TYB
NASA Astronomy Picture of the Day
Dec 31, 2023
Illustris: A Simulation of the Universe
How did we get here? Click play, sit back, and watch. A computer simulation of the evolution of the universe provides insight into how galaxies formed and perspectives into humanity's place in the universe. The Illustris project exhausted 20 million CPU hours in 2014 following 12 billion resolution elements spanning a cube 35 million light years on a side as it evolved over 13 billion years. The simulation tracks matter into the formation of a wide variety of galaxy types. As the virtual universe evolves, some of the matter expanding with the universe soon gravitationally condenses to form filaments, galaxies, and clusters of galaxies. The featured video takes the perspective of a virtual camera circling part of this changing universe, first showing the evolution of dark matter, then hydrogen gas coded by temperature (0:45), then heavy elements such as helium and carbon (1:30), and then back to dark matter (2:07). On the lower left the time since the Big Bang is listed, while on the lower right the type of matter being shown is listed. Explosions (0:50) depict galaxy-center supermassive black holes expelling bubbles of hot gas. Interesting discrepancies between Illustris and the real universe have been studied, including why the simulation produced an overabundance of old stars.
https://apod.nasa.gov/apod/astropix.html?
Mysterious 'ghostly' shadows larger than planet Earth reappeared on Saturn's rings. NASA says it expects even more to appear soon.
Dec 29, 2023
NASA's Hubble telescope observed the latest series of mysterious dark spots on Saturn's rings.
Scientists have observed these "spokes" for decades but don't know their origin or cause.
NASA said Saturn is approaching a key point in its orbit that may make them more common.
Saturn's rings hold a secret that has mystified scientists for decades.
Strange dark shadows, called spokes, occasionally appear and disappear on the planet's rings.
NASA's Voyager 2 spacecraft first observed Saturn's spokes in 1981, and other instruments, including Cassini and Hubble, have spotted them multiple times before.
The latest sighting was in October when Hubble spotted several dancing around the ringed planet.
Scientists have an idea of what they are and what causes them, but aren't certain.
Spokes have a "ghostly appearance" and rotate with Saturn's rings as they orbit the planet, NASA said in a statement.
And while they may look small compared to Saturna's rings, spokes can grow to lengths longer than our entire planet, NASA said.
What are Saturn's spokes?
Scientists suspect that spokes have something to do with interactions between Saturn and the sun.
Similar to Earth, Saturn has a magnetic field that surrounds the planet. And that magnetic field is susceptible to the charged particles in the solar wind that our sun regularly fires into space.
So when the solar wind smashes into Saturn's magnetic field at a million miles per hour, it's going to have some effects, like generating aurora borealis on Saturn's poles.
But scientists also suspect it may trigger the right conditions for those ethereal spokes on Saturn's rings to pop up.
"The leading theory is that spokes are tied to Saturn's powerful magnetic field, with some sort of solar interaction with the magnetic field that gives you the spokes," Amy Simon, a scientist with NASA's Goddard Space Flight Center, said in NASA's statement.
Electrostatic forces may cause dust or ice in Saturn's rings to levitate slightly higher than everything else around them, casting a dark shadow on the material below it, in the form of a spoke, per NASA. But this is just one possible explanation.
Astronomers must observe and analyze more spokes to determine what's triggering these mysterious marks.
Lucky for them, NASA predicts more spokes will be coming soon. Because even though scientists aren't sure what spokes are, or what causes them, they're fairly certain from observations over the decades that spokes vary with Saturn's seasons.
And Saturn's fall season, aka its autumnal equinox, is coming up.
When that happens, the planet's tilt allows solar winds to bombard the planet's magnetic field with more force, per Space.com.
"We are heading towards Saturn equinox, when we'd expect maximum spoke activity, with higher frequency and darker spokes appearing over the next few years," Simon said in the statement.
Saturn's northern hemisphere will reach autumnal equinox on May 6, 2025, per NASA. Perhaps this will be the decade scientists finally solve the spoke mystery, once and for all.
https://www.msn.com/en-us/news/technology/mysterious-ghostly-shadows-larger-than-planet-earth-reappeared-on-saturn-s-rings-nasa-says-it-expects-even-more-to-appear-soon/ar-AA1magKR
Defense specialist encounters unidentified object 'going faster than the speed of sound underwater' while doing classified work on the Navy's USS Hampton submarine
UPDATED: 16:43 EST, 29 December 2023
Satellites are searching for alien life on distant planets, but a scientist's strange encounter suggests we may want to look deeper into our world.
Bob McGwire, a professor at Virginia Tech and with the Institute for Defense Analyses, was carrying out classified work on the USS Hampton submarine when he heard the sound of 'something whizzing by.'
The onboard sonar determined the unidentified submerged object (USO) was traveling through the water faster than the speed of sound, he has calimed.
Such speeds underwater should have crushed the submarine, according to McGwire, but he said it was as if they were standing still.
McGwire said he urged the naval team to report the encounter, but they determined it would hinder the mission.
'When I left there with the knowledge in my head, not having been told to be quiet, not having been told it was classified… It is mine to tell whoever I want. They blew it,' McGwire said, noting he would not discuss the classified work done on the sub.'
The strange incident happened in the late 1990s, but McGwire recently came forward with the story on the YouTube channel UAP Society, where he wanted to 'blow the whole thing wide open.'
The story has also resurfaced online, sparking the attention of many people on social media who 'wonder what it was.'
McGwire has not shared what he was doing on the the Navy submarine, the location and depth it was at due to the information being classified.
The engagement lasted for just a few seconds, he said.
'We were underway, and, all of a sudden, I heard a sound. It is really strange and clear that something is whizzing by us,' said McGwire.
The Los Angeles-class fast attack submarine USS Hampton (SSN 767) is assigned to Submarine Squadron 11 in San Diego, California.
McGwire boarded the sub from an undisclosed location and snapped a picture before heading down into the depths of the sea.
The USS Hampton is limited by how fast it can travel due to the incompressibility of water in front of it, but the USO 'blew by' the sub.
'A person with knowledge of onboard systems' who was likely monitoring the sonar tech is said to have announced that something just soared past the submarine faster than the speed of sound, McGwire said during the YouTube interview.
Sound travels faster in water, about 3,330 miles per hour because the liquid is about 1,000 times denser than air.
The only manmade object comparable would be Russia's Shkval torpedo, but this can only hit speeds of 230 miles per hour.
And the fastest sea animal is the sailfish, which can swim 68 miles per hour.
Lehto said that McGwire 'has extensive experience in the Navy' and has done work with classified radio frequencies.
McGwire has also served as a high-security-clearance intelligence officer and has a Ph.D. from Brown University.
While the account is bizarre, McGwire's statements echo the 2021 video showing US Naval personnel having a close encounter with an unidentified flying object (UFO).
https://www.dailymail.co.uk/sciencetech/article-12910629/defense-specialist-unidentified-object-navy-submarine.html
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