Free Republic

Explanation: Orion never had a sword like this. As Comet C/2025 R3 (PanSTARRS) heads out of the inner Solar System, it is putting on quite a show for long exposure cameras. Currently seen toward the constellation of Orion the Hunter, the distant Orion Nebula is visible on the upper right. Comet R3 PanSTARRS is now showing two distinct tails: a short dust tail pointing toward the top of the image and a long and wavy ion tail trailing off toward the upper left. The ion tail points away from the Sun and glows blue from excited carbon monoxide. Large particles...

In a new physics milestone, scientists report that a time crystal and an external system have been successfully linked for the first time. The achievement, made by researchers at Aalto University’s Department of Applied Physics, marks the first demonstration of converting a time crystal—an unusual quantum system in which particles are in constant, repetitive motion in its ground state—into an optomechanical system. A range of potential technological applications, including new high-precision sensors, quantum storage systems, and other innovative capabilities, could result from the research, led by Jere Mäkinen and detailed in a new paper appearing in Nature Communications. A New...

Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by the extremely shallow-angle trajectory followed by an impactor, moving left to right, that gouged out the craters. The shallow impact also resulted in two...

The beams are an in-kind contribution from CERN. Matthew Kapust / SURF The US has begun lowering 10 million pounds of steel nearly a mile underground to build the Deep Underground Neutrino Experiment (DUNE), widely regarded as one of the world’s most ambitious particle physics experiments. The Fermi National Accelerator Laboratory (Fermilab), the premier US national lab for high-energy particle physics announced the start of the underground detector assembly for the massive neutrino project in South Dakota on May 7. It is carried out along with the Sanford Underground Research Facility and CERN. Transported deep underground, the steel beams will...

Beneath a section of Chicago, there is a hidden several mile wide impact crater. This might initially seem like a crazy claim but it is true, existing underneath the city of Des Plaines. The only reason it isn't highly visible today is due to sediments emplaced during extensive glaciers during the last 2 million years. It is for this reason that I will discuss when this crater formed, what evidence we have, and what immediate effects its formation had. Thumbnail Photo Credit: Google Earth. This image was overlaid with text, and then overlaid with GeologyHub made graphics (the image border,...

Explanation: Which way is Comet R3 PanSTARRS going? Not towards the star at the top of the image, because that is Rigel, which, being far in the background, is unrelated to the comet. Not through the nebula in the image middle, because that is the Witch Head Nebula and it, too, is far in the distance -- but not far from Rigel. Not into northern skies because over the past week Comet C/2025 R3 (PanSTARRS) has moved into southern skies and is now best visible in Earth's Southern Hemisphere toward the west after sunset. Angularly, Comet R3 PanSTARRS is slowly...

Manned Circumnavigation of the Inner Solar System Posted on April 27, 2026 by Kirk Sorensen In 1969, a Bellcomm engineer named A. A. VanderVeen published a paper describing a family of trajectories so elegant they seem almost accidental. Fifty-five years later, the most attractive instance of that trajectory family departs Earth in August 2034. This post is about what it would mean to fly it. Back in February 2009, I opened a thread on the NASASpaceFlight.com forum with what I thought was a simple thought experiment: what interplanetary mission might be within reach of an extremely wealthy private individual —...

Explanation: A long time ago, in a distant galaxy, a massive star was destroyed in a supernova explosion. The light of this event travelled for tens of millions of years and reached Earth last week as Supernova 2026kid. The featured video shows a time-lapse over three nights of the host galaxy NGC 5907, an edge-on spiral also known as the Splinter or Knife Edge Galaxy, as the supernova appears and becomes brighter. (The occasional streaks are satellites in Earth orbit.) At its brightest, a supernova can outshine the sum of all other stars in its galaxy. Supernova 2026kid appears relatively...

Explanation: What does it mean for Saturn and Neptune to be in retrograde? Featured is a composite of images taken over 34 nights from May 2025 to February 2026 tracing Saturn (brighter, foreground) and Neptune (dimmer, background). Over that time, the two planets exhibited retrograde motion, meaning they appeared to move backward in the sky. This apparent backwards motion occurs when Earth overtakes the slower outer planets as they orbit the Sun. Imagine the Solar System is a running track. Earth "runs" faster along the inside of the track compared to the outer planets. As Earth approaches, aligns, and then...

How time travel could work: Scientists have uncovered a way to send messages into the past Time machines may seem better suited to science fiction than the physics lab, but experts say this futuristic technology could become a reality. Researchers have revealed how time travel could really work by using the laws of quantum physics. While their method won't let you hop back to the time of the dinosaurs, scientists say it could be possible to send messages into the past. The researchers even say this mind–bending technique would work just like in Christopher Nolan's sci–fi epic, Interstellar. In the...

A team of astronomers in Japan has detected a thin atmosphere around (612533) 2002 XV93, a trans-Neptunian object about 500 km in diameter — an object far too small and cold to retain one. An artist’s conception of the trans-Neptunian object 2002 XV93. Image credit: NAOJ. “In the cold reaches of the outer Solar System lie thousands of small objects known as trans-Neptunian objects (TNOs) because they lie outside the orbit of Neptune,” said Dr. Ko Arimatsu from Ishigakijima Astronomical Observatory and colleagues. “A thin atmosphere has been observed around Pluto, the most famous TNO, but studies of other TNOs...

Explanation: Orion is rarely seen like this. To achieve this majestic vista, you need a camera capable of taking such long duration exposures that faint features in the night sky become revealed. Iconic nebulas that appear include the Orion Nebula, the Flame Nebula, and Barnard's Loop. For contrast, it also helps to have a volcano on the foreground, in this case the Teide volcano on Tenerife on the Canary Islands of Spain. But if you want your Teide volcano snow-covered, you also need good timing -- because that only happens, typically, for a few days each year. Good timing also...

Explanation: Why are there huge, unusual masses inside the Earth? No one is sure. By noting how earthquakes rumble through our planet's interior, humanity has discovered two deep structures that appear to have unusual temperatures and/or chemical compositions. One hypothesis holds that the superplumes are sunken debris left over from the Earth-shattering collision that created Earth's Moon about 4.5 billion years ago. A competing hypothesis is that they are graveyards for old tectonic plates that slowly slid under each other over the past few billion years. No matter their origin, the superplumes are thought to affect Earth’s surface volcanism, possibly...

I still remember fondly the time I got an A- on my 8th grade earth science paper. It was one of my proudest moments as a student. Meanwhile, as MIT boasts, some folks are, well, a bit beyond that. Physics is riddled with paradoxes: Think of how information leaks from supposedly inescapable black holes or how the conventional laws of physics break down at the quantum scale. Sabrina Gonzalez Pasterski '13 believes that within these apparent contradictions, new discoveries await. Ah yes, "how the conventional laws of physics break down at the quantum scale." I think about that often! Well,...

Explanation: Dust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are slowly being eroded away by a hostile environment. Visible in the featured picture by the Hubble Space Telescope is the end of a huge gas and dust pillar in the Trifid Nebula (M20), punctuated by a smaller pillar pointing up and an unusual jet pointing to the upper left. Many of the bright dots are newly formed stars. A star near the small pillar's end is slowly being stripped of its accreting gas by radiation from a tremendously brighter star...

Explanation: Shrouded in a thick atmosphere, the surface of Saturn's largest moon, Titan, is really hard to see. Small particles suspended in Titan's upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding surface features from prying eyes. Still, Titan's surface is better imaged at infrared wavelengths, where scattering is weaker and atmospheric absorption is reduced. Arrayed around this visible light image (center) of Titan are some of the clearest global infrared views of the tantalizing moon so far. In false color, the six panels present a consistent processing of 13 years of infrared image...

The prototype thruster is enclosed in a condensable metal propellant (CoMeT) vacuum facility at NASA's JPL. NASA/JPL-Caltech NASA engineers recently tested a next-generation electric propulsion system that could one day power a crewed mission to Mars. NASA fired up a prototype of its electromagnetic thruster inside a vacuum chamber, reaching power levels of up to 120 kilowatts—the highest achieved in U.S. tests of an electric propulsion system. That’s over 25 times the power of the electric thrusters aboard the current Psyche mission, which launched in 2023 on a journey to explore a metal-rich asteroid. VIDEO AT LINK.......... “Designing and building...

Uranus in near-infrared. Image credit: NASA, ESA, CSA, STScI The rings of Uranus were only discovered in 1977 and the outer rings, named for the Greek letters μ and ν (mu and nu), have been a nice puzzle. First of all, they are different colors, with ν being redder and μ being bluer. This already hints at a difference in composition. New research now suggests a different origin for the two altogether. Researchers have combined observations from JWST, Hubble, and the Keck Observatory to better understand what these rings are made of and where they come from. “By decoding the...

Explanation: Near the heart of the Virgo Galaxy Cluster, a string of galaxies known as Markarian's Chain stretches across this telescopic field of view. Anchored in the frame at bottom right by prominent lenticular galaxies, M84 (bottom) and M86, you can follow the chain's gentle arc up and toward the left. Near center you'll spot the pair of interacting galaxies NGC 4438 and NGC 4435, known to some as Markarian's Eyes. An estimated 50 million light-years distant, the Virgo Cluster itself is the nearest galaxy cluster. With up to about 2,000 member galaxies, it has a noticeable gravitational influence on...

The five-year survey finished ahead of schedule and with more data, hinting at unexpected dark energy properties. The Dark Energy Spectroscopic Instrument (DESI) has achieved its goal. Every single area of the sky that the collaboration set out to map has been mapped, and slightly ahead of its five-year target. DESI was set to gather data on 34 million galaxies and quasars. The final tally of the survey was 47 million galaxies and quasars, the largest high-resolution 3D map of the Universe ever assembled. The ultimate goal is to understand dark energy. Dark energy is a crucial component that is...