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A global survey of more than a thousand cities shows heat and air pollution in urban environments often have a measurable influence on rainfall, creating urban "wet islands"

Here at UT, we’ve had several stories that describe the concept of a space elevator. They are designed to make it easier to get objects off Earth and into space. That, so far, has proven technically or economically infeasible, as no material is strong enough to support the structure passively, and it’s too energy-intensive to support it actively. However, it could be more viable on other worlds, such as the Moon. But what about worlds farther afield? A student team from the University of Colorado at Colorado Springs looked at the use case of a space elevator on Ceres and found that it could be done with existing technology.

Before we discuss why anyone would want to put a space elevator on Ceres, let’s first examine the technologies that would make it possible. Every space elevator design has three different components: an anchor, a tether, and a counterweight. Each would require its own technologies.

The anchor is simple enough; it’s how the system interfaces with Ceres. The surface of Ceres is primarily made of clay, which is relatively good for anchoring technologies. Luckily, the force the anchor needs to withstand is only around 300N, which is much lower than the force on Earth, given Ceres’ small mass. There have already been asteroid anchoring technologies for other missions that can provide up to 500N of force resistance, so an anchor on Ceres should prove no real challenge.

Fraser describes the general idea of a space elevator.

The tether is where the technology falls short on Earth – no material known to science can withstand the forces exerted on the tether of a passively controlled space elevator when it is tied to Earth. However, the closest we can come, something space elevator enthusiasts mention as almost a holy grail, is carbon nanotubes. In the analysis for the space elevator on Ceres, they once again came out ahead. However, the limitation of actually physically creating a long tether will still plague any space elevator design on Ceres.

The counterweight is much simpler, as it can be just a big, dumb mass. However, its mass is proportional to the necessary length of cable—the heavier the mass, the shorter the cable. So, the tradeoff between having a heavier counterweight and a shorter cable is another design consideration when considering these systems.

Calculations from the team show that, with only a little more technological development, all three main systems could be ready for installation on Ceres itself. But what advantages does it have? It could be helpful as a launching point for accessing other asteroids in the asteroid belt. Ceres also has water relatively near the surface, which is helpful for all kinds of human exploration, either as rocket fuel or biological systems. It’s also well placed to quickly get things back to Earth using Jupiter as a gravity assist.

Isaac Arthur goes into a deeper description of space elevators and their advantages.

But before it can provide any of those advantages, someone is going to have to pay for it. Estimates of the overall cost of the system total about $5.2 billion — not too far out of the range of larger-scale space exploration projects. But more than most countries are likely willing to pony up for a grand infrastructure project that hasn’t yet proven its benefit.

So, for now, any space elevator will remain in the realm of science fiction. But research like this and other ongoing technological improvements is how we will eventually push forward to that future. Whether it’s a space elevator on Ceres, on the Moon, or some other novel launch technology, someday humans will need a better way to get off Earth rather than burning dead living organisms. Hopefully, that day will come sooner rather than later.

Learn More:
Bate et al. – Analyzing the Potential of Space Elevator Technology for Sustainable Asteroid Mining
UT – What is a Space Elevator?
UT – A New Method for Making Graphene has an Awesome Application: A Space Elevator!
UT – A Japanese Company is About to Test a Tiny Space Elevator… in Space

Lead Image:
Artistic view of a possible space elevator.
Credit: NASA

The post Using A Space Elevator To Get Resources Off the Queen of the Asteroid Belt appeared first on Universe Today.

Are humanoid robots the future of space exploration? New Scientist reporter James Woodford took NASA's Valkyrie for a spin to find out

The Arrhenius equation, which has accurately described rates of chemical reactions for more than a century, may have to be tweaked for the quantum realm

Levels of certain cells, fatty molecules and proteins in the blood are different in people with chronic fatigue syndrome than in those without it, which could help doctors spot the condition sooner

X-ray videos of Japanese eels swallowed whole by dark sleeper fish have revealed how the eels can make a daring escape from being digested

Forget atomic clocks. Nuclear clocks, which only drop a second every 300 billion years, can test whether nature's fundamental constants are constant after all

Exoplanets have been discovered with a wide range of environmental conditions. WASP-76b is one of the most extreme with a dayside temperature of over 2,000 degrees. A team of researchers have found that it’s even more bizarre than first thought! It’s tidally locked to its host star so intense winds encircle the planet. They contain high quantities of iron atoms that stream from the lower to upper layers around the atmosphere.

Exoplanets exist outside of our Solar System and orbit other stars. The first confirmed discovery was back in the 1990’s and since then, over 5,200 have been discovered. Many of them are gas giants like Jupiter or Saturn and others are small rocky Earth like planets, minus perhaps their habitability status. As more advanced telescopes and detection techniques are developed not only will our detection levels increase further but so will our ability to explore these alien worlds. 

Artist impression of glory on exoplanet WASP-76b. Credit: ESA

One such exoplanet, WASP-76b has received quite a lot of attention of late. It is an ultra-hot gas giant that is 640 light years from us in the direction of the constellation Pisces. It was discovered back in 2013 and has an orbit that is very close to its host star, completing one orbit in just 1.8 Earth days! It’s the proximity to the star that has led to the extreme daytime temperatures of over 2,000 degrees. The intense heat is thought to vaporise iron which then condenses into liquid on the cooler night-time side and fall as iron rain! 

A team of astronomers, with some from the University of Geneva, announced their findings in the journal Astronomy & Astrophysics of evidence for intense iron winds in the atmosphere of WASP-76b. Astronomers have been focussing on this planet since its discovery to try and understand the mechanisms in the atmosphere of this ultra-hot Jupiter world. It really is a fascinating world and even a rainbow was detected there last April! 

The team kept their attention on the day-time side where the temperatures are far higher. They used the ESPRESSO spectrograph that was installed on the European Southern Observatory’s Very Large Telescope (yes that’s its name!) It is known for its stability and high spectral resolution so it can discern wonderfully fine levels of detail in a stellar spectrum. 

The four 8.2-metre Unit Telescopes of the Very Large Telescope at the Paranal Observatory complex. ESO/VLT

Using a technique known as high resolution emission spectroscopy, the team studied the visible light spectrum. The approach relies upon the detection of emission lines in a spectrum and enables the chemical composition to be decoded. Here they detected the chemical signature of iron and found that they were moving from lower levels to the higher layers of the atmosphere.

The study of exoplanet atmospheres help us to further develop our understanding of the range of environments on these alien worlds. As a gas giant, the discoveries on WASP-76b help us learn a little more about the climates of worlds that are barraged by extreme levels of radiation from their host star.

Source : Iron winds on an ultra-hot exoplanet

The post Iron Winds are Blowing on WASP-76 b appeared first on Universe Today.

A camera trap at an Australian nature refuge has captured a boisterous interaction between a northern hairy-nosed wombat and an echidna

Chemists discover how key contrast agent works, paving a way to create new markers needed for correlative microscopy that can image the structure and signaling of cells at the same time.

Researchers have developed a robotic leg with artificial muscles. Inspired by living creatures, it jumps across different terrains in an agile and energy-efficient manner.

Researchers have developed a robotic leg with artificial muscles. Inspired by living creatures, it jumps across different terrains in an agile and energy-efficient manner.

A new molecular engineering technique can precisely influence the development of organoids. Microbeads made of specifically folded DNA are used to release growth factors or other signal molecules inside the tissue structures. This gives rise to considerably more complex organoids that imitate the respective tissues much better and have a more realistic cell mix than before.

Cement-based materials provide a potential solution for mitigating climate change by trapping and storing atmospheric carbon dioxide as minerals, via a process known as carbonation. Despite extensive studies, however, the exact mechanism of this process is not yet understood. Now, researchers have conducted a comprehensive investigation of carbonation reaction using a new method, revealing the role of structural changes and water transport, paving the way for advanced carbon dioxide-absorbing building materials.

Converting biomass such as waste cooking oil into useful chemicals through catalysis can help create a more sustainable chemical industry. However, conventional techniques require enormous energy and generate harmful chemicals. Moreover, such techniques reduce the lifetime of catalysts. Now, researchers reveal a zeolite catalyst that can be efficiently heated up using microwaves.

Well, it was a grueling 15¼-hour flight from Cape Town to Dulles Airport in the Virginia suburbs of Washington, D.C.,  and that was on top of a five-hour wait for my plane at Cape Town International Airport, resulting from an 8 p.m. departure when I had to check out of the hotel a bit after noon.

I tried to sleep on the plane, but it was largely futile. So, as usual, I watched a passel of movies, which included the first film (1972) of the movie trilogy “The Godfather” directed by Francis Ford Coppola.  After watching the whole three-hour movie carefully (and for about the fifth time), my opinion is only strengthened that this is one of the best American movies ever made (my top choice, which I’ve often mentioned is “The Last Picture Show,” released a year before “The Godfather”).

I know some people don’t or can’t rank movies, but if you’re daring enough to do so, I’d be delighted to hear readers’ choices for Best American Movie. (As for best foreign films, I’d choose two Japanese ones: Kurosawa’s “Ikiru” (1952) and Ozu’s “Tokyo Story” (1953).

BTW, I had forgotten that Marlon Brando, playing Don Corleone, is not the first character to speak in the movie; rather, it’s an undertaker asking the Godfather to exact justice on the undertaker’s daughter, beaten up by a gang of sexual predators. The first sign of the Godfather is the movement of his hand at 1:30. Here are the first 6.5 minutes:

The movie won the Oscar for Best Picture, and Brando nabbed it for Best Actor, but declined the award. It won a third Oscar for Best Adapted Screenplay, shared by Coppola and author Mario Puzo.

I’m now cooling my heels at Dulles for two hours, waiting for the 2.5-hour flight to Chicago. After that it’ll be another 1.5-2 hours before I get home. It’s been a long, long flight, but less grueling than my canceled flight to South Africa, which I rebooked flying (after our flight to Cape Town to Dulles was canceled) from Dulles to Newark, then from Newark to Johannesburg, and then from Joburg to Cape Town.

I still have at least two photo-and-text posts left for South Africa, including a visit to the Kirstenbosch National Botanical Garden in southern Cape Town, perhaps the best such garden I’ve ever seen. I hae photos of many flowers, including the resplendent King Protea (Protea cynaroides), the national flower of South Africa. Here’s a preview (these flowers can be as much as a foot across):

Meanwhile, in Dobrzyn, Hili is being a typical cat:

A: Here you are!
Hili: Yes, because it’s a good place for a siesta.

Ja: Tu jesteś!
Hili: Tak, bo to dobre miejsce na siestę.

Shortly after endorsing Donald Trump for President, Robert F. Kennedy Jr. claimed he and Trump will "make America healthy again." His proposals to do that range from semi-reasonable to outright quackery.

The post RFK Jr.’s MAHA manifesto: How not to “make America healthy again” first appeared on Science-Based Medicine.

According to Nebula Theory, stars and their systems of planets form when a massive cloud of gas and dust (a nebula) undergoes gravitational collapse at the center, forming a new star. The remaining material from the nebula then forms a disk around the star from which planets, moons, and other bodies will eventually accrete (a protoplanetary disk). This is how Earth and the many bodies that make up the Solar System came together roughly 4.5 billion years ago, eventually settling into their current orbits (after a few migrations and collisions).

However, there is still debate regarding certain details of the planet formation process. On the one hand, there are those who subscribe to the traditional “bottom-up” model, where dust grains gradually collect into larger and larger conglomerations over tens of millions of years. Conversely, you have the “top-down” model, where circumstellar disk material in spiral arms fragments due to gravitational instability. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence of the “top-down” model when observing a protoplanetary disk over 500 light-years away.

The team was led by Jessica Speedie, an astronomy and astrophysics Ph.D. candidate at the University of Victoria. She was joined by colleagues from the Kavli Institute for Astronomy and Astrophysics (KIAA-PKU), the Center for Simulational Physics (CSP-UGA), the Cambridge Institute of Astronomy, the Centre de Recherche Astrophysique de Lyon (CNSA-CRAL), the Institute of Astronomy and Astrophysics (ASIAA), the Department of Earth, Atmospheric, and Planetary Sciences (MIT EAPS), the National Astronomical Observatory of Japan (NAOJ), the European Southern Observatory (ESO), and multiple universities and observatories.

The paper that details their research, “Gravitational instability in a planet-forming disk,” was recently published in the journal Nature.

Located in the Atacama desert in the Chilean Andes, ALMA is the largest radio telescope in the world dedicated to studying the parts of the Universe that are otherwise invisible to astronomers. This includes cold dust clouds in space, protoplanetary disks, and some of the earliest galaxies in the Universe, which are only visible at millimeter and submillimeter wavelengths. Using ALMA, Speedie and her colleagues observed the well-characterized protoplanetary disk around AB Aurigae, a young star system (4 million years old) located about 530 light-years from Earth.

The star is a pre-main sequence A-type star (blue-white) approximately 2.5 times the size of our Sun and about 2.4 times as massive. Beginning in 2017, scientists at ALMA began observing the star’s protoplanetary disk to learn more about planet formation in young star systems. Since then, astronomers have observed several developing protoplanets forming in AB Aurigae’s disk, as well as a gas giant nine times the mass of Jupiter that was confirmed in 2022. These appear as clumps within the protoplanetary disk’s spiral arms, rotating counterclockwise around the star.

The detection of these bodies around such a young star raised doubts about the “bottom-up” process. According to this model, these protoplanets did not have nearly enough time to become as large as they have. Along with her PhD advisor Ruobing Dong, Speedie and their team were determined to study how the gas in the system’s vast spiral arms is moving. ALMA’s sensitivity and high velocity resolution was crucial to that task and enabled the team to probe the gas deep within the disk and measure its motion precisely.

Dr. Cassandra Hall, an Assistant Professor of Computational Astrophysics at the University of Georgia was also a co-author on the research. Four years ago, Hall led a study where she and her colleagues (which included Dong and other members of Speedie’s team) simulated how a gravitationally unstable disk would behave. As she indicated in a NRAO press release:

“Disks that are gravitationally unstable should have distinctive ‘wiggles’ in their velocity field, unlike disks that are stable. Back in 2020, we performed some of the most advanced simulations in the world to predict the existence of this hallmark signature of gravitational instability. It was clear, it was testable, and it was a bit scary – if we didn’t find it, then something had to be very, very wrong with our understanding of these disks.”

Spiral arms form in a protoplanetary disk when the disk-to-star mass ratio is sufficiently high. Over time, changes in density lead to changes in gravity, which causes variations in the velocities of gas in and around the spiral arms. These variations in velocity are seen as “wiggles,” and the magnitude can be used to infer the mass ratio between the host star and the material in its disk. Using ALMA’s array of radio antennas, Speedie and her team mapped the velocity of carbon monoxide isotopes within the disk’s spiral arms and looked for indications of the predicted “wiggles.”

These measurements yielded a three-dimensional rectangular “data cube” that mapped gas velocity and position within the protoplanetary disk along the observatory’s line of sight. As is customary with ALMA’s interferometry measurements, the data was parsed into “slices” (or strategically oriented cuts), allowing Speedie and her team to conclusively identify the velocity wiggle indicating gravitational instability. This constitutes the first direct observational confirmation that the “top-down” pathway to planet formation is correct.

What’s more, it indicates that planetary systems may form much faster than previously thought, which could have significant implications for astrogeology and exoplanet research. As Speedie explained, Hall’s work, ALMA’s sensitivity, and the quality data products it created for them were what made this discovery possible:

“This is a classic science story of, ‘we predicted it, and then we found it’. The Hall-mark of gravitational instability. We worked with one of the deepest ALMA observations taken with such high-velocity resolution toward a single protoplanetary disk to date. The ALMA data provides a clear diagnosis of gravitational instability in action. There is no other mechanism we know of that can create the global architecture of spiral structure and velocity patterns that we observe.”

In the near future, Speedie and her colleagues plan to continue using ALMA to learn more about how planetary systems form around young stars. As part of the NFS/NRAO ALMA ambassador program, Speedie is training alongside other postdoctoral students and early career astronomers to share ALMA’s resources and capabilities with the wider astronomical community.

Further Reading: NRAO, Nature

The post ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk appeared first on Universe Today.

In 2012, two previous dark matter detection experiments—the Large Underground Xenon (LUX) and ZonEd Proportional scintillation in Liquid Noble gases (ZEPLIN)—came together to form the LUX-ZEPLIN (LZ) experiment. Since it commenced operations, this collaboration has conducted the most sensitive search ever mounted for Weakly Interacting Massive Particles (WIMPs) – one of the leading Dark Matter candidates. This collaboration includes around 250 scientists from 39 institutions in the U.S., U.K., Portugal, Switzerland, South Korea, and Australia.

On Monday, August 26th, the latest results from the LUX-ZEPLIN project were shared at two scientific conferences. These results were celebrated by scientists at the University of Albany‘s Department of Physics, including Associate Professors Cecilia Levy and Matthew Szydagis (two members of the experiment). This latest result is nearly five times more sensitive than the previous result and found no evidence of WIMPs above a mass of 9 GeV/c2. These are the best-ever limits on WIMPS and a crucial step toward finding the mysterious invisible mass that makes up 85% of the Universe.

Led by the Department of Energy’s (DoE) Lawrence Berkeley National Laboratory, the LZ experiment is located at the Sanford Underground Research Facility in South Dakota, about 1,500 meters (nearly a mile) beneath the surface. The experiment relies on an ultra-sensitive detector made of 10 tonnes (11 U.S. tons) of liquid xenon to hunt for the elusive signals caused by WIMP-nucleus interactions. While direct detections are yet to be made, these latest results have helped scientists narrow the search.

As Levy explained in a recent UofA press release:

“Dark matter interacts very, very rarely with normal matter, but we don’t know exactly how rarely. The way we measure it is through this cross-section or how probable an interaction is within our detector. Depending on the mass of a dark matter particle, which we don’t know yet, an interaction within the detector is more or less probable. What the new LZ results tell us is that dark matter interacts with normal matter even more rarely than we thought, and the only instrument in the world that is sensitive enough to measure that is LZ.”

The existence and nature of Dark Matter are among the greatest mysteries in modern astrophysics. Originally proposed to explain the rotational curves of galaxies, the existence of Dark Matter is vital to the most widely accepted cosmological model – the Lambda Cold Dark Matter (LCDM) model. Unfortunately, according to the prevailing theories, DM only interacts with normal (aka. “luminous”) matter via gravity, the weakest of the four fundamental forces. Detecting these interactions requires incredibly sensitive instruments and an environment free of electromagnetic energy (including heat and light).

While no direct detections have been made, the latest results from LZ have narrowed the range of possibilities for one of the leading DM candidates. As Szydagis said:

“It’s often misunderstood what is meant by the phrase ‘world’s best dark matter experiment’ since no one has made a conclusive, unambiguous discovery yet. However, new, stricter null results like LZ’s are still extremely valuable for science. UAlbany, as one part of the multinational collaboration that is LZ, has been making important contributions ensuring the robustness of LZ’s results, going back to the very beginning of the experiment.”

Although DM remains “invisible” to us, the presence of its gravitational pull is fundamental to our understanding of the Universe. For example, the formation and movement of galaxies are attributed to DM, and its existence is vital for explaining the large-scale structure and evolution of the Universe. If DM does not exist, then our understanding of gravity – as described by Einstein’s Theory of General Relativity – is essentially wrong and needs revision. However, General Relativity has been experimentally validated again and again over the past century.

Therefore, narrowing the search for its constituent particle is vital to proving that our foundational theories about the Universe are correct. As Levy noted, UAlbany scientists have been making integral contributions to LZ for over a decade, and their work is far from done! “Working on LZ is always so exciting, even if we still have not made a discovery yet,” she said. “We all know that if it were easy, someone else would have done it already! I think right now what we need to take out of this result is that LZ is a great team of scientists, our detector is working superbly, our analysis is extremely robust, and we are nowhere near done taking data.”

Further Reading: University at Albany

The post Largest Dark Matter Detector is Narrowing Down Dark Matter Candidate appeared first on Universe Today.