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We collected some of the wildest physics that New Scientist covered in 2024, findings that are forcing scientists – and us – to rethink reality

We collected some of the wildest physics that New Scientist covered in 2024, findings that are forcing scientists – and us – to rethink reality

Astrophysicists come up with a lot of whacky ideas, some of which actually turn out to be possibly true (like the Big Bang, black holes, accelerating cosmic expansion, dark matter). Of course, all of these conclusions are provisional, but some are now backed by compelling evidence. Evidence is the real key – often the challenge is figuring out a way to find evidence that can potentially support or refute some hypothesis about the cosmos. Sometimes it’s challenging to figure out even theoretically (let alone practically) how we might prove or disprove a hypothesis. Decades may go buy before we have the ability to run relevant experiments or make the kinds of observations necessary.

Black holes fell into that category. They were predicted by physics long before we could find evidence of their existence. There is a category of black hole, however, that we still have not confirmed through any observation – primordial black holes (PBH). As the name implies, these black holes may have been formed in the early universe, even before the first stars. In the early dense universe, fluctuations in the density of space could have lead to the formation of black holes. These black holes could theoretically be of any size, since they are not dependent on a massive star collapsing to form them. This process could lead to black holes smaller than the smaller stellar remnant black hole.

In fact, it is possible that there are enough small primordial black holes out there to account for the missing dark matter  – matter we can detect through its gravitational effects but that we cannot otherwise see (hence dark). PBHs are considered a black hole candidate, but the evidence for this so far is not encouraging. For example, we might be able to detect black holes through microlensing. If a black hole happens to pass in front of a more distant star (from the perspective of an observer on Earth), then gravitational lensing will cause that star to appear to brighten, until the black hole passes. However, microlensing surveys have not found the number of microlensing events that would be necessary for PBHs to explain dark matter. Dark matter makes up 85% of the matter in the universe, so there would have to be lots of PBHs to be the sole cause of dark matter. It’s still possible that longer observation times would detect larger black holes (brightening events can take years if the black holes are large). But so far there is a negative result.

Observations of galaxies have also not shown the effects of swarms of PBHs, which should have (those > 10 solar masses) congregated in the centers of small galaxies over the age of the universe. This would have disturbed stars near the centers of these galaxies, causing the galaxies to appear fluffier. Observations of dwarf galaxies so far have not seen this effect, however.

A recent paper suggest two ways in which we might observe small PBHs, or at least their effects. These ideas are pretty out there, and are extreme long shots, which I think reflects the desperation for new ideas on how we might confirm the existence of PBHs. One idea is that small PBHs might have been gravitationally captured by planets. If the planet had a molten core, it’s then possible that the PBH would consume the molten core, leaving behind a hollow solid shell. The researchers calculate that for planets with a radius smaller than one tenth that of Earth, they outer solid shell could remain intact and not collapse in on itself. This idea then requires that a later collision knocks the PBH out of the center of this hollowed out small planet.

If this sequence of events occurs, then we could theoretically observe small hollow exoplanets to confirm PBHs. We could know a planet is hollow if we can calculate its size and mass, which we can do for some exoplanets. An object can have a mass much too small for its apparent size, meaning that it could be hollow. Yes, such an object would be unlikely, but the universe is a big place and even very unlikely events happen all the time. Being unlikely, however, means that such objects would be hard to find. That doesn’t matter if we can survey large parts of the universe, but finding exoplanets requires lots of observations. So far we have identified over 5 thousand exoplanets, with thousands of candidates waiting for confirmation. Most of these are larger worlds, which are easier to detect. In any case, it may be a long time before we find a small hollow world, if they are out there.

The second proposed method is also highly speculative. The idea here is that there may be really small PBHs that formed in the early universe, which can theoretically have masses in the range of 10^17 to 10^24 grams. The authors calculate that a PBH with a mass of 10^22 grams, if it passed through a solid object at high speed, would leave behind a tunnel of radius 0.1 micrometers. This tunnel would make a long straight path, which is otherwise not something you would expect to see in a solid object.

Therefore, we can look at solid objects, especially really old solid objects, with light microscopy to see if any such tiny straight tunnels exist. If they do, that could be evidence of tiny PBHs. What is the probability of finding such microscopic tunnels? The authors calculate that the probability of a billion year old boulder containing such a tunnel is 0.000001. So on average you would have to examine a million such boulders to find a single PBH tunnel. This may seem like a daunting task – because it is. The authors argue that at least the procedure is not expensive (I guess they are not counting the people time needed).

Perhaps if there were some way to automate such a search, using robots or equipment designed for the purpose. I feel like if such an experiment were to occur, it would be in the future when technology makes it feasible. The only other possibility is to crowd source it in some way. We would need millions of volunteers.

The authors recognize that these are pretty mad ideas, but they also argue that at this point any idea for finding PBHs, or dark matter, is likely to be out there. Fair enough. But unless we can practically do the experiment, it is likely to remain just a thought experiment and not really get us closer to an answer.

The post Finding Small Primordial Black Holes first appeared on NeuroLogica Blog.

From Alzheimer's disease to depression to heart disease, Ozempic and other GLP-1 agonist drugs appear to offer a solution. Can one type of drug really tackle so many conditions, and if so, how does it actually work?

Astronomers spotted a 70-centimetre asteroid hours before it hit the atmosphere above northern Siberia, making a fireball in the sky

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On this Giving Tuesday, please consider supporting Skeptoid Media (a 501(c)(3) nonprofit organization) and our mission of cultivating critical thinking and science literacy skills. Donations will be matched by our Board of Directors!

In a first-of-its-kind breakthrough, a team of researchers has developed an artificial adhesion system that closely mimics natural biological interactions. Their research focuses on understanding how cells physically interact with each other and their environment, with the ultimate goal of developing innovative tools for disease diagnosis and therapy.

NASA has given SpaceX the contract to launch the Dragonfly mission to Saturn’s moon Titan. A Falcon Heavy will send the rotorcraft and its lander on their way to Titan in 2028, if all goes according to plan, and the mission will arrive at Titan in 2034. Dragonfly is an astrobiology mission designed to measure the presence of different chemicals on the frigid moon.

Dragonfly will be the second craft to visit Titan, along with the Huygens probe and its short visit back in 2005.

Titan is remarkable because it’s the only body besides Earth with liquids on its surface. The liquids are hydrocarbons, not water, though there may be surface deposits of water ice from impacts or cryovolcanic eruptions. Researchers think that prebiotic chemicals are also present, making the moon an enticing target to understand how far prebiotic chemistry may have advanced.

These images of Titan’s well-known hydrocarbon seas are from Cassini radar data. Image Credit: [JPL-CALTECH/NASA, ASI, USGS]

Titan is benign when it comes to powered flight; its atmosphere is dense and its gravity is weak, compared to Earth. Dragonfly is an octocopter, a large quadcopter with double rotors, that can take advantage of Titan’s flight-friendly conditions. It will travel at about 36 kmh (22 mph) and will be powered by a Radioisotope Thermoelectric Generator (RTG), a type of engine proven in multiple missions. The craft is designed to be redundant; it can lose one of its motors or rotors and still function.

Dragonfly will land near a feature on Titan called Shangri-La, east of where the Huygens probe landed. Shangri-La is one of three large sand seas near the moon’s equator.

Dragonfly’s target is the Selk impact structure, near the edge of Shangri-La. Selk is a young impact crater about 90 km (56 mi) in diameter that features melt pools, sites where liquid water and organics could mix together to form amino acids or other biomolecules. Dragonfly will initially land at some dunes near the structure then begin exploring the region and its chemistry.

Thanks largely to Cassini and Huygens, researchers have made progress understanding Titan. In a 2020 paper, researchers examined two types of craters on the moon: dune craters and plains craters. Selk is a dune crater, and in the paper, researchers said that the dune craters are richer in organics than plains craters, and in fact are almost entirely composed of organics. However, Titan’s thick atmosphere makes it difficult to observe, and these findings stem from interpreting albedo and emissivity.

Selk and the other dune craters may have originally had more water ice, according to the research, but much of it’s been eroded away. However, there was a long period of time where the water ice was present, and Dragonfly is heading for Selk to examine the chemistry in the crater and to try and determine if water and organics interacted and if prebiotic chemistry made any headway.

It’s up to SpaceX’s Falcon Heavy to send Dragonfly on its way to Titan. Falcon Heavy has 11 launches under its belt, including the launch of the Europa Clipper in October. After Falcon Heavy launches Dragonfly, the spacecraft will perform one flyby of Earth to gain additional velocity.

It’ll take six years for Dragonfly to reach Titan, and just as it arrives, the entry capsule will separate from the cruise module. With the help of an aeroshell and two chutes, the lander will endure an approximately 105-minute descent. At approximately 1.2 km above the surface, the lander will deploy its skids, and based on its lidar and radar data, will perform and autonomous landing.

From its landing site, Dragonfly will deploy itself and perform a series of flights up to 8km (5 mi) long. There’s diverse geology in the region, and the rotorcraft will acquire samples and then analyze them during Titan’s nights, which last about 8 Earth days or about 192 hours. After that, it will head to the Selk crater.

Titan is an important astrobiology target in our Solar System, and unlike the frozen ocean moons Europa and Enceladus, there’s no added complexity of somehow working its way through thick ice before its potentially biological environment can be examined.

SpaceX’s Falcon Heavy rocket sends NASA’s Europa Clipper into space from its Florida launch pad. If all goes well, the Falcon Heavy will launch the Dragonfly mission to Titan in July, 2028. (NASA Photo / Kim Shiflett)

But for all of this to succeed, it needs a successful launch first. NASA is paying SpaceX about $256 million to launch Dragonfly, and it the launch goes off without a hitch, it’ll be money well-spent.

The post Dragonfly is Going to Titan on a Falcon Heavy appeared first on Universe Today.

The algorithms behind generative AI tools like DallE, when combined with physics-based data, can be used to develop better ways to model the Earth's climate. Computer scientists have now used this combination to create a model that is capable of predicting climate patterns over 100 years 25 times faster than the state of the art.

A group of young students became bonafide biomedical scientists before they even started high school. Through a partnership with a nearby university, the middle schoolers collected and analyzed environmental samples to find new antibiotic candidates. One unique sample, goose poop collected at a local park, had a bacterium that showed antibiotic activity and contained a novel compound that slowed the growth of human melanoma and ovarian cancer cells in lab tests.

Researchers explore the transformation dynamics of cubic liquid crystals using direct simulation and machine learning, offering new possibilities for advanced materials development.

Covid-19 emerged in 2019, but some questions are still unanswered as to its origins

Research is paving the way for advanced diamond-based technologies in electronics and quantum computing.

Research is paving the way for advanced diamond-based technologies in electronics and quantum computing.

A researcher has helped create a new 3D printing approach for shape-changing materials that are likened to muscles, opening the door for improved applications in robotics as well as biomedical and energy devices.

A researcher has helped create a new 3D printing approach for shape-changing materials that are likened to muscles, opening the door for improved applications in robotics as well as biomedical and energy devices.

A research team has taken inspiration from the brains of insects and animals for more energy-efficient robotic navigation.

A research team has taken inspiration from the brains of insects and animals for more energy-efficient robotic navigation.

A research team has developed liquid-processed thin-film transistors that can maintain high performance at low temperatures -- They are expected to be used in the next generation of high-performance flexible electronics and wearable devices as they can operate on plastic substrates and maintain stable performance under repeated mechanical bending.