnik Planum is only about one million years old, very young in planetary geology terms.
What’s next for New Horizons? The probe is flying towards its next target, an icy body known as 2014 Mu 69. New Horizons’ arrival date at the object is January 1, 2019. Two Maunakea Observatories played a critical role in the search and selection of the target. The Canada-France-Hawaii Telescope and the Subaru Telescope were used to search for a target. Ultimately, the Hubble Space Telescope spied 2014 MU 69 by using a model of the region generated by astronomers using CFHT data. They found 2014 Mu 69 in the center of the field predicted by the models.
Calculating the precise orbit of an object past Neptune normally requires years of observations. By making extremely high precision measurements of a location in the sky, astronomers reduced the time to two years. Using the camera Megacam at CFHT, members of the New Horizons encounter team mapped the star fields in the search area and created a new catalogue of stars which bridged two existing catalogs; a high precision but sparse catalogue created by the US Naval Observatory and a faint, but rich, star field in the Hubble images.
According to JJ Kavelaars, a member of the encounter team and longtime CFHT user, the creation of such a catalogue was only doable with “telescope system as well understood as Megacam on CFHT.”
