Items tagged with: hole
Katie Bouman, 29, has earned plaudits for helping develop the algorithm that made the photo possible.
Article word count: 674
HN Discussion: https://news.ycombinator.com/item?id=19632086
Posted by tigerlily (karma: 437)
Post stats: Points: 252 - Comments: 107 - 2019-04-11T08:25:22Z
#HackerNews #behind #black #bouman #computer #first #hole #image #katie #scientist #the
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Media captionKatie Bouman designed an algorithm that made the image possible
A 29-year-old computer scientist has earned plaudits worldwide for helping develop the algorithm that created the first-ever image of a black hole.
Katie Bouman led development of a computer programme that made the breakthrough image possible.
The remarkable photo, showing a halo of dust and gas 500 million trillion km from Earth, was released on Wednesday.
For Dr Bouman, its creation was the realisation of an endeavour previously thought impossible.
Excitedly bracing herself for the groundbreaking moment, Dr Bouman was pictured loading the image on her laptop.
"Watching in disbelief as the first image I ever made of a black hole was in the process of being reconstructed," she wrote in the caption to the Facebook post.
She started making the algorithm three years ago while she was a graduate student at the Massachusetts Institute of Technology (MIT).
There, she led the project, assisted by a team from MITʼs Computer Science and Artificial Intelligence Laboratory, the Harvard-Smithsonian Center for Astrophysics and the MIT Haystack Observatory.
The black hole image, captured by the Event Horizon Telescope (EHT) - a network of eight linked telescopes - was rendered by Dr Boumanʼs algorithm.
In the hours after the photoʼs momentous release, Dr Bouman became an international sensation, with her name trending on Twitter.
Image caption The first ever photo of a black hole, taken using a global network of telescopes
In a tweet, New York Democratic Rep Alexandria Ocasio-Cortez wrote that Ms Bouman should take her "rightful seat in history".
"Congratulations and thank you for your enormous contribution to the advancements of science and mankind," she tweeted. "Hereʼs to #WomenInSTEM!," which stands for science, technology, engineering and mathematics.
Dr Bouman was also hailed by MIT and the Smithsonian on social media.
"3 years ago MIT grad student Katie Bouman led the creation of a new algorithm to produce the first-ever image of a black hole," MITʼs Computer Science & Artificial Intelligence Lab wrote. "Today, that image was released."
But Dr Bouman, now an assistant professor of computing and mathematical sciences at the California Institute of Technology, insisted the team that helped her deserves equal credit.
The effort to capture the image, using telescopes in locations ranging from Antarctica to Chile, involved a team of more than 200 scientists.
"No one of us couldʼve done it alone," she told CNN. "It came together because of lots of different people from many different backgrounds."
What do we know about the black hole?
* The black hole, which is "unseeable" to the naked eye, measures 40 billion km across, or three million times the size of the Earth * It was scanned over a period of 10 days in the Messier 87 galaxy * It is "larger than the size of our entire Solar System", Prof Heino Falcke, of Radboud University in the Netherlands, who proposed the experiment, told the BBC
How did her algorithm create the image?
Put simply, Dr Bouman and others developed a series of algorithms that converted telescopic data into the historic photo shared by the worldʼs media.
In mathematics and computer science, an algorithm is a process or set of rules used to solve problems.
No single telescope is powerful enough to capture the black hole, so a network of eight was set up to so do using a technique called interferometry.
The data they captured was stored on hundreds of hard drives that were flown to central processing centres in Boston, US, and Bonn, Germany.
Image caption The eventual EHT array will have 12 widely spaced participating radio facilities
Dr Boumanʼs method of processing this raw data was said to be instrumental in the creation of the striking image.
She spearheaded a testing process whereby multiple algorithms with "different assumptions built into them" attempted to recover an photo from the data.
The results of the algorithms were then analysed by four separate teams to build confidence in the veracity of their findings.
"Weʼre a melting pot of astronomers, physicists, mathematicians and engineers, and thatʼs what it took to achieve something once thought impossible," Dr Bouman says.
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On 10 April 2019 at 15:00 CEST (Brussels time) the European Commission will present a ground-breaking discovery by Event Horizon Telescope - an international...
Article word count: 88
HN Discussion: https://news.ycombinator.com/item?id=19624226
Posted by doktorn (karma: 155)
Post stats: Points: 293 - Comments: 87 - 2019-04-10T13:08:34Z
#HackerNews #black #conference #first-ever #hole #image #live #press #the #unveiling #video
On 10 April 2019 at 15:00 CEST (Brussels time) the European Commission will present a ground-breaking discovery by Event Horizon Telescope - an international scientific collaboration aiming to capture the first image of a black hole by creating a virtual Earth-sized telescope. EU-funded researchers play a key role in the project.
Six press conferences around the world will take place simultaneously In Europe, Commissioner Moedas and lead scientists funded by the European Research Council will hold a press conference in Brussels to unveil the discovery.
#EHTBlackHole #BlackHoleDay #RealBlackHole
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When he was considering white dwarfs and neutron stars in the context of what he called ‘gravitational machines,’ Freeman Dyson became intrigued by the fate of a neutron star binary. He calculated in…
Article word count: 1129
HN Discussion: https://news.ycombinator.com/item?id=19329199
Posted by elorant (karma: 5682)
Post stats: Points: 160 - Comments: 56 - 2019-03-07T16:12:51Z
#HackerNews #black #hole #propulsion #technosignature
When he was considering white dwarfs and neutron stars in the context of what he called ‘gravitational machines,’ Freeman Dyson became intrigued by the fate of a neutron star binary. He calculated in his paper of the same name (citation below) that gradual loss of energy through gravitational radiation would bring the two neutron stars together, creating a gravitational wave event of the sort that has since been observed. Long before LIGO, Dyson was talking about gravitational wave detection instruments that could track the ‘gravitational flash.’
Image: Artist conception of the moment two neutron stars collide. Credit: LIGO / Caltech / MIT.
Observables of this kind, if we could figure out how to do it (and we subsequently have) fascinated Dyson, who was in this era (early 1960s) working out his ideas on Dyson spheres and the capabilities of advanced civilizations. As to the problematic merger of neutron stars in a ‘machine,’ he naturally wondered whether astrophysical evidence of manipulations of these would flag the presence of such cultures, noting that “…it would be surprising if a technologically advanced species could not find a way to design a nonradiating gravitational machine, and so to exploit the much higher velocities which neutron stars in principle make possible.”
He goes on in the conclusion to the “Gravitational Engines” paper to say this: “In any search for evidences of technologically advanced societies in the universe, an investigation of anomalously intense sources of gravitational radiation ought to be included.”
Searching for unusual astrophysical activity is part of what would emerge as ‘Dysonian SETI,’ or in our current parlance, the search for ‘technosignatures.’ It’s no surprise that since he discusses using binary black holes as the venue for his laser-based gravity assist, David Kipping should also be thinking along these lines. If the number of black holes in the galaxy were large enough to support a network of transportation hubs using binary black holes, what would be the telltale sign of its presence? Or would it be observable in the first place?
Remember the methodology: A spacecraft emits a beam of energy at a black hole that is moving towards it, choosing the angles so that the beam returns to the spacecraft (along the so-called ‘boomerang geodesic’). With the beam making the gravitational flyby rather than the spacecraft, the vehicle can nonetheless exploit the kinetic energy of the black hole for acceleration. Huge objects up to planetary size could be accelerated in such a way, assuming their mass is far smaller than the mass of the black hole. No fuel is spent aboard the spacecraft which, using stored energy from the beam, continues to accelerate up to terminal velocity.
Image: Simulated image of the two merging black holes detected by LIGO, viewed face-on. LIGO’s gravitational-wave detection is the first direct observation of such a merger. Credit: LIGO / AAS Nova.
Kipping likes to talk about the process in terms of a mirror. Because light loops around the approaching black hole and returns to the spacecraft, the black hole exhibits mirror-like behavior. Thus on Earth, if we bounce a ping-pong ball off a mirror, the ball returns to us. But if the mirror is moving towards us quickly, the ball returns faster because it has picked up momentum from the mirror. Light acts the same way, but light cannot return faster than the speed of light. Instead, in gaining momentum from the black hole, the light blueshifts.
We exploit the gain in energy, and we can envision a sufficiently advanced civilization doing the same. If it can reach a black hole binary, it has gained an essentially free source of energy for continued operations in moving objects to relativistic speeds. Operations like these at a black hole binary result in certain effects, so there is a whisper of an observable technosignature.
I discussed the question with Kipping in a recent email exchange. One problem emerges at the outset, for as he writes: “The halo drive is a very efficient system by design and that’s bad news for technosignatures: there’s zero leakage with an idealized system.” But he goes on:
The major effect I considered in the paper is the impact on the black hole binary itself. During departure, one is stealing energy from the black binary, which causes the separation between the two dead stars to shrink slightly via the loss of gravitational potential energy. However, an arriving ship would cancel out this effect by depositing approximately the same energy back into the system during a deceleration maneuver. Despite this averaging effect, there is presumably some time delay between departures and arrivals, and during this interval the black hole binary is forced into a temporarily contracted state. Since the rate of binary merger via gravitational radiation is very sensitive to the binary separation, these short intervals will experience enhanced infall rates. And thus, overall, the binary will merge faster than one should expect naturally. It may be possible to thus search for elevated merger rates than that expected to occur naturally. In addition, if the highway system is not isotropic, certain directions are preferred over others, then the binary will be forced into an eccentric orbit which may also lead to an observational signature.
Tricky business, this, for a black hole binary in this formulation can be used not only for acceleration but deceleration. The latter potentially undoes the distortions caused by the former, though Kipping believes elevated merger rates between the binary pair will persist. Our technosignature, then, could be an elevated binary merger rate and excess binary eccentricity.
I was also interested in directionality — was the spacecraft limited in where it could go? I learned that the halo drive would be most effective when moving in a direction that lies along the plane of the binary orbit. Traveling out of this plane is possible, though it would involve using onboard propellant to attain the correct trajectory. The potential of reaching the speed of the black hole itself remains, but excess stored energy would then need to be applied to an onboard thruster to make the course adjustment. Kipping says he has not run the numbers on this yet, but from the work so far be believes that a spacecraft could work with angles as high as 20 degrees out of the plane of the binary orbit and still reach an acceleration equal to that of the black hole.
For more on the halo drive, remember that Kipping has made available a video that you can access here. The other citations are Kipping, “The Halo Drive: Fuel-free Relativistic Propulsion of Large Masses via Recycled Boomerang Photons,” accepted at the Journal of the British Interplanetary Society (preprint); and Dyson, “Gravitational Machines,” in A.G.W. Cameron, ed., Interstellar Communication, New York: Benjamin Press, 1963, Chapter 12.
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A black hole for Internet advertisements. Contribute to pi-hole/pi-hole development by creating an account on GitHub.
Article word count: 43
HN Discussion: https://news.ycombinator.com/item?id=19258717
Posted by tosh (karma: 33344)
Post stats: Points: 171 - Comments: 68 - 2019-02-26T22:02:01Z
#HackerNews #advertisements #black #for #hole #internet #pi-hole
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