INFORMATION

String theory, like most revolutions, had humble origins. It started all the way back in the 1960’s as an attempt to understand the workings of the strong nuclear force, which had only recently been discovered. Quantum field theory, which had been used successfully to explain electromagnetism and the weak nuclear force, wasn’t seeming to cut it, and so physicists were eager for something new. A group of physicists took a formalism developed (and later abandoned) by quantum godfather Werner Heisenberg and expanded it. In that expansion they found mathematical structures that repeated themselves in spacetime: the first strings. Unfortunately this proto-string theory made incorrect predictions for the nature of the strong force , and also had a variety of troublesome artifacts (like the existence of tachyons, particles that only traveled faster than light). Once another theory came into prominence, the one we know today based on quarks and gluons, string theory faded from the scene. Bu...

The Fermi Gamma-ray Space Telescope , named in honor of noted physicist Enrico Fermi, has been in operation for almost a decade and a half, monitoring the cosmos for gamma rays. As the highest-energy form of light, these rays are produced by extremely energetic phenomena – like supernovae, neutron stars, quasars, and gamma-ray bursts (GRBs). In honor of this observatory’s long history, NASA’s Goddard Spaceflight Center has released a time-lapse movie that shows data acquired by the Fermi Space Telescope between August 2008 and August 2022. The movie shows gamma rays with energies above 200 million electron volts (MeV), where brighter colors indicate more intense gamma-ray sources detected by Fermi’s Large Area Telescope (LAT) during its 14-year run. The movie also shows the gamma-ray sky from two perspectives. First, there’s the rectangular view that shows a full-sky view with the central plane of the Milky Way Galaxy in the center. The disk glows predominantly from gamma rays prod...

In November, we reported how an impact on the Moon from a Chinese Long March rocket booster created an unusual double crater. For a single booster to create a double crater, some researchers thought there must have been an additional – perhaps secret – payload on the forward end of the booster, opposite from the rocket engines. But that may not necessarily be the case. Other researchers feel the extra mass wasn’t anything secretive, but possibly an inert structure such as a payload adapter added to the rocket to support the primary mission payload. Chang’e 5-T1 was an experimental robotic spacecraft, launched on October 23, 2014, by the China National Space Administration (CNSA) to test out the return capsule design planned for use on the future Chang’e 5 mission, China’s first-ever sample-return effort. Chang’e 5 landed on the Moon in November 2020 and successfully gathered lunar samples from the Moon’s Ocean of Storms region, with the container landing back on Earth on December 1...

Living in space comes with risks. For astronauts on the International Space Station (ISS), those risks occasionally make themselves intrusively apparent. Earlier this month, European Space Agency astronaut Andreas Mogensen snapped a photo of the Canadarm2, in which damage from a micrometeorite impact is clearly visible. “The hole was made in 2021, where a 1 mm object, traveling at over 25,000 km/h relative to the Space Station hit the robotic arm. Fortunately, no critical components were damaged,” said Mogensen on social media. The impact punched through the arm’s thermal blanket and impacted the boom. The robotic arm, which has been in service on the ISS for over twenty years, continues to function normally. But the ISS isn’t always so lucky. In October, the Nauka science module suffered damage from a similar micrometeorite impact, causing 72 litres of coolant to leak from the module’s radiator out into space. After determining that the leaking coolant might contaminate astronau...

On December 14th , at 12:02 PM Eastern (09:02 AM Pacific), the Sun unleashed a massive solar flare. According to the Space Weather Prediction Center , part of the National Oceanic Atmospheric Administration (NOAA), this was the strongest flare of Solar Cycle 25 , which began in 2019 and will continue until 2030. What’s more, scientists at the SWPC estimate that this may be one of the most powerful solar flares recorded since 1755 when extensive recording of solar sunspot activity began. Solar flares occur in the Sun’s active regions, and activity varies over an 11-year solar cycle. This phenomenon is believed to result from stored magnetic energy in the Sun’s atmosphere accelerating charged particles in the surrounding plasma. These flares release radiation across the electromagnetic spectrum and are often accompanied by Coronal Mass Ejections (CME) and other solar phenomena. According to the SWPC, this recent flare may have triggered an Earth-bound CME, which they are currently ana...

Astronomers have been observing Saturn with the Hubble Space Telescope and several other spacecraft for decades and have noticed something unusual. During seasonal changes, transient spoke-like features appear in the rings. These dark, ghostly blobs orbit around the planet 2-3 times, and then disappear. As Saturn is approaching its equinox, this is prime spoke activity time. Once again, Hubble has been called to gaze at Saturn, tracking the behavior of the spokes and hopefully giving astronomers more clues as to why they occur. Earlier this year in February, Hubble took an image showing the spokes only on one side of the rings. The latest image, above, taken on October 22, 2023, shows spokes structures appearing on both sides of the planet simultaneously as they spin around the giant world. While these features might look small compared with Saturn, their length and width can stretch longer than Earth’s diameter. The spokes were first seen by the Voyager missions in the 1980s, an...

A quarter century ago, physicist Juan Maldacena proposed the AdS/CFT correspondence, an intriguing holographic connection between gravity in a three-dimensional universe and quantum physics on the universe’s two-dimensional boundary. This correspondence is at this stage, even a quarter century after Maldacena’s discovery, just a conjecture. A statement about the nature of the universe that seems to be true, but one that has not yet been proven to actually reflect the reality that we live in. And what’s more, it only has limited utility and application to the real universe. Still, even the mere appearance of the correspondence is more than suggestive. It’s telling that there is something deeply fundamental to the hologram, that the physics of the volume of the universe might just translate to the physics on the surface, and that there is more to be learned there. It’s one thing to cast problems of physics in a new language, even a new set of dimensions, to make them easier to solve....