In an article published in the journal Leonardo, the researchers draw upon a fresh look at one of da Vinci's notebooks to show that the famed polymath had devised experiments to demonstrate that gravity is a form of acceleration—and that he further modeled the gravitational constant to around 97 percent accuracy. 

Da Vinci, who lived from 1452 to 1519, was well ahead of the curve in exploring these concepts. It wasn't until 1604 that Galileo Galilei would theorize that the distance covered by a falling object was proportional to the square of time elapsed and not until the late 17th century that Sir Isaac Newton would expand on that to develop a law of universal gravitation, describing how objects are attracted to one another. Da Vinci's primary hurdle was being limited by the tools at his disposal. For example, he lacked a means of precisely measuring time as objects fell.

Da Vinci's experiments were first spotted by Mory Gharib, the Hans W. Liepmann Professor of Aeronautics and Medical Engineering, in the Codex Arundel, a collection of papers written by da Vinci that cover science, art, and personal topics. In early 2017, Gharib was exploring da Vinci's techniques of flow visualization to discuss with students he was teaching in a graduate course when he noticed a series of sketches showing triangles generated by sand-like particles pouring out from a jar in the newly released Codex Arundel, which can be viewed online courtesy of the British Library.

"What caught my eye was when he wrote ‘Equatione di Moti' on the hypotenuse of one of his sketched triangles—the one that was an isosceles right triangle," says Gharib, lead author of the Leonardo paper. "I became interested to see what Leonardo meant by that phrase."

To analyze the notes, Gharib worked with colleagues Chris Roh, at the time a postdoctoral researcher at Caltech and now an assistant professor at Cornell University, as well as Flavio Noca of the University of Applied Sciences and Arts Western Switzerland in Geneva. Noca provided translations of da Vinci's Italian notes (written in his famous left-handed mirror writing that reads from right to left) as the trio pored over the manuscript's diagrams. 

In the papers, da Vinci describes an experiment in which a water pitcher would be moved along a straight path parallel to the ground, dumping out either water or a granular material (most likely sand) along the way. His notes make it clear that he was aware that the water or sand would not fall at a constant velocity but rather would accelerate—also that the material stops accelerating horizontally, as it is no longer influenced by the pitcher, and that its acceleration is purely downward due to gravity.

If the pitcher moves at a constant speed, the line created by falling material is vertical, so no triangle forms. If the pitcher accelerates at a constant rate, the line created by the collection of falling material makes a straight but slanted line, which then forms a triangle. And, as da Vinci pointed out in a key diagram, if the pitcher's motion is accelerated at the same rate that gravity accelerates the falling material, it creates an equilateral triangle—which is what Gharib originally noticed that da Vinci had highlighted with the note "Equatione di Moti," or "equalization (equivalence) of motions."

Da Vinci sought to mathematically describe that acceleration. It is here, according to the study's authors, that he didn't quite hit the mark. To explore da Vinci's process, the team used computer modeling to run his water vase experiment. Doing so yielded da Vinci's error.

"What we saw is that Leonardo wrestled with this, but he modeled it as the falling object's distance was proportional to 2 to the t power [with t representing time] instead proportional to t squared," Roh says. "It's wrong, but we later found out that he used this sort of wrong equation in the correct way." In his notes, da Vinci illustrated an object falling for up to four intervals of time—a period through which graphs of both types of equations line up closely.

"We don't know if da Vinci did further experiments or probed this question more deeply," Gharib says. "But the fact that he was grappling with this problem in this way—in the early 1500s—demonstrates just how far ahead his thinking was."

The paper is titled "Leonardo da Vinci's Visualization of Gravity as a Form of Acceleration."

The University of North Florida's Information Technology Services recently received a congressional directed appropriation in the amount of $750,000 to support a much-needed cloud supercomputing and cybersecurity infrastructure initiative.

The enhanced virtual cloud supercomputing infrastructure will address the need to create a scalable secure learning and research environment for UNF students, faculty, and staff. The project will benefit both traditional and non-traditional students by providing a consistent set of tools, software, security, and a level of interactivity with faculty during their academic career at UNF.

It will provide the UNF community with access to secure campus lab computers and systems from any location; enhance existing computer and research labs; allow university resources to be utilized anytime, anywhere, in a device-agnostic environment; and provide the tools students need to build real-world systems while providing faculty the ability to closely monitor and assist students both on and off campus.

The new virtual infrastructure will allow cyber security instruction, research, and operations in a controlled and scalable environment.  The environment will seamlessly allow remote access to software restricted to running on university-owned hardware. In addition, it will provide remote control of a dedicated machine for student assignments and projects.

Using this technology, UNF will be able to utilize pools of available computers to work together to solve a common problem, as in a supercomputing cluster or a Google-like indexing and search task. Additionally, this environment and service will offload the need for students to continually upgrade their computers to handle demanding assignments and projects. Students will be able to use software or hardware when classroom computers are not powerful enough. 

The update includes more Arctic data, the longer historical record

NOAA’s National Centers for Environmental Information (NCEI) is updating its current global climate dataset to provide more information about the Earth’s climate, while also extending the planet’s observed temperature record by 30 years.

The update to NCEI’s current NOAA Global Temperature dataset — one of the most visible and widely used datasets to assess global climate — will debut in the upcoming January 2023 global climate report to be released on February 14, 2023. This new global climate dataset will expand upon and replace the current one used since 2019.  

"This new version of NOAA's global surface temperature dataset is part of NCEI’s commitment to providing a complete and comprehensive perspective of the Earth’s climate," said NCEI director Deke Arndt. “Regular updates to our datasets help us expand our understanding of our dynamic planet."

There are two significant additions in this update:

• More data for the Arctic region are included, as well as new scientific methods for monitoring climate in other locations with limited climate data. 
• Using improved methodology to analyze NCEI’s archival land and ocean observations, 30 more years will be added to the world’s current climate record, extending to 1850. 

NOAA’s Global Temperature datasets consist of data from weather stations across the world’s land surface, as well as ocean surface data from ships, buoys, surface drifters, profiling floats, and other uncrewed automatic systems. Until recently, however, monitoring environmental conditions around the Arctic and Antarctic has been more challenging due to fewer temperature observations in these regions. 

The updated version now includes data from more buoys from around the Arctic, along with enhanced methods of calculating temperatures in the Earth’s polar regions. 

The new version of NOAA’s Global Temperature dataset shows similar warming trends in the Earth’s climate when compared to the previous version, indicating that short-and long-term climate trends remain consistent across datasets.

This new information comes at a critical time in the Earth’s climate history. The Arctic is the fastest-warming region globally, warming at least three times faster than any other region. The top 10 warmest years on record for the globe have all occurred after 2010. The last nine years (2014–2022) have been the warmest on record.

Spacecraft and mission hardware designed by artificial intelligence may resemble bones left by some alien species, but they weigh less, tolerate higher structural loads, and require a fraction of the time parts designed by humans take to develop. 

“They look somewhat alien and weird,” research engineer Ryan McClelland said, “but once you see them in function, it makes sense.”

McClelland pioneered the design of specialized, one-off parts using commercially available AI software at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, producing hardware he has dubbed evolved structures.

To create these parts, a computer-assisted design (CAD) specialist starts with the mission’s requirements and draws in the surfaces where the part connects to the instrument or spacecraft – as well as any bolts and fittings for electronics and other hardware. The designer might also need to block out a path so that the algorithm doesn’t block a laser beam or optical sensor. Finally, more complex builds might require spaces for technicians’ hands to maneuver for assembly and alignment.

Once all off-limits areas are defined, the AI connects the dots, McClelland said, producing complex structure designs in as little as an hour or two. “The algorithms do need a human eye,” he said. “Human intuition knows what looks right, but left to itself, the algorithm can sometimes make structures too thin."

These evolved structures save up to two-thirds of the weight compared to traditional components, he said and can be milled by commercial vendors. “You can perform the design, analysis, and fabrication of a prototype part, and have it in hand in as little as one week,” McClelland said. “It can be radically fast compared with how we’re used to working.”

Parts are also analyzed using NASA-standard validation software and processes to identify potential points of failure, McClelland said. “We found it lowers risk. After these stress analyses, we find the parts generated by the algorithm don’t have the stress concentrations that you have with human designs. The stress factors are almost ten times lower than parts produced by an expert human.”

McClelland’s evolved components have been adopted by NASA missions in different stages of design and construction, including astrophysics balloon observatories, Earth-atmosphere scanners, planetary instruments, space weather monitors, space telescopes, and even the Mars Sample Return mission.

Goddard physicist Peter Nagler turned to evolved structures to help develop the EXoplanet Climate Infrared TElescope (EXCITE) mission, a balloon-borne telescope developed to study hot Jupiter-type exoplanets orbiting other stars. Currently, under construction and testing, EXCITE plans to use a near-infrared spectrograph to perform continuous observations of each planet's orbit about its host star.

“We have a couple of areas with very tricky design requirements,” Nagler said. “There were combinations of specific interfaces and exacting load specifications that were proving to be a challenge for our designers.”

McClelland designed a titanium scaffold for the back of the EXCITE telescope, where the IR receiver housed inside an aluminum cryogenic chamber connects to a carbon fiber plate supporting the primary mirror. “These materials have very different thermal expansion properties,” Nagler said. “We had to have an interface between them that won’t stress either material.”

A long-duration NASA Super-Pressure Balloon will loft the EXCITE mission’s SUV-sized payload, with an engineering test flight planned as early as the fall of 2023.

Ideal Design Solution for NASA’s Custom Parts

AI-assisted design is a growing industry, with everything from equipment parts to entire car and motorcycle chassis being developed by computers.

The use case for NASA is particularly strong, McClelland said.

“If you’re a motorcycle or car company,” McClelland said, “there may be only one chassis design that you’re going to produce, and then you’ll manufacture a bunch of them. Here at NASA, we make thousands of bespoke parts every year.”

3D printing with resins and metals will unlock the future of AI-assisted design, he said, enabling larger components such as structural trusses, complex systems that move or unfold, or advanced precision optics. “These techniques could enable NASA and commercial partners to build larger components in orbit that would not otherwise fit in a standard launch vehicle, they could even facilitate construction on the Moon or Mars using materials found in those locations.”

Merging AI, 3D printing or additive manufacturing, and in-situ resource utilization will advance In-space Servicing, Assembly, and Manufacturing (ISAM) capabilities. ISAM is a key priority for U.S. space infrastructure development as defined by the White House Office of Science and Technology Policy’s ISAM National Strategy and ISAM Implementation Plan.

This work is supported by the Center Innovation Fund in NASA's Space Technology Mission Directorate as well as Goddard’s Internal Research and Development (IRAD) program.