- 4298 - BLACKHOLES
- what do we know in 2023? Black holes are some of the most
mysterious objects in the universe. Yet scientists can learn plenty about black
holes by examining their environments, the conditions their intense gravity
generates, and the jets of matter they blast out at near light speed.
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------------- 4298 - BLACKHOLES - what do we know in 2023?
- In March, 2023,
researchers revealed that they had found what may be one of the most massive
black holes ever discovered. The cosmic titan sits at the heart of the
elliptical galaxy “Abell 1201 BCG”, located 2.73 billion light-years from
Earth, and the galaxy itself is in a massive cluster of galaxies called Abell
1201.
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- The Abel 1201 BCG
black hole is believed to have a mass equivalent to 32.7 billion suns and was
discovered through the effect of its gravitational influence on space. It is 30 billion times the mass of our sun,
is one of the biggest ever detected and on the upper limit of how large we
believe black holes can theoretically become.
-
- For many years,
scientists have pondered how supermassive black holes reach such tremendous
sizes. This is particularly challenging when supermassive black holes with
millions or billions of times the mass of the sun are discovered in the early
epoch of the universe, when they would not have had time to feed on matter or
even merge with other black holes enough to reach such titanic masses.
-
- In October,
2023, astronomers discovered a
supermassive black hole binary system in the aftermath of two merging galaxies.
At just 90 million light-years away, it's the closest pair of supermassive
black holes to Earth yet discovered.
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- The black holes
have masses 54 million times that of the sun and 6.3 million times that of the
sun. Currently, they orbit each other at a respectable distance of 1,600
light-years. But in around 250 million years, they will spiral together and
merge, just as their parent galaxies did 1 billion years ago, creating a
daughter supermassive black hole with a combined mass of around 60 million
solar masses.
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- As black hole
mergers occur, they set space-time ringing with tiny ripples called
“gravitational waves”, which were first predicted in Einstein's 1915 theory of
general relativity.
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- What Einstein
didn't predict was that gravitational waves would one day be detectable here on
Earth. This detection of space-time ripples got a major boost in October, when
the 'Laser Interferometer Gravitational-Wave Observatory'” (LIGO) got an
upgrade that will push beyond the so-called "quantum limit," allowing
it to detect even smaller undulations in space from even more distant black
hole mergers. We can now reach a deeper
universe and are expected to detect about 60 percent more mergers than before.
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- In June, NASA's
“Imaging X-ray Polarimetry Explorer” caught the echoes of an outburst from our
galaxy's supermassive black hole, Sagittarius A* (Sgr A*). Sgr A* is believed
to have belched this high-energy light around the turn of the 19th century, and
scientists caught its echo in the form of X-rays shining from dense molecular
clouds of gas surrounding the center of the Milky Way and birthing new stars.
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- The 200-year-old
burst of radiation is believed to be the result of a chunk of an asteroid, a
gas cloud or a star venturing too close to Sgr A* and being shredded by the
immense tidal forces generated by the supermassive black hole's intense
gravity.
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- In April, the
first-ever image of a black hole, dubbed the "fuzzy orange doughnut"
because it is notoriously blurry, got a major makeover thanks to AI. To improve
the sharpness of the image, researchers used a supercomputer running a
machine-learning technique called “principal-component interferometric
modeling” (PRIMO).
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- This allowed them
to fill in the gaps missed by the “Event Horizon Telescope” (EHT) when it
captured the first image of the black hole in 2019 and to slim down the glowing
ring of the supermassive black hole to learn more about it.
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- PRIMO is a new
approach to the difficult task of constructing images from EHT
observations. It provides a way to
compensate for the missing information about the object being observed, which
is required to generate the image that would have been seen using a single
gigantic radio telescope the size of the Earth.
-
- In November,
researchers studied the black hole Messier 87 and its jets to see how they
release energy. This energy isn't coming
from within the black hole; the boundaries of black holes, called event
horizons, prevent anything from escaping. Instead, the spinning of the black
hole twists up magnetic fields, which slow its rotational speed, and then
launches highly collimated jets of material that the team described as "million-light-year-long
Jedi lightsabers."
-
- If you took the
Earth, turned it all into TNT, and blew it up 1,000 times a second for millions
and millions of years, that's the amount of energy that we're getting out of
M87.
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- In April, a
collimated blast of energy emerging from M87's supermassive black hole became
the first black hole jet to be directly imaged. The image shows for the first time how the
base of the jet connects to matter swirling around the supermassive black hole
and gradually being fed to it.
-
- In March,
astronomers watched for the first time as the jets launched from the active
heart of a galaxy powered by a feeding supermassive black hole switched
direction and pointed straight at Earth.
-
- The galaxy, “PBC
J2333.9–2343”, located around 656 million light-years from Earth, had been seen
emitting jets but had appeared to fall quiet until firing up again and
realigning its jet by 90 degrees to point at Earth.
-
- In February, the
EHT collaboration revealed observations of the supermassive black hole-powered
“blazar” at the heart of the galaxy NRAO 530. The blazar represents the most
distant object the EHT has ever imaged.
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- The light that we
see traveled toward Earth for 7.5 billion years through the expanding universe,
but with the power of the EHT, we see the details of the source structure on a
scale as small as a single light-year.
-
- Scientists knew
that supermassive black holes are messy eaters, but they didn't realize that
black holes may have light diets because they "recycle" a lot of the material
they fail to consume.
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- In November,
astronomers discovered material engaged in an intricate dance around the
supermassive black hole at the heart of the Circinus Galaxy, located around 13
million light-years away.
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- They found that
the central black hole feeds on only around 3% of the material that falls
toward it and the energy it generates pushes the rest away, meaning it is a
much lighter eater than previously thought. That doesn't mean this matter keeps
its distance, however; much of it falls back to the central supermassive black
hole in an arrangement almost akin to a water fountain.
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- In April,
astronomers used the Gaia spacecraft to discover what seemed to be the closest
black holes to Earth. Designated Gaia BH1 and Gaia BH2, the black holes are
located 1,560 and 3,800 light-years away.
-
- But just a few
months later, scientists discovered that there may be several black holes in
the Hyades cluster, which, at just 150 light-years away, would make them 10
times closer than Gaia BH 1.
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- These two, or
possibly three, black holes could be even more remarkable because they might
not be in the dense star cluster at all but were ejected from the Hyades 150
million years ago to wander the Milky Way alone.
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-
December 31, 2023
BLACKHOLES - what do we know in 2023? 4298
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