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Today we have a second batch of underwater photos from reader Peter Klaver (first batch here). Today we have underwater wildlife (corals). Peter’s captions are indented, and you can enlarge the photos by clicking on them.

Here is the second batch of photos from scuba diving around San Pedro, Belize earlier this month.

Apart from many animals, the coral reefs there also have a rich abundance of underwater vegetation.

Most of the sea floor in the reefs is covered with various kinds of soft corals.

There are also some hard corals:

. . . including brain corals:

. . .And there are various cylindrical or tubular species whose names I don’t know.

Particle physics is not everyone’s cup of tea.  A team of physicists have theorised the existence of a strange type of particle that behaves differently depending on its direction of travel—massless in one direction but possessing mass when moving the other way! This strange, elusive particle, known as a semi-Dirac fermion or “quasiparticle,” has actually been observed in action. To detect it, researchers cooled a semi-metal crystal to near absolute zero, exposed it to a powerful magnetic field and infrared light, and successfully captured the signal of these unusual quasiparticles.

Particle physics is the branch of physics that studies the fundamental make up of matter and the forces that govern their interactions. It focuses on the smallest building blocks of the universe—particles such as quarks, leptons, and bosons—which make up atoms and everything around us. These subatomic particles interact through fundamental forces like electromagnetism, gravity, the strong nuclear force, and the weak nuclear force. The study of particle physics often involves high-energy experiments, where particles are accelerated to near the speed of light and collided, allowing for observations of their behaviour and properties.

Particle physics experiments address mysteries at subatomic and astronomical levels. (Illustration by Olena Shmahalo for U.S. Particle Physics)

Discoveries in particle physics are not all that common but a team of researchers from the Penn State University have announced their discovery of a new type of particle known as a quasiparticle. Quasiparticles are a quantum of energy in a crystal structure or other lattice structure that has momentum and position and can in some cases be considered a particle. They have named their new quasiparticle the semi-Dirac fermion, until the announcement it had been 16 years since this strange particle had been theorised. 

Often in particle physics, things can go against every thing your common sense tells you. It’s most definitely the case with the semi-Dirac fermion which was discovered in a ZrSiS crystal (Zirconium silicon sulfide.) When it is moving in one direction it seems to have mass but in the other direction it appears massless! This is possible when a particle derives its energy from its motion and in this case its almost pure energy travelling at the speed of light. 

The discovery is in accordance with Einstein’s theory of Special Relativity that says anything travelling at the speed of light cannot have mass. According to lead researcher Yinming Shao ‘In solid materials, the collective behaviour of many particles, also known as quasiparticles, can have different behaviour than the individual particles, which in this case gave rise to particles having mass in only one direction.’ 

Albert Einstein, pictured in 1953. Photograph: Ruth Orkin/Hulton Archive/Getty Images Ruth Orkin/Getty

The team used the hybrid magnet at the National High Magnetic Field Laboratory in Florida to generate a magnetic field 900,000 times stronger than the Earth’s! They cooled a piece of ZrSiS crystal down to just a few degrees above absolute zero and exposed it to the magnetic field while directing infrared light at it to explore its quantum properties. This enabled them to study how electrons inside the material responded to the light revealing many features that were expected, plus a few more that puzzled the team.

The magnetic field was a crucial element to their experiment which caused the electrons inside the crystal to become quantised into discrete states called Landau Levels that have fixed values. The difference between the levels depends on the mass of the electrons and the strength of the magnetic field. If the magnetic field increases, the energy level of the electrons should increase based on their mass, but they didn’t!

Shao went on to explain their findings ‘Imagine the particle is a tiny train confined to a network of tracks, which are the material’s underlying electronic structure. Now, at certain points the tracks intersect, so our particle train is moving along its fast track, at light speed, but then it hits an intersection and needs to switch to a perpendicular track. Suddenly, it experiences resistance, it has mass. The particles are either all energy or have mass depending on the direction of their movement along the material’s tracks.’

Source : Particle that only has mass when moving in one direction observed for first time

The post This Particle Only Has Mass When Moving in One Direction appeared first on Universe Today.

Although popular AI models score highly on medical exams, their accuracy drops significantly when making a diagnosis based on a conversation with a simulated patient

An incredible image of Mars has been released that captures the relentless activity of dust devils, swirling across the planet’s surface. These Martian whirlwinds form, move across the surface and dissipate before others take their place. The image was taken by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter in September 2022 and shows part of the Haldane Crater, where dust devils have left their mark on the landscape. Scientists study the image tracks and the rate at which dust accumulates on Mars, helping them better understand the planet’s atmospheric processes.

Mars, the fourth planet from the Sun, is often referred to as the “Red Planet” because of its reddish colour, which results from iron oxide in its soil. Its atmosphere is thin and mostly made up of carbon dioxide which contributes to its cold climate with an average temperature of around -60°C. The surface of Mars features plains, volcanoes (like Olympus Mons) and the vast canyon system Valles Marineris. Geological evidence suggests that Mars had liquid water once and a thicker atmosphere suggesting the potential for past life.

Mars from 2020. Credit: Andrew Symes.

The atmosphere of Mars is thin and made up mostly of carbon dioxide (about 95%.) There are traces of nitrogen, argon, and oxygen too. This sparse atmosphere is only about 1% the density of Earth’s and is unable to support human life without significant technological aid. Despite its thinness, the Martian atmosphere is active, and one of its most fascinating phenomena is the occurrence of dust devils. These swirling columns of dust and air are similar to tornadoes on Earth. 

The atmosphere of Mars

Dust devils are created when the surface heats up and causes warm air to rise rapidly, drawing in dust particles into a rotating column. They can range in size from small, harmless whirlwinds to massive, kilometer-wide spirals that can last for hours. Dust devils on Mars are important for scientists because they help to redistribute dust across the planet’s surface, driving its weather patterns and even the Martian climate. 

A Martian dust devil was captured winding its way along the Amazonis Planitia region of Northern Mars on March 14, 2012 NASA’s Mars Reconnaissance Orbiter.

A fascinating phenomenon but a friend and foe to machines on the surface of the red planet; they can both deposit and clear particles of dust from solar panels and other instruments. The swirling nature of these vortex weather events can lift up the fine dust particles, carry them across the Martian surface and over time, they can accumulate on surfaces. When depositing on solar panels, the effect can reduce the efficiency by blocking sunlight, and reduce power output. Their strong winds though can act as cleaners by scrubbing the panels clean. 

An image recently released by NASA JPL shows dust devils tracking across the surface of Mars. Teams of astronomers are studying their fading tracks to calculate the rate of deposition of dust over time. Gaining a better ujnderstanding of this helps to safeguard future space misssions. 

Source : The Art of Dust Devils

The post Crisscrossing Dust Devil Tracks Across the Surface of Mars appeared first on Universe Today.

Groundbreaking cerium oxide-based thermal switches achieve remarkable performance, transforming heat flow control with sustainable and efficient technology.

In 2020, the GBD was all about herd immunity via natural immunity. Today, its defenders censor that.

The post A Challenge For Dr. Edward Livingston: Defend the Great Barrington Declaration Without Censoring the Great Barrington Declaration first appeared on Science-Based Medicine.

Researchers report that they have invented new nanoscale sensors of force. They are luminescent nanocrystals that can change intensity and/or color when you push or pull on them. These 'all-optical' nanosensors are probed with light only and therefore allow for fully remote read-outs -- no wires or connections are needed.

Researchers report that they have invented new nanoscale sensors of force. They are luminescent nanocrystals that can change intensity and/or color when you push or pull on them. These 'all-optical' nanosensors are probed with light only and therefore allow for fully remote read-outs -- no wires or connections are needed.

Astronomers pinned down the origins of at least one fast radio burst, a brief and brilliant explosion of radio waves emitted by an extremely compact object. The team's novel technique might also reveal the sources of other FRBs.

Getting back to the Moon is the primary goal of NASA’s Artemis program, but what do we do once we get there? That is the challenge tackled by a group of students at the University of Illinois Urbana-Champaign, who wrote a proposal for a lunar infrastructure module they call the Trans-lunar Hub for Exploration, ISRU, and Advancement – or THEIA, after the proposed object that crashed into the Earth that created the Moon as we know it today. Their submission was part of the NASA Revolutionary Aerospace Systems Concepts – Academic Linkage project, where teams from various academic institutions submitted papers focusing on the theme of Sustained Lunar Evolution for 2024.

To be clear, THEIA is not meant to serve as the central hub of NASA’s lunar exploration activities. The responsibility would still go to the Artemis base the agency has been working on. It is meant to serve as a hub for four main things that the team believes every long-term lunar mission will need: power, communications, transportation, and In-situ resource utilization (ISRU). 

The project’s mission requirements include providing local positioning, communications, and power to an area surrounding the lunar south pole. Various organizations are developing several pieces of infrastructure to do so.

The UIUC team’s presentation at the NASA RASC-AL challenge.
Credit – NASA Vimeo website

First would be the delivery method to get there—like much of the overall Artemis project, THEIA would rely on delivery from a SpaceX Starship. The team calculated the initial launch requirements to get a basic setup up and running to be around 73 tons, well below the threshold of 100 tons the rocket is expected to be able to carry to the lunar surface.

That first set of equipment would include two other vital pieces of infrastructure – some LUNARSABER poles and robots to set them up. We previously did an entire article on the LUNARSABER project from Honeybee Robotics. Still, as a succinct overview, it is an extendable tower with solar panels along its sides to collect energy. Then, it uses a series of transmitters and receivers at its top to broadcast both power and communication signals. They can also bounce signals between two towers, creating a basic mesh network on the lunar surface.

A LUNARSABER is essential for supplying power and communications, but the UIUC team needs robotic help to deploy it. They suggest using several robotic rovers, including a multilimbed one designed on NASA’s Athlete prototype and a more traditional lunar rover based around the current Lunar Terrain Vehicle contract NASA has outstanding, with several companies still vying to provide the final design.

Fraser discusses how NASA plans to sign up the Moon’s infrastructure.

Other essential infrastructure pieces include ground antennas to transmit data and communications back to the Lunar Gateway and habitats that would allow both scientific experiments to operate and, eventually, crew to live. An essential additional part of THEIA’s design philosophy is that there should be space for experiments to operate inside a semi-controlled environment.

That would still be a long time from now, with original missions to launch THEIA not planned until 2035 and crewed missions to follow years later. However, THEIA was initially drawn up by a group of undergraduates, who presented a technical paper in response to the NASA RASC-AL proposal. It was one of many such proposals that resulted in groups from Virginia Polytechnic, the University of Maryland, and South Dakota University winning prizes. We’ll look at some of the other projects submitted by teams shortly, but congratulations to the UIUC team, who made it through the competition as a finalist, for the effort they put into theirs.

Learn More:
Bojinov et al – THEIA
UT – A Tower On The Moon Could Provide Astronauts With Light, Power, and Guidance
UT – NASA has Plans for More Cargo Deliveries to the Moon
UT – NASA Focuses in on Artemis III Landing Sites.

Lead Image:
THEIA Concept of Operations.
Credit – Bonjinov et al

The post A Long-Term Lunar Infrastructure Hub Named After the Object That Created the Moon appeared first on Universe Today.

We asked our writers to pick their favourite science fiction television series. Here are the results, from Battlestar Galactica to Futurama

Many dates stick in our minds as we reflect on five years of living with covid-19 - here are some of the most memorable ones

Covid-19 is responsible for the deaths of millions of people around the world, but researchers fear the next global outbreak could be even worse, making it vital that we start preparing for that unknown pathogen now

mRNA vaccines have been a long time coming, but were only approved after covid-19 emerged, marking the beginning of a new way of preventing – and treating – various conditions

Some people have been living with long covid for five years, but we are still just starting to learn about its exact causes and how best to treat the condition

Many emotive and inspiring photographs were taken when covid-19 turned our lives upside down – here are some of the best pictures from the past five years

Many of us experienced time differently in the pandemic. Learning why can help us, say Ruth Ogden and Patricia Kingori

Despite studying the SARS-CoV-2 virus for five years, scientists still have questions, from the extent to which it can survive and mutate in animals to the thorny argument over its origins

A little help from Lewis Carroll will enable you to impress friends and family by calculating which day of the week any date is, says Peter Rowlett

From M3gan 2 to 28 Years Later, this year is all about inventive sequels, series and remakes – plus some dazzling adaptations like Mikey 17, says Simon Ings