Members Can Post Anonymously On This Site
-
Similar Topics
-
By European Space Agency
Image: These two images acquired by Copernicus Sentinel-2 highlight how the mission can help distinguish between clouds and snow. View the full article
-
By NASA
3 min read
Buckle Up: NASA-Funded Study Explores Turbulence in Molecular Clouds
This image shows the distribution of density in a simulation of a turbulent molecular cloud. NASA/E. Scannapieco et al (2024) On an airplane, motions of the air on both small and large scales contribute to turbulence, which may result in a bumpy flight. Turbulence on a much larger scale is important to how stars form in giant molecular clouds that permeate the Milky Way.
In a new NASA-funded study in the journal Science Advances, scientists created simulations to explore how turbulence interacts with the density of the cloud. Lumps, or pockets of density, are the places where new stars will be born. Our Sun, for example, formed 4.6 billion years ago in a lumpy portion of a cloud that collapsed.
“We know that the main process that determines when and how quickly stars are made is turbulence, because it gives rise to the structures that create stars,” said Evan Scannapieco, professor of astrophysics at Arizona State University and lead author of the study. “Our study uncovers how those structures are formed.”
Giant molecular clouds are full of random, turbulent motions, which are caused by gravity, stirring by the galactic arms and winds, jets, and explosions from young stars. This turbulence is so strong that it creates shocks that drive the density changes in the cloud.
The simulations used dots called tracer particles to traverse a molecular cloud and travel along with the material. As the particles travel, they record the density of the part of the cloud they encounter, building up a history of how pockets of density change over time. The researchers, who also included Liubin Pan from Sun Yat Sen University in China, Marcus Brüggen from the University of Hamburg in Germany, and Ed Buie II from Vassar College in Poughkeepsie, New York, simulated eight scenarios, each with a different set of realistic cloud properties.
This animation shows the distribution of density in a simulation of a turbulent molecular cloud. The colors represent density, with dark blue indicating the least dense regions and red indicating the densest regions. Credit: NASA/E. Scannapieco et al (2024) The team found that the speeding up and slowing down of shocks plays an essential role in the path of the particles. Shocks slow down as they go into high-density gas and speed up as they go into low-density gas. This is akin to how an ocean wave strengthens when it hits shallow water by the shore.
When a particle hits a shock, the area around it becomes more dense. But because shocks slow down in dense regions, once lumps become dense enough, the turbulent motions can’t make them any denser. These lumpiest high-density regions are where stars are most likely to form.
While other studies have explored molecular cloud density structures, this simulation allows scientists to see how those structures form over time. This informs scientists’ understanding of how and where stars are likely to be born.
“Now we can understand better why those structures look the way they do because we’re able to track their histories,” said Scannapieco.
This image shows part of a simulation of a molecular cloud. The colors represent density, with dark blue indicating the least dense regions and red indicating the densest regions. Tracer particles, represented by black dots, traverse the simulated cloud. By examining how they interact with shocks and pockets of density, scientists can better understand the structures in molecular clouds that lead to star formation. NASA/E. Scannapieco et al (2024) NASA’s James Webb Space Telescope is exploring the structure of molecular clouds. It is also exploring the chemistry of molecular clouds, which depends on the history of the gas modeled in the simulations. New measurements like these will inform our understanding of star formation.
View the full article
-
By USH
Over the years, numerous mysterious events have been witnessed in the sky, defying explanation. Recently, yet another unusual sky phenomenon was observed over Southern Australia capturing attention and sparking curiosity.
Video footage reveals what appears to be a dome-shaped structure, with an even stranger detail: lightning seems to bounce off or perhaps even originate from within the dome.
The mysterious formation has led to numerous theories. Some viewers suggest it could be a unique (red) rainbow or a rare weather event like a haboob (sandstorm). Others speculate it might be the result of weather manipulation or even an energy field projected over the region.
Opinions also vary on the lightning, some say it’s bouncing off the dome, while others believe it could be emanating from within. Although it may just be an unusual natural phenomenon, the seemly strange interaction with the lightning remains unexplained.
View the full article
-
By USH
A strange image has been circulating across social media in Thailand, showing a large, dark pillar-like structure mysteriously appearing in the sky over Ubon Ratchathani. According to the photographer, the picture was taken on Sunday, October 20, 2024, while they were trying to capture the "beautiful, colorful sky.
This peculiar sighting isn't entirely unprecedented. Similar strange phenomena have been reported before. On October 7, 2015, a mysterious "floating city" with skyscrapers appeared in the clouds over Foshan, Guangdong province in China. Again, on March 18, 2016, ghostly buildings were seen above the sea along the port of Dalian, in Liaoning Province, China, lingering in the sky for several minutes.
Most recently, on September 11, 2020, an eerie image resembling the Hogwarts School from Harry Potter was spotted hovering over modern buildings in Jinan, Shandong Province. On July 14, 2022, a bizarre occurrence was also witnessed by residents in Haikou, Hainan, where a mysterious floating city appeared in the sky.
Scientists suggest that these events are most likely optical illusions, with mirages being the leading theory. Mirages occur when light rays bend, causing distant objects or parts of the sky to appear displaced. One specific type, known as a Fata Morgana, can create towering, distorted images of distant objects, contributing to these surreal sights.
Although the sightings between 2015 and 2022 were witnessed by many, the photographer in Thailand later realized that the mysterious pillar hadn't been visible to the naked eye at the time. This discovery has led some to speculate that the phenomenon might have been caused by a Project Blue Beam test, holographic technology, or even a temporary vortex connected to a parallel universe.
View the full article
-
By European Space Agency
With the initial images from each of the instruments aboard ESA’s EarthCARE satellite now in hand, it's time to reveal how these four advanced sensors work in synergy to measure exactly how clouds and aerosols influence the heating and cooling of our atmosphere.
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.