Universe Today
Chandrasekhar and the Limits of Physics, Part 3: Exile and Beauty
Driven from Europe by the feud, Chandrasekhar rebuilt his life in America and turned mastery-and-move-on into an art form. On his conviction that beautiful physics is true physics, and the two students he drove through blizzards to teach.
The Milky Way's Most Powerful Particle Accelerator
Astronomers have conclusively identified a source of the highest energy cosmic ray protons in the Milky Way, solving a long standing puzzle near the star Altair. By combining gamma ray, radio, and X-ray data from three separate observatories, a Hiroshima University led team ruled out competing explanations and confirmed the object as a genuine “PeVatron”. These natural particle accelerators are far more powerful than anything humans have ever built and helps us in the hunt for similar sources across the Galaxy.
Electrically Charged Mars Storms Threaten Future Exploration
Martian dust storms are some of the most fascinating and mysterious planetary surface processes ever observed, as Earth, Mars, and Saturn’s moon Titan are the only known planetary bodies to have active dust storms. However, the major difference for Mars is its dust storms can blanket the entire planet at once, resulting in the surface becoming completely unobservable and blocking out sunlight, with the scientific community concerned this might hinder robotic, and even human, space exploration. But what if covering the surface and blocking sunlight wasn’t the only issue Martian global dust storms pose for future missions?
NASA's Psyche Spacecraft Captured a Time-Lapse Video of its Mars Flyby
NASA's Psyche mission used a gravity assist maneuver at Mars to gain velocity and adjust its trajectory to its eventual target. The asteroid 16 Psyche is a metal-rich asteroid that may be the remnant rocky core of a protoplanet. The flyby not only shepherded the spacecraft on to its target, it was also an opportunity to test Psyche's science instruments and cameras. NASA has released a timelapse of the flyby.
Astronomers Are Still Trying to Understand How a Galaxy's Spiral Arms Form
Spiral galaxies, including grand spirals like the Whirlpool galaxy, are plentiful. But it's still a mystery how their spiral arms form and persist for hundreds of millions of years, and why some galaxies have one, two, or three or more arms. New research based on Euclid data finds links between galaxy mass, star formation rate, and number of arms, and hints at their formation.
Astronomers Catch a "Dark Comet" Red-Handed
Our ability to track and visualize small rocks in space is still improving. And occasionally we’ll find a space rock that will remind us of that fact. One such rock is detailed in a new paper, led by Davide Farnocchia of NASA’s Jet Propulsion Laboratory, and recently published in Nature Astronomy, where the research team discovered what they thought was a normal, run of the mill asteroid, was actually a “dark comet”.
800 Million Years Ago, a Catastrophic Asteroid Breakup Rained Fire on the Inner Solar System
On Earth, it’s hard to track events that reshape its surface, as the surface itself is being reshaped constantly by weather and tectonic or volcanic upheavals. However, the Moon is much more static, and scientists have been slowly unraveling a pattern that is noticeable in its craters - that something dramatic happened around 800 million years ago. A new paper by researchers at the Southwest Research Institute (SwRI), led by Dr. William F. Bottke, and accepted for publication in the Planetary Science Journal, suggests they might have found a culprit - the parent body of a family of asteroids now known as Eulalia.
Catch Comet 10P Tempel While You Can
A low-number periodic comet is stalking our fair planet this summer, and putting on its best show of several generations. We’re talking about Comet 10P/Tempel. The comet is currently loitering in the early dawn sky, presenting a good target for large binoculars or a small telescope. But act fast, as the comet is taking the plunge southward in August, post-perihelion.
Chandrasekhar and the Limits of Physics, Part 2: Humiliation
In 1935 the most eminent astronomer alive stood up in a packed room and called Chandrasekhar's discovery "stellar buffoonery." The story of Arthur Eddington's years-long campaign against a result that everyone privately knew was correct.
Researchers Narrow Down the Type of Meteorite that Killed the Dinosaurs
An international team of Earth scientists has narrowed down the class of impactor that caused the Cretaceous-Paleogene extinction event. According to their findings, it was a rare type of rock that originated in the outer Solar System.
Astronomers Determine that Exoplanets Around Barnard's Star are Extremely Uninhabitable
Scientists have painted the most detailed portrait yet of the planetary system orbiting Barnard’s Star. Unfortunately, the picture is not encouraging, as all four planets appear to be "extremely uninhabitable."
Meet Our Newest Stellar Neighbours That Hid in the Glare of Other Stars
Astronomers have found four new white dwarfs within about 65 light years. Even though the sky has been studied thoroughly, these escaped detection. That's because they're tight binaries with red dwarf partners, and the much brighter red dwarfs hide the white dwarfs. The binaries used to share common envelopes.
Finding Venus Zone Planets with PLATO Will Show Us How Habitable Planets Evolve
While simply finding exoplanets was an important first step in exoplanet science, more ambitious goals await. The ESA will launch PLATO in 2027 to search for rocky planets. But it will also find planets in the Venus Zone, a region bounded on its outer edge by a runaway greenhouse climate and on the inner edge by loss of atmosphere due to stellar flux. Understanding these planets will help scientists understand how Earth's path led to sustained habitability, while Venus, its sister planet, ended up with a runaway greenhouse climate.
A Star Orbiting Our Galaxy's Supermassive Black Hole Tests the Limits of Relativity
A Sun-like star orbits the supermassive black hole in our Milky Way so closely that it comes within the distance of Neptune's orbit of the Sun. It has a top speed of more than 8% of light speed. With such extreme motion the star gives astronomers the opportunity to test the limits of general relativity.
Chandrasekhar and the Limits of Physics, Part 1: Triumph
The story of Subrahmanyan Chandrasekhar, who as a teenager on an ocean voyage worked out that white dwarf stars have a maximum mass of 1.4 Suns. A tour of degeneracy pressure, the relativistic insight everyone else missed, and the number that would define his life.
The Case of the Sun's Missing Silver
Astronomers have solved a decades old puzzle about the Sun's missing silver, not by finding something new, but by modelling something old far more accurately. A revised, more realistic model of the Sun's atmosphere reveals it actually contains 55 per cent more silver than previously calculated, finally matching what meteorites have been telling us all along. It's a quiet reminder that some of the biggest revelations in astronomy come not from new data, but from asking familiar questions with sharper tools.
The First Breath of Another World
Astronomers have detected an atmosphere around a rocky planet in another star's habitable zone for the very first time. It’s a milestone that brings us a step closer to answering whether life could exist beyond our Solar System. Predicted by a mathematical model before it was ever observed, and confirmed using a rare planetary alignment 48 light years away, this discovery does more than identify one intriguing world, it provides us with a whole new way to search for others like it.
NASA's Perseverance Rover Uncovers Evidence of 4 Billion Year Old Impacts
Old rocks exposed on the rim of Jezero Crater preserve a roughly 4-billion-year-old cosmic “weather report” from the solar system’s most dynamic era.
NASA’s Artemis III Lander Test Will be a "Dress Rehearsal" for Returning to the Moon!
Before Artemis astronauts land on the Moon’s surface in 2028, NASA will conduct the Artemis III demonstration mission in 2027, allowing teams on Earth and in orbit to practice rendezvous and docking operations between commercial human landing systems and the Orion spacecraft. Data from that mission, along with future uncrewed demonstration missions at the Moon,
Submillimeter Array Catches a Gamma-Ray Burst Thanks to new Fast-Response System
The Submillimeter Array's (SMA) new semi-automated alert system demonstrates how the radio interferometer quickly responds to discoveries from space-based telescopes.
