This week may mark the end of the year, but it also marks a new beginning for the New Horizons spacecraft. The space probe best known for its incredible photos of Pluto in 2015 is embarking on a new adventure: a flyby of an object far beyond Pluto, called Ultima Thule. The object hides at the edge of our solar system in the Kuiper belt.
The overflight is scheduled for January 1, 2019, although the spacecraft will continue to study the Kuiper Belt until at least 2021.
Ultima Thule is even more mysterious than Pluto. On the one hand, it is much smaller: with an estimated diameter of 30 kilometers, Ultima Thule is little more than a glorified asteroid. In the icy, empty space beyond Pluto, Ultima Thule makes its slow orbit around our sun, spinning once every 296 years. Scientists have theories about what Ultima Thule might look like in close-up, although most expect surprises; after all, there has never been a flyby of such a distant object before in the history of any space program. Since scientists have never before studied a Kuiper Belt object like this closely, Ultima Thule can produce many new insights into the history of our solar system's formation.
As it approaches, New Horizons has begun to take photos of its goal, which has already yielded an interesting discovery. According to scientists, there is a lack of a "light curve", which means periodic pulsations in the brightness.
"It's really a riddle," New Horizons chief researcher Alan Stern of the Southwest Research Institute said in a statement. "I call this Ultima Ultima's puzzle – why does it have such a small light curve that we can not even detect it? I hope the detailed flyby images bring us a lot more mysteries, but I did not expect that, and then brief. "
Scientists have some theories, but nothing will be truly confirmed until the flyby on January 1.
"It is possible that Ultima's rotation pole is facing the ship or near it," Marc Buie of the Southwest Research Institute said in a statement.
Another explanation could be that Ultima is surrounded by a cloud of dust.
"Another explanation," said Mark Showalter of the SETI Institute, "is that Ultima may be surrounded by a cloud of dust that obscures his light curve, just as coma coma often outweighs the light reflected by its central nucleus ".
One scientist suggested that it could be due to the object being surrounded by multiple moons.
"If each moon has its own light curve, then together they can create a superposition of light curves that make New Horizons, as Ultima has a small curve of light," Anne Verbiscer of the University of Virginia, a New York assistant scientist Horizons, explained.
New Horizons will have high resolution images that will be available on Earth a few days later. The world can expect interesting discoveries given the details that New Horizons is known to provide. When the spacecraft took photos of Pluto, it confused scientists at first.
"Pluto is showing us a diversity of relief shapes and process complexity that rival anything we saw in the solar system," Stern said of the photos. "If an artist had painted this Pluto before our overflying, it would probably have called it over – but that's what's really there."
The photos showed an unexpected complexity of the planet.
"The surface of Pluto is as complex as that of Mars," said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging team at NASA's Ames Research Center in Moffett Field, California. "Randomly cluttered mountains can be huge blocks of water ice floating inside a vast, dense and softer reservoir of frozen nitrogen within the region, informally called the Sputnik Planum."
Close-up data from New Horizon's Ultima Horizon observations will begin arriving on Earth on the first day of 2019.