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A Strange Black Hole Is Shooting Out Wobbly Jets Because It's Dragging Spacetime:
Some 7,800 light-years away, in the constellation of Cygnus, lies a most peculiar black hole. It's called V404 Cygni, and in 2015, telescopes around the world stared in wonder as it woke from dormancy to devour material from a star over the course of a week.
That one event provided such a wealth of information that astronomers are still analysing it. And they have just discovered an amazing occurrence: relativistic jets wobbling so fast their change in direction can be seen in mere minutes.
[...] V404 Cygni is a binary microquasar system consisting of a black hole about nine times the mass of the Sun and a companion star, an early red giant slightly smaller than the Sun.
The black hole is slowly devouring the red giant; the material siphoned away from the star is orbiting the black hole in the form of an accretion disc, a bit like water circling a drain. The closest regions of the disc are incredibly dense and hot, and extremely radiant; and, as the black hole feeds, it shoots out powerful jets of plasma, presumably from its poles.
[...] "We think the disc of material and the black hole are misaligned," [astrophysicist James] Miller-Jones said. "This appears to be causing the inner part of the disc to wobble like a spinning top and fire jets out in different directions as it changes orientation."
[...] It's a bit like a spinning top that starts to wobble as it's slowing down, the researchers said. This change in the rotational axis of a spinning body is called precession. In this particular instance, we have a handy explanation for it courtesy of Albert Einstein.
In his theory of general relativity, Einstein predicted an effect called frame-dragging. As it spins, a rotating black hole's gravitational field is so intense that it essentially drags spacetime with it. (This is one of the effects scientists hoped to observe when they took a picture of PÅwehi.)
In the case of V404 Cygni, the accretion disc is about 10 million kilometres (6.2 million miles) across. The misalignment of the black hole's rotational axis with the accretion disc has warped the inner few thousand kilometres of said disc.
The frame-dragging effect then pulls the warped part of the disc along with the black hole's rotation, which sends the jet careening off in all directions. In addition, that inner section of the accretion disc is puffed up like a solid doughnut that also precesses.
"This is the only mechanism we can think of that can explain the rapid precession we see in V404 Cygni," Miller-Jones said.
[...] the team had to [take] 103 separate images with exposure times of just 70 seconds and [stitch] them together to create a movie - and sure enough, there were the wibbly wobbly spacetimey jets.
A video explaining the activity is available on Vimeo.
A rapidly changing jet orientation in the stellar-mass black-hole system V404 Cygni, Nature (DOI: doi:10.1038/s41586-019-1152-0)
(Score: 2) by barbara hudson on Friday January 03 2020, @02:24AM (3 children)
SoylentNews is social media. Says so right in the slogan. Soylentnews is people, not tech.
(Score: 2) by c0lo on Friday January 03 2020, @03:34AM (2 children)
Not yet there. I could only buy orange shellac at the hardware store, but I need a very pale blond one (clear if possible).
And it is possible [google.com] starting with the flakes (the linky starts with the raw material) to bleach darker tints. Dissolve the flakes (slowly) in slightly basic solution, add a few drops of bleach and stir for some 15mins then precipitate by turning the pH to acid (vinegar's good enough). Filtering and washing the precipitate of the remaining salts are a pain in the ass when using only coffee filters in a funnel, especially when the solubility of the original is somewhere around 1:15 ratio (like 10g of shellac in 150+ solution - more like 200ml when you can't strictly control the temperature; then wait for the 15+ parts of water to sloooowly go through the filter. At least twice, 3 times recommended)
Understandable, given that you need as pure alcohol as possible in which to dissolve shellac (on the risk of having a cloudy appearance at pretty low water content), it's really like breathing alcohol vapors.
Better done in an open space - take a beer with you, tho, or more - the risk of dehydration in summer is higher.
But I'm being pedantic at the beginning of the new year, apologies for that.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by barbara hudson on Friday January 03 2020, @04:48PM (1 child)
Extra information is always good. We can never tell when some odd fact or reference will come in handy when we need to McGyver something.
SoylentNews is social media. Says so right in the slogan. Soylentnews is people, not tech.
(Score: 0) by Anonymous Coward on Friday January 03 2020, @06:15PM
I like your attitude.
Indeed, the only useless information, is inaccurate information.
I never really thought about MacGyver as an intellectual, but my personal definition of intelligence in humans is the ability to apply knowledge/information to solve problems. Knowledge of facts/data does not equal intelligence, but the ability to apply that does equal intelligence...IMHO.
MacGyver in spades!
But on the other hand, sometimes we can outsmart ourselves, 'Wiley E. Coyote, Super Genius' style.(ie: 'educated beyond his/her intelligence'-as seen frequently in politcs)