Comet 67P/Churyumov-Gerasimenko (67P) has no magnetic field, according to new findings obtained by the Rosetta spacecraft and its attendant lander, Philae. Comets are ancient bodies within our family of planets, and this discovery could help astronomers better understand the role played by magnetic fields during the formation of the solar system.
The landing craft did not touch down gently on the comet as planned on Nov. 12, 2014, but bounced and rolled before coming to a halt on the frozen surface. Astronomers were able to confirm the lack of a magnetic field surrounding Comet 67P by examining readings taken by Philae as the lander bounced over the icy body.
"The unplanned flight across the surface actually meant we could collect precise magnetic field measurements with Philae at the four points we made contact with, and at a range of heights above the surface," Hans-Ulrich Auster, a member of the Philae lander team, said.
During the formation of the solar system, a protoplanetary disk of gas and dust orbited the sun, slowly coalescing into planets, asteroids and comets. A portion of this material consisted of iron, and some of this turned into magnetite, researchers believe. This substance may have helped bring matter together into clumps when clusters were small, but as they grew, gravity likely became the dominant force driving accretion. Many astrophysicists had believed that comets and other bodies would retain their magnetism as they grew in size. However, this new finding provides evidence this may not be the case.
"Because comets contain some of the most pristine materials in the solar system, they offer a natural laboratory for investigating whether or not these larger chunks could have remained magnetized. However, detecting the magnetic field of comets has proven difficult in previous missions, which have typically made rapid flybys, relatively far from comet nuclei," European Space Agency (ESA) officials announced.
The Rosetta spacecraft was launched on a mission to explore comet 67P, and place the Philae lander down on the surface of the body. This vehicle is the first spacecraft to ever orbit a comet. On the way to its final destination, Rosetta examined the planet Mars, along with a pair of asteroids — 2867 Steins and 21 Lutetia.
The Philae lander has been silent since its unexpected rough landing, but mission planners hope the craft will wake up once again as temperatures start to warm as the comet and spacecraft approach the sun. The spacecrafts are accompanying the comet on its journey to the point at which it is closest to the sun - the comet loops around the sun between the orbits of Jupiter and Earth, the ESA notes, between about 800 million km (497 million miles) and 186 million km (115 million miles) from the sun.
The investigation that revealed the lack of a magnetic field on Comet 67P was detailed in the journal Science.
Photo: DLR German Aerospace Center | Flickr