Posted on 01/03/2022 5:56:49 AM PST by Red Badger
(LOFAR/LOL Survey)
The image above may look like a fairly normal picture of the night sky, but what you're looking at is a lot more special than just glittering stars. Each of those white dots is an active supermassive black hole.
And each of those black holes is devouring material at the heart of a galaxy millions of light-years away – that's how they could be pinpointed at all.
Totaling 25,000 such dots, astronomers created the most detailed map to date of black holes at low radio frequencies in early 2021, an achievement that took years and a Europe-sized radio telescope to compile.
"This is the result of many years of work on incredibly difficult data," explained astronomer Francesco de Gasperin of the University of Hamburg in Germany. "We had to invent new methods to convert the radio signals into images of the sky."
(LOFAR/LOL Survey)
When they're just hanging out not doing much, black holes don't give off any detectable radiation, making them much harder to find. When a black hole is actively accreting material – spooling it in from a disc of dust and gas that circles it much as water circles a drain – the intense forces involved generate radiation across multiple wavelengths that we can detect across the vastness of space.
What makes the above image so special is that it covers the ultra-low radio wavelengths, as detected by the LOw Frequency ARray (LOFAR) in Europe. This interferometric network consists of around 20,000 radio antennas, distributed throughout 52 locations across Europe.
Currently, LOFAR is the only radio telescope network capable of deep, high-resolution imaging at frequencies below 100 megahertz, offering a view of the sky like no other. This data release, covering four percent of the Northern sky, was the first for the network's ambitious plan to image the entire Northern sky in ultra-low-frequencies, the LOFAR LBA Sky Survey (LoLSS).
Because it's based on Earth, LOFAR does have a significant hurdle to overcome that doesn't afflict space-based telescopes: the ionosphere. This is particularly problematic for ultra-low-frequency radio waves, which can be reflected back into space. At frequencies below 5 megahertz, the ionosphere is opaque for this reason.
The frequencies that do penetrate the ionosphere can vary according to atmospheric conditions. To overcome this problem, the team used supercomputers running algorithms to correct for ionospheric interference every four seconds. Over the 256 hours that LOFAR stared at the sky, that's a lot of corrections.
This is what has given us such a clear view of the ultra-low-frequency sky.
"After many years of software development, it is so wonderful to see that this has now really worked out," said astronomer Huub Röttgering of Leiden Observatory in the Netherlands.
Having to correct for the ionosphere has another benefit, too: It will allow astronomers to use LoLSS data to study the ionosphere itself. Ionospheric traveling waves, scintillations, and the relationship of the ionosphere with solar cycles could be characterized in much greater detail with the LoLSS. This will allow scientists to better constrain ionospheric models.
And the survey will provide new data on all sorts of astronomical objects and phenomena, as well as possibly undiscovered or unexplored objects in the region below 50 megahertz.
"The final release of the survey will facilitate advances across a range of astronomical research areas," the researchers wrote in their paper.
"[This] will allow for the study of more than 1 million low-frequency radio spectra, providing unique insights on physical models for galaxies, active nuclei, galaxy clusters, and other fields of research. This experiment represents a unique attempt to explore the ultra-low frequency sky at a high angular resolution and depth."
The results have been published in Astronomy & Astrophysics.
A version of this article was first published in February 2021.
The Great Wall of China, often cited as the only human-made structure visible from space, is not visible from low Earth orbit without magnification, and even then can be seen only under perfect conditions.
But you can see the Pyramids of Giza!
I opened this thread expecting to see a map of the US at night where all the blue cities are lit up.
Black holes are everywhere, and they vote for communists.
I think you left it in the Albert Hall.
FAKE NEWS! I’ve seen plenty of pictures of black holds and plenty of pictures of stars - these are stars.
The black holes will devour each other until we end up with ONE massive gigantic black hole. When that happens, the gravitational forces will keep compressing that black hole until it reaches the critical level, and then it will explode in another big bang. And the cycle will repeat all over again.
fantastic link, thanks for posting
"I am THE ONE! I AM the One!"
If the universe is closed and everything within it will all collapse back together in a “big crunch” far in the future, then we are indeed inside the event horizon of a huge black hole right now.
Great. Give the democrats new places to hide their fake ballots after the next election. Thanks a lot…
It is because the Chicoms painted the wall to a different color!~
What if the entire universe is just a component of a quark inside a proton of an atom of a molecule that is inside the zit on the face of a giant Pelosi?
Just think, every atom in your body has been in existence since the Big Bang!.....................
Yeah, every time I hear “dark matter” I think “fudge factor”.
Nicely Anamaniaced.
It is clear that he studied the techniques taught by Mesmer, who also was studied by Hitler. The pose and the cadence are learned to “mesmerize” a crowd. See the Nuremburg rallies.
“We are so small in the universe.”
And they want us to worry about global warming.
Pffft...
“When they’re just hanging out not doing much, black holes don’t give off any detectable radiation, making them much harder to find. When a black hole is actively accreting material – spooling it in from a disc of dust and gas that circles it much as water circles a drain – the intense forces involved generate radiation across multiple wavelengths that we can detect across the vastness of space.”
These verses in Psalms 19 came to mind:
Psalm 19:1-4(a) (NIV)
1 The heavens declare the glory of God; the skies proclaim the work of his hands. 2 Day after day they pour forth speech; night after night they reveal knowledge. 3 They have no speech, they use no words; no sound is heard from them. 4 Yet their voice goes out into all the earth, their words to the ends of the world
LOL! We sure have some good ones here.
We also have only two seasons: Winter & Construction.
LOL--they should clock in and get to work.
Remarkable research. Rather like the XDF, a useful overview or census.
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