We’ve known about “black hole jet systems” for some time, but never one as big as Porphyrion: a 23,000,000 light-year giant.
I’ll be talking about that today, along with how astronomers have been studying it, a plausible explanation for its extraordinary length, and a quick overview of how we’ve been thinking about this universe.
- Cosmology: From the Cosmic Ocean to the Cosmic Web
- Porphyrion and Cosmic Scale
- Radio Telescopes: LOFAR and —
- Fanaroff-Riley Classification
- That’s Odd: Porphyrion’s Size, and an Explanation
- “…The Heavens … Like a Tent to Dwell In”
Cosmology: From the Cosmic Ocean to the Cosmic Web
One of the problems — or needful decisions, take your pick — I deal with when I write these things is figuring out where to start.
On the one hand, I could start talking about radio galaxies, cosmic walls, and active galactic nuclei.
On the other hand — I’ll try starting with stories folks have told about the universe. I’ll be covering nearly four millennia in a few hundred words, so this’ll be concise.
Mesopotamian Musings
Around the time Ahmose the First put Egypt back under Egyptian management, folks in Mesopotamia were spinning tales involving a flat, circular Earth surrounded by a cosmic ocean.
If that sounds familiar, it should.
It’s imagery we see in the Old Testament.
“Then God said: Let there be a dome in the middle of the waters, to separate one body of water from the other.
“God made the dome, and it separated the water below the dome from the water above the dome. And so it happened.
“God called the dome ‘sky.’ Evening came, and morning followed—the second day.”
(Genesis 1:6–8)
Instead of being shocked, horrified, and upset about Genesis including cultural references that folks living near the eastern Mediterranean understood — I’ll accept that descendants of Abraham lived there, and move on.
About a millennium later, folks like Anaximander and Democritus were thinking about the universe in what we’d call “scientific” terms. In other words, they were making sense of reality by considering what we can observe, without mythic elements.
Parmenides generally gets credit for showing that Earth is spherical, not a cylinder; and we’re still not sure about Anaximander’s multiple universes.
Fast-forward again, this time about two millennia. European scholars were overly-impressed by Aristotle, but folks like Galileo Galilei started using what we’d call a spyglass.
In the half-millennium since then, we’ve been developing technologies that let us see more: and make more precise measurements. That’s led to new ideas about how this universe works.1
Quite a few new ideas, actually. And, so far, each time scientists got their hands on more data; the universe they’ve been describing got bigger.
William Herschel, “Our Sidereal System”, and Finding Galaxies
A musician and composer, Frederick William Herschel, fled to England in 1757. There’s a story behind that, involving the Seven Years’ War, and that’s another topic.
Somewhere along the line, Herschel got interested in astronomy. Serious, professional astronomers were mostly interested in studying the planets, but not Herschel.
He was interested in stars, and planets, and the Moon, and sunspots — and building telescopes. Lots of telescopes.
He also thought he’d worked out a method for mapping the universe. Making not-unreasonable assumptions, like the sun being pretty much in the center, and stars being evenly distributed.
Seriously: that made sense. Observation told us that the sky is more-or-less equally crowded with stars in opposite quadrants, no matter which pair we’re looking at.
About “quadrant”: despite the name, the sky’s been divided into eight quadrants. When, and why, that happened: I don’t know. Mercifully, I don’t have to say “celestial quadrant” all that often.
Anyway, Herschel mapped “our sidereal system”, publishing his results in 1785.
By that time, Fr. Angelo Secchi had shown that our Sun is a star, or the stars are suns. Take your pick.
Astronomers, including William Herschel, had been studying nebulae: those fuzzy patches that kept getting mistaken for comets. William Huggins analyzed their spectra. He learned that about one out of three nebulae were luminous gas, while the rest were massive collections of stars.
By 1924, with 20-20 hindsight, we see that Edwin Hubble had proof that the Andromeda Nebula was huge, made of stars, and far outside our galaxy. By the time I was in school, a few textbooks talked about “island universes”.2
Galaxies, Clusters, Superclusters, and the Cosmic Web
Meanwhile, physicists were working out how the sun made light and heat. Astronomers were making increasingly accurate — and puzzling — measurements of distant galaxies.
Working together, they learned that this universe is right around 13,787,000,000 years old: give or take 20,000,000.
Probably.
The Big Bang theory, with tweaking, has been a pretty good match with observations for nearly a century. My guess is that it’s an essentially-accurate model for how this universe has been working.
But I figure we’ll keep learning, and develop a more-nearly-complete model.
Just over 40 years ago, the Center for Astrophysics finished charting around 2,400 galaxies, out to a distance of approximately 600,000,000 light-years: their first 3-dimensional map of our cosmic neighborhood.
Margaret Geller and John Huchra spotted CfA2, ‘the Great Wall’, in 1986. It’s (very) roughly 300,000,000 light-years wide, 15,000,000 light-years thick, and at least 500,000,000 light-years long. Probably longer, but dust in our Milky Way galaxy blocks our view.
We’ve been learning that, on a large scale, this universe is bubbly.
Galaxies, galaxy clusters, and superclusters, are concentrated along vast sheets and filaments; separated by even vaster voids. NASA calls it the cosmic web, focusing more on the filaments than on the walls.3
We’ve also been learning that this universe is big. That awareness can be unsettling.
“…The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. … The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age….”
(“The Call of Cthulhu” , H. P. Lovecraft (1929); via WikiQuote)
As it happens, I like living in a vast and almost-unthinkably ancient universe. But even if I didn’t, my opinion wouldn’t change reality. Besides, I wasn’t consulted when this place was planned: which is just as well.
Porphyrion and Cosmic Scale
“Black Hole’s Colossal Jets Pierce the Cosmic Void”
Monica Young, Sky & Telescope (September 18, 2024)“A pair of plasma jets powered by a supermassive black hole span far beyond their host galaxy — potentially affecting the cosmic web around it.
“The supermassive black hole at the center of a massive galaxy has powered a giant pair of plasma jets, spanning 23 million light-years long from tip to tip. That’s almost 10 times the distance between our Milky Way and the Andromeda Galaxy.
“Astronomers have nicknamed the record-breaking system Porphyrion, after the king of the giants in Greek mythology. And the giant is indeed the king of many: A new catalog of such radio-emitting giant jet pairs tallies more than 11,000 of them, each spanning more than 2.3 million light-years.
“‘Giant jets were known before we started the campaign, but we had no idea that there would turn out to be so many,’ says Martin Hardcastle (University of Hertfordshire, UK), coauthor on two associated studies. Porphyrion’s discovery is published in Nature; the accompanying catalog will appear in Astronomy & Astrophysics….”
Black holes — good grief. If I start talking about those things, and what we’ve been learning about them, I’ll still be working on this next week.
Backgrounder: Black Holes, Accretion Disks, and Relativistic Jets
Short version: black holes are parts of spacetime where gravity is so strong that light — or any other electromagnetic radiation, or matter — can’t escape.
Some black holes are as massive as big stars: which they used to be, before the star ran out of fuel, collapsed, had one spectacularly bright moment as a supernova; and collapsed again.
Other black holes are bigger — they’re called supermassive black holes, which isn’t a particularly imaginative name, but is quite descriptive.
There’s a supermassive black hole at the center of our Milky Way: and very probably one inside every large galaxy.
Stuff falling toward a supermassive black hole ends up orbiting it in an accretion disk. That’s a disk — more like a flat doughnut or Saturn’s rings, actually — where stuff whips around the black hole until it falls across the event horizon, or gets shot off into space.
The accretion disk gets hot, very hot. Physics happens — it’s complicated — and then ionized matter goes shooting out at right angles to the accretion disk.
That ionized stuff isn’t just hot, it’s clipping along at a fair fraction of the speed of light. Which is why such things are called relativistic jets.4
Radio Galaxies and Porphyrion’s Position
Depending on who’s talking, Porphyrion is a Fanaroff-Riley class II radio galaxy. I’ll get back to Fanaroff-Riley classes, briefly, in a bit.
Radio galaxies look bigger in radio frequencies than they do in the visible spectrum. That’s because they’ve got “energetic radio lobes”, lit up by jets from an active galactic nucleus.
Sometimes you’ll see radio galaxies called “black hole jet systems”. That’s supposed to be less confusing than calling them “radio galaxies”, but I have no idea why.
“…The term ‘radio galaxy’ is often used to refer to the entire jet system, rather than solely to its host galaxy. Some scientists consider the term ‘black hole jet system’ more accurate and less confusing. Radio galaxies that reach the size of around 0.7 megaparsecs or more, are commonly called ‘giant radio galaxies’….”
(Radio galaxy, Wikipedia)
One more thing. A megaparsec is 1,000,000 parsecs.
A parsec is about 3.26 light-years. “Parsec” is short for “parallax of one second”. Astronomer Herbert Hall Turner coined the term in 1913. Astronomers and astrophysicists use it because it makes working with their data easier.
I talk about light-years, because that’s what pretty much everyone else says.
Getting back to Porphyrion, it’s a radio galaxy that’s about 7,500,000,000,000 light-years out, in the general direction of Iota Draconis. I put a red circle around its location in that sky chart.
Iota Draconis is a star in the constellation Draco, with at least two planets. It’s just over a hundred light-years away, and that’s yet again another topic.
Porphyrion’s host galaxy is J152932.16+601534.4, which is about 10 times as massive as the Milky Way — as I keep saying, don’t try memorizing these names and designations. Unless you feel like it, of course.
It’s the biggest radio galaxy/black hole jet system in what Sky & Telescope called a “new catalog of such radio-emitting giant jet pairs”. I think it’s the LoTSS Data Release 2 (DR2).
I’ve put links in the footnotes, as usual.5
I’ll wrap up this bit with a three minute, 37 second video.
Black Hole Jets and the Scale of the Cosmic Web
And there you have it.
Up to now, the longest know black hole jet was Alcyoneus, a Fanaroff–Riley class II radio galaxy that’s 3,5oo,000,000 light-years away, in the constellation Lynx.
The giant jet pairs qualify as “giant” if they’re more than 2,300,000 light-years long. That new catalog lists upwards of 11,000 of them.
The point is that Alcyoneus is big, Porphyrion — 23,000,000 light-years long — is bigger, and both are on the scale of features in the cosmic web.
Comparison time.
A light-year is the distance light travels in one year. That’s 5,879,000,000,000 miles. Multiply it by 4.25 and you’ve got the distance to the nearest star.
The Solar System is a few dozen light-years ‘north’ (GNP in that illustration) of the Milky Way galaxy’s central plane, and 27,000 light-years from our galaxy’s center.
Since we’re inside the Milky Way, we’re not sure about its size, but it’s right around 80,000 light-years across.
The Milky Way, where we live, is the second-largest galaxy in the Local Group, after the Andromeda Galaxy. The Andromeda Galaxy is 2,500,000 light-years away.
The Local Group is 10,000,000 light-years across. We’re also in the Virgo Supercluster, which is something like 110,000,000 light-years across.
I checked, and sure enough: Porphyrion’s length is “on the scale of the cosmic web”, as that video said.6 Within a power of ten, at any rate.
| To Milky Way center | 27,000 light-years |
| Across Milky Way | 80,000 light-years |
| To Andromeda Galaxy | 2,500,000 light-years |
| Across Local Group | 10,000,000 light-years |
| Alcyoneus length | 16,000,000 light-years |
| Porphyrion length | 23,000,000 light-years |
| Across Virgo Supercluster | 110,000,000 light-years |
| Grus Wall length | 300,000,000 light-years |
| Perseus-Pegasus Filament length | 1,000,000,000 light-years |
| Sloan Great Wall length | 1,300,000,000 light-years |
| To Prophyrion | 7,500,000,000 light-years |
Radio Telescopes: LOFAR and —
The radio telescope image of Porphyrion isn’t all that eye-catching. As my oldest daughter said, news services had obvious reasons for using an artist’s impression for their main graphic.
Even so, I think that grainy green-and-sort-of-yellowish image is impressive.
It was made with LOFAR: the Low-Frequency Array that’s mostly in the Netherlands, but — as of 2019 — spreads out onto seven other European countries.
It’s a phased array of about 20,000 dipole antennas, where signals get combined in analog electronics, digitized, recombined — eventually ending up at a central station. There’s a mind-boggling amount of math involved, but all that equipment lets us “see” things like Porphyrion.
The LOFAR image lacks the pizzazz of artistic interpretations, but it’s an actual image of something that’s longer than the Local Galaxy Group is wide — and is an image from a radio telescope.
I remember when the Arecibo Observatory and Goldstone Deep Space Communications Complex were putting radio astronomy on the map. Getting decent-resolution images from radio telescopes — it impresses me. A lot.
LOFAR uses interferometry to make images, still another topic. topics, actually.7
— GMRT
Okay. These scientists spotted Porphyrion, a “radio galaxy” or “black hole jet system”, but still hadn’t found the galaxy those jets came shooting out of.
So they teamed up with folks in Maharashtra and Arizona.
“…The giant black hole jet system was named after Porphyrion, a Giant from Greek mythology, by co-discoverer Aivin Gast from the University of Oxford.
“To find the galaxy from which Porphyrion originated, the Giant Metrewave Radio Telescope in India was used along with ancillary data from the Dark Energy Spectroscopic Instrument in Arizona….”
(Porphyrion (radio galaxy), Wikipedia) (emphasis mine)
And that explains why “black hole jet system” is less confusing than “radio galaxy”. I still think “radio galaxy” is easier to say, write, and — arguably — remember; but the folks have a point.
Data from the the Giant Metrewave Radio Telescope (GMRT) and Dark Energy Spectroscopic Instrument (DESI) showed that Porphyrion’s host galaxy is J152932.16+601534.4: which doesn’t, as far as I know, have a catchy name yet.
GMRT uses interferometry to make images, but it’s an array of 30 parabolic radio telescopes, each 45 meters. 49 and a fraction yards, across. I’ve read that it’s “the biggest and most sensitive radio interferometer in the world at low frequencies”.
A little checking showed me that LOFAR ‘sees’ wavelengths of 30 to 1.3 meters and is effectively 1,000-plus kilometers across. GMRT ‘sees’ at wavelengths of 6.00 0.2 meters, or upwards of 0.299 meters; with an effective diameter of up to 25 kilometers.8
Maybe I’m comparing apples, oranges, and the price of peanuts. In any case, sorting out which, if either, of those radio telescopes is the bigger and more sensitive would take more time than I’ve got this week.
What is important, I think, is that they’re both very effective scientific instruments: and that scientists are using both. I remember when this level of cooperation was as newsworthy as the latest research papers.
— and DESI?!
The other observatory, DESI: these names! I’ve gotten the impression that scientists — particularly those involved with physics and related fields — have gotten a whole less stuffy, and I mentioned that a couple months back.
DESI stands for Dark Energy Spectroscopic Instrument; and as far as I know has nothing to do with Desi Arnaz.
DESI isn’t a radio telescope. It’s sensitive to wavelengths between 360 and 980 nanometers: a unit of measure that’s handy for describing things on an atomic scale. That range runs from the short end of infrared to the long end of ultraviolet.
DESI Isn’t particularly big, either, but it does have 5,000 fiber-positioning robots on its focal plane, with a bank of spectrographs fed by those fibers. It’s been used by scientists making surveys of distant galaxies.9
Fanaroff-Riley Classification
Back in 1974, an astronomer and an astrophysicist noticed that they could sort 57 radio galaxies out into two groups. One subset was brighter near their sources than at their ends, the other were brighter at the ends.
The bright-in-the-middle bunch is Fanaroff-Riley Class I (FR-I), while a bright-at-the-ends radio galaxy’s label is Fanaroff-Riley Class II (FR-II).
Porphyrion is brighter at its ends, so it’s a Fanaroff-Riley class II radio galaxy.10
There’s probably a reason, or reasons, why radio galaxies fall neatly into those two categories; but either scientists don’t know yet: or, at least as likely, I didn’t find the reason(s).
That’s Odd: Porphyrion’s Size, and an Explanation
What’s really odd about Porphyrion isn’t so much being brighter at its ends than its middle, as it being so cosmically long.
Material in “black hole jet systems” is moving fast.
The Kelvin-Helmholtz instability — wave-like billows like the ones we see in clouds, Earth’s ocean, and the Solar corona — should have slowed or stopped Porphyrion’s jets before they got to be some 23,000,000 light-years long.
That didn’t happen.
I was going to talk more about this, but suboptimal time management and a couple household tasks got in the way. So I’ll highlight parts of this Sky & Telescope article, which covers most of what I was going to say.11
“…’Although [Porphyrion] is certainly an extreme and curious case, the reason why [its] jets are so long is related with the position of the galaxy in the cosmic web,’ explains Manel Perucho (University of Valencia, Spain), who was not involved in the study.
We’re seeing the jet and its massive host galaxy as they were when the universe was half its current age and, generally, about 10 times denser than it is today. But the environment around this galaxy is unusually sparse. As the jets exit the galaxy, they penetrate millions of light-years into a cosmic void, where the galaxies and even the gas between galaxies is much more spread out. There, the Kelvin-Helmholtz effect is weaker, Perucho says: ‘With these ingredients, a long and fantastic trip is ensured.’
“The circumstances are unusual not only in the surroundings but also in the black hole itself. ‘My interpretation is that we need an unusually long-lived and stable accretion event around the central, supermassive black hole to allow it to be active for so long — about a billion years,’ [University of Hertfordshire, UK’s Martin] Hardcastle [coauthor on two associated studies] says. What’s more, the jets have to be pointing in the same direction for the duration, so that means the black hole has wobbled very little on its spin axis during that time….”
(“Black Hole’s Colossal Jets Pierce the Cosmic Void” , Monica Young, Sky & Telescope (September 18, 2024)) (emphasis mine)
“…The Heavens … Like a Tent to Dwell In”
As I said earlier, I like living in a vast and ancient universe.
Maybe that’s because I grew up during a time when we were learning a great deal about this cosmos. Or maybe it’s just me and my personality.
H. P. Lovecraft also lived during a time when science was opening “terrifying vistas of reality”, and he wrote “The Call of Cthulhu”.
Whatever explains personal preferences like this, we’ve known about cosmic scale and “our frightful position therein” for a long time.
Me? I’m okay with it.
“The one who is enthroned above the vault of the earth,
its inhabitants like grasshoppers,
Who stretches out the heavens like a veil
and spreads them out like a tent to dwell in.”
(Isaiah 40:22)“Raise your eyes to the heavens,
look at the earth below;
Though the heavens vanish like smoke,
the earth wear out like a garment
and its inhabitants die like flies,
My salvation shall remain forever
and my victory shall always be firm.”
(Isaiah 51:6)“Indeed, before you the whole universe is like a grain from a balance,
or a drop of morning dew come down upon the earth.
But you have mercy on all, because you can do all things;
and you overlook sins for the sake of repentance.”
(Wisdom 11:22–23)
I’ve talked about studying this universe before:
- “Galaxies, Gravity and a Hot Terrestrial Planet”
(February 25, 2023) - “Exoplanets, Dust, and Who Sees Data First?”
(February 11, 2023) - “Stars, Galaxies, XBONGs and Me”
(January 21, 2023) - “A Star by Any Other Name, and a Galilean Interlude”
(November 13, 2021) - “Science, Faith, and Me”
(November 5, 2017)
1 A little history, a little philosophy:
- Wikipedia
- Ahmose I
- Anaximander
- Cosmic ocean
- Cosmology
- Cosmology in the ancient Near East
- Democritus
- Flat Earth
- Galileo Galilei
- Multiverse
- Parmenides
- Physical cosmology
- Timeline of cosmological theories
- “A Star by Any Other Name, and a Galilean Interlude” (November 13, 2021)
- “Einstein’s Waves: New Views” (October 6, 2017)
- Wikipedia
- Andromeda Galaxy (Formerly known as the Andromeda nebula.)
- Angelo Secchi
- Astronomical spectroscopy
- Edwin Hubble
- Galaxy
- Great Debate (astronomy) (whether spiral nebulae are swirly things inside this galaxy, or other galaxies (1920))
- Nebula
- Seven Years’ War
- Stellar classification
- William Huggins
- Timeline of cosmological theories
- William Herschel (AKA Frederick William Herschel)
- William Huggins
- Celestial Quadrant
eSky: the electronic sky - NASA/ADS (Harvard)
- “William Herschel’s ‘Hole in the Sky’ and the discovery of dark nebulae” , Wolfgang Steinicke, abstract, Journal of Astronomical History and Heritage (December 2016)
- “Herschel and the Construction of the Heavens” , M. A. Hoskin, Journal of the British Astronomical Association (1981)
- “On the Construction of the Heavens“, William Herschel, No abstract/no text, Philosophical Transactions of the Royal Society of London (1785)
- “On the Construction of the Heavens. By William Herschel, Esq. F. R. S.” , William Herschel, Philosophical Transactions of the Royal Society of London (1785) on JSTOR
- “note on construction of Heavens” , R. A. Proctor, Monthly Notices of the Royal Astronomical Society (1871)
- Angelo Secchi, by Joseph Pohle
Catholic Encyclopedia (1913)
- Wikipedia
- Age of the universe (Estimate, based on what we’ve observed — and a whacking great deal of analysis)
- Big Bang
- CfA Redshift Survey (Center for Astrophysics (CfA) Redshift Survey was the first attempt to map the large-scale structure of the universe. First part completed in 1982.)
- Cosmology
- Galaxy
- Galaxy cluster
- Galaxy filament
- Hercules-Coma Borealis Great Wall (So far, the biggest feature we’ve seen in this universe.)
- Light-year
- Milky Way
- Observable universe
- Physical cosmology
- Supercluster
- Timeline of cosmological theories
- Universe
- The CfA Redshift Survey
John Huchra, Harvard - The Cosmic Distance Scale, Imagine the Universe!, NASA
- BBC Sky at Night Magazine
- “CfA2 Great Wall of galaxies” , Marcus Chown (March 8, 2024)
- “A history of 3D mapping the Universe” , Govert Schilling (June 23, 2023)
- Center for Astrophysics Harvard & Smithsonian
- “To Map the Universe, Astrophysicists Launch Largest Sky Survey Yet” , press release (June 17, 2021)
- Galaxies, Welcome to the Universe, NASA Science
- “The Large Scale Structure of the Universe”
ASTRO 801 – Planets, Stars, Galaxies, and the Universe; The John A. Dutton Institute for Teaching and Learning Excellence; Penn State University
4 Stuff that’s real, and how some of us think about stuff that’s real:
- Wikipedia
- Accretion disk
- Active galactic nucleus (A (relatively) small part of a galaxy’s center that’s producing a whole lot of electromagnetic energy.)
- Astrophysical jet (AKA plasma jet.)
- Black hole
- Cartesian coordinate system (A way of defining positions in an n-dimensional Euclidean space.)
- Electromagnetic spectrum
- Euclidean space (A mathematical model, describing a physical space.)
- Event horizon
- Ionization
- Mathematical model (Describing a concrete, real-world, system, using math.)
- Milky Way (The galaxy I call home.)
- Quasar (A galaxy with a very active active galactic nucleus.)
- Space (AKA physical space: “…a three-dimensional continuum containing positions and directions….”)
- Porphyrion (radio galaxy)
- Spacetime (A mathematical model describing the four dimensions we live in.)
- Supermassive black hole
- Supernova
- System (Things that follow a set of rules, forming a unified whole.)
- Three-dimensional space
- “Extragalactic Jets” (image)
National Radio Astronomy Observatory (May 16, 2019)
5 Astronomy and physics, mostly:
- Wikipedia
- Electromagnetic field
- Electromagnetic radiation (Light: from the longest radio waves to the shortest X-rays. We see light with wavelengths between 380 and 750 nanometers.)
- Electromagnetic spectrum
- Draco (constellation)
- Herbert Hall Turner
- Iota Draconis (AKA Edasich.) (A K-type giant star, about 101.2 light-years out: give or take 0.3.)
- Iota Draconis b (AKA Hypatia.) (A super-Jupiter, about a dozen times Jupiter’s mass.)
- Parsec
- Porphyrion (radio galaxy)
- Radio galaxy
- Radio wave
- Visible spectrum
- “LoTSS Data Release 2 (DR2)”
LOFAR Surveys - “Gargantuan Black Hole Jets Are Biggest Seen Yet”
Whitney Clavin, press release, Caltech (September 18, 2024 ) - “Constraining the giant radio galaxy population with machine learning and Bayesian inference”
Rafaël I.J. Mostert, Martijn S.S.L. Oei, B. Barkus, Lara Alegre, Martin J. Hardcastle, Kenneth J. Duncan, Huub J.A. Röttgering, Reinout J. van Weeren, Maya Horton (submitted April 30, 2024) via arXiv
- Wikipedia
- Galaxies, Welcome to the Universe, NASA Science
- Wikipedia
- Antenna array
- Arecibo Observatory
- Dipole antenna (One of the two simplest and most widely-used types of antenna, along with monopole antennas.)
- Giant Metrewave Radio Telescope (GMRT)
- Goldstone Deep Space Communications Complex (when it’s not networking with spacecraft, it’s an astronomical observatory.)
- Interferometry
- Karl Guthe Jansky (Got radio astronomy going, when he spotted radio interference coming from the constellation Sagittarius in the 1930s.)
- Low-Frequency Array (LOFAR)
- Monopole antenna (One of the two simplest and most widely-used types of antenna, along with dipole antennas.)
- Phased array
- Porphyrion (radio galaxy)
- Radio astronomy
- Radio telescope
- Wikipedia
- Giant Metrewave Radio Telescope (AKA GMRT.)
- Low-Frequency Array (LOFAR)
- Maharashtra (A state in India.)
- Parabolic antenna
- The Giant Metrewave Radio Telescope
National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus - “Gargantuan Black Hole Jets Are Biggest Seen Yet”
Whitney Clavin, press release, Caltech (September 18, 2024 ) - “Constraining the giant radio galaxy population with machine learning and Bayesian inference”
Rafaël I.J. Mostert, Martijn S.S.L. Oei, B. Barkus, Lara Alegre, Martin J. Hardcastle, Kenneth J. Duncan, Huub J.A. Röttgering, Reinout J. van Weeren, Maya Horton (submitted April 30, 2024) via arXiv
- Wikipedia
- Astronomical survey
- Dark Energy Spectroscopic Instrument (AKA DESI.)
- Desi Arnaz (Part of the Lucille Ball – Desi Arnaz media team.)
- Electromagnetic spectrum
- Lucille Ball (Part of the Lucille Ball – Desi Arnaz media team.
- Lucy Does a TV Commercial (Vitameatavegamin health tonic: “Well, are you? The answer to all your problems is in this little ol’ bottle, Vitameatavegamin.” (IMDb))
- Nanometre
10 Two scientists and a useful classification system:
- Wikipedia
- Bernard L. Fanaroff
- Fanaroff-Riley classification (Used when describing radio galaxies since 1974.)
- Julia M. Riley
11 Fluid dynamics and a big discovery:
- Wikipedia
- Kelvin-Helmholtz instability (“This article includes a list of general references, but it lacks sufficient corresponding inline citations….”)
- “Black Hole’s Colossal Jets Pierce the Cosmic Void”
Monica Young, Sky & Telescope (September 18, 2024)
