Many space researchers have been eagerly awaiting the photos from the planet Pluto, but two of them – Prof. Hagai Perets and doctoral student Erez Michaeli of the Physics Faculty of the Technion-Israel Institute of Technology – are particularly tense, since they have been researching potential moons likely to be discovered around the small planet.
More than nine years after its launch, a United States spacecraft sailed past Pluto on Tuesday, capping a nearly 5 billion km journey to the solar system’s farthest reaches, NASA said.
The craft flew by the distant “dwarf” planet at 7:49 A.M. after reaching a region beyond Neptune called the Kuiper Belt that was discovered in 1992. The achievement is the culmination of a 50-year effort to explore the solar system.
“Pluto was discovered in 1930, but its chief moon, Charon, was only discovered in 1978,” explains Michaeli. “Over the past decade, thanks to the Hubble space telescope four more moons have been discovered orbiting Pluto on the same plane. Since then the question has arisen if Pluto has other moons.”
In their joint research, Perets and Michaeli, “don’t presume to say whether there are such moons, but only map those regions in which they are likely to be found,” Michaeli says.
The new findings provided by NASA’s New Horizons spacecraft will put the model they’d developed to the test. He says the discovery of new moons will help them better understand how Pluto was formed.
“As an astrophysicist I want very much for new things to be discovered, and I’d be very pleased even if they find moons in other places,” Michaeli said. “It will of course mean that there was something we hadn’t considered, but to some extent it would be even more interesting. After all, that’s one of the best things about science; surprises often tell us more than our successful predictions.”
Why study a hunk of rock at the outlying edge of the solar system? Perets explains that Pluto and similar heavenly bodies provide a special opportunity to explore the building blocks of the solar system, “some of which have survived virtually unchanged. Pluto gives us a look at the birth pangs of the solar system and the origin of the Earth, and now we’re getting it live.”
Meanwhile, they are excited by the New Horizon mission’s success thus far.
“It’s truly a mark in human history,” said John Grunsfeld, NASA’s associate administrator for science from the mission control center at Johns Hopkins University Applied Physics Laboratory on Tuesday.
The spacecraft is so far from Earth that radio signals, traveling at the speed of light, take about four and a half hours to reach Earth.
“We’ll get information from the spacecraft and know if it’s healthy,” said Alice Bowman, the mission operations manager.
New Horizons is planned to spend nearly a day in radio silence, running through a tightly choreographed series of observations as it shoots past Pluto and its entourage of five moons, traveling at about 14 km per second.
For several hours following closest approach, the diminutive nuclear-powered probe, which is about the size of a baby grand piano, will look back at Pluto, now backlit by the sun, to study its atmosphere using radio signals beamed from Earth as a probe.
Scientists have many questions about Pluto, which when New Horizons launched in 2006 was still considered the solar system’s ninth planet. It was demoted to the status of “dwarf planet” after the discovery of other Pluto-like, ice-and-rock worlds orbiting beyond Neptune in the Kuiper Belt.
The objects are believed to be remnants from the formation of the solar system 4.6 billion years ago.
It will take about 16 months for New Horizons to transmit back all the images and measurements taken during Tuesday's flyby. By then, the spacecraft will be even deeper into the Kuiper Belt, heading for a possible follow-on visit to one of Pluto’s cousins.