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SMU have created SmartCADD. This open-source virtual tool combines artificial intelligence, quantum mechanics and Computer Assisted Drug Design (CADD) techniques to speed up the screening of chemical compounds, significantly reducing drug discovery timelines.

Two Americans, Gary Ruvkun of Massachusetts General Hospital and Harvard University, and Victor Ambrose of the University of Massachusetts Medical School, have split this year’s Nobel Prize in Physiology or Medicine for the discovery of microRNAs (miRNAs), single-stranded bits of RNA that do not code for proteins but act to regulate other genes.  The Nobel organization’s press release explains the significance of the discovery, but you can read the whole thing, which is much longer than this:

This year’s Nobel Prize honors two scientists for their discovery of a fundamental principle governing how gene activity is regulated.

The information stored within our chromosomes can be likened to an instruction manual for all cells in our body. Every cell contains the same chromosomes, so every cell contains exactly the same set of genes and exactly the same set of instructions. Yet, different cell types, such as muscle and nerve cells, have very distinct characteristics. How do these differences arise? The answer lies in gene regulation, which allows each cell to select only the relevant instructions. This ensures that only the correct set of genes is active in each cell type.

Victor Ambros and Gary Ruvkun were interested in how different cell types develop. They discovered microRNA, a new class of tiny RNA molecules that play a crucial role in gene regulation. Their groundbreaking discovery revealed a completely new principle of gene regulation that turned out to be essential for multicellular organisms, including humans. It is now known that the human genome codes for over one thousand microRNAs. Their surprising discovery revealed an entirely new dimension to gene regulation. MicroRNAs are proving to be fundamentally important for how organisms develop and function.

And here’s how it started: as so often, with a seemingly minor observation that blew up big time, leading to generalizations about control of gene expression in all organisms—even viruses (but not bacteria).

In the late 1980s, Victor Ambros and Gary Ruvkun were postdoctoral fellows in the laboratory of Robert Horvitz, who was awarded the Nobel Prize in 2002, alongside Sydney Brenner and John Sulston. In Horvitz’s laboratory, they studied a relatively unassuming 1 mm long roundworm, C. elegans. Despite its small size, C. elegans possesses many specialized cell types such as nerve and muscle cells also found in larger, more complex animals, making it a useful model for investigating how tissues develop and mature in multicellular organisms. Ambros and Ruvkun were interested in genes that control the timing of activation of different genetic programs, ensuring that various cell types develop at the right time. They studied two mutant strains of worms, lin-4 and lin-14, that displayed defects in the timing of activation of genetic programs during development. The laureates wanted to identify the mutated genes and understand their function. Ambros had previously shown that the lin-4 gene appeared to be a negative regulator of the lin-14 gene. However, how the lin-14 activity was blocked was unknown. Ambros and Ruvkun were intrigued by these mutants and their potential relationship and set out to resolve these mysteries.

After his postdoctoral research, Victor Ambros analyzed the lin-4 mutant in his newly established laboratory at Harvard University. Methodical mapping allowed the cloning of the gene and led to an unexpected finding. The lin-4 gene produced an unusually short RNA molecule that lacked a code for protein production. These surprising results suggested that this small RNA from lin-4 was responsible for inhibiting lin-14. How might this work?

Here’s the announcement, which I always find exciting:

AND THE TWO CONTESTS:

1.) Guess who will win the other two Nobel Prizes in science: Physics and Chemistry.  One guess per discipline, and the first person who guesses both winners gets one of my trade books, autographed per their choice (including cat drawings).

2.) Alternatively you can choose the other contest: Guess who will win these two prizes: Literature and Peace.  Same rules as above, and same prize.

You can guess in only one of these two competitions.

In previous years, people have failed miserably in these contests, but someday someone will win. . . .

While the 20th century saw rapid rises in average life expectancy at birth, more recent years have seen a slowdown, suggesting we may be reaching the limit of human lifespan

A pair of ctenophores, or comb jellies, can fuse their bodies together, merging their digestive and nervous systems, without any issues with immune rejection

Daniele Oriti’s pursuit of a theory of quantum gravity has led him to the startling conclusion that the laws of nature don’t exist independently of us – a perspective shift that could yield fresh breakthroughs

Some environmental phenols are known to have cardiac toxicities. Now, a new study is revealing their adverse impact on the heart's electrical properties.

Planet-forming disks, maelstroms of gas and dust swirling around young stars, are nurseries that give rise to planetary systems, including our solar system. Astronomers have discovered new details of gas flows that sculpt those disks and shape them over time.

New experimental results suggest that sprinkling boron into a tokamak could shield the wall of the fusion vessel and prevent atoms from the wall from getting into the plasma. A new computer modeling framework shows the boron powder may only need to be sprinkled from one location.

New experimental results suggest that sprinkling boron into a tokamak could shield the wall of the fusion vessel and prevent atoms from the wall from getting into the plasma. A new computer modeling framework shows the boron powder may only need to be sprinkled from one location.

Researchers conducted innovative simulations of spinning black holes grounded in general relativity, which clarified that the ultraluminous accretion disk (i.e., gaseous spiral surrounding a black hole) exhibits a precessional motion driven by the black hole's spin. This finding underscores the potential of this spin to be the primary driver of the periodic fluctuations in luminosity observed within these ultraluminous accretion disks.

Researchers have developed a novel method using facet-selective, ultrafine cocatalysts to efficiently split water to create hydrogen -- a clean source of fuel.

Researchers have created a high-performance polymer that can be chemically recycled without compromising its heat and chemical resistance. The revolutionary design includes a directing group that allows links in the polymer to be broken easily with a catalyst and the original polymer to be reformed in few steps. The directing group could be included in many polymers, potentially providing a new generation of high-performance plastics that can be recycled indefinitely.

Researchers have discovered the most distant Milky-Way-like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current understanding of galaxy formation, such early galaxies are expected to appear more chaotic.

Global warming could increase the threat posed to whale sharks from large ships, according to a new study.

Motion sensors in smartphones can be turned into makeshift microphones to eavesdrop on conversations, outsmarting security features designed to stop such attacks

Scientists have just published in Nature that they have completed the entire connectome of a fruit fly: Network statistics of the whole-brain connectome of Drosophila. The map includes 140,000 neurons and more than 50 million connections. This is an incredible achievement that marks a milestone in neuroscience and is likely to advance our research.

A “connectome” is a complete map of all the neurons and all the connections in a brain. The ultimate goal is to map the entire human brain, which has 86 billion neurons and about 100 trillion connections – that’s more than six orders of magnitude greater than the drosophila. The human genome project was started in 2009 through the NIH, and today there are several efforts contributing to this goal.

Right now we have what is called a mesoscale connectome of the human brain. This is more detailed than a macroscopic map of human brain anatomy, but not as detailed as a microscopic map at the neuronal and synapse level. It’s in between, so mesoscale. Essentially we have built a mesoscale map of the human brain from functional MRI and similar data, showing brain regions and types of neurons at the millimeter scale and their connections. We also have mesoscale connectomes of other mammalian brains. These are highly useful, but the more detail we have obviously the better for research.

We can mark progress on developing connectomes in a number of ways – how is the technology improving, how much detail do we have on the human brain, and how complex is the most complex brain we have fully mapped. That last one just got its first entry – the fruit fly or drosophila brain.

The Nature paper doesn’t just say – here’s the Drosophila brain. It does some interesting statistics on the connectome, showing the utility of having one. The ultimate goal is to fully understand how brains process information. Learning such principles (which we already have a pretty good idea of) can be applied to other brains, including humans. For example, the study finds that the Drosophila brain has hubs and networks, which vary in terms of their robustness. It also reflects what is known as rich-hub organization.

Rich-hub organization means that there are hubs of neurons that have lots of connections, and these hubs have lots of connections to other hubs. This structure allows brains to efficiently integrate and disseminate information. This follows the same principle as with any distribution system. Even Amazon follows a similar model, with distribution centers serving as hubs. Further, the researchers identified specific subsets of the hubs that serve as integrators of information and other subsets that serve as broadcasters.

The connectome also includes synapse and neurotransmitter level data, which is critical to asking any questions about function. A connectome is not just a map of wiring. Different neurons use different neurotransmitters, which have different functions. Some neurotransmitters, for example, are excitatory, which means they increase the firing rate of the neuron in which they synapse. Some neurotransmitters are inhibitory, which means they decrease firing rate. So at the very least we need to know if a connection is increasing or decreasing the activity of the neurons it connects to.

Now that the model is complete, they are just getting started examining the model. This is the kind of research that is primarily meant to facilitate other research, so expects lot of papers using the Drosophila connectome as its subject.

Meanwhile scientists are working on completing the connectome of the mouse, which will likely be the first mammalian brain connectome. We already have mesoscale connectomes, and detailed connectomes of small sections of mouse brain. A completed mouse brain connectome is likely 10-15 years off (but of course, could be longer). That would be a huge milestone, as all mammalian brains share a lot of anatomy in common. With the Drosophila brain we can learn a lot about network principles, but the anatomy evolved completely independently from mammals (beyond the very rudimentary brain of our common ancestor).

One type of research that I would love to see is not just mapping a connectome, but emulating it in a computer. This information may be out there somewhere, but I have not found it so far – do we have a computer powerful enough to emulate the functioning of a Drosophila brain in real time? That would be a good test of the completeness and accuracy of our connectome – does it behave like an actual fruit  fly?

Creating this would likely require more than just the connectome itself. We need, as I referenced above, some biological data as well. We need to know how the neurons are behaving biologically, not just as wires. We need to know how the neurotransmitters are behaving chemically. And we need to know how other cells in the brain, other than neurons, are affecting neuronal function. Then we need to give this virtual brain some input simulating a body and an environment, and simulate the environment’s response to the virtual fruit fly. That sounds like a lot of computing power, and I wonder how it compares to our current supercomputers. Likely we will be able to do this before we can do it in real time, meaning that a second of the life of our virtual Drosophila may take a day to compute (that is just a representative figure, I have no idea what the real current answer is). Then over time, our virtual Drosophila will go faster and faster until it catches up to real time.

Eventually the same will be true for a human. At some point we will have a full human connectome. Then we will be able to emulate in a computer, but very slowly. Eventually it will catch up to real time, but why would it stop there? We may eventually have a computer that can simulate a human’s thought processes 1000 times faster than a human.

There is another wrinkle to this whole story – the role of our current and likely short term future AI. We are already using AI as a tool to help us make sense of the mesoscale connectomes we have. Our predictions of how long it will take to have complete connectomes may be way off. What if someone figures out a way to use AI to predict neuron level connectomes from our current mesoscale connectomes? We are already seeing, in many contexts, AI being used to do literally years of research in days or weeks, or months of research in hours. This is especially true for information-heavy research questions involving highly complex systems – exactly like the connectome. It would therefore not surprise me at all if AI-boosted connectome research suddenly progresses orders of magnitude faster than previous predictions.

Another potential area of advance is using AI to figure out ways to emulate a mammalian or even human brain more efficiently. We don’t necessarily need to emulate every function of an entire brain. We can probably cheat our way to make simple approximations of the functions we are not interested in for any particular emulation or research project. Then dedicate the computing power to what we are interested in, such as higher level decision-making.

And of course I have to mention the ethical considerations of all of this? Would a high fidelity emulation of a human brain be a human? I think the answer is either yes, or very close to yes. This means we have to consider the rights of the emulated human. For this reason it actually may be more useful to emulate a mouse brain. We already have worked out ethical considerations for doing mouse research, and this would be an extension of that. I can imagine a future where we do lots of behavioral research on virtual mice in simulated environments. We could run millions of trials in a few minutes, without having to care for living creatures. We can then work our way evolutionarily toward humans. How far will we go? Would virtual primate research be OK? Can we guarantee our virtual models don’t “suffer”. Does it matter that they “exist” for just a fraction of a second? We’ll have to sort all this out eventually.

The post Fruit Fly Connectome Completed first appeared on NeuroLogica Blog.

The 2024 Nobel prize in physiology or medicine has gone to Victor Ambros and Gary Ruvkun for their discovery that tiny pieces of RNA called microRNAs play a key role in controlling genes

Antivax is more ideology and conspiracy than science. The recent accusation that antivax influencers are running "limited hangouts" as part of "controlled opposition helps illustrate this characteristic, in which the insufficiently radical are portrayed as useful idiots for the enemy or even heretics.

The post Antivax as ideology: “Limited hangouts” run by “controlled opposition” first appeared on Science-Based Medicine.

I’ve been struggling to understand the new articles in Nature on the fly brain, and it’s not easy! I will write about the issue, but not until I have something clear and interesting to impart to readers.

When I look at my draft posts, I see that many of them are about Israel, which prompted me to call Malgorzata and whine, “Everything I’m writing is about Israel; people are going to think I’m obsessed.” Malgorzata responded that. as with her, I likely have two reasons. First, I’m a Jew and am naturally concerned with an existential crisis threatening the Jewish state. Second, she said, both she and I have been worried about the new rise in anti-Semitism that goes by the name of “anti-Zionism”.

Before 1880, anti-Semitism was called “Jew hatred,” but that was deemed too crass, so “anti-Semitism”, coined by Wilhelm Marr, arose as a softer, more scientific euphemism. Now with the rise of Jew and Israel hatred, and the reluctance of liberals to say they are “antisemitic”, we have yet another euphemism: “anti-Zionism”.  But at bottom they’re all the same thing, softened variants of “Jew hatred.”  And that hatred, expressed as approbation for eliminating the existence of Israel, threatens not only the Jewish state, but the West as a whole, for the sentiments are more than “Jew hatred”: they’re “West hatred.”

Or so Malgorzata said, and sent me a video, saying that I would get a better explanation by watching the section of this video between 9:15 to 22:30. I’ve pasted it in so it starts at 9:15. The speaker is Dr. Einat Wilf, “former Knesset member and expert on Israel’s foreign policy,” and she’s quite eloquent.  Wikipedia notes that “Wilf describes herself as a Zionist, a feminist and an atheist.”

 

At any rate, that’s her take, and I guess I have no choice about the topics I cover, since they just issue from the determined molecular movements going on inside my head. So here’s my post.

The BBC, accused repeatedly of biased reporting, has formed a division called “BBC Verify”, dedicated to fact checking and preventing misinformation.  The announcement of its inception says this:

We’ve brought together forensic journalists and expert talent from across the BBC, including our analysis editor Ros Atkins and disinformation correspondent Marianna Spring and their teams. In all, BBC Verify comprises about 60 journalists who will form a highly specialised operation with a range of forensic investigative skills and open source intelligence (Osint) capabilities at their fingertips.

They’ll be fact-checking, verifying video, countering disinformation, analysing data and – crucially – explaining complex stories in the pursuit of truth.

This is a different way of doing our journalism. We’ve built a physical space in the London newsroom, with a studio that BBC Verify correspondents and experts will report from, transparently sharing their evidence-gathering with our audiences. They will contribute to News Online, radio and TV, including the News Channel and our live and breaking streaming operation, both in the UK and internationally.

But investigative journalist David Collier, who has investigated “Verify,” cannot verify that it’s fulfilled its mission. In fact, on this post on his website (click to read), he calls for this BBC unit to be shut down.

One example: Verify purported to verify that the Iranian missiles raining down on Israel last week were aimed solely at military targets. (Regardless of what they were aimed at, of course, it was an attack unprovoked by any Israeli attack on Iran.)  But some elementary fact-checking showed that Verify dissimulated:

On Tuesday evening, 1 October 2024, Iran fired approximately 180 ballistic missiles at Israel. Many were intercepted, but several sites were hit. On Wednesday evening BBC Verify published a 1 minute 20 second video – titled ‘where Iran’s missiles struck in Israel’.

The BBC Verify team tells us they have been looking at ‘where Iran’s missiles have landed’ and the video is to counter ‘a lot of false imagery’ being circulated online. They say they managed to verify strikes in the vicinity of three key locations – all of them military sites:

Here’s the figure from “Verify”, showing the verified Iranian missile strikes:

More from Collier:

This creates an immediate problem. Why only these three? For example, a verified strike by Ramat Gan shopping mall has not been included. The BBC had reported on this – and so were well aware of it – but for some reason, BBC Verify left the shopping mall strike out of their analysis.

It is difficult to escape the conclusion that BBC Verify were deliberately pushing a pro-Iranian propaganda line that the missiles were fired only at military targets.

But it gets a lot, lot worse.

Having told us that the three targets verified were ‘in the vicinity’ of military targets, we are then shown the evidence. The first we see are several apparent strikes on Nevatim airbase, but it is when the journalist turns her attention to the attack on the Tel Nof base that things become surreal.

We find the base was not hit at all. This is the script:

Location two is the Tel Nof airbase. In this video you can see a crater where a missile has landed. It is not the airbase itself, but a school a few miles away”:

And Collier makes a clever analogy:

What? So the Iranian’s didn’t hit Tel Nof airbase with this missile – they hit a school. So why isn’t the school listed in the original map. How on earth can BBC Verify know that the intended target of this missile was an airbase? They can’t.

The school that was hit is the Shalhavot Chabad school in Gadera. About 5 miles from the place BBC verify tells us was the target.

. . . . To put this into context. Below on the map are two marks, Gaza City Centre and Jabalia camp. The distance between them is approximately the same distance as between the school and the airbase. Can you imagine Israel hitting a school in Jabalia camp and BBC Verify virtually forgiving them by suggesting it was a close call on a Hamas military target 5 miles away.

There is no excuse for this – and it appears to be a deliberate attempt to whitewash an Iranian ballistic missile strike on a school. Why on earth didn’t the BBC put the school as one of the verified strikes on the map at the start? We all know why. For the same reason they didn’t mention the strike on the shopping mall. It doesn’t fit the propaganda story they are seeking to tell.

Yes, this is of course biased reporting, made worse that it was made by the “Verify” team.  This is just one more incident in the Beeb’s history of biased anti-Israel reporting. I’ve written before about the Asserson Report that accused the Beeb of violating its own journalistic guidelines 1500 times during the Gaza War, and you can see my collection of pieces on the BBC’s bias here. The Beeb is the British equivalent of the NYT, and it’s doing exactly what the NYT does—passing off biased reporting as if it were unbiased.

Collier discusses the author of this “verified” piece, Verify correspondent Nawal Al-Maghafi, showing that she has a history of reporting for anti-Israeli publications like Middle East Eye, Al-Jazeera, and even for PRESS TV, the state media outlet of Iran!  This is hardly the person for Verify to choose as author of a piece that tries to exonerate Iran of trying to kill civilians!  He concludes that BBC Verify should be shut down (indeed, the Beeb needs a top-to-bottom housecleaning). Check out the numbered links.

The BBC has spent decades demonising Israel – but since Oct 7, the situation has become blatant and inexcusable (a few examples 1, 2, 3, 4, 5, 6, 7, 8, 9). Two damning reports have recently been published on BBC Bias (Asserson, Cohen)

The BBC has gone completely off the rails. It isn’t just that it is incapable of putting together proper impartial coverage of Israel’s conflict with its neighbours – it is that it doesn’t think it is doing anything wrong. The inability to even begin to identify the problem it has – means it cannot be salvaged in its current form. No public funds should ever be used to finance something so deeply and irredeemably flawed.

Well, so much for that. Nobody claimed that the liberal MSM media, whether in the US or UK, was objective when it came to the Gaza war.

After reading that, I immediately came upon Tom Gross’s newsletter, which said this:

No surprise here. Just a publicly-funded BBC journalist leaving today after 4.5 years to go and officially work as an anti-Zionist influencer.

Check out the Palestine Media Centre yourself; I’m not sure it’s a mouthpiece for anti-Zionism, but there are suggestions of that in its mission, for how many Palestinians dare speak against their rulers?

The Britain Palestine Media Centre connects media professionals with Palestinians – from academics and artists, to human rights activists and ordinary people with extraordinary stories.

An independent non-profit, the Centre is an invaluable resource for journalists, editors, and producers seeking expert opinion, information, and contacts in a timely and reliable manner.

How we can help:

• Looking for Palestinian experts to talk to for an article or report? We can connect you with the right person for your topic.

• We can provide quick turnaround Palestinian guests for TV, radio or online broadcasting, to respond to breaking news.

• Need information or data for a Palestine-related story? Let us know what you’re researching, and we’ll be happy to help.

********

Finally, something that I read today in the Times of Israel: a report on a woman who used to be “a vocal supporter of the Islamic Republic” but now heads a pro-Israel group that accuses the BBC of war coverage biased towards Hamas (this, of course, is not a new accusation).

When Catherine Perez-Shakdam took the helm of Britain’s biggest grassroots pro-Israel campaign group this summer, she inherited a bulging inbox .

Aside from the continuing domestic fallout from the conflict between Israel and Hamas, the UK’s new Labour government has made a string of decisions that have dismayed and infuriated large elements of the country’s Jewish community and supporters of Israel.

Since taking the helm in July, Labour has restored funding for the UN’s Palestinian refugee agency, UNRWA; pulled out of a legal case opposing the International Criminal Court application for arrest warrants for Prime Minister Benjamin Netanyahu and Defense Minister Yoav Gallant; and partially suspended arms exports to Israel.

The last paragraph surprised me, though I knew about the suspension of arms exports. But I thought Labour had purged itself of its anti-Israelism and anti-Semitism.  In this case, we have the reverse of the case of Karishma Patel (above), for Perez-Shakdam was once a talking head for Iran and is now excoriating the Beeb for its anti-Israel bias. The article continues:

Born to Jewish parents in Paris whose own parents had fled Nazi persecution, Perez-Shakdam lived as a Muslim while studying in the UK after marrying a Muslim man from Yemen. She later spent years as a journalist and commentator in the Middle East and began appearing on Iranian state media. Increasingly trusted and valued by the regime, Perez-Shakdam was granted an audience with Supreme Leader Ayatollah Ali Khamanei; interviewed the late Ebrahim Raisi during his initial, unsuccessful 2017 bid for the presidency (he would succeed in 2021 and serve as president until his death this year); and was invited to a pro-Palestinian conference in Tehran attended by Hamas terror chief Khaled Mashaal.

That was then; this is now. Influenced by her “Zionist” daughter, Perez-Shakdam did a 180°:

Perez-Shakdam’s journey was capped by her appointment last month as director of We Believe In Israel. She replaces Luke Akehurst, who was elected as a Labour MP in the July general election. The campaign group seeks to counter the well-organized pro-Palestinian lobby by mobilizing grassroots support for the Jewish state.

For years, I was motivated by a kind of self-hate. But you realize that you can’t deny who you are

The group’s latest campaign has the BBC firmly in its crosshairs.

The new report into the BBC led by British-Israeli lawyer Trevor Asserson says the public service broadcaster’s coverage associated Israel with war crimes, genocide, and international law violations far more often than it did Hamas. It claims that the BBC downplayed Hamas terrorism, and finds that the BBC’s Arabic service was among the most biased global media outlets in covering the Israel-Hamas conflict.

. . . . Perez-Shakdam says her organization’s campaigning is not driven by hostility to the BBC, which is prevalent in the opposition Conservative party and its media allies, as well as on the far left. “It’s not a witch hunt. This is not an effort to bring down the BBC,” she says. “It’s just to elevate the level of journalism and to make sure that ethic [of impartiality] is at the forefront of it all.”

“The BBC has a lot of answering to do and I don’t think that it’s willing to do that; it [has] already doubled down,” she says. She believes the government may have to take action. “Taxpayers’ money is being used, through the vehicle of the TV license. The government needs to do something about it. This is not a case of free speech. It’s a case of holding the BBC accountable for a service that it is not providing in violation of its own [guidelines].”

You can read the Asserson Report here. But if you’ve followed the Beeb’s coverage of the war you hardly need to  Just think of all those British Jews who have to pay for a television license to listen to the distortions of the BBC.

Small primordial black holes (PBHs) are one of the hot topics in astronomy and cosmology today. These hypothetical black holes are believed to have formed soon after the Big Bang, resulting from pockets of subatomic matter so dense that they underwent gravitational collapse. At present, PBHs are considered a candidate for dark matter, a possible source of primordial gravitational waves, and a resolution to various problems in physics. However, no definitive PBH candidate has been observed so far, leading to proposals for how we may find these miniature black holes.

Recent research has suggested that main-sequence neutron and dwarf stars might contain small PBHs in their interiors that are slowly consuming their gas supply. In a recent study, a team of physicists extended this idea to include a new avenue for potentially detecting PBHs. Basically, we could search inside objects like planets and asteroids or employ large plates or slabs of metal to detect PBHs for signs of their passage. By detecting the microchannels these bodies would leave, scientists could finally confirm the existence of PBHs and shed light on some of the greatest mysteries in cosmology today.

The research was conducted by De-Chang Dai, a physicist at National Dong Hwa University in Taiwan and the Center for Education and Research in Cosmology and Astrophysics (CERCA) at Case Western Reserve University, and Dejan Stojkovic, a physicist from High Energy Physics and Cosmology group at the State University of New York Buffalo. The paper that details their findings recently appeared online and is being reviewed for publication in the journal Physics of the Dark Universe.

How we might discover primordial black holes and help solve the dark matter mystery. Credit: ESA

Scientists have been fascinated by PBHs for decades since Russian scientists Igor D. Novikov and Yakov Zeldovich predicted their existence in 1966. They were also a source of interest for Stephen Hawking, whose work on PBHs led to his breakthrough discovery in 1974 that black holes can evaporate over time. While larger and intermediate black holes would take longer to evaporate than the current age of the Universe (ca. 13.8 billion years), smaller PBHs may have already or could be in the process of doing so.

However, interest in PBHs has experienced a renaissance in recent years because they serve as dark matter candidates, a source of primordial gravitational waves (GWs), and more. Like Dark Matter, their existence could help resolve some major cosmological mysteries, but no confirmed observations have been made yet. As De-Chang and Stojkovic told Universe Today via email, this is what motivated them to propose novel detection methods:

“If an asteroid, or a moon, or a small planet (planetoid) has a liquid core surrounded by a solid crust, then a small PBH will consume the dense liquid core relatively quickly (within weeks to months). The crust will remain intact if the material is strong enough to support gravitational stress. Thus, we will end up with a hollow structure. If the central black hole is ejected (due to collisions with other objects), the density will be lower than the usual density of a rocky object with a liquid core.”

In addition, De-Chang and Stojkovic calculated the gravitational stress small PBHs would generate. They then compared this to the compressive strength of materials that make up a planet’s crust – such as silicate minerals (rock), iron, and other elements. They also considered the strongest manufactured materials, such as multiwall carbon nanotubes. “We found, for example, that granite can support hollow structures up to the radius of 1/10 of the Earth’s radius,” said Stojkovic. “That is why we should concentrate on planetoids, moons, or asteroids.”

An image based on a supercomputer simulation of the cosmological environment where primordial gas undergoes direct collapse to create black holes. Credit: Aaron Smith/TACC/UT-Austin.

These calculations offer a means to search for evidence of PBHs in space and here on Earth. Possible candidate planetoids, moons, or asteroids could be identified in our Solar System by observing their mass and radius to provide estimates of their density. This would allow astronomers to identify potentially hollow objects for follow-up studies by probes, landers, and other robotic space missions. Alternatively, they recommend that sensors be built to search for PBHs by detecting their passage. Said Stojkovic:

“If a small PBH passes through some solid material, it will leave a straight long tunnel of the radius comparable to the PBH’s radius. For example, a 1023 g PBH should leave a tunnel with a radius of 0.1 micron. [The energies] that such PBHs can have are significant, but [the energies] which they deposit into the material are very low. In fact, such a PBH can even pass through a human body, and we would not even notice because human body tissue has a very low tension.”

In this vein, scientists can scan for micro tunnels in commonplace materials we find lying around (like glass or rocks). At the same time, say De-Chang and Stojkovic, large slabs of polished metal could be prepared for this purpose. Similar to neutrino detection, these slabs would need to be isolated so that any sudden change in their properties could be recorded. “The expected flux of these PBHs is very small and we may end up finding nothing, but a possible payoff of finding a PBHs will be huge, especially since such experiments will be very cheap,” said Stojkovic.

As De-Chang added, it has been proposed in recent years that some primordial black holes may be hidden in stars. Stephen Hawking once proposed the idea, which became the basis of two studies, one released in 2019 and another this past year. “It is also proposed that primordial black holes may radiate Gamma rays. Strong gamma rays in the Milky Way’s dark matter halo can be a good hint for the existence of primordial black holes,” said De-Chang. “Gravitational microlensing can be another way to identify the primordial black holes.”

Further Reading: arXiv

The post Primordial Holes Could be Hiding in Planets, Asteroids, and Here on Earth appeared first on Universe Today.