Members Can Post Anonymously On This Site
Satellites launched to boost connectivity and create jobs
-
Similar Topics
-
By NASA
3 min read
NASA Develops Process to Create Very Accurate Eclipse Maps
New NASA research reveals a process to generate extremely accurate eclipse maps, which plot the predicted path of the Moon’s shadow as it crosses the face of Earth. Traditionally, eclipse calculations assume that all observers are at sea level on Earth and that the Moon is a smooth sphere that is perfectly symmetrical around its center of mass. As such, these calculations do not take into account different elevations on Earth or the Moon’s cratered, uneven surface.
For slightly more accurate maps, people can employ elevation tables and plots of the lunar limb — the edge of the visible surface of the Moon as seen from Earth. However, now eclipse calculations have gained even greater accuracy by incorporating lunar topography data from NASA’s LRO (Lunar Reconnaissance Orbiter) observations.
Using LRO elevation maps, NASA visualizer Ernie Wright at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, created a continuously varying lunar limb profile as the Moon’s shadow passes over the Earth. The mountains and valleys along the edge of the Moon’s disk affect the timing and duration of totality by several seconds. Wright also used several NASA data sets to provide an elevation map of Earth so that eclipse observer locations were depicted at their true altitude.
The resulting visualizations show something never seen before: the true, time-varying shape of the Moon’s shadow, with the effects of both an accurate lunar limb and the Earth’s terrain.
“Beginning with the 2017 total solar eclipse, we’ve been publishing maps and movies of eclipses that show the true shape of the Moon’s central shadow — the umbra,” said Wright.
A map showing the umbra (the Moon’s central shadow) as it passes over Cleveland at 3:15 p.m. local time during the April 8, 2024, total solar eclipse. NASA SVS/Ernie Wright and Michaela Garrison “And people ask, why does it look like a potato instead of a smooth oval? The short answer is that the Moon isn’t a perfectly smooth sphere.”
The mountains and valleys around the edge of the Moon change the shape of the shadow. The valleys are also responsible for Baily’s beads and the diamond ring, the last bits of the Sun visible just before and the first just after totality.
A computer simulation of Baily’s beads during a total solar eclipse. Data from Lunar Reconnaissance Orbiter makes it possible to map the lunar valleys that create the bead effect. NASA SVS/Ernie Wright Wright is lead author of a paper published September 19 in The Astronomical Journal that reveals for the first time exactly how the Moon’s terrain creates the umbra shape. The valleys on the edge of the Moon act like pinholes projecting images of the Sun onto the Earth’s surface.
A visualization of Sun images being projected from lunar valleys that are acting like pinhole projectors. Light rays from the Sun converge on each valley, then spread out again on their way to the Earth. NASA SVS/Ernie Wright The umbra is the small hole in the middle of these projected Sun images, the place where none of the Sun images reach.
Viewed from behind the Moon, the Sun images projected by lunar valleys on the Moon’s edge fall on the Earth’s surface in a flower-like pattern with a hole in the middle, forming the umbra shape. NASA SVS/Ernie Wright The edges of the umbra are made up of small arcs from the edges of the projected Sun images.
This is just one of several surprising results that have emerged from the new eclipse mapping method described in the paper. Unlike the traditional method invented 200 years ago, the new way renders eclipse maps one pixel at a time, the same way 3D animation software creates images. It’s also similar to the way other complex phenomena, like weather, are modeled in the computer by breaking the problem into millions of tiny pieces, something computers are really good at, and something that was inconceivable 200 years ago.
For more about eclipses, refer to:
https://science.nasa.gov/eclipses
By Ernie Wright and Susannah Darling
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Nancy Neal-Jones
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov
Share
Details
Last Updated Sep 19, 2024 Editor wasteigerwald Contact wasteigerwald william.a.steigerwald@nasa.gov Location NASA Goddard Space Flight Center Related Terms
Lunar Reconnaissance Orbiter (LRO) Solar Eclipses Uncategorized Explore More
3 min read Eclipse Soundscapes AudioMoth Donations Will Study Nature at Night
Article
3 weeks ago
14 min read The Making of Our Alien Earth: The Undersea Volcanoes of Santorini, Greece
Article
4 weeks ago
4 min read Into The Field With NASA: Valley Of Ten Thousand Smokes
To better understand Mars, NASA’s Goddard Instrument Field Team hiked deep into the backcountry of…
Article
4 weeks ago
View the full article
-
By European Space Agency
The European Galileo satellite navigation system Galileo keeps growing: a new pair of satellites has joined the constellation after a journey on a Falcon 9 rocket, launched from the Kennedy Space Center in Florida on 18 September at 00:50 CEST (17 September 18:50 local time).
View the full article
-
By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Tests on Earth appear to confirm how the Red Planet’s spider-shaped geologic formations are carved by carbon dioxide.
Spider-shaped features called araneiform terrain are found in the southern hemisphere of Mars, carved into the landscape by carbon dioxide gas. This 2009 image taken by NASA’s Mars Reconnaissance Orbiter shows several of these distinctive formations within an area three-quarters of a mile (1.2 kilometers) wide. NASA/JPL-Caltech/University of Arizona Dark splotches seen in this example of araneiform terrain captured by NASA’s Mars Reconnaissance Orbiter in 2018 are believed to be soil ejected from the surface by carbon dioxide gas plumes. A set of experiments at JPL has sought to re-create these spider-like formations in a lab. NASA/JPL-Caltech/University of Arizona Since discovering them in 2003 via images from orbiters, scientists have marveled at spider-like shapes sprawled across the southern hemisphere of Mars. No one is entirely sure how these geologic features are created. Each branched formation can stretch more than a half-mile (1 kilometer) from end to end and include hundreds of spindly “legs.” Called araneiform terrain, these features are often found in clusters, giving the surface a wrinkled appearance.
The leading theory is that the spiders are created by processes involving carbon dioxide ice, which doesn’t occur naturally on Earth. Thanks to experiments detailed in a new paper published in The Planetary Science Journal, scientists have, for the first time, re-created those formation processes in simulated Martian temperatures and air pressure.
Here’s a look inside of JPL’s DUSTIE, a wine barrel-size chamber used to simulate the temperatures and air pressure of other planets – in this case, the carbon dioxide ice found on Mars’ south pole. Experiments conducted in the chamber confirmed how Martian formations known as “spiders” are created.NASA/JPL-Caltech “The spiders are strange, beautiful geologic features in their own right,” said Lauren Mc Keown of NASA’s Jet Propulsion Laboratory in Southern California. “These experiments will help tune our models for how they form.”
The study confirms several formation processes described by what’s called the Kieffer model: Sunlight heats the soil when it shines through transparent slabs of carbon dioxide ice that built up on the Martian surface each winter. Being darker than the ice above it, the soil absorbs the heat and causes the ice closest to it to turn directly into carbon dioxide gas — without turning to liquid first — in a process called sublimation (the same process that sends clouds of “smoke” billowing up from dry ice). As the gas builds in pressure, the Martian ice cracks, allowing the gas to escape. As it seeps upward, the gas takes with it a stream of dark dust and sand from the soil that lands on the surface of the ice.
When winter turns to spring and the remaining ice sublimates, according to the theory, the spiderlike scars from those small eruptions are what’s left behind.
These formations similar to the Red Planet’s “spiders” appeared within Martian soil simulant during experiments in JPL’s DUSTIE chamber. Carbon dioxide ice frozen within the simulant was warmed by a heater below, turning it back into gas that eventually cracked through the frozen top layer and formed a plume.NASA/JPL-Caltech Re-Creating Mars in the Lab
For Mc Keown and her co-authors, the hardest part of conducting these experiments was re-creating conditions found on the Martian polar surface: extremely low air pressure and temperatures as low as minus 301 degrees Fahrenheit (minus 185 degrees Celsius). To do that, Mc Keown used a liquid-nitrogen-cooled test chamber at JPL, the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE.
“I love DUSTIE. It’s historic,” Mc Keown said, noting that the wine barrel-size chamber was used to test a prototype of a rasping tool designed for NASA’s Mars Phoenix lander. The tool was used to break water ice, which the spacecraft scooped up and analyzed near the planet’s north pole.
To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
This video shows Martian soil simulant erupting in a plume during a JPL lab experiment that was designed to replicate the process believed to form Martian features called “spiders.” When a researcher who had tried for years to re-create these conditions spotted this plume, she was ecstatic. NASA/JPL-Caltech For this experiment, the researchers chilled Martian soil simulant in a container submerged within a liquid nitrogen bath. They placed it in the DUSTIE chamber, where the air pressure was reduced to be similar to that of Mars’ southern hemisphere. Carbon dioxide gas then flowed into the chamber and condensed from gas to ice over the course of three to five hours. It took many tries before Mc Keown found just the right conditions for the ice to become thick and translucent enough for the experiments to work.
Once they got ice with the right properties, they placed a heater inside the chamber below the simulant to warm it up and crack the ice. Mc Keown was ecstatic when she finally saw a plume of carbon dioxide gas erupting from within the powdery simulant.
“It was late on a Friday evening and the lab manager burst in after hearing me shrieking,” said Mc Keown, who had been working to make a plume like this for five years. “She thought there had been an accident.”
The dark plumes opened holes in the simulant as they streamed out, spewing simulant for as long as 10 minutes before all the pressurized gas was expelled.
The experiments included a surprise that wasn’t reflected in the Kieffer model: Ice formed between the grains of the simulant, then cracked it open. This alternative process might explain why spiders have a more “cracked” appearance. Whether this happens or not seems dependent on the size of soil grains and how embedded water ice is underground.
“It’s one of those details that show that nature is a little messier than the textbook image,” said Serina Diniega of JPL, a co-author of the paper.
What’s Next for Plume Testing
Now that the conditions have been found for plumes to form, the next step is to try the same experiments with simulated sunlight from above, rather than using a heater below. That could help scientists narrow down the range of conditions under which the plumes and ejection of soil might occur.
There are still many questions about the spiders that can’t be answered in a lab. Why have they formed in some places on Mars but not others? Since they appear to result from seasonal changes that are still occurring, why don’t they seem to be growing in number or size over time? It’s possible that they’re left over from long ago, when the climate was different on Mars— and could therefore provide a unique window into the planet’s past.
For the time being, lab experiments will be as close to the spiders as scientists can get. Both the Curiosity and Perseverance rovers are exploring the Red Planet far from the southern hemisphere, which is where these formations appear (and where no spacecraft has ever landed). The Phoenix mission, which landed in the northern hemisphere, lasted only a few months before succumbing to the intense polar cold and limited sunlight.
News Media Contacts
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2024-122
Share
Details
Last Updated Sep 11, 2024 Related Terms
Mars Jet Propulsion Laboratory Explore More
5 min read NASA JPL Scientists, Engineers Collaborate With Artists for Exhibition
Article 2 days ago 6 min read NASA’s Hubble, MAVEN Help Solve the Mystery of Mars’ Escaping Water
Mars was once a very wet planet as is evident in its surface geological features.…
Article 6 days ago 5 min read NASA JPL Developing Underwater Robots to Venture Deep Below Polar Ice
Article 2 weeks ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By European Space Agency
The two new Galileo satellites launched in April have entered service, completing the second of three constellation planes. With every addition to the constellation, the precision, availability and robustness of the Galileo signal is improved. The next launch is planned in the coming weeks and the remaining six Galileo First Generation satellites will join the constellation in the next years.
View the full article
-
By NASA
4 Min Read Eclipses Create Atmospheric Gravity Waves, NASA Student Teams Confirm
In this photo taken from the International Space Station, the Moon passes in front of the Sun casting its shadow, or umbra, and darkening a portion of the Earth's surface above Texas during the annular solar eclipse Oct. 14, 2023. Credits: NASA Student teams from three U.S. universities became the first to measure what scientists have long predicted: eclipses can generate ripples in Earth’s atmosphere called atmospheric gravity waves. The waves’ telltale signature emerged in data captured during the North American annular solar eclipse on Oct. 14, 2023, as part of the Nationwide Eclipse Ballooning Project (NEBP) sponsored by NASA.
Through NEBP, high school and university student teams were stationed along the eclipse path through multiple U.S. states, where they released weather balloons carrying instrument packages designed to conduct engineering studies or atmospheric science. A cluster of science teams located in New Mexico collected the data definitively linking the eclipse to the formation of atmospheric gravity waves, a finding that could lead to improved weather forecasting.
“Climate models are complicated, and they make some assumptions about what atmospheric factors to take into account.”
Angela Des Jardins
Director of the Montana Space Grant Consortium, which led NEBP.
“Understanding how the atmosphere reacts in the special case of eclipses helps us better understand the atmosphere, which in turn helps us make more accurate weather predictions and, ultimately, better understand climate change.”
Catching Waves in New Mexico
Previous ballooning teams also had hunted atmospheric gravity waves during earlier eclipses, research that was supported by NASA and the National Science Foundation. In 2019, an NEBP team stationed in Chile collected promising data, but hourly balloon releases didn’t provide quite enough detail. Attempts to repeat the experiment in 2020 were foiled by COVID-19 travel restrictions in Argentina and a heavy rainstorm that impeded data collection in Chile.
Project leaders factored in these lessons learned when planning for 2023, scheduling balloon releases every 15 minutes and carefully weighing locations with the best potential for success.
“New Mexico looked especially promising,” said Jie Gong, a researcher in the NASA Climate and Radiation Lab at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, and co-investigator of the research on atmospheric gravity waves. “The majority of atmospheric gravity sources are convection, weather systems, and mountains. We wanted to eliminate all those possible sources.”
The project created a New Mexico “supersite” in the town of Moriarty where four atmospheric science teams were clustered: two from Plymouth State University in Plymouth, New Hampshire, and one each from the State University of New York (SUNY) Albany and SUNY Oswego.
Students began launching balloons at 10 a.m. the day before the eclipse.
“They worked in shifts through the day and night, and then everyone was on site for the eclipse,” said Eric Kelsey, research associate professor at Plymouth State and the NEBP northeast regional lead.
“Our hard work really paid off. The students had a real sense of accomplishment.”
Eric Kelsey
Research Associate Professor at Plymouth State and the NEBP Northeast Regional Lead.
Each balloon released by the science teams carried a radiosonde, an instrument package that measured temperature, location, humidity, wind direction, and wind speed during every second of its climb through the atmosphere. Radiosondes transmitted this stream of raw data to the team on the ground. Students uploaded the data to a shared server, where Gong and two graduate students spent months processing and analyzing it.
Confirmation that the eclipse had generated atmospheric gravity waves in the skies above New Mexico came in spring 2024.
“We put all the data together according to time, and when we plotted that time series, I could already see the stripes in the signal,” Gong said. “I bombarded everybody’s email. We were quite excited.”
Plymouth State University students Sarah Brigandi, left, and Sammantha Boulay release a weather balloon from Moriarty, New Mexico, to collect atmospheric data on Oct. 14, 2023.NASA For Students, Learning Curves Bring Opportunity
The program offered many students their first experience in collecting data. But the benefits go beyond technical and scientific skill.
“The students learned a ton through practicing launching weather balloons,” Kelsey said. “It was a huge learning curve. They had to work together to figure out all the logistics and troubleshoot. It’s good practice of teamwork skills.”
“All of this is technically complicated,” Des Jardins said. “While the focus now is on the science result, the most important part is that it was students who made this happen.”
NASA’s Science Mission Directorate Science Activation program funds NEBP, along with contributions from the National Space Grant College and Fellowship Project and support from NASA’s Balloon Program Office.
Learn More:
Montana State-led ballooning project confirms hypothesis about eclipse effects on atmosphere
Nationwide Eclipse Ballooning Project
NASA Selects Student Teams for High-Flying Balloon Science
NASA Science Activation
NASA Space Grant
Explore More
2 min read Leveraging Teacher Leaders to Share the Joy of NASA Heliophysics
Many teachers are exceptionally skilled at bridging students’ interests with real-world science. Now for the…
Article 22 hours ago 9 min read Proyecto de la NASA en Puerto Rico capacita a estudiantes en biología marina
Article 2 days ago 2 min read NASA Earth Science Education Collaborative Member Co-Authors Award-Winning Paper in Insects
On August 13, 2024, the publishers of the journal Insects notified authors of three papers…
Article 2 days ago View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.