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One of my favorite paintings is Starry Night by Vincent van Gogh — for obvious astronomical reasons. But another favorite of van Gogh’s works is Lane of Poplars at Sunset. This painting depicts the setting Sun perfectly aligned with a long lane of trees, casting long shadows.

The geometry of the Earth and Sun means that this scene had to be painted on one specific day of the year when the alignment would be possible. An astronomer has now used 19th-century maps to discover where the lane was, and then used astronomical calculations to determine which date the Sun would be in the exact position as the painting. His result? The painting depicts a stretch of road known as Weverstraat in the Dutch town of Nuenen, on November 13 or 14, 1884.

Professor Donald Olson is an astronomer and physics professor emeritus at Texas State University (TSU). He is no stranger to studying van Gogh paintings, as in the past he has uncovered clues to help date three other of the noted painter’s works: Moonrise (July 13, 1889), Road with Cypress and Star (May 1890) and White House at Night (June 1890).

Van Gogh produced more than 2,000 paintings, drawings, and sketches in his lifetime, and many include scenery from The Netherlands, the Dutch master’s home. Olson was originally inspired to determine the date of Lane of Poplars at Sunset because the scene shows something similar to what happens twice a year for New York City’s “Manhattanhenge,” where the setting sun aligns with Manhattan’s east–west streets on dates near May 29 and July 12.  

Manhattanhenge from 42nd Street shot at 8:23 p.m. on July 13, 2006, the building on the right is the Chrysler Building. Photo by Roger Rowlett, via Wikipedia.

The first thing Olson wanted to figure out was where the lane might be.

“If we could identify the lane on 19th-century maps, then we’d be able to establish the compass direction of the road appearing in the artworks,” Olson explained in a news release from TSU. “Next, we could use astronomical calculations to determine the date when the disk of the setting sun aligned as van Gogh portrayed it.”

Olson called in assistance from Louis Verbraak and Ferry Zijp, members of the Eindhoven Weather and Astronomy Club in the Netherlands. After an exhaustive search of maps and correlating historic and recent imagery, the team narrowed it down to three possible streets. Further investigations led them to determine that Weverstraat in Nuenen must be the street, as it contained a long straightaway of 1,200 feet, or 365 meters, more than long enough for the scene painted by van Gogh.

As for determining the date, Olson and team relied on historical information. All of van Gogh’s paintings assigned catalog numbers, in order by dates determined by art historians. Lane of Poplars at Sunset is assigned as F123. The previous painting in the catalog, F122, is called Lane of Poplars in the Autumn, which shows the same scenes with vivid fall colors, while the leaves are almost completely gone from the trees in the sunset depiction. That means the painting had to be done in late fall.

The painting “Line of Poplars in Autumn” by Vincent van Gogh (F122, Nueun 1884).

Art historians have also long depended on van Gogh’s many letters to his brother Theo to help date most of the artist’s work. A total of three letters, written by Vincent during late October and early November of 1884, describe the lovely autumn weather he was experiencing. One letter, dated on or about Oct. 25, 1884, includes a description that matches Lane of Poplars in the Autumn:

“The last thing that I made is a rather large study of a lane of poplars with the yellow autumn leaves, where the Sun makes glittering patches here and there on the fallen leaves on the ground, alternating with the long shadows cast by the trunks. At the end of the road is a peasant cottage, and above it the blue sky between the autumn leaves.”

“White House at Night” by Vincent van Gogh. (F766 Auvers-sur-Oise, 1990).

A subsequent letter dated on or about Nov. 14, 1884, van Gogh indicated that freezing weather forced him to abandon painting outdoors for the rest of the season. Additional letters helped establish a time frame between Nov. 5-Nov. 14 for van Gogh to have painted Lane of Poplars at Sunset. Within this range of dates, planetarium software shows that the sun set in the southwest, in the range of azimuths, or compass direction of a celestial object, between 240° and 244°.

Then using astronomical calculations, Olson and team determined the setting sun would’ve been visible setting over Weverstraat on Nov. 13 or 14, 1884. Historical weather records indicate these dates fall within a five-day span where the area experienced unseasonably clear weather.

Olson said that because van Gogh rarely painted from memory and preferred to have his subject in front of him, Nov. 13 or 14, 1884, are the only possible dates for the creation of Lane of Poplars at Sunset.

“Today, we can still gaze down the same stretch of road where van Gogh walked on a chilly autumn afternoon and ponder how the artist, in his native Netherlands, was already interested in portraying sky phenomena, four years before he began to create his famous starry nights in the south of France,” Olson said.

Read more details about the search at TSU.

The post Astronomer Calculates When van Gogh Painted This appeared first on Universe Today.

The organization scapegoated by the lab leak-promoting GOP-led House Covid subcommittee publishes its defense

The post EcoHealth Alliance Fights Back first appeared on Science-Based Medicine.

The infinite monkey theorem states that illiterate primates could write great literature with enough time, but the amount of time needed is much longer than the lifespan of the universe

Meanwhile, in Dobrzyn, Hili is doing an experiment:

A: What are you doing?
Hili: I’m testing the efficacy of prayer for a rabbit pâté.

Ja: Co ty robisz?
Hili: Testuję skuteczność modlitwy o pasztet z krolika.

The US Census Bureau processes data before publishing it in order to keep personal information private – but a new approach could maintain the same privacy while improving accuracy

In the summer of ’69, Apollo 11 delivered humans to the surface of the Moon for the first time. Neil Armstrong and Buzz Aldrin spent just over two hours exploring the area near their landing site on foot. Only during Apollo 15, 16, and 17 did astronauts have a vehicle to move around in.

Artemis astronauts on the Moon will have access to a vehicle right away, and NASA is starting to test a prototype.

Momentum is building behind NASA’s Artemis program despite some setbacks. Artemis astronauts will explore the Moon far more thoroughly than the Apollo astronauts did, and technology is behind the improvement. Surface mobility is a key piece of Artemis. In April of 2024, NASA selected three vendors as part of their Lunar Terrain Vehicle Services contract.

NASA engineers at the Johnson Space Center are designing an unpressurized rover prototype known as the Ground Test Unit. It’s a human-rated, unpressurized LTV (Lunar Terrain Vehicle). The unit is being designed and built as a platform to evaluate rover designs being developed by three private companies: Intuitive Machines, Lunar Outpost, and Venturi Astrolab.

Intuitive Machines is known for its IM-1 mission with its Nova-C Lander. They were the first private company to land a spacecraft on the Moon.

Intuitive Machines’ Nova-C lunar lander was the first private spacecraft to land on the Moon. Image Credit: By NASA Marshall Space Flight Center / Intuitive Machines Photo ID: IM_00309., Public Domain, https://commons.wikimedia.org/w/index.php?curid=145130774

Lunar Outpost is known for its Mobile Autonomous Prospecting Platform (MAPP) rover (MAPP) rover. MAPP will be used on Intuitive Machines’ IM-2 and IM-3 missions and will demonstrate aspects of In-Situ Resource Utilization.

Venturi Astrolab is known for developing hyper-deformable wheels and batteries for lunar rovers. They’re also developing their FLEX rover, a larger vehicle designed to be modular to meet different objectives.

The LTV will be used to test the technologies these three companies develop. It’ll be used to evaluate crew compartment design, rover maintenance, science payload, and many other aspects of their rovers.

“The Ground Test Unit will help NASA teams on the ground, test and understand all aspects of rover operations on the lunar surface ahead of Artemis missions,” said Jeff Somers, engineering lead for the Ground Test Unit. “The GTU allows NASA to be a smart buyer, so we are able to test and evaluate rover operations while we work with the LTVS contractors and their hardware.”

Two engineers in suits sit on the prototype during testing at the Johnson Space Center. Image Credit: NASA/Bill Stafford

NASA has some requirements that the three selected companies need to meet. The rover must support two crew members and be able to be operated remotely. It can use multiple control concepts, such as supervised autonomy, different drive modes, and self-levelling.

NASA used its ‘Moon Buggy’ or Lunar Roving Vehicle (LRV) on Apollo 15, 16, and 17 in 1971 and 1972. It could carry 440 kg, including two astronauts, and had a top speed of 18 km/h. Though it provided range and mobility, it never travelled further than walking distance from the landers in case of breakdown. Image Credit: By NASA/Dave Scott; Public Domain, https://commons.wikimedia.org/w/index.php?curid=6057491

By supplying the Ground Test Unit, NASA is making it easier to test the designs from the three companies. It also helps build private sector capacity by enabling testing and iterative design without the separate companies needing to spend money on a GTU. Ground testing also allows for a safer testing environment.

An artist’s illustration of astronauts at the lunar south pole. Image Credit: NASA

When Apollo 11 reached the Moon, it was a civilization-defining moment. There was no reason to explore beyond the landing site since it was as unexplored as the rest of the Moon. But things are much different now.

Thanks to other missions and satellites that orbit the Moon, we have an almost encyclopedic knowledge of our natural satellite compared to the Apollo days. We know what questions we want answered, where we can do the best science, and where useful resources like water ice is. The idea behind Artemis is to go to the Moon and create an infrastructure that will allow us to maintain a presence there.

The Artemis lunar missions will rely on mobility to meet their goals. The LTV will be critical to Artemis’ success by allowing each mission to explore and develop a larger area. NASA intends to use the new rovers starting in Artemis V, which will launch no sooner than 2030.

The post Artemis V Astronauts Will be Driving on the Moon appeared first on Universe Today.

Artificial intelligence (AI) may one day play a larger role in medicine than the online symptom checkers available today. But these 'AI doctors' may need to get more personal than human doctors to increase patient satisfaction, according to a new study. Researchers found that the more social information an AI doctor recalls about patients, the higher the patients' satisfaction, but only if they were offered privacy control.

The success of the $1 trillion that was recently invested by the U.S. federal government to mitigate climate climate change through the Inflation Reduction Act and the Bipartisan Infrastructure Law largely depends on how well state and local governments spend the money, according to new a commentary.

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The Renaissance artist Michelangelo had carried out human dissections, which may have led him to include women with breast cancer in some of his pieces

More accurate orbit predictions for satellites and space debris as well as a better understanding of the water masses present on Earth: Researchers at achieved both using satellite laser ranging.

More accurate orbit predictions for satellites and space debris as well as a better understanding of the water masses present on Earth: Researchers at achieved both using satellite laser ranging.

In June 2018, Japan’s Hayabusa 2 mission reached asteroid 162173 Ryugu. It studied the asteroid for about 15 months, deploying small rovers and a lander, before gathering a sample and returning it to Earth in December 2020.

The Ryugu sample contains some of the Solar System’s most ancient, primitive, and unaltered material, opening a window into its earliest days about 4.6 billion years ago.

The Ryugu sample is small, only about 5.4 grams (0.19 oz). However, scientific instruments that examine the sample’s chemical characteristics don’t need a large sample.

In new research, scientists examined tiny fragments of Ryugu using the Argonne National Laboratory’s Advanced Photon Source (APS). The APS is a particle accelerator that accelerates photons to nearly the speed of light. These photons release X-rays that are used in a wide variety of scientific endeavours. (The APS was even involved in developing COVID-19 vaccines.) In this research, the APS X-rays were used in a special technique called Mössbauer spectroscopy that can determine the oxidation rate of iron in the Ryugu sample.

The research is titled “Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples.” It’s published in the journal Science, and the lead author is Tetsuya Nakamura from Tohoku University in Sendai, Japan.

Ryugu is a rare type of asteroid. As a Cb spectral type, it has characteristics of both C-type carbonaceous asteroids, the most common type by far, and B-type asteroids, a more uncommon type of carbonaceous asteroid.

5.4 grams is not a large sample, but it’s large enough to reveal the nature and history of asteroid Ryugu. Image Credit: Yada et al./Nature Astronomy 2021

JAXA, the Japan Aerospace Exploration Agency, chose Ryugu for their sampling mission for several reasons. As a Near-Earth Asteroid (NEA), Ryugu was easier to reach. It’s also classified as a primitive, carbon-rich asteroid, so they hoped it would contain organic chemicals that hold clues about the early Solar System. Ryugu is also relatively small (900 metres) and rotates slowly, making sampling easier. The asteroid’s orbit also brings it close to Earth, making it easier to return the sample.

Ryugu could answer certain questions, all related to the history of the Solar System. Ryugu’s structure and composition, including the presence of water and organic matter, can reveal details about how planets and asteroids formed and how these essential materials for life may have been delivered to Earth. Scientists also hoped to classify Ryugu in more detail and understand its internal structure and how it might have evolved. Researchers also wondered about the asteroid’s resource potential.

Scientists working with the samples have already learned a lot. They’ve found that the asteroid is rich in organic matter, which supports the idea that asteroids could have delivered these materials to Earth. Ryugu contains water-bearing minerals, which is evidence that it held more water or water ice in the past. Scientists have also detected the effects of space weathering on the asteroid’s surface and solar wind particles trapped within its grains.

Artist’s impression of the Hayabusa2 taking samples from the surface of the asteroid Ryugu. Credit: Akihiro Ikeshita/JAXA

This new research added to the bounty of knowledge provided by the tiny 5.4-gram sample. The researchers analyzed 17 Ryugu particles, ranging in size from 1 to ~8 mm. They were mostly interested in uncovering a more detailed understanding of the asteroid’s history. They wanted to find answers to several specific questions:

1. When and where did Ryugu’s parent body form?
2. What is the original mineralogy, elemental abundances as a whole, and chemical compositions of the accreted materials, including their ice content?
3. How did these materials evolve through chemical reactions?
4. How was Ryugu ejected from its parent?

The APS and its Mossbauer Spectroscopy revealed more detail about Ryugu, and the researchers used impact simulators and other tools to piece together the history of the asteroid and its parent.

The researchers found carbon dioxide-bearing water inclusions in a certain type of crystal. This is evidence that Ryugu’s parent body formed in the outer Solar System, where cold temperatures allowed water ice to be incorporated. APS also identified a large concentration of pyrrhotite in the sample. Pyrrhotite is an iron sulphide found nowhere in meteorite fragments that resemble Ryugu. This helps limit the location and temperature of the parent body when it formed. The research team says that the parent body formed about 1.8 million to 2.9 million years after the beginning of Solar System formation.

In the outer Solar System, materials that form at low temperatures are dominant, and Ryugu’s parent was largely made of ice. The parent body formed beyond the H2O and CO2 snow lines and possibly beyond Jupiter.

The samples are porous and fine-grained, indicating that the parent contained ice that melted over a long period of time. The researchers say that radioactive heating in the parent body’s interior melted the water ice about three million years ago. Over time, reactions between the water and rock slowly changed the asteroid’s initial anhydrous mineralogy to a largely hydrous mineralogy.

The material was initially less altered at shallow depths and more hydrous at deeper depths. After about five million years, all of the material in the parent body reached its maximum temperature, and aqueous alteration continued.

The catastrophic head-on collision that blasted Ryugu’s parent happened about one billion years ago. The parent was about 50km in diameter, and the impactor was about 6 km. Ryugu isn’t a single chunk of its parent. Instead, it’s a rubble pile asteroid, a collection of debris dislodged from its parent body by the impact. Ryugu’s material originated at different depths on the opposite side of its parent from the impact and then coagulated into Ryugu.

This research helps paint a timeline of Ryugu’s parent and Ryugu itself on its long journey through the Solar System.

Ryugu itself began its journey as part of a larger body only about two million years after the birth of the Solar System. After billions of years as part of its parent body, it was created in the aftermath of a collision. After a long time, it made its way into its near-Earth orbit, and in the last blink of an eye, humanity arose and built a technological civilization. We’ve reached out and sampled this messenger from the past, and it’s taught us a lot about our Solar System’s history.

Hayabusa 2 is now on an extended mission to visit two other asteroids. In 2026, it will perform a high-speed fly-by of the S-type asteroid 98943 Torifune. In 2031, it will rendezvous with 1998 KY26, a small 30m asteroid that is a fast rotator.

Hayabusa 2 won’t sample either of these asteroids, but its observations will add to its already impressive contribution.

The post Tiny Fragments of a 4-Billion Year Old Asteroid Reveal Its History appeared first on Universe Today.

Researchers have succeeded in observing the effects of spin current transfer and spin current generation from the non-magnetic side of a device, using a multilayer device consisting of a ferromagnetic layer and an organic semiconductor material.

Researchers have succeeded in observing the effects of spin current transfer and spin current generation from the non-magnetic side of a device, using a multilayer device consisting of a ferromagnetic layer and an organic semiconductor material.

Researchers have developed a new imagining system to monitor pluripotent stem cells during incubation. The new device -- INSPCTOR -- uses lens-free imaging technology integrated with thin-film transistors. The device is the same size as a standard culture plate, allowing multiple units to be monitored within a compact incubator. By improving quality control during the growth process, this innovation could help accelerate advancements in customized regenerative medicine.

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In space exploration, long-distance optical links can now be used to transmit images, films and data from space probes to Earth using light. But in order for the signals to reach all the way and not be disturbed along the way, hypersensitive receivers and noise-free amplifiers are required. Now, researchers have created a system that, with a silent amplifier and record-sensitive receiver, paves the way for faster and improved space communication.

The advanced drug testing system screens multiple potential therapies simultaneously in beating heart cells.