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Turbulence in the Sun’s corona
Solar wind is a never-ending stream of charged particles coming from the Sun. Rather than a constant breeze, this wind is rather gusty. As solar wind particles travel through space, they interact with the Sun's variable magnetic field, creating chaotic and fluctuating motion known as turbulence.
This video confirms something long suspected: the turbulent motion of solar wind begins very close to the Sun, inside the solar atmosphere known as the corona. Small disturbances affecting solar wind in the corona are carried outward and expand, generating turbulent flow further out in space.
By blocking out direct light coming from the Sun, the Metis coronagraph instrument on Solar Orbiter is able to capture the fainter visible and ultraviolet light coming from the solar corona. Its high-resolution images show the detailed structure and movement within the corona, revealing how solar wind motion already becomes turbulent at its roots.
The red-tinted ring in the video shows Metis observations made on 12 October 2022. At the time, the spacecraft was just 43.4 million km from the Sun, less than a third of the Sun–Earth distance. The video of the Sun in the centre of the video was recorded by Solar Orbiter’s Extreme Ultraviolet Imager (EUI) on the same day. (Read more about Solar Orbiter’s instruments here.)
“This new analysis provides the first-ever evidence for the onset of fully developed turbulence in the Sun’s corona. Solar Orbiter’s Metis coronagraph was able to detect it very close to the Sun, closer than any spacecraft could approach the Sun and make local measurements,” explains Daniel Müller, ESA’s Solar Orbiter Project Scientist.
Turbulence affects how solar wind is heated, how it moves through the Solar System and how it interacts with the magnetic fields of planets and moons it passes through. Understanding solar wind turbulence is crucial for predicting space weather and its effects on Earth.
‘Metis observation of the onset of fully developed turbulence in the solar corona’ by Daniele Telloni et al. was published today in Astrophysical Journal Letters.
[Video description: The Sun is shown in the centre, surrounded by a ring of data from Solar Orbiter’s Metis coronagraph. The data show changes in brightness of the solar corona, which directly relates to the density of charged particles. These changes are made visible by subtracting consecutive coronal brightness images taken two minutes apart. Red regions show no change, while white and black regions highlight positive and negative changes in brightness. This reveals how charged solar wind particles within the corona move in a chaotic, turbulent way. The video repeats three times.]
AI tweaks to photos and videos can alter our memories
AI tweaks to photos and videos can alter our memories
The W boson caused a particle mystery — but scientists have cracked the case
How Polio Entered Gaza, and How the Vaccination Campaign is Going
Flawed implementation of a global eradication strategy brought poliovirus to Gaza, and wartime conditions let the infection spread
NASA Invites Public to Join as Virtual Guests for SpaceX Crew-9 Launch
NASA invites the public to participate as virtual guests in the launch of the agency’s SpaceX Crew-9 mission. NASA astronaut Nick Hague, commander, and Roscosmos cosmonaut Aleksandr Gorbunov, mission specialist, will embark on a flight aboard a SpaceX Dragon spacecraft, launching no earlier than 1:17 p.m. EDT on Saturday, Sept. 28, from Space Launch Complex-40 at Cape Canaveral Space Force Station in Florida.
Members of the public can register to attend the launch virtually. Virtual guests for this mission will receive curated resources, interactive opportunities, updates with the latest news, and a mission-specific collectible stamp for their virtual guest passport after liftoff. Don’t have a passport yet? Print yours here and get ready to add a stamp!
Live coverage and countdown commentary will begin at 9:10 a.m. EDT Saturday, Sept. 28, streaming on NASA+ agency’s website. Learn how to stream NASA content on a variety of platforms, including social media.
Want to learn more about the mission and NASA’s Commercial Crew Program? Follow along on the mission blog, Commercial Crew blog, @commercial_crew on X, or check out Commercial Crew on Facebook.
Dark Matter Could a Have Slight Interaction With Regular Matter
The reason we call dark matter dark isn’t because it’s some shadowy material. It’s because dark matter doesn’t interact with light. The difference is subtle, but important. Regular matter can be dark because it absorbs light. It’s why, for example, we can see the shadow of molecular clouds against the scattered stars of the Milky Way. This is possible because light and matter have a way to connect. Light is an electromagnetic wave, and atoms contain electrically charged electrons and protons, so matter can emit, absorb and scatter light. Dark matter isn’t electrically charged. It has no way to connect with light, and so when light and dark matter meet up they simply pass through each other.
All of our observations suggest that dark matter and light only have gravity in common. When dark matter is clustered around a galaxy, for example, its gravitational tug can deflect light. Because of this we can map the distribution of dark matter in the Universe by observing how light is gravitationally lensed around it. We also know that dark and regular matter interact gravitationally. The tug of dark matter causes galaxies to gather together into superclusters. But an unanswered question is whether dark and regular matter only interact gravitationally. If an atom and dark matter particle intersected, would they really just pass through each other?
Since we haven’t directly observed dark matter particles we can only speculate, but most dark matter models argue that gravity is the only common link with light and regular matter. Dark and regular matter clump around each other, but they don’t collide and merge like interstellar clouds. But a new study suggests the two do interact, which could reveal subtle aspects of the mysterious stuff.
The study looks at six ultrafaint dwarf galaxies, or UFDs. They are satellite galaxies near the Milky Way that seem to have far fewer stars than their mass would suggest. This is because they are mostly made of dark matter. If regular and dark matter only interact gravitationally, then the distribution of stars in these small galaxies should follow a certain pattern. If dark and regular matter interact directly, then this distribution will be skewed.
To test this the team ran computer simulations of both scenarios. They found that in the non-interacting model the distribution of stars should become more dense in the center of the UFDs and more diffuse at the edges. In the interacting model the stellar distribution should be more uniform. When they compared these models with observations of the six galaxies, they found the interacting model was a slightly better fit.
So it seems dark and regular matter interact in ways beyond their gravitational tugs. There isn’t enough data to pin down the exact nature of the interaction, but the fact there is any interaction at all is a surprise. It means that our traditional models of dark matter are at least partly wrong. It may also point the way toward new methods of detecting dark matter directly. In time we may finally solve the mystery of this dark, but not entirely invisible, material.
Reference: Almeida, Jorge Sánchez, Ignacio Trujillo, and Angel R. Plastino. “The Stellar Distribution in Ultrafaint Dwarf Galaxies Suggests Deviations from the Collisionless Cold Dark Matter Paradigm.” The Astrophysical Journal Letters 973.1 (2024): L15.
The post Dark Matter Could a Have Slight Interaction With Regular Matter appeared first on Universe Today.
Camellia oil could be the greenest cooking oil – and the healthiest
Camellia oil could be the greenest cooking oil – and the healthiest
Why I'm going to Easter Island for the 'ring of fire' annular solar eclipse
Milgram’s Infamous Shock Studies Still Hold Lessons for Confronting Authoritarianism
Why ordinary people will follow orders to the point of hurting others remains a critical question for scientists—though some answers have emerged
A New Rover Design Could Crawl Across the Moon for Decades Harvesting Water
We have known that water ice exists on the Moon since 1998. These large deposits are found in the permanently shadowed craters around the polar region. The challenge is how to get it since shadowed craters are not the best place for solar powered vehicles to operate. A team of engineers have identified a design for an ice-mining vehicle powered by americium-241. With a half-life of 432 years, this element is an ideal power source for a vehicle to operate in the dark for several decades.
Ice in the polar regions of the Moon is of vital importance for our future space explorations, not just lunar visits but as we stretch our legs in the Solar System. Its thought to be ancient material deposited by comets or formed by interactions with solar wind. It is expensive to take materials to the Moon so harvesting on site is far more efficient. Ice on the Moon can provide drinking water, oxygen for breaking and even hydrogen for rocket fuel. Surveys suggest something in the region of 600 billion kilograms of ice deposited at the lunar poles.
Exposed water ice (green or blue dots) in lunar polar regions and temperature. Credit: Shuai LiThe challenge facing future lunar harvesting missions is that operations in the permanently shadowed regions (or PSRs as they have been called) cannot be powered by solar panels as is often the case. The environment is cold too, in the region of 40K, that’s -233?C and at those temperatures special power considerations are required.
A team of researchers have been exploring the use of Radioisotope Power Systems (RPS) to provide thermal and electrical power systems. These power systems have been used before during deep space missions for example Voyager and New Horizons. They work by generating electricity using the heat that is released from the natural decay of a radioactive isotope usually plutonium-238.
Artist rendition of Voyager 1 entering interstellar space. (Credit: NASA/JPL-Caltech)The team led by Marzio Mazzotti from the University of Leicester have explored an ice-mining rover using power generated by the radio activate decay fo Americium-241. It has a half-life of 432 years which means it takes 432 years for half of a sample of Americium to decay. During this time, half of the atoms in the substance will transform into a different element. Using this power source will provide a stable power supply for an ice-mining rover in the darkness of the lunar polar craters for decades.
Apollo 17 commander Eugene Cernan with the lunar rover in December 1972, in the moon’s Taurus-Littrow valley. Credit: NASAUsing a radioisotope power system is not new however the team came upon the idea that the excess heat that is not used can be used to thermally mine ice from samples of lunar material. The rover would be fitted with a sublimation plate that would turn any ice deposits into a gas which would be collected in a cold trap.
The team developed a model of its Thermal Management System and tested it for icy regolith (the fine dusty lunar surface) material with a water ice content of 0-10 vol %. Their simulations showed that it is possible to mine ice using thermal techniques in the PSR of the Moon using an RPS (I had to really concentrate writing that sentence!) powered lunar rover.
Source : Ice-Mining Lunar Rover using Americium-241 Radioisotope Power Systems
The post A New Rover Design Could Crawl Across the Moon for Decades Harvesting Water appeared first on Universe Today.
What Really Happened at the Pentagon’s Once-Hidden UFO Office?
An office in the Pentagon investigated UFOs—and the paranormal—over a decade ago, segueing into a long saga leading to Congressional hearings and breathless news stories today. But the real story looks more like former defense officials pushing their personal mythology, rather than any cover-up of aliens