Magnetic Waves From Distant Black Hole Shake Like Whip Being Held by Giant Hand

Posted on July 10, 2015

NASA scientists say fast-moving waves coming from a distant supermassive black hole undulate like a whip whose handle is being held by a giant hand. NASA released a series of slinky-like images that illustrate the undulating waves. The observation was made by scientists studying data from National Radio Astronomy Observatory's Very Long Baseline Array. The galaxy/black hole system is called BL Lacertae (BL Lac).

This is the first time Alfven waves have been identified in a black hole system. The waves are generated when magnetic field lines interact with charged particles or ions. They then become twisted or coiled. The ions from BL Lac are in the form of particle jets flung from opposite sides of the black hole at speeds about 98 percent the speed of light. The jet is a flow of charged particles, called a plasma. It has a helical magnetic field that permeates the plasma.

David Meier, a retired astrophysicist from NASA's Jet Propulsion Laboratory and the California Institute of Technology, says in a statement, "The waves are excited by a shaking motion of the jet at its base. By analyzing these waves, we are able to determine the internal properties of the jet, and this will help us ultimately understand how jets are produced by black holes."

Marshall Cohen, an astronomer at Caltech and first author of the study, says, "Imagine running a water hose through a slinky that has been stretched taut. A sideways disturbance at one end of the slinky will create a wave that travels to the other end, and if the slinky sways to and fro, the hose running through its center has no choice but to move with it."

The researchers say it is common for black hole particle jets to bend but it typically takes place of thousands of millions of years. Cohen says what is happening with the BL Lacertae system takes place in a matter of weeks.

He says, "We're taking pictures once a month, and the position of the waves is different each month."

SPACE