Become a fan of Slashdot on Facebook

 



Forgot your password?
typodupeerror

Submission + - Another large Black hole in "our" Galaxy (arxiv.org)

RockDoctor writes: A recent paper on ArXiv reports a novel idea about the central regions of "our" galaxy.

Remember the hoopla a few years ago about radio-astronomical observations producing an "image" of our central black hole — or rather, an image of the accretion disc around the black hole — long designated by astronomers as "Sagittarius A*" (or SGR-A*)? If you remember the image published then, one thing should be striking — it's not very symmetrical. If you think about viewing a spinning object, then you'd expect to see something with a "mirror" symmetry plane where we would see the rotation axis (if someone had marked it). If anything, that published image has three bright spots on a fainter ring. And the spots are not even approximately the same brightness.

This paper suggests that the image we see is the result of the light (radio waves) from SGR-A* being "lensed" by another black hole, near (but not quite on) the line of sight between SGR-A* and us. By various modelling approaches, they then refine this idea to a "best-fit" of a black hole with mass around 1000 times the Sun, orbiting between the distance of the closest-observed star to SGR-A* ("S2" — most imaginative name, ever!), and around 10 times that distance. That's far enough to make a strong interaction with "S2" unlikely within the lifetime of S2 before it's accretion onto SGR-A*.)

The region around SGR-A* is crowded. Within 25 parsecs (~80 light years, the distance to Regulus [in the constellation Leo] or Merak [in the Great Bear]) there is around 4 times more mass in several millions of "normal" stars than in the SGR-A* black hole. Finding a large (not "super massive") black hole in such a concentration of matter shouldn't surprise anyone.

This proposed black hole is larger than anything which has been detected by gravitational waves (yet) ; but not immensely larger — only a factor of 15 or so. (The authors also anticipate the "what about these big black holes spiralling together?" question : quote "and the amplitude of gravitational waves generated by the binary black holes is negligible.")

Being so close to SGR-A*, the proposed black hole is likely to be moving rapidly across our line of sight. At the distance of "S2" it's orbital period would be around 26 years (but the "new" black hole is probably further out than than that). Which might be an explanation for some of the variability and "flickering" reported for SGR-A* ever since it's discovery.

As always, more observations are needed. Which, for SGR-A* are frequently being taken, so improving (or ruling out) this explanation should happen fairly quickly. But it's a very interesting, and fun, idea.

Submission + - Surado, formerly Slashdot Japan, is closing at the end of the month. (srad.jp) 1

AmiMoJo writes: Slashdot Japan was launched on May 28, 2001. On 2025/03/31, it will finally close. Since starting the site separated from the main Slashdot one, and eventually rebranded as "Surado", which was it's Japanese nickname.

Last year the site stopped posting new stories, and was subsequently unable to find a buyer. In a final story announcing the end, many users expressed their sadness and gratitude for all the years of service.

Comment Re:Re-stolen (Score 1) 89

You don't get to come back a year (or a century) later and say, "Hey, I just found out what that painting is actually worth. Give it back."

Actually... Why not? You said yourself you're in the wrong and you certainly acted in bad faith, so why shouldn't your victim have their demand to annul the deal enforced?

Comment Re:Balancing act (Score 1) 115

As opposed to people with nativist and inward looking views, companies like Apple HAVE to work overseas, and if you keep following the US govt kool-aid, then you will only be able to do business with Western Europe and other allies.

Try to understand that a big part of the world actually sees the US as the big bad empire that they portray China to be and it makes sense that they ask Stewart to tone it down a bit.

It's not that China is a big bad empire, it's that Xi is an emperor who's unable to placate his people with promises of a better tomorrow due to China's economy having caught up enough that the rubber band has gone slack and dictatorships being inherently incompatible with the rule of law which a strong economy requires, so his only hope for survival is to placate them with promises of glory which makes a confrontation with China and West pretty much inevitable, and Xi knows that. It's the same deal as with Russia, US is simply being wiser than EU was.

Basically, what's business to Apple is a weapon to China, and China is a fundamentally hostile nation to anyone who doesn't think Xi would make a great world leader, which he wouldn't judging by everything I know about life in China and also because he's a genocidal tyrant. That's not "nativist" or "inward looking", that's simply realism.

I recently saw a very insightful interview where dictatorships are defined by things you cannot criticize, like the CCP in China, Kim Jong-un in Korea, etc. In the US the thing that will absolutely get you canceled will be talking about the Israeli lobby and the influence such a small group holds over US culture in general.

Seriously? You're equating getting canceled with getting disappeared?

Comment Re:1984 (Score 1) 115

Note that such a system would also prevent Slashdot from leaning left and censoring conservatives, which they're doing now by institution an idiotic "karma". Slashdot karma is all about politics. And Slashdot is left leaning. One could express that cutely as "CowboyNeal is an imbecile".

But you're not being censored. Your comment is right here, readable for all who care to engage with users with bad reputation. That you have managed to earn a bad reputation through your own actions does not reflect badly on Slashdot or CowboyNeal, it reflects badly on you. It is the consequence of your actions, in other words, your karma.

That most people ignore you doesn't mean you're being censored, it just means that they think you and your opinions are not worth listening to. That your response to this is that the government should force them to pay attention just serves to demonstrate that their judgement is completely right. It's not a political judgement, it's a judgement about you as a person.

Given your vitriol here, I think you know that too, and judging by the fact that you keep posting on Slashdot despite hating the place I doubt you're more welcome elsewhere either. So perhaps you should reflect on the only common factor for a change, try to see your self from other people's eyes and maybe, just maybe accept that you might actually be the one who's in the wrong and needs to change? It's painful, but so is eternal bitterness, and there is no government big enough to make other people like you, so those are your options.

Comment Pro Audio Devices (Score 1) 69

Windows11 anecdotally has some distinct glitches on systems that run multiples of certain types of pro audio devices. Because pro audio is the single application for which I use Windows, and in fact the only reason I've *ever* used Windows at all, this is of enormous concern for me. The only truly annoying thing I've noticed is that as a side-docker, I can't handle the fixed location of the taskbar. But as strictly a single application user I really don't want a desktop environment at all, just a host OS for my application and maybe a terminal console for file management and administration.

I've never run Windows for anything else real. Linux was either my 4th or 5th Unix, depending on whether Coherent counts. I went straight from the minicomputer world of the 80s to the Unixes of the 90s and was an early adopter of Linux, which works for absolutely everything I do except pro audio. I know Apple is a thing. I know Linux audio is a thing, I've had a hand in developing it. I don't even hate Windows, but I dislike forced platform changes.

Comment Carnot Efficiency (Score 1, Informative) 123

Like other posters have said, converting the electricity to heat is nearly 100% efficient. And with a temp of 500C, the carnot efficiency is (773K (hot) - 293K (cold)) / 773K = 62%. This is the maximum efficiency possible. Newer supercritical coal plants operate in this same temperature regime and are 40-45% efficient.

Slashdot Top Deals

The most difficult thing in the world is to know how to do a thing and to watch someone else doing it wrong, without commenting. -- T.H. White

Working...