JUICE in Trouble, Sun-Like Star Devours a Planet, Space Station with Artificial Gravity
JUICE is having problems extending its radar antenna. Astronomers watch a star eat its planet. A design for a space station with artificial gravity.
JUICE Has Problems
ESA’s Jupiter Ice Moons Explorer spacecraft is on its way to the Jovian System, where it’ll be mapping out several of its icy moons. Unfortunately, a critical antenna has failed to deploy. The 16-meter radar antenna should have been fully deployed, but it’s only unfolded about a third of the way. Engineers think a tiny pin might be protruding out and blocking it from extending. Their next plan is to try firing its engines to shake the spacecraft and deploy the antenna. They’ve still got time. Juice won’t arrive at Jupiter until 2031.
More about JUICE antenna problems
Sun-Like Star Eats its Planet
Astronomers witnessed a star devouring one of its planets. In the past, we’ve seen evidence of such events but never saw it actually happen. A hot Jupiter got to close to its parent star and got destroyed by the tidal forces. It was just 12,000 light-years away, so pretty close. Actually, the Earth might one day follow the same path when the Sun becomes a red giant and expands.
More about the planet getting eaten by its star
Although SpaceX’s Starship cleared the launch pad, it didn’t make it to orbit. Instead, the enormous rocket gouged out a giant hole in the concrete at its launch pad and rained debris around it. The flight termination system failed to destroy the rocket as quickly as SpaceX had hoped. Because of these issues, the FAA has placed an indefinite hold on rocket launches from Boca Chica while SpaceX fixes the problems. According to Elon Musk, they’ll be ready for another test in 6-8 weeks, but we’ll see if they clear the regulatory hurdles by then.
More about SpaceX Starship
Space Station With Artificial Gravity
Airbus showed a concept of an orbital space station called Loop. One interesting aspect of it is a centrifuge at the bottom. It is designed to provide some extent of artificial gravity to mitigate the negative effects that weightlessness has on the human body. So far there have been few realistic concepts of space stations that incorporate artificial gravity. However, it is worth noting that Loop is also just a concept for now with no announced plans for development or launch.
More about Airbus Loop space station
Starship | First Integrated Flight Test | Recap
Starship gave us quite a show during the first flight test of a fully integrated Starship (S24) and Super Heavy rocket (B7) from Starbase in Texas.
On April 20, 2023 at 8:33 a.m. CT, Starship successfully lifted off from the orbital launch pad for the first time. The vehicle cleared the pad and beach as Starship climbed to an apogee of ~39 km over the Gulf of Mexico – the highest of any Starship to-date.
With a test like this, success comes from what we learn, and we learned a tremendous amount about the vehicle and ground systems today that will help us improve on future flights of Starship.
Did you miss our previous article…
ARABSAT BADR-8 Mission Control Audio
This is the vehicle trajectory and mission control audio without any additional commentary. There may be very long periods of silence. For our full hosted webcast, visit
Did you miss our previous article…
When Black Holes Merge, They’ll Ring Like a Bell
When two black holes collide, they don’t smash into each other the way two stars might. A black hole is an intensely curved region of space that can be described by only its mass, rotation, and electric charge, so two black holes release violent gravitational ripples as merge into a single black hole. The new black hole continues to emit gravitational waves until it settles down into a simple rotating black hole. That settling down period is known as the ring down, and its pattern holds clues to some of the deepest mysteries of gravitational physics.
Gravitational wave observatories such as the Laser Interferometry Gravitational-Wave Observatory (LIGO) have mostly focused on the inspiral period of black hole mergers. This is the period where the two black holes orbit ever closer to each other, creating a rhythmic stream of strong gravitational waves. From this astronomers can determine the mass and rotation of the original black holes, as well as the mass and rotation of the merged black hole. The pattern of gravitational waves we observe is governed by Einstein’s general relativity equations, and by matching observation to theory we learn about black holes.
General relativity describes gravity extremely well. Of all the gravitational tests we’ve done, they all agree with general relativity. But Einstein’s theory doesn’t play well with the other extremely accurate physical theory, quantum mechanics. Because of this, physicists have proposed modifications to general relativity that are more compatible with quantum theory. Under these modified theories, there are subtle differences in the way merged black holes ring down, but observing those differences hasn’t been possible. But a couple of new studies show how we might be able to observe them in the next LIGO run.
The modified Teukolsky equation. Credit: Li, Dongjun, et al
In the first work, the team focused on what is known as the Teukolsky Equation. First proposed by Saul Teukolsky, the equations are an efficient way of analyzing gravitational waves. The equations only apply to classical general relativity, so the team developed a way to modify the equations for modified general relativity models. Since the solutions to both the Teukolsky and modified Teukolsky equations don’t require a massive supercomputer to solve, the team can compare black hole ring downs in various gravitational models.
The second work looks at how this would be done with LIGO data. Rather than focusing on general differences, this work focuses on what is known as the no-hair theorem. General relativity predicts that no matter how two black holes merge, the final merged black hole must be described by only mass, rotation, and charge. It can’t have any “hair”, or remnant features of the collision. In some modified versions of general relativity, black holes can have certain features, which would violate the no-hair theorem. In this second work, the authors show how this could be used to test general relativity against certain modified theories.
LIGO has just begun its latest observation run, so it will be a while before there is enough data to test. But we may soon have a new observational test of Einstein’s old theory, and we might just prove it isn’t the final theory of gravity after all.
Reference: Li, Dongjun, et al. “Perturbations of spinning black holes beyond General Relativity: Modified Teukolsky equation.” Physical Review X 13.2 (2022): 021029.
Reference: Ma, Sizheng, Ling Sun, and Yanbei Chen. “Black hole spectroscopy by mode cleaning.” Physical Review Letters 130.2 (2023): 141401.
The post When Black Holes Merge, They’ll Ring Like a Bell appeared first on Universe Today.
Did you miss our previous article…
Mens Health3 years ago
8 Things I Do Before 8 Am: My Morning Routine
Fashion2 years ago
Best Timepieces To Buy For The Holiday Season
Fashion3 years ago
Steampunk Clothing & Jewelry
Sports2 years ago
Best Christmas Gift For Your Golfer Co-Worker
Trending Stories2 years ago
Dior Homme Cologne Men’s Fragrance Review
Motor2 years ago
2022 Infiniti QX55 Carigami Can Be Yours
Uncategorized3 years ago
How To Attract Women Easily (Without Talking)
Grooming3 years ago
5 Men’s Hairstyles For Thin Hair – Haircuts For Receding Hairlines