Black hole is located 7.5 billion light-years from Earth
19/9/2024 5:49
Two mighty beams of
energy have been detected shooting in opposite directions from a
supermassive black hole inside a distant galaxy - the largest
such jets ever spotted, extending about 140 times the diameter
of our vast Milky Way galaxy.
The black hole resides at the heart of a galaxy about 7.5
billion light-years from Earth. A light-year is the distance
light travels in a year, 5.9 trillion miles (9.5 trillion km).
Because of the time it takes for light to travel, looking across
great distances is peering back in time, with these observations
dating to when the universe was less than half its current age.
Black holes are extraordinarily dense objects with gravity
so strong that not even light can escape. Most galaxies,
including the Milky Way, have a large black hole at their core.
Some of these shoot jets of high-energy particles and magnetic
fields into space from their two poles as they devour material
such as gas, dust and stars falling into them due to their
immense gravitational strength.
The two jet structures documented in the new study - using
the LOFAR (Low-Frequency Array) radio telescope, a network of
antennas centered in the Netherlands - extend 23 million
light-years from end to end.
These super-heated jets, caused by the violent events around
the black hole, are comprised of subatomic particles called
electrons and positrons, and magnetic fields, moving at nearly
the speed of light.
The researchers have nicknamed these two jets Porphyrion
(pronounced poor-FEER-ee-ahn), named after a giant from ancient
Greek mythology. Porphyrion is about 30% longer than the
previous record-holder for such jets.
"Jet systems like Porphyrion appear to be among the most
energetic spectacles that have occurred in the universe since
the Big Bang," said Caltech astrophysicist Martijn Oei, lead
author of the study published in the journal Nature, referring
to the event that initiated the universe about 13.8 billion
years ago.
"The general understanding is that jets are formed when
magnetized material falls onto a rotating black hole," added
astrophysicist and study co-author Martin Hardcastle of the
University of Hertfordshire in England. "They need to be
sustained by a continued infall of matter into the black hole,
something of the order of one solar mass (the mass of the sun) a
year of material."
Such jets, not visible to the naked eye, start out small and
grow over time.
"We've known for a while that black holes can generate these
jets. But what is interesting is that to generate a large
structure like this, the jets must stay on for a long time -
about a billion years," Hardcastle said.
The Porphyrion jets reach far beyond their home galaxy, with
an energetic output equivalent to trillions of stars like the
sun.
"That is equivalent to the energy released during the most
cataclysmic cosmic collisions: for example, those that occur
when two galaxy clusters, each sometimes containing thousands of
galaxies, merge together," Oei said.
"The fact that it extends so far from its parent black hole
means that it may be carrying energy, particles and magnetic
fields into the voids in the cosmic web, the gaps between groups
and filaments of galaxies which we know make up the large-scale
structure of the universe. This may help us to understand the
ubiquitous magnetic fields in the present-day universe,"
Hardcastle said.
Such jets could heat up gas in interstellar space, shutting
down the formation of new stars that requires cold clouds of
gas, and could damage habitable planets, the researchers said.
The Milky Way's supermassive black hole, in its current
quiescent state, does not have such jets.
"The key finding is that jets from black holes can, if
circumstances are right, become as large as the universe's major
cosmic structures - galaxy clusters, cosmic filaments, cosmic
voids," Oei said. "This means that individual black holes can
have a sphere of influence that extends way beyond the galaxy in
which they reside."
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