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

Submitted by RockDoctor
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

Submitted by AmiMoJo
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.
Education

University of Michigan Study Advocates Ban of Facial Recognition in Schools (venturebeat.com) 18

Posted by msmash from the moving-forward dept.
University of Michigan researchers recently published a study showing facial recognition technology in schools has limited efficacy and presents a number of serious problems. From a report: The research was led by Shobita Parthasarathy, director of the university's Science, Technology, and Public Policy (STPP) program, and finds the technology isn't just ill-suited to security purposes, it can actively promote racial discrimination, normalize surveillance, and erode privacy while marginalizing gender nonconforming students. The study follows the New York legislature's passage of a moratorium on the use of facial recognition and other forms of biometric identification in schools until 2022. The bill, a response to the Lockport City School District launching a facial recognition system, was among the first in the nation to explicitly regulate or ban use of the technology in schools. That development came after companies including Amazon, IBM, and Microsoft halted or ended the sale of facial recognition products in response to the first wave of Black Lives Matter protests in the U.S.

Submission + - Woz Turns 70th Birthday into Charity Event (wozbday.com)

Submitted by NoMoreACs
NoMoreACs writes: Join Apple Computer inventor and co-Founder Steve Wozniak for "11 Days of Wozdom", a social media "Scavenger Hunt" featuring creative challenges that speak to the things he values most: Happiness, creativity, ingenuity and fun.

The challenges will officially begin on August 11th, but you can get a head start by going to WOZBDAY.COM for details.

The first challenge will be to help Woz spread the word about his birthday party and fundraiser on August 11th. All challenges will be due on August 21st at 11:59pm PDT. Challenge winners get special prizes!

Woz also stated:

"Iâ(TM)m lucky to be able to do this for a foundation oriented towards helping children, especially ones in need of finding themselves."

A livestream featuring a star-studded list of performers (see list at the birthday site) and other guests will begin on August 11, 2020 at 5 pm, PDT.

Come celebrate the life of one of the true pioneers in the Personal Computer Revolution. Listen to some music, hear some great stories, and maybe even help some kids in need!

Comment Late-Breaking News from the Council... (Score 3, Funny) 95

by Tackhead (#58119004) Attached to: NASA's Mars Rover Opportunity Concludes a 15-Year Mission

Early this evening, the Council of Elders announced a planetary day of mourning and magnanimity.

K'Nord, Speaker for the Council, spoke thusly:

"Citizens and Podmates, the Council is pleased to announce that after seven and a half full years -- the longest campaign in the history of the Martian Defense Force -- the diabolical mechanized adversary from the blue world has been defeated. Our defense forces, counted in the billions, have finally surrounded and denied the invader the light and warmth it needs to survive. The blueworlders have acknowledged defeat and ceased contact. Ths invasion, at least on this front, is now over.

Let us raise our glasses to mourn the lost gelsacs of at least half our press corps, some of whose entire careers have been dedicated to coverage of this conflict -- and in a spirit of magnanimity in victory, we -- the victors of the Conflict at Endeavour Crater -- must also raise our glasses in awe and respect of our longest-lived and most challenging foe."

Shortly thereafter, a wizened old retired Councilmember, his gelsacs having long ago been ceremonially ground into a fine tartare and shared amongst the Council, wiped a perchlorate tear from his eye: "Well-done, blueworlders. Well-done."

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