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A dog's mouth is likely less 'dirty' than a meth mouth.

The post Licking first appeared on Science-Based Medicine.

An analysis of daily carbon dioxide emissions since 1970 has revealed increasingly large spikes that appear to be caused by growing energy use during extreme weather events

If I were to summarize how and why I do what I do, I might put it this way.

Meanwhile, in Dobrzyn, Hili is having trouble being a clairvoyant:

Hili: I do not see the future.
A: It’s not visible from here.

Hili: Nie widzę przyszłości.
Ja: Stąd jej nie widać.

How common are Earth-like exoplanets—also called exo-Earths—and which exoplanetary systems should we target to find them? This is what a recently submitted study hopes to address as a team of researchers investigated potential targets for the planned Habitable Worlds Observatory (HWO), which was recommended during the Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020) and is slated to launch in the 2040s. Most notably, HWO will use the direct imaging method to identify exo-Earths, and this study holds the potential to create a more scientifically cost-effective approach for identifying and studying exoplanets.

Here, Universe Today discusses this incredible research with Dr. Stephen Kane, who is a Professor of Planetary Astrophysics at UC Riverside and lead author of the study, regarding the motivation behind the study, significant results, potential system candidates for identifying exo-Earths, the significance of using the direct imaging method, and how this research could influence the 2030 decadal survey. Therefore, what was the motivation behind the study?

“The Habitable Worlds Observatory (HWO) is a direct imaging mission that was the top-ranked priority from the last Astrophysics decadal survey,” Dr. Kane tells Universe Today. “Part of the current effort is to select the most suitable stars that will be the target of HWO observations. There is presently a list of 164 stars on the HWO target list that the community is working with. Since some of the HWO targets are known to already have planets, I conducted a dynamical analysis of those systems to determine if a terrestrial planet in the Habitable Zone (HZ) could maintain a stable orbit.”

Out of those 164 stars in the study, 30 host a total of 70 known planets: 11 systems with 1 planet, 7 systems with 2 planets, 6 systems with 3 planets, 4 systems with 4 planets, 1 system with 5 planets, and 1 system with 6 planets. The system with 5 planets is HD 75732, more commonly known as 55 Cancri, and is located approximately 41 light-years from Earth. The five planets range in size between 8 Earth masses (planet e) and approximately 3 Jupiter masses (planet d), with the orbit of planet f at least partially traversing the HZ throughout its approximate 260-day orbit. The system with 6 planets is HD 219134, also called Gliese 892, and is located approximately 21 light-years from Earth. The six planets range in size between approximately 4.37 Earth masses (planet c) to more than 98 Earth masses (planet h), with the orbit of planet g hypothesized to partially traverse the HZ during its orbit based on a 2015 study and 2021 study.

For the study, the researchers used a series of computer models to calculate the plausible size of each star’s habitable zone, referred to as a dynamically viable habitable zone (DVHZ). The team then inserted a terrestrial planet into the habitable zone to ascertain if it could maintain a stable orbit for the 10,000,000-year duration of the computer model based on the current planetary population in each system, also known as system architecture. Therefore, what were the most significant results from the study and what follow-up studies are in the works?

“We investigated 30 stars on the HWO target list and found that 11 of those have a HZ that is severely impacted by the presence of a giant planet in the system,” Dr. Kane tells Universe Today. “This shows that there needs to be a much more thorough analysis of the remaining HWO target stars to determine if they might have similar dynamical problems. We are already planning a detailed radial velocity study of those stars to search for additional planets.”

Regarding which exoplanetary systems are the most promising candidates for identifying exo-Earths, Dr. Kane tells Universe Today, “Actually, what we do in our study is identify the LEAST promising targets by ruling out the presence of Earth mass planets in the HZ of those systems. Amongst those systems is the bright star pi Mensae, which hosts a giant planet whose orbit sends it regularly crashing through the HZ, ensuring that no habitable planets can exist there.”

Identifying and studying exoplanets is conducted through a variety of detection methods, including transit, radial velocity, gravitational microlensing, timing, and direct imaging. For the transit method, astronomers collect data on the dip in starlight that occurs when an exoplanet passes in front of it. For the radial velocity method, astronomers detect tiny wobbles that a star exhibits as it tugs on an exoplanet orbiting it. For the gravitational microlensing method, astronomers use a star’s gravitational field as a lens when it is almost exactly alignment with a distant star, magnifying the distant star within the front star’s gravitational field. When this happens, the gravitational field of a present exoplanet in the front star influences the front star’s gravitational field.

For the timing method, also called the transit-timing variation method, astronomers used data from an exoplanet that was detected using the transit method to try and find other planets within the system by detecting changes in the timing of the first planet caused by another planet. For the direct imaging method, astronomers used a coronagraph to block the brightness of a star, revealing exoplanets that would have otherwise been lost in the star’s glare.

Of the 5,743 exoplanets confirmed by NASA, 74.5 percent are from the transit method, 19 percent are from the radial velocity method, 3.9 percent are from microlensing, 1.4 percent are from the direct imaging method, 0.52 percent are from the transit-timing variation method, with the remaining from other methods, including eclipse timing variations, orbital brightness modulation, pulsar timing, astrometry, pulsating timing variations, and disk kinematics. With the planned Habitable Worlds Observatory, astronomers plan to use the direct imaging method, despite it achieving one of the lowest numbers of detected exoplanets. Therefore, why was the direct imaging method chosen for the HWO mission, and is the direct imaging the most viable method for identifying exo-Earths? If not, what method(s) would work best?

“We currently primarily use indirect methods to detect and characterize exoplanets,” Dr. Kane tells Universe Today. “Though these methods can be used to infer planetary properties such as mass, radius, and some atmospheric composition, this can only be achieved for a very limited number of planets. Direct imaging provides much more additional information, such as detailed atmospheric composition, and may even be used to infer surface topography and rotation rate.”

As noted, HWO was recommended during the Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020), the latter of which is sponsored by the National Research Council of the National Academy of Sciences and is a report conducted approximately every 10 years to ascertain the current state of the field of astronomy and astrophysics and the direction of research for the following 10 years. Along with pursuing further research on black holes, neutron stars, and galaxy evolution, Astro2020 also emphasized the search for habitable exoplanets and extraterrestrial life, and HWO was born from previous proposed missions known as the Habitable Exoplanet Observatory (HabEx) and Large Ultraviolet Optical Infrared Surveyor (LUVOIR). Therefore, with HWO being recommended by the 2020 decadal survey, how could the results from this study influence HWO being discussed in the 2030 decadal survey?

“Our results refine the HWO target list and so strengthen the science output of the mission,” Dr. Kane tells Universe Today. “The elimination of nearby bright targets may mean that HWO will need to shift to fainter, farther targets which, in turn, may require a larger telescope to achieve the same goals. HWO is an exciting mission and will provide incredible insights into the prevalence of habitable planets. As we learn more about the nearest planetary systems, we will greatly increase the odds of the success for HWO.”

How will HWO help discover Earth-like exoplanets in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Earth-like exoplanets might be in short supply for the Habitable Worlds Observatory appeared first on Universe Today.

Scientists have developed a model capable of predicting the cycle lives of high-energy-density lithium-metal batteries by applying machine learning methods to battery performance data. The model proved able to accurately estimate batteries' longevity by analyzing their charge, discharge and voltage relaxation process data without relying on any assumption about specific battery degradation mechanisms. The technique is expected to be useful in improving the safety and reliability of devices powered by lithium-metal batteries.

Finding the next groundbreaking polymer is always a challenge, but now researchers are using artificial intelligence (AI) to shape and transform the future of the field.

Finding the next groundbreaking polymer is always a challenge, but now researchers are using artificial intelligence (AI) to shape and transform the future of the field.

After over a year of record-high global sea temperatures, the equatorial Atlantic is cooling off more quickly than ever recorded, which could impact weather around the world

After over a year of record-high global sea temperatures, the Atlantic is cooling off more quickly than ever recorded, which could impact weather around the world

Artificial intelligence (AI) has exploded in popularity as of late. But just like a human, it's hard to read an AI model's mind. Explainable AI (XAI) could help us do just that by providing justification for a model's decisions. And now, researchers are using XAI to scrutinize predictive AI models more closely, which could help make better antibiotics.

Some of the attractive hues of brightly colored, cloth-bound books from the Victorian era come from dyes that could pose a health risk to readers, collectors or librarians. The latest research on these 'poison books' used three techniques -- including one that hasn't previously been applied to books -- to assess dangerous dyes in a university collection and found some volumes had levels that might be unsafe.

Children born with certain heart defects undergo a series of invasive surgeries early in life. The first surgery includes implantation of a shunt to improve blood flow. However, as children grow, the shunt must be replaced to accommodate their changing bodies. Now, researchers report designing a shunt that expands when activated by light. This device could reduce the number of open-chest surgeries these children receive.

When a global pandemic forced previous a graduate student out of the lab and onto the computer, he found a world of difference hidden in the long-studied species of Botryoccocus braunii -- and discovered that it isn't one species at all, but three.

According to NASA’s Perseverance rover, ancient rocks in Jezero Crater formed in the presence of water. These sedimentary rocks are more than 3.5 billion years old and may predate the appearance of life on Earth. When and if these samples are returned to Earth, scientists hope to determine if they hold evidence of ancient Martian life.

In 2022, the Perseverance Rover worked its way along Jezero Crater’s western slope and sampled rocks from a feature called the ‘fan front.’ Scientists hypothesized that some of the rocks in this region were formed in the ancient lakebed when the crater was filled with water. Perseverance analyzed the rocks’ chemistry and captured images of their surroundings. Members of the Perseverance science team studied this data and have published their results.

“These rocks confirm the presence, at least temporarily, of habitable environments on Mars.”

Professor Tanja Bosak, MIT

Their work is titled “Astrobiological Potential of Rocks Acquired by the Perseverance Rover at a Sedimentary Fan Front in Jezero Crater, Mars.” It’s published in the journal AGU Advances, and the lead author is Tanja Bosak, professor of geobiology in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

“These rocks confirm the presence, at least temporarily, of habitable environments on Mars,” said lead author Bosak. “What we’ve found is that indeed there was a lot of water activity. For how long, we don’t know, but certainly for long enough to create these big sedimentary deposits.”

Perseverance collected seven samples from the fan front. Each of the samples is of a sedimentary rock, and some of them may predate life on Earth. “The samples include a sulphate- and clay-bearing mudstone and sandstone, a fluvial sandstone from a stratigraphically low position at the fan front, and a carbonate-bearing sandstone deposited above the sulphate-bearing strata,” the authors explain.

Sulphates and clays typically form in the presence of water, and so do carbonates. Depending on the types of sulphates, it reveals clues about the ancient water’s chemistry, temperature, and acidity. Carbonates are similar and can also reveal things about Mars’ atmosphere when they formed, like how much carbon dioxide it contained.

“The hydrated, sulphate-bearing mudstone has the highest potential to preserve organic matter and biosignatures, whereas the carbonate-bearing sandstones can be used to constrain when and for how long Jezero crater contained liquid water,” the authors explain.

While the samples were placed in sealed tubes for eventual return to Earth, Perseverance also abraded the rock next to each sample location, allowing the rover to analyze the mineral content of the rocks.

This image from the research article shows the rock cores acquired during the Fan Front Campaign. CacheCam images of the cores in their container tubes are on the left. Red symbols on the High-Resolution Imaging Experiment (HiRISE) map on the right show the locations of the sampled outcrops and the corresponding cores. Image Credit: Bosak et al. 2024

Mars rovers have found other rocks that were deposited by water, but none this old. These ancient Martian rocks are the oldest sedimentary rocks ever studied, and they likely formed when the Jezero Crater was a habitable lake. Because they’re sedimentary rocks, they could hold ancient organic matter. But that determination will have to wait until they make it safely to labs on Earth.

“These are the oldest rocks that may have been deposited by water, that we’ve ever laid hands or rover arms on,” said co-author Benjamin Weiss, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. “That’s exciting, because it means these are the most promising rocks that may have preserved fossils, and signatures of life.”

(A) gives the local context for the Amalik outcrop, where two samples were taken. (B) shows the workspace after sampling and abrasion. The white arrow on the left shows where the Mageik sample was taken. The center arrow shows how the rock was fractured when the Shuyak core was sampled. The arrow on the right shows the Novarupta abrasion. (C) is a close-up of the abrasion patch. Image Credit: Bosak et al. 2024.

Most sedimentary rock has two components: grains, which are like the building blocks for sedimentary rock, and cement, which are mineral deposits that come along later and bind the grains together. Over time, pressure forces cement into the rock pores, filling them and creating solid rock in a process called lithification. The researchers think that both the grains and the cement in the fan front sedimentary rocks likely formed in aqueous environments. During lithification, organic matter from ancient life could’ve been trapped in the rock.

The fan front is a prime place to search for evidence of ancient life. “We found lots of minerals like carbonates, which are what make reefs on Earth,” Bosak says. “And it’s really an ideal material that can preserve fossils of microbial life.”

Though sulphates form in the presence of water, the water tends to be very salty, which isn’t necessarily great for life. But it could work out for the best because of salt’s preservative effect. If the brine was restricted to the lake bottom, life could’ve persisted in the upper portions of the ancient lake. When lifeforms died, they could’ve sunk to the bottom. In this case, the brine would’ve acted to preserve signs of ancient life.

“However salty it was, if there were any organics present, it’s like pickling something in salt,” Bosak says. “If there was life that fell into the salty layer, it would be very well-preserved.”

NASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rocks in the face of a cliff in the delta, as well as one of the locations where the rover abraded a circular patch to analyze a rock’s composition. Image Credit: NASA/JPL-Caltech/ASU/MSSS

It’s fairly well-established that Mars was once warm and wet. The next question is, did life ever exist there? To answer that, we need to find organic matter. But even that can be tricky since some organic matter can be produced geologically without life. The Curiosity Rover found organic carbon in Gale Crater, but scientists showed that UV fractionation is responsible.

Previously, Perseverance also found evidence of organic matter on the floor of Jezero Crater. Subsequent analysis showed that it could be matter that had no connection to life. This is a cautious reminder of the rovers’ limitations. Though they’re powerful, and it’s an amazing feat to have them roam around on another planet studying rocks, they can’t do the same science that’s possible in labs here on Earth.

That’s why the Mars Sample Return is so critical. Only by finally bringing pieces of Mars back to Earth can we fully understand the evidence that Perseverance is collecting.

“On Earth, once we have microscopes with nanometer-scale resolution, and various types of instruments that we cannot staff on one rover, then we can actually attempt to look for life,” Bosak says.

The post Ancient Rocks in Mars’ Jezero Crater Confirm Habitability appeared first on Universe Today.

Black holes are notoriously destructive to stars near them. Astronomers often see flashes representing the death throes of stars collapsing past the event horizon, a black hole they got too close to. However, in rare instances, a star isn’t wholly swallowed by its gigantic neighbor and is pulled into an orbit, causing a much slower death, which would probably be more painful if stars could feel anything. A new study using X-ray results from Chandra and some other instruments details a supermassive black hole at the center of a galaxy far, far away that is slowly devouring a star it has captured in an orbit, and it could teach them more about a variety of interest physical processes. 

The new paper is the latest in a series that goes back a few years. It started with the discovery of AT2018fyk, a “tidal disruption event” (TDE), back in 2018. A TDE is what astronomers see when a star is devoured by a black hole. AT2018fyk was originally captured by NASA’s Neutron star Interior Composition Explorer (NICER). Follow-up observations were completed by Chandra and XMM-Newton, ESA’s X-ray telescope. 

In a typical scenario, that would have been the end of the story – the star got eaten, emitted some exceptionally strong X and UV rays, and we captured them using our instrumentation 860 million light years away. However, astronomers noticed another spike in X-ray and UV emissions coming from the same black hole about two years later. 

Fraser discusses the world’s first direct image of black hole and why it’s important.

That second luminosity spike was likely caused by the star being partially devoured again as it was captured in a highly elliptical orbit around the black hole. Once every few years, it approaches closely enough that more of its material is ripped away, causing another TDE. But this time, scientists were ready and devised a hypothesis for when the TDE would end.

Their calculations pointed to August 2023, so they asked for observational time on Chandra. Sure enough, on August 14th, 2023, they saw a significant dimming of the emissions from the black hole. Either the star finally succumbed completely and was torn apart, or it made it out alive again and will continue its eccentric dance around its much bigger neighbor.

Either way, it definitely loses mass each time, as the second event is less luminous than the first. By that logic, the next one should be even less luminous if there is even a third event.

Video describing the new research around the black hole “snacking”.
Credit – Chandra X-ray Observatory YouTube Channel

The star at the heart of AT2018fyk might not have been alone originally. The researchers predicted that it was part of a binary star system, but its partner star was ejected once the pair were caught up in the gravitational well of the black hole. It is now traveling much faster away from that black hole and might have enough momentum to leave its galaxy entirely. 

Its partner was not so lucky. It remains to be seen if the star has enough material left for a third round of luminous burnoff. The system’s physical characteristics predict that the subsequent increase in brightness will happen between May and August of 2025 and would last for approximately two years, much longer than previous changes. Given the interest this system has now piqued and its ability to test theories about rare events like TDEs, the research team will likely be able to find some more observational time next year to check for the potential third snack of this exciting black hole.

Learn More:
Chandra – NASA Telescopes Work Out Black Hole’s Snack Schedule
Pasham et al. – A Potential Second Shutoff from AT2018fyk: An updated Orbital Ephemeris of the Surviving Star under the Repeating Partial Tidal Disruption Event Paradigm
UT – A Black Hole Consumed a Star and Released the Light of a Trillion Suns
UT – Supermassive Black Holes Grew by Consuming Gas and Entire Stars

Lead Image:
Artist’s depiction of a black hole pulling apart a star.
Credit – NASA/CXC

The post We Know When a Black Hole Will Have its Next Feast appeared first on Universe Today.

Detecting diseases early requires the rapid, continuous and convenient monitoring of vital biomarkers. Researchers have now developed a novel sensor that enables the continuous, and real-time detection of solid-state epidermal biomarkers, a new category of health indicators. The team's wearable, stretchable, hydrogel-based sensor overcomes the limitations of current methods that rely on biofluid samples, such as blood, urine and sweat. This makes it a promising alternative for wearable, continuous, and real-time health monitoring, facilitating the early detection of conditions such as cardiovascular diseases and stroke.

The design of streets and layout of buildings have an impact on a city's resilience in the face of increasingly severe floods brought on by climate change. Researchers look at buildings and other urban structures as physicists consider elements in complex material systems. With this insight, the researchers have developed a new approach to urban flood modelling and found their results helpful in analyzing city-to-city variations in flood risk globally.

Swiping through online videos to relieve boredom may actually make people more bored and less satisfied or engaged with the content, according to new research.

A new study found that using ChatGPT-4 to read medical notes from Emergency Department admissions to determine whether injured scooter and bicycle riders were wearing a helmet finds that AI can't yet do this reliably.