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Star Spotted Speeding Near Black Hole at Centre of Milky Way (theguardian.com)
Astronomers have observed a star speeding close to the massive black hole at the centre of the Milky Way for the first time. From a report: The observations, made using the Very Large Telescope in Chile, tracked a star called S2 as it passed through the extreme gravitational field at the heart of our galaxy. As the star approached its nearest point to the black hole on 19 May, it was accelerated to mind-boggling speeds, causing it to be subject to effects predicted by Einstein's theory of general relativity. Astronomers had been tracking the star and preparing to make the observations for the past 16 years -- the time taken for the star to complete a single elliptical orbit of the black hole. "We have been preparing intensely for this event over several years, as we wanted to make the most of this unique opportunity to observe general relativistic effects," said Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, who led the international team. The findings can be found here.
I can see this all ending badly.
-- Tigger warning: This post may contain tiggers! --
I don't know what is going on here, somehow /. has managed to post a topic that is something it's members might actually be interested in, instead of squabble-bait. Mods must be off their meds today.
Albert Einstein was right with his theory? Imagine that. I only wish he had lived to see his theories validated like this because he was an exceptional thinker who kept working to within days of his death. He would have loved to see his theories work out such complex problems yet be as simple as they are expressed. I applaud that he was right and I applaud the man, the work ethic and his abilities. We will be lucky to ever know his equal again.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
If you throw enough heavy stars past a black hole you can accelerate its rotation. If it rotates fast enough it should flatten into a disk. If you keep doing this you'll force the black hole into a torus, no? At which point you'll be able to deduce the size of the matter inside it.
If video games influenced behavior the Pac Man generation would be eating pills and running away from their problems.
But the planet Trantor was not so lucky - it got ripped away from the star and crossed the event horizon a few days ago.
#DeleteChrome
Apparently, this particular star will soon find itself in Scientology Heaven.
There is a maximum rate at which a black hole is allowed to rotate, and such a black hole is not a torus.
https://astronomy.stackexchang...
Now... they should have taken advantage of the wording in the story. Instead of "mind-boggling speeds" it should have been "astronomical speeds". Or, "faster than your standard astronomical speeds". Or something.
Speaking of astronomy being interesting to some here at Slashdot, perhaps some here could suggest things in astronomy that would be interesting to look at with a small telescope?
My young daughter is very interested in astronomy so I picked up a 114mm reflector telescope off Craigslist. So far we've seen Saturn's rings (which look like one big ring from our location in the suburbs, with that scope), and seen the discs of the other planets.
There's a lot of light pollution here in the Dallas suburbs and apparently we have to drive an at least an hour to find significantly darker skies. What else can we look at other than the overall color of the planets, and the banding on Jupiter? Any other objects worth seeing?
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A funny story related to this. When I took her outside to look at Saturn, she pointed to a different part of the sky and said "daddy I see Jupiter!" She just turned four years old. How the heck a barely four year old recognizes Jupiter with no assistance, I have no idea. I had to use my sky chart app to confirm she was correct, she had indeed correctly identified Jupiter.
Don't overlook the moon-- for somebody new to astronomy, the moon is AMAZING.
Pro tip: DON'T look at the moon when it's full-- the full-on sunlight washes out all the contrast. Look at it first or second quarter.
This is a great season to spot planets-- you can get Venus, Mars, Jupiter, and Saturn in an evening without even staying up very late. Mars, unfortunately, although it's unusually close and bright right now, is in the middle of a hellacious dust storm, so you won't see much features. You should be able to spot the polar cap, though.
Pro tip: you don't have to wait for sunset to observe Venus. It's actually better to observe it with some skylight, because it's so bright.
Other than that, if there's light pollution you're not going to seem much in the way of nebulae, but double stars are still interesting. Mizar-- the star at the bend of the Big Dipper-- is easy to find. Some stars where the two components are different colors are interesting. Check this site: https://www.skyandtelescope.co...
http://www.geoffreylandis.com
While that depends on how easily impressed you are, I'd said there's not a lot to really utterly floor you with, using a small scope, and without the benefit of astrophotography and a motorized equatorial mount, because so few photons arrive to properly stimulate your retinas in real time, particularly the cones which process color. Everything except the moon (which is pretty monochrome anyway), the major planets, and the Orion Nebula will be monochrome. The Orion nebula has a matrix-like greenish tint.
While it's still exciting to see nebulae and galaxies in real time with your "own" eyes (not an image, anyway) it's a little bit of a letdown that everything looks like blurry old black & white TV.
The height of my interest in astronomy was probably around 2003, 2004, but the light pollution of my area killed my enthusiasm.
Nonetheless, I did see a number of nebulae and galaxies with my simple 8" dobsonian, which was cool, and I could make out the polar ice caps on Mars when it was it's nearest in 60 years.
Another neat thing is with Jupiter, not only do so see the clouds but you should easily make out the 4 Galilean moons. Actually, you can see those with just decent binoculars.
You can look for the Sagittarius Trifid nebula, M51, Andromeda galaxy, and the Ring and Dumbell nebulae as well.. it was years ago but I distinctly remember seeing those.
Look back up at my post, now look back down, you're on the Internet. Now look back up. I'm a signature.
Try M31 (the Andromeda galaxy). I'm not sure how it will appear in the telescope though.
Stars of different colours, e.g. Rigel (blue) and Betelgeuse (red) in Orion.
Surface details on the moon.
A good star chart book should list interesting objects for each constellation. Try checking out galaxies and nebulae. Just one thing to note: Don't expect to see colour except in stars. Nebulae will appear greenish (at least they do to my eye).
"Very Large Telescope"
I suppose the next will be the "Quite Big, Actually, Telescope".
Nope, no sig
So what you're saying is a black hole CAN rotate faster, but if it does it better hope no cops are around?
About 225 million years actually.
Galactic center is ~26k light years away, Circumference is ~163k, to travel it in 250k years Sun would need speed ~62% of c.
For for all of that. Your comments on Venus and Mars especially were interesting.
We had our first look at Mars last night, due to her 9:00 PM bed time. It hasn't been visible until late at night. We were a bit disappointed that we didn't see more features, though I knew that since at was near opposition (full moon / full Mars) we wouldn't have the shadows to help us see features. It's good to find out about the dust storm. Maybe we can see more in a month or two.
Speaking of her bed time, that's also interesting about Venus - I've just learned we'd have been better off looking at Venus BEFORE her bedtime rather than AFTER. :)
Thanks for all of that. We'll definitely try looking for the Galilean moons of Jupiter. My 4yo actually said she saw them, but I didn't see them and didn't know they should be visible, so I thought she was wrong.
This is a weird situation for me - I'm a major nerd, my hobby is studying. Therefore I'm used being "the smartest guy in the room". Finding out my four year old is right I was wrong is weird. She's been doing that lately. She knows all about the dwarf planets. I didn't know there were five of them until she told me, and told me their names. Lol
Don't encourage the summary-writer's lazy hyperbowl.
What we are looking for is 7,650 km/s -- or some 4,781 mph -- about 2.5% of the speed of light.
I come here for the love
It's not the first time the star has been seen, it's been tracked for decades. What's new (the first time seen) is the confirmation of Einstein's GR prediction of change in redshift as the star got closer to the black hole (doppler effect). It matched exactly what was predicted. Once again (as always), Einstein's GR is confirmed correct.... THAT is how scientists do theory.
Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
Actually, the black hole is a metaphor for Trump, and the star being jerked around it is a metaphor for Congress.
Sorry, but you got played again.
Table-ized A.I.
Okay, General Relativity makes it an impossibility to exceed the speed of light because the mass of an object increases as it near's C. Since the mass increases, the amount of energy/force required to accelerate it further also increases -- wash, rinse, repeat.
Clearly, at some stage (due to the increasing mass of the object), the force required to exceed C becomes infinite(?) and therefore C can not be exceeded under any circumstances.
But how does this work when the force is provided by gravity?
Galileo pretty much proved that the acceleration of a mass by gravity is unaffected by the magnitude of that mass. So, if a gravitational field (such as that of a black hole) is creating an acceleration of x meters per second per second, an object should continue to accelerate to and beyond the speed of light, even though its mass increases (infinitely) as it approaches C -- n'est pas?
Yes, I am ignorant but I'm sure some physicist can put me straight on this.
Not "past" a black hole. Gravity (at least the static kind; not entirely sure about with the dynamic kind governed by Einstein equations) is a central force and no transfer of angular momentum takes place. Put it this way: angular momentum is a conserved quantity; unless there is some way to take angular momentum (about the center of black hole) out of the passing star, the black hole can't gain any angular momentum. You could cause the star to fall into the black hole (carrying its angular momentum with it), but you are going to run into some issues doing that; you might just end up with a really elliptical orbit.
Mind boggling, really? For me, 300 MPH is mind boggling... my mind would absolutely boggle if I could get up to that on the freeway. Mind boggling is really not a term that belongs in a Slashdot summary. It doesn't tell us much. Our minds are sufficiently boggled by matter travelling at relativistic speeds, thank you, could you please say it that way? Oh I forgot, the editor just cut and pasted this from the original article, which was aimed at knuckledraggers.
When all you have is a hammer, every problem starts to look like a thumb.
We fought a whole war, and traveled across an icy Delaware River on Christmas night to murder people who spell "center" wrong.
Is that when you started murdering your allies? Those damned French, not spelling their own work correctly and helping your war.
And no, the trunk of a car is not a boot.
Now that's true, the rear of a car is definitely related to an elephants nose.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
Thanks again. I just showed my 4yo the Galilean moons and she was super excited. Even my wife got into it this time.
Kiddo corrected herself after first identifying one of the moons as Titan. :)
Is that when you started murdering your allies?
The British soldiers stationed in the colonists' homes, where the the colonists were taxed without representation and denied their ability to defend themselves or manufacture their own finished goods ... those were not "allies." And that's kinda the point, right?
Don't disappoint your bird dog. Go to the range.
Try M51 - it's a whirlpool galaxy that can be easily seen from Earth with a small telescope.
You said "murder people who spell "center" wrong." which wasn't the English. Besides Americans don't believe in letting others do those other things. Lots of people in America who are taxed without representation, at that your whole system seems to be setup to not allow various people representation, including many citizens. yYou've been making trade agreements that screw up other countries manufacturing and continue to do it and then there are all the people who you do your best to not allow to defend themselves.
https://en.wikipedia.org/wiki/Inverted_totalitarianism