These glowing wisps are the visible remains of a star that went supernova about 7,000 years ago. Today the supernova remnant is known as the Veil Nebula and is visible only through telescopes. In the image, red marks hydrogen gas and blue marks oxygen. First carried by shock waves, these remains of a former star now serve as seed material for other stars and planetary systems to form. (Image credit: A. Alharbi; via APOD)
Tag: shockwave
Cat’s Eye Halo
The Cat’s Eye Nebula is a planetary nebula located in the Draco constellation. At its center is a dying star. Seen here is the faint halo that stretches 3 light-years around the central nebula. The filaments of the halo are estimated to be 50,000 to 90,000 years old and were shed during earlier periods in the star’s evolution. Their shape is reminiscent of Rayleigh-Taylor instabilities, to my eye. (Image credit: T. Niittee; via APOD)
Fediverse Reactions
-
Interstellar Jets
This JWST image shows a couple of Herbig-Hero objects, seen in infrared. These bright objects form when jets of fast-moving energetic particles are expelled from the poles of a newborn star. Those particles hit pockets of gas and dust, forming glowing, hot shock waves like those seen here in red. The star that birthed the object is out of view to the lower-right. The bright blue light surrounded by red spirals that sits near the tip of the shock waves is actually a distant spiral galaxy that happens to be aligned with our viewpoint. (Image credit: NASA/ESA/CSA/STScI/JWST; via APOD)
Fediverse Reactions
-
Imaging a New Era of Supersonic Travel
Supersonic commercial travel was briefly possible in the twentieth century when the Concorde flew. But the window-rattling sonic boom of that aircraft made governments restrict supersonic travel over land. Now a new generation of aviation companies are revisiting the concept of supersonic commercial travel with technologies that help dampen the irritating effects of a plane’s shock waves.
One such company, Boom Supersonic, partnered with NASA to capture the above schlieren image of their experimental XB-1 aircraft in flight. The diagonal lines spreading from the nose, wings, and tail of the aircraft mark shock waves. It’s those shock waves’ interactions with people and buildings on the ground that causes problems. But the XB-1 is testing out scalable methods for producing weaker shock waves that dissipate before reaching people down below, thus reducing the biggest source of complaints about supersonic flight over land. (Image credit: Boom Supersonic/NASA; via Quartz)
Fediverse Reactions
-
Tracking Tonga’s Boom
When the Hunga Tonga-Hunga Ha’apai volcano erupted in January 2022, its effects were felt — and heard — thousands of kilometers away. A new study analyzes crowdsourced data (largely from Aotearoa New Zealand) to estimate the audible impact of the eruption. The researchers found that the volume, arrival time, and nature of the rolling rumble reported by survey takers correlated well with seismic measurements. But humans provided data that monitoring equipment couldn’t. For example, reports of shaking buildings and rattling windows let researchers estimate the shock wave‘s overpressure far from the volcano. The team suggests that acting quickly to collect human impressions of rare events like this one can add valuable data that’s otherwise overlooked. (Image credit: NASA; research credit: M. Clive et al.; via Gizmodo)
A Dandelion-Like Supernova Remnant
In 1181 CE, astronomers in China and Japan recorded a new, short-lived star in the constellation Cassiopeia. After burning for nearly six months, this historic supernova disappeared from the naked eye. It was only in 2013 that an amateur astronomer identified a nebula in the vicinity of that supernova, and, in the years since, astronomers have collected evidence that identifies the object, known as Pa 30, as the remnants of that 1181 supernova. Now, astronomers have mapped the supernova remnant, revealing an unusual dandelion-like structure (shown in an artist’s conception above and below). Filaments of sulfur project outward from a dusty central region that houses the remains of the original star. Normally, a supernova destroys its original star, but this was a Type Iax supernova, a “failed” explosion that left behind a hot, inflated star that may eventually cool into a white dwarf star.
Why the supernova remnant has this strange shape remains unclear. Scientists speculate that shock waves may have helped concentrate sulfur into these clumpy filaments. The material’s velocity suggests a ballistic trajectory (meaning, essentially, that it has neither sped up nor slowed down since the original explosion). Winding the trajectory backwards pegs their origin to 1181, helping confirm that Pa 30 is, indeed, the remains of that 1181 supernova. (Image and video credit: W.M. Keck Observatory/A. Makarenko; research credit: R. Fesen et al.; via Gizmodo)
Gigapixel Supernova
Eleven thousand years ago, a star exploded in the constellation Vela, blowing off its outer layers in a spectacular shock wave that remains visible today. Today’s image is a piece of a 1.3-gigapixel composite image of the supernova remnant, captured by the Dark Energy Camera of the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile. Below is a labeled version of the image, identifying the original star — now a fast-spinning pulsar that packs our sun’s mass into an object only kilometers across — its shock wave, and other features. To explore the full-sized image, see NOIRLab. (Image credit: CTIO/NOIRLab/DOE/NSF/AURA; via Colossal)
A labeled version of the image shows the shock wave and other features. 
Simeis 147
Sometimes known as the Spaghetti Nebula, Simeis 147 is the remnant of a supernova that occurred 40,000 years ago. The glowing filaments of this composite image show hydrogen and oxygen in red and blue, respectively. These are the outlines of the shock waves that blew off the outer layers of the one-time star within. What remains of that star’s core is now a pulsar, a fast-spinning neutron star with a solar wind that continues to push on the dust and gas we see here. (Image credit: S. Vetter; via APOD)
Lasers and Soap Films
Soap films are a great system for visualizing fluid flows. Researchers use them to look at flags, fish schooling and drafting, and even wind turbines. In this work, researchers explore the soap film’s reaction to lasers. When surfactant concentrations in the soap film are low, laser pulses create shock waves (above) in the film that resemble those seen in aerodynamics. The laser raises the temperature at its point of impact, lowering the local surface tension. That temperature difference triggers a Marangoni flow that draws the heated fluid outward. The low surfactant concentration gives the soap film relatively high elasticity, and that allows the shock waves to form.
In contrast, a soap film with a high concentration of surfactants has relatively little elasticity. In these films (below), the laser creates a mark that stays visible on the flowing soap film. This “engraving” technique could be used to visualize flow in the soap film without using tracer particles. (Image and research credit: Y. Zhao and H. Xu)
When surfactant concentrations are high, a laser pulse “engraves” spots onto a flowing soap film. Shown in terms of interference (left) and Schlieren (right) imaging. 
Can Explosions Deflect Bullets?
In one of their most Mythbusters-like videos ever, the Slow Mo Guys ask: can an explosion deflect a bullet? To find out, they built out a system to trigger a C4 explosive using a 9mm bullet, all while watching with a series of high-speed cameras. As you’d expect, there are lots of blast waves and neat flame propagation to watch. As for the fundamental question, well, you’ll have to watch to find out! (Video and image credit: The Slow Mo Guys)
