Science

RNA is thought to have sparked the origin of life by self-copying. Researchers have now revealed the atomic structure of an 'RNA copy machine' through cryo-EM. This breakthrough sheds light on a primordial RNA world and fuels advancements in RNA nanotechnology and medicine.

Researchers have improved the efficiency of heat-to-electricity conversion in gallium arsenide semiconductor microstructures. By judicious spatial alignment of electrons within a two-dimensional electron gas system with multiple subbands, one can substantially enhance the power factor compared with previous iterations of analogous systems. This work is an important advance in modern thermoelectric technology and will benefit the global integration of the Internet of Things.

Researchers have improved the efficiency of heat-to-electricity conversion in gallium arsenide semiconductor microstructures. By judicious spatial alignment of electrons within a two-dimensional electron gas system with multiple subbands, one can substantially enhance the power factor compared with previous iterations of analogous systems. This work is an important advance in modern thermoelectric technology and will benefit the global integration of the Internet of Things.

Neuroscientists have investigated whether playing violent video games leads to a reduction in human empathy. To do this, they had adult test subjects play a violent video game repeatedly over the course of an experiment lasting several weeks. Before and after, their empathic responses to the pain of another person were measured. It was found that the violent video game had no discernible effect on empathy and underlying brain activity.

A new experiment could in principle test the quantumness of an object regardless of its mass or energy.

Traders could have earned a threefold return on their investments by analysing trends in cryptocurrency forums on Reddit

The salt we spread to keep roads safe in winter is damaging ecosystems and threatening water supplies. Do alternatives, from coffee grounds to cheese brine, work?

A healthy rhesus monkey has been born after being cloned from fetal cells, but creating a clone of an adult human being would be much harder

With sperm counts falling around the world, researchers are finally getting to grips with the underlying causes - and coming up with ways to reverse the trend

Sperm counts are down worldwide, but researchers are finally getting to grips with why - and coming up with ways to reverse the trend

From The Matrix to Sliding Doors via Everything Everywhere All at Once, physicist Paul Halpern reveals his favourite films about the multiverse

Soil samples from a long-running UK experiment show that microplastic pollution has risen sharply in the past 50 years and is much higher in fields treated with organic or inorganic fertilisers

Expedition leaders say they have found several new species of octopus using a remotely operated vehicle around 3 kilometres deep near Costa Rica

A couple of years ago I wrote a series of posts (see below) showing how anyone, with a little work, can verify the main facts about the Earth, Moon, Sun and planets. This kind of “Check-It-Yourself” astronomy isn’t necessary, of course, if you trust the scientists who write science textbooks. But it’s good to know you don’t have to trust them, because you can check it on your own, without special equipment.

The ability to “do it yourself” is what makes science, as a belief system, most robust than most other belief systems, past and present. It also explains why there aren’t widely used but competing scientific doctrines that fundamentally disagree about the basics of, say, the Sun and its planets. Although science, like religion, is captured in texts and teachings that have been around for generations, one doesn’t need to have faith in those books, at least when it comes to facts about how the world works nowadays. The books may be from the past, but most of what they describe can be independently verified now. In many cases, this can be done by ordinary people without special training, as long as they have some guidance as to how to do it. The purpose of the “Check-It-Yourself-Astronomy” series is to provide that guidance.

As I showed, nothing more than pre-university geometry, trigonometry, and algebra, along with some star-gazing and a distant friend or two, is required to

• confirm that the Earth’s a spinning (almost-)sphere,
• estimate the size of the Earth and Moon and the distance between them,
• show the Sun’s larger than the Earth and much further than the Moon, and that the stars are further still,
• verify the other planets orbit the Sun and estimate their relative distances from the Sun and their orbital times,
• infer a relation between these distances and times known as Kepler’s law, and show that a similar Kepler-type law works for objects orbiting the Earth,
• infer from these laws that the same gravity that makes ordinary objects fall does so by creating an inward acceleration, one that follows Newton’s inverse square law, holding certain objects in orbit around the Earth and others in orbit around the Sun
• confirm that the Earth orbits the Sun, by invoking Kepler’s law.
  • (Incidentally, this last statement is unambiguous, despite some claims to the contrary, even in Einstein’s theory of gravity.)

However this list is missing something important. From these methods, one can only obtain the ratios of planetary sizes to each other and to the Sun’s size, and the ratios of distances between planets and the Sun. Yet I did not explain how to measure the distance from the Earth to the Sun, or the distance from the Sun to any of the other planets, or the sizes of the other planets. It’s difficult to learn these things without sophisticated equipment and extremely precise measurements; the easiest things to measure about the planets and the Sun — their locations, motions and sizes — aren’t sufficient. (I’ll explain why they’re not sufficient in my next post.)

But shouldn’t there be a way around this problem?

Just One Good Measurement

It shouldn’t be that hard, should it? If we knew any one of these distances or sizes, we could figure out all the others.

For example, in earlier posts we saw how easily one can determine that the ratio of Jupiter’s distance from the Sun to Earth’s distance from the Sun is about 5. [In this paragraph, to keep the argument simple, I use very rough numbers.] Once we learn Earth is about 100 million miles [about 150 million km] from the Sun (which also allows us to compute the Sun’s size), we just multiply this number by 5 to get Jupiter’s distance, about 500 million miles [750 million km] from Earth. That means that Jupiter is about 400 million miles [600 million km] from Earth when the two planets are closest. Then, knowing from a simple backyard telescope that when Jupiter is closest to Earth, and thus 4 times the distance to the Sun, its apparent diameter on the sky is about 1/40 of the Sun’s diameter, we learn that Jupiter’s true diameter is about 4*(1/40) = 1/10 that of the Sun. The same methods can be applied to all the other planets as well as their moons.

The distance between Jupiter and the Sun is about 5 times that of the Earth and Sun, and so, when Jupiter, Earth and the Sun lie in a line, the Jupiter-Earth distance is about 4 times the Earth-Sun distance. This knowledge, combined with the apparent sizes of Jupiter and the Sun, can be used to infer the ratio of Jupiter’s size to that of the Sun. But not one of these sizes or distances is easy to measure. (Not to scale.)

However, finding any one of these distances or sizes is challenging for you and me. A simple geometric method used by Aristarchus in classical Greek times can be used by anyone to prove that that the Sun is at least a few million miles away and thus larger than the Earth. (This in turn tells us that Jupiter is far away and that its size is comparable to or larger than Earth.) But this method does not provide a crisp measurement. It can’t distinguish between the true answer of 100 million miles and a distance of several billion or even several trillion miles.

(Note: Later pre-telescope astronomers claimed a measurement that is only a factor of 2 below the true answer. However, it is not clear to me, from what I’ve read of the historical record, if they truly measured the distance or simply bounded it from below using Artistarchus’ approach, and got lucky that their bound is not far from the real answer. Part of the problem is that estimates of uncertainties are a modern invention; the Greek authors just state a value without any recognition that this value might be wildly off [especially on the high end] simply because of the method used. If any readers have additional insight into this, please let me know. In any case, I am currently unaware of any easy and accurate check-it-yourself method that ancient astronomers could have employed.)

In the 1600s and 1700s, the distances to other nearby planets were determined using difficult parallax measurements, in which a planet was observed carefully at two distant locations (or two different times) on Earth. Modern methods often involve firing a strong radar pulse at another planet, Mars or Venus typically; the pulse reflects off that distant planet, and the arrival time of the faint echo, times the known speed of light (also known as the cosmic speed limit, 186000 miles [300000 km] per second), equals twice Earth’s distance to the planet. As I emphasized above, it only takes one such measurement to fix the distances and sizes of all the distant, large objects in the solar system. Unfortunately, none of these techniques is easily reproduced without highly precise measurements and/or fancy equipment.

Nevertheless, it turns out that there are less well-known methods that, via an indirect route, can get us a good estimate of the distance to the Sun, in ways that don’t suffer from the problems of Artistarchus’ approach. This is what I will explain over the next few posts…

Captain, the immune system is boosted, and I donno what to do.Mr. Scott. Starship Enterprise. I think he said boosted. Might be one of those bacon/beer can examples. It is flu and cold season and there are no end of suggestions that one should boost their immune system. Two million hits on the googles for the phrase ‘Boost Immune System’. Everyone from […]

The post Boosting. What To Do. first appeared on Science-Based Medicine.

You think you know someone, then you see them in a slightly different way and BAM, they surprise you. I’m not talking about other people of course, I’m talking about a fabulous star that has been studied and imaged a gazillion times. Beta Pictoris has been revealed by many telescopes, even Hubble to be home to the most amazing disk. Enter James Webb Space Telescopd and WALLOP, with its increased sensitivty and instrumentation a new, exciting feature emerges. 

Beta Pictoris is the second brightest star in the southern constellation Pictor. It is a very young star, thought to be about 20 million years old and at a distance of just 63 light years, is in our cosmic backyard. Observations in 1984 revealed that Beta Pictoris had the most amazing dust disk out of which planets are forming. The European Southern Observatory has since confimred there are at least two planets (imaginitively called Beta Pictoris b and Beta Pictoris c) orbiting within the dust disk. 

Over the years, Beta Pictoris has been the target for many observations including those from the Hubble Space Telescope that revealed a second, previously unseen disk. The second disk is slightly inclined to the first but further observations from the James Webb Space Telescope (JWST) have revealed a new structure in this second disk. 

The team, led by Isabel Rebollido from the Astrobiology Center in Spain used the Near-Infrared Camera (NIRI) and the Mid-Infrared Instrument (MIRI) of the JWST to explore the disks of Beta Pictoris in more detail.  They were surprised to find a new structure at an angle to the secondary disk that was shaped like a cats tail. Despite the plethora of previous observations including those from the space busting HST, the instruments on JWST are more sensitive and have greater resolution. 

MIRI, ( Mid InfraRed Instrument ), flight instrument for the James Webb Space Telescope, JWST, during ambient temperature alignment testing in RAL Space’s clean rooms at STFC’s Rutherford Appleton Laboratory, 8th November 2010.

The “Cat’s Tail” was not the only surprise. When the MIRI data was studied, it revealed that the two disks were different temperatures revealing they were composed of different material. The secondary disk and Cat’s Tail were shown to be a higher temperature than the main disk. It’s also easy to deduce they are both made of dark material since they have not been previously observed in visible or near infra-red light but are bright under mid infra-red wavelengths. 

One of the theories to explain the higher temperature is that the material is highly porous, similar perhaps to the material found on comets and asteroids. The nature of the dust is one question that is perhaps easily addressed, something a little more challenging to answer is the nature and origin of the Cat’s Tail. 

The team explored a number of possible hypotheses that could explain the tail’s shape but failed to settle on a satisfactory model. One of their favoured theories is that the tail is the result of an event that occured within the disk around a hundred years ago! The event may have been a collision sending the dust into a trajectory that mirrors that of the impactor but then it starts to spread out to produce a curve. A contributory factor may simply be the angle of the tail from our vantage point causing the angle of the tail to seem steeper than it actualy is. 

One thing is for certain, the recent observations of Beta Pictoris have revealed some surprises of a very well loved and observed object. Further research will help us to gain a more fuller understanding of these new features but it leaves me wondering what other objects that we are familiar with still hold some surprises. 

Source : Webb discovers dusty cat’s tail in Beta Pictoris system

The post Webb Blocks the Star to See a Debris Disk Around Beta Pictoris appeared first on Universe Today.

Greater covid-19 vaccine uptake could have prevented several thousand deaths and hospitalisations in UK during a coronavirus wave in 2022

About 164 light-years away, a Hot Jupiter orbits its star so closely that it takes fewer than four days to complete an orbit. The planet is named WASP-69b, and it’s losing mass into space, stripped away by the star’s powerful energy. The planet’s lost atmosphere forms a trail that extends about 560,000 km (350,000 miles) into space.

Scientists know that stars can strip mass from planets that get too close. It’s called mass loss, and it’s driven by extreme UV (EUV) and/or X-ray energy from a star and by the stellar wind. It’s not a rare phenomenon, even though researchers don’t fully understand it.

But seeing the actual stream of gas coming from the planet is a rare opportunity to study mass loss.

Researchers have known about WASP-69b’s predicament and have predicted how much of the planet’s atmosphere is being stripped away. Previous research even identified a very small, subtle tail. But new research shows that the tail, which would stretch from Earth to well beyond the Moon in our Solar System, is much longer than previously thought.

The new research is titled “WASP-69b’s Escaping Envelope Is Confined to a Tail Extending at Least 7 Rp.” It’s published in The Astrophysical Journal. The first author is Dakotah Tyler, a doctoral student in the Department of Physics and Astronomy at UCLA.

“Work by previous groups showed that this planet was losing some of its atmosphere and suggested a subtle tail or perhaps none at all,” said first author Tyler. “However, we have now definitively detected this tail and shown it to be at least seven times longer than the planet itself.”

As we began to detect more and more exoplanets with NASA’s Kepler mission, followed by the TESS mission, something became apparent. There are gaps in the exoplanet population. The Neptunian Desert refers to the dearth of Neptune-sized planets on two to four-day orbits around their stars. The Small Planet Radius Gap refers to a dearth of exoplanets with radii between 1.5 and 2 times Earth’s radius. Scientists think that mass loss plays a role in both phenomena, and it’s unlikely that there’s a lack of exoplanets that form in the Gap and the Desert.

But the details of atmospheric loss are not well understood. WASP-69b and its extended tail of stripped gas give astronomers a rare opportunity to study it more closely.

“Studying the escaping atmospheres of highly irradiated exoplanets is critical for understanding the physical mechanisms that shape the demographics of close-in planets,” the authors write in their paper.

Previous researchers found the tail, so Tyler and his co-authors knew where to look. But Tyler and the other researchers used a much larger telescope for their observations. They used the 10-meter telescope at the Keck Observatory and its high-resolution spectrograph, NIRSPEC. They found that the stream, which is primarily hydrogen and helium, is much longer than thought.

This figure from the research illustrates some of the findings. In the left panel, T1 through 4 represent observation times with Keck. The orange circle is the star, and the black circle is WASP-69b. The right panel shows what the system would look like from the top down. Image Credit: Tyler et al. 2023.

“Over the last decade, we have learned that the majority of stars host a planet that orbits them closer than Mercury orbits our sun and that the erosion of their atmospheres plays a key role in explaining the types of planets we see today,” said co-author and UCLA professor of physics and astronomy Erik Petigura. “However, for most known exoplanets, we suspect that the period of atmospheric loss concluded long ago. The WASP-69b system is a gem because we have a rare opportunity to study atmospheric mass-loss in real-time and understand the critical physics that shape thousands of other planets.”

There are two different forces at work here. Radiation from the star and the stellar wind. Both forces work together to strip away WASP-69b’s and then shepherd it away. The tail is a direct result of how both of those forces work together.

“These comet-like tails are really valuable because they form when the escaping atmosphere of the planet rams into the stellar wind, which causes the gas to be swept back,” Petigura said. “Observing such an extended tail allows us to study these interactions in great detail.”

Neutral hydrogen is really hard to see, so the researchers measured the Helium in the tail and used it to estimate the overall mass loss from the planet. One of the reasons that previous research found a smaller tail is because the telescope they used is smaller. Larger telescopes gather more photons from whatever they’re observing. The figure below compares the current research, done with a larger telescope, with the previous observations. Both show helium light curves.

This figure from the research shows two nights of observations from CARMENES with four observations from the much larger Keck and its NIRSPEC instrument. Notice that the point-to-point scatter for CARMENES is much larger than with NIRSPEC, which has a higher signal-to-noise ratio. NIRSPEC’s better performance allowed the researchers to measure the helium more accurately. Image Credit: Dakotah et al. 2024

The researchers say that the star is losing about one Earth mass of material every 100 million years. But WASP-69b is a massive gas giant of about 0.29 Jupiter’s mass. This means that it would take an awfully long time to be reduced to nothing.

But it’ll never be reduced to nothing, according to the authors.

“At around 90 times the mass of Earth, WASP-69b has such a large reservoir of material that even losing this enormous amount of mass won’t affect it much over the course of its life. It’s in no danger of losing its entire atmosphere within the star’s lifetime,” Tyler said.

Exoplanets may also stabilize once they’ve been reduced to a specific mass. Some research shows that exoplanets with atmospheres that are double the radius of their core are the most stable and resist atmospheric loss. If the atmosphere is larger than this, then the planet is susceptible to atmospheric erosion and will eventually reach the more stable state outlined above. For planets with smaller atmospheres than this, runaway atmospheric loss is likely.

This figure is from separate research published in 2017. It shows the erosion of atmospheres as a function of time for planet models with a range of initial envelopes. Low-mass envelopes are stripped clean, while higher-mass ones are herded toward a stable state. Image Credit: Owen and Wu, 2017.

This new research is based on fairly brief observations. The authors point out that there’s likely more variability in the system that changes the mass loss rate over time. Understanding the variability is critical to understanding the mass loss in more detail.

“Repeat observations are valuable to probe any variability in the outflow properties, especially with different instruments,” they conclude.

The post A Hot Jupiter With a Comet-Like Tail appeared first on Universe Today.

The day when human beings finally set foot on Mars is rapidly approaching. Right now, NASA, the China National Space Agency (CNSA), and SpaceX have all announced plans to send astronauts to the Red Planet “by 2040”, “in 2033”, and “before 2030”, respectively. These missions will lead to the creation of long-term habitats that will enable return missions and scientific research that will investigate everything from the geological evolution of Mars to the possible existence of past (or even present) life. The opportunities this will create are mirrored only by the challenges they will entail.

One of the greatest challenges is ensuring that crews have access to water, which means that any habitats must be established near an underground source. Similarly, scientists anticipate that if there is still life on Mars today, it will likely exist in “briny patches” beneath the surface. A possible solution is to incorporate a system for large-scale water mining operations on Mars that could screen for lifeforms. The proposal, known as an Agnostic Life Finding (ALF) system, was one of thirteen concepts selected by NASA’s Innovative Advanced Concept (NIAC) program this year for Phase I development.

The concept was proposed by Steven Benner and a team from the Foundation for Applied Molecular Evolution (FfAME) in Alachua, Florida. Benner is a former professor of chemistry at Harvard University, ETH Zurich, and the University of Florida, where he was the V.T. & Louise Jackson Distinguished Professor of Chemistry. In 2005, he founded the Foundation For Applied Molecular Evolution, where he and his colleagues became the first scientists to synthesize a gene, thus giving birth to the field of synthetic biology.

As Benner and his team explained in their proposal, the ALF system is designed to simplify astrobiological studies on Mars before any crewed missions arrive. Its purpose is also to address several foregone conclusions raised at NASA’s 2019 Conference (Extant Life on Mars: What’s Next?) held in Carlsbad, New Mexico. During this conference, it was generally agreed that scientists have good reason to suspect the following about life on Mars:

• Life started on Mars using the same geo-organic chemistry that started life on Earth.
• Martian life persists today on Mars, in near-surface ice, low elevations, and caves, all with transient liquid brines, environments that today on Earth host microbial life.
• Martian life must use informational polymers (like DNA); Darwinian evolution requires these, and Darwinian evolution is the only way matter can organize to give life.
• While Martian “DNA” may differ (possibly radically) in its chemistry from Terran DNA, the “Polyelectrolyte Theory of the Gene” limits the universe of possible alien DNA structures.
• Those structures ensure that Martian DNA can be concentrated from Martian water, even if very highly diluted, and even if Martian “DNA” differs from Earth DNA.
• On Mars, as it exists today, information polymers cannot be generated without life (unlike other less reliable biosignatures such as methane), ensuring that life will not be “detected” if it is not present (the “false positive problem”).

Citing a previous study by SETI Institute senior scientist John D. Rummel and NASA Planetary Protection Officer (PPO) Catherine A. Conley, Benner and his team note that there are several fallacies when it comes to proposed efforts to search for extant evidence of Martian life. Addressing the planetary protection policy of the Committee on Space Research (COSPAR), Rummel and Conley concluded that there are four significant “shortcomings in their plans to look for evidence of life on Mars.” First, they addressed the contention that appropriate levels of spacecraft cleanliness are unaffordable.

Second, they challenged claims that there are major risks in assuming life could be identified through nucleic acid sequence comparison, especially if those sequences are obtained from a “Special Region” contaminated with Earth life. They also challenge the contention that present-day exploration by “dirty robots” is preferable to the possibility of contamination spread by future human exploration and that the potential effects of contaminating resources and environments essential to future human missions to Mars were not being addressed. Based on these considerations, Rummel and Conley concluded that scientists did not consider the detection of extant life on Mars “a high priority.”

Graphic depiction of the Agnostic Life System (ALF) to screen for introduced and alien life. Credit: Steven Benner

According to Benner and his colleagues, the purpose of this NIAC project is to change this view before the arrival of crewed missions, which will undoubtedly complicate the search for indigenous Martian life. Therefore, the plans for crewed missions in the coming decades place a very strict deadline on the search or life on Mars, but also offer an opportunity that can be exploited. In particular, Benner and his team indicate how mission proposals emphasize the need for in-situ resource utilization (ISRU), especially where near-surface water ice is concerned. As they wrote:

“Propellant (methane and oxygen) will be generated from that water and atmospheric carbon dioxide for the return trip back to Earth. That water ice will be mined on the scale of tens to hundreds of tons. Further, to maximize the likelihood of safe return of the crew to Earth, robotic operations that mine tons of near-surface water ice will be in place before the first human astronauts arrive. Thus, water mined in preparation for human arrival is correctly seen as an extremely large-scale astrobiological sample, far larger than dry cached rocks.”

The mined water ice, they claim, will contain dust deposited over time by Martian dust storms, allowing scientists to obtain information about the accessible surface of Mars. Therefore, the massive sample of water ice will enable a highly sensitive survey of the Martian surface for potential signs of life. The ALF system will allow for the extraction of genetic polymers – be they alien or the result of contamination from robotic missions. The ALF system also offers tools to conduct partial in-situ analysis of any polymers that dissociate in water (polyelectrolytes).

According to Benner, the system is called “agnostic” because of how it “exploits what synthetic biology taught us about the limited kinds of Darwinian genetic molecules.” Since it is an add-on system, including an ALF system represents a negligible burden in terms of mass and energy to any existing mining operation. Despite that, it will allow for science operations that will establish a strict lower limit on the amount of biomaterial that is accessible on the Martian surface and will do so before a human presence is established on Mars.

As Benner and his team summarized, the system will also be useful on other bodies humanity hopes to explore for signs of life (and possibly settle) someday. “[I]t will do so before Homo sapiens becomes a multiplanetary species. And “multiplanetary” is the correct term,” they wrote. “This add-on ALF system can be used on all celestial bodies where water will be mined to search for and analyze life, indigenous or introduced, Earth-like or alien. This includes Europa, Enceladus, the Moon, and exotic locales on Earth.”

Further Reading: NASA

The post NASA Selects New Technology to Help Search for Life on Mars appeared first on Universe Today.

The latest coronavirus variant, JN.1, is more infectious, but seems to be causing less severe illness than in previous waves