Space

Astronomers have used the James Webb and Hubble space telescopes to confirm one of the most troubling conundrums in all of physics — that the universe appears to be expanding at bafflingly different speeds depending on where we look.

This problem, known as the Hubble Tension, has the potential to alter or even upend cosmology altogether. In 2019, measurements by the Hubble Space Telescope confirmed the puzzle was real; in 2023, even more precise measurements from the James Webb Space Telescope (JWST) cemented the discrepancy.

Now, a triple-check by both telescopes working together appears to have put the possibility of any measurement error to bed for good. The study, published February 6 in the Astrophysical Journal Letters, suggests that there may be something seriously wrong with our understanding of the universe.

More info from Britannica

Ignition! is part memoir and part history book from the 70's, written by John D. Clark who was an American rocket fuel chemist.

It doesn't go too deep into the chemistry side of things, so even if you're like me and don't understand that side at all you might enjoy reading it if you're into space history nerdery. Clark had a pretty hilarious writing style, so it's a surprisingly entertaining book considering the subject matter. As an example, here's what he had to say about chlorine trifluoride:

All this sounds fairly academic and innocuous, but when it is translated into the problem of handling the stuff, the results are horrendous. It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water — with which it reacts explosively. It can be kept in some of the ordinary structural metals — steel, copper, aluminum, etc. — because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminum keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.

"Engineers are optimistic they can find a way for the FDS to operate normally."

https://archive.is/SRZ5P

https://esawebb.org/images/potm2403b/

[Image Description: Many small galaxies are scattered on a black background: mainly, white, oval-shaped and red, spiral galaxies. The image is dominated by a dwarf irregular galaxy, which hosts a bright region of white and blue stars at its core that appear as two distinct lobes. This region is surrounded by brown dusty filaments. At the bottom centre of the image, a companion galaxy is visible that appears as a collection of blue stars.]

Cropped version

https://www.flickr.com/photos/197464132@N05/53610345625/

cross-posted from: https://lemm.ee/post/27670808

RocketStar Announces Successful Demonstration of Fusion-Enhanced Pulsed Plasma Electric Propulsion

https://esawebb.org/images/weic2408a/

[Image description: A face-on spiral galaxy with four spiral arms that curve outward in a counterclockwise direction. The spiral arms are filled with young, blue stars and peppered with purplish star-forming regions that appear as small blobs. The middle of the galaxy is much brighter and more yellowish, and has a distinct narrow linear bar angled from 11 o’clock to 5 o’clock. Dozens of red background galaxies are scattered across the image. The background of space is black

https://esawebb.org/images/weic2407d/

[Image description: At the centre of the image is a nebula on the black background of space. The nebula is composed of clumpy, red, filamentary clouds. At the centre-right of the red clouds is a large cavernous bubble, and at the centre of the bubble there is an opaque blue glow with speckles of stars. At the edges of the bubble, the dust is white. There are several other smaller cavernous bubbles at the top of the nebula. There are also some smaller, red stars and a few disc-shaped galaxies scattered about the image.]

This is a part of a Rocket Engineer's ongoing series of live reviews on various Space missions, mostly NASA

Full disclosure: He does acknowledge that the most likely explanation is that it's not aliens.

"Misinterpretation is obviously the most boring on that list, which perhaps means it's the most likely to be the case. ... No one's ever actually put this stuff in a 10,000-Kelvin oven and measured how they absorb light. So the characteristic frequencies are theoretical, and it's quite possible that they are slightly wrong, and instead of seeing radioactive elements, we are instead seeing a far more mundane set of elements just behaving in an unexpected way."

https://esawebb.org/images/WR140a/

[Image Description: The background of this Webb image of star Wolf-Rayet 140 is black. A pair of bright stars dominates the center of the image, with at least 17 pink-orange concentric dust rings emanating from them. Throughout the scene are a range of distant galaxies, the majority of which are very tiny and red, appearing as splotches.]

Each ring was created when the two stars came close together and their stellar winds (streams of gas they blow into space) met, compressing the gas and forming dust. The stars’ orbits bring them together about once every eight years; like the rings of a tree’s trunk, the dust loops mark the passage of time.

https://esawebb.org/images/potm2306a/

[Image Description: A large, face-on spiral galaxy. The core is radiating very brightly. Streaks of dust glow intensely red, in the centre and across most of the galaxy. This gas is surrounded by a dark grey halo made of the galaxy’s stars. The halo stretches out into a tidal tail at the upper-left, and another at the bottom. Small stars and galaxies surround the spiral galaxy, on a black background.]

https://esawebb.org/images/weic2322a/

[Image description: At the centre is a thin horizontal multi-coloured cloud tilted from bottom left to top right. At its centre is a dark brown cloud from which both outflows are spewing from. These outflows transition from colours of yellow/orange, to a light blue region, with prominent light pink features in the outer regions.]

https://esawebb.org/images/weic2319a/

[Image description: At the centre is a thin horizontal orange cloud tilted from bottom left to top right. It takes up about two-thirds of the length of this angle, but is thin at the opposite angle. At its centre is a set of very large red and pink diffraction spikes in Webb’s familiar eight-pointed pattern. It has a central yellow-white blob, which hides two tightly orbiting stars. The background is filled with stars and galaxies.]

https://esawebb.org/images/weic2316a/

[Image description: Red dual opposing jets coming from young stars fill the darker top half of the image, while a glowing pale-yellow, cave-like structure is bottom centre, tilted toward two o’clock, with a bright star at its centre. The dust of the cave structure becomes wispy toward eight o’clock. Above the arched top of the dust cave three groupings of stars with diffraction spikes are arranged. A dark cloud sits at the top of the arch of the glowing dust cave, with one streamer curling down the right-hand side. The dark shadow of the cloud appears pinched in the centre, with light emerging in a triangle shape above and below the pinch, revealing the presence of a star inside the dark cloud. The image’s largest jets of red material emanate from within this dark cloud, thick and displaying structure like the rough face of a cliff, glowing brighter at the edges. At the top centre of the image, a star displays another, larger pinched dark shadow, this time vertically. To the left of this star is a more wispy, indistinct region.]