Advanced supercomputers have simulated extremely powerful
energy jets squirted out by black holes, the most exotic and
powerful objects in the Universe.
“This research helps us unlock the mysteries of rotating
black holes and confirms that their rotation actually produces
power output,” said Dr. David Meier, an astrophysicist at
NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Meier is
co-author of a paper that will appear in the journal Science.
The leader of the research team is Dr. Shinji Koide of Toyama
University, Toyama, Japan.
A black hole is an object so dense and powerful that
nothing, not even light, can escape. A black hole gobbles up
stars and other material that approaches it, including other
black holes. These odd objects form in one of two ways — when
a dying star collapses, or when many stars and black holes
collapse together in the center of a galaxy, like our Milky
Way.
Both types of black holes can rotate very rapidly,
dragging along the space around them. When more material
falls in, it swirls and struggles wildly before being
swallowed. Astronomers have witnessed this violence,
including the ejection of jets, with radio and X-ray
observations, but they are not able to see a black hole
itself.
“We can’t travel to a black hole, and we can’t make one
in the lab, so we used supercomputers,” Meier said. This
simulation process is similar to weather-prediction
techniques, which create animation of how clouds are expected
to move, based on current satellite views and knowledge about
Earth’s atmosphere and gravity effects. In much the same
way, the scientists combined data about plasma swirling into a
black hole with knowledge about how gravity and magnetic
fields would affect it.
“We have modeled a rotating black hole with magnetized
plasma falling into it,” said Koide. “We simulated the way
that the magnetic field harnesses energy from the rotation of
the black hole.”
“In this case, jets of pure electromagnetic energy are
ejected by the magnetic field along the north and south poles
above the black hole,” Meier added. “The jets contain energy
equivalent to the power of the Sun, multiplied ten billion
times and then increased another one billion times.”
This jet phenomenon had been predicted by Professor Roger
Blandford of the California Institute of Technology, Pasadena,
Calif., and his colleague, Roman Znajek, in the 1970s, but the
new computer simulation confirms that prediction. The latest
research was conducted in late 2001 using supercomputers at
Japan’s National Institute for Fusion Science.
Scientists have theorized the existence of black holes
since the 1700s and identified jet-producing objects in the
centers of galaxies since the early 1900s. In the 1960s,
scientists explored the possibility that these jet-emitting
objects were supermassive black holes between one million and
several billion times heavier than our Sun. In the 1990s, it
was discovered that such jets also are ejected by much smaller
black holes in double star systems. A black hole ten times as
massive as the Sun can form when the center of a dying star,
20 to 30 times the mass of the Sun, collapses on itself. This
creates a tiny object, only a few miles across, with an
intense gravitational pull. The other supermassive type of
black hole is formed when many stars and black holes collapse
together in the center of a galaxy.
In addition to Koide and Meier, the team includes
colleagues Dr. Kazunari Shibata, Kyoto University, Kyoto, and
Dr. Takahiro Kudoh, National Astronomical Observatory, Mitaka.
Images of the research are available at
http://www.jpl.nasa.gov/images/blackholes .
The research was partially funded by an Astrophysics
Theory Grant from NASA. The California Institute of
Technology in Pasadena manages JPL for NASA.
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Rotating Black Hole Simulation: Time Sequence
This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan’s National Institute for Fusion Science. |
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Rotating Black Hole: 3-D View
This three-dimensional illustration shows how the rotating space around a black hole twists up the magnetic field in the plasma falling toward the black hole. The black sphere at the center of the figure is the black hole itself, and the yellow region around it represents the area where space is being twisted. The red tubes depict magnetic field lines threading this twisting space, while the green ones show magnetic field lines which have not yet entered that space. This simulation was conducted using supercomputers at Japan’s National Institute for Fusion Science. |
