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posted by Fnord666 on Friday June 02 2017, @05:51PM   Printer-friendly
from the abandon-all-hope-ye-who-enter-here dept.

Black holes are perhaps the strangest objects predicted by Einstein's theory of General Relativity, objects so dense that gravity reigns supreme, and not even light can escape beyond a certain distance, known as the event horizon. The actual existence of black hole event horizons has not been proved, but some clever observations made by astronomers at the University of Texas at Austin and Harvard University have tested the alternative hypothesis: instead of an event horizon, there might instead be a solid surface to a black hole that objects colliding against it will hit. They found results that show that this alternative can't be true, and that an event horizon as predicted by GR is more likely. ScienceDaily has an article:

Astronomers at The University of Texas at Austin and Harvard University have put a basic principle of black holes to the test, showing that matter completely vanishes when pulled in. Their results constitute another successful test for Albert Einstein's General Theory of Relativity.

Most scientists agree that black holes, cosmic entities of such great gravity that nothing can escape their grip, are surrounded by a so-called event horizon. Once matter or energy gets close enough to the black hole, it cannot escape — it will be pulled in. Though widely believed, the existence of event horizons has not been proved.

"Our whole point here is to turn this idea of an event horizon into an experimental science, and find out if event horizons really do exist or not," said Pawan Kumar, a professor of astrophysics at The University of Texas at Austin.

Supermassive black holes are thought to lie at the heart of almost all galaxies. But some theorists suggest that there's something else there instead — not a black hole, but an even stranger supermassive object that has somehow managed to avoid gravitational collapse to a singularity surrounded by an event horizon. The idea is based on modified theories of General Relativity, Einstein's theory of gravity.

While a singularity has no surface area, the noncollapsed object would have a hard surface. So material being pulled closer — a star, for instance — would not actually fall into a black hole, but hit this hard surface and be destroyed.

The team figured out what a telescope would see when a star hit the hard surface of a supermassive object at the center of a nearby galaxy: The star's gas would envelope the object, shining for months, perhaps even years.

Once they knew what to look for, the team figured out how often this should be seen in the nearby universe, if the hard-surface theory is true.

[...] "Given the rate of stars falling onto black holes and the number density of black holes in the nearby universe, we calculated how many such transients Pan-STARRS should have detected over a period of operation of 3.5 years. It turns out it should have detected more than 10 of them, if the hard-surface theory is true," Lu said.

They did not find any.

"Our work implies that some, and perhaps all, black holes have event horizons and that material really does disappear from the observable universe when pulled into these exotic objects, as we've expected for decades," Narayan said. "General Relativity has passed another critical test."

The full text of the original paper "Stellar disruption events support the existence of the black hole event horizon" (DOI: 10.1093/mnras/stx542) is available open access from the Monthly Notices of the Royal Astronomical Society.

Further evidence for or against the existence of black hole event horizons will have to wait for the Event Horizon Telescope, which is due to release its first results later this year.


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  • (Score: 2) by kaszz on Saturday June 03 2017, @06:59AM (9 children)

    by kaszz (4211) on Saturday June 03 2017, @06:59AM (#519761) Journal

    Point is that a lot of technology comes from people subsidized at universities. But profits from products enabled by them would most likely finance their "subsidy".

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  • (Score: 1) by khallow on Saturday June 03 2017, @12:38PM (8 children)

    by khallow (3766) Subscriber Badge on Saturday June 03 2017, @12:38PM (#519827) Journal

    Point is that a lot of technology comes from people subsidized at universities.

    A lot more comes from people who aren't. Most of that list didn't come from universities even when the technology was heavily subsidized - for example, nuclear anything, computers, rockets, electronics, submarines, satellites, and cryptography. I don't know if there is any context for Reagan's quip any more. But my suspicion is that it was in reply to someone who saw public funding as a dial that you could crank up arbitrarily high to make more science.

    And the question does remain. Why do we need to subsidize (some) intellectual curiosity? Is no one going to develop important things, if we're not throwing public funds at them? Are you going to be more intellectually incurious in the absence of such subsidies? Is the development of highly profitable technologies not adequate compensation for our collective intellectual curiosity?

    • (Score: 3, Interesting) by stormwyrm on Saturday June 03 2017, @05:22PM (7 children)

      by stormwyrm (717) on Saturday June 03 2017, @05:22PM (#519917) Journal
      My favourite rebuttal to this is Maxwell's Equations. What would have happened had Queen Victoria's government not seen fit to endow an institution like King's College London with enough funding such that someone like James Clerk Maxwell could make a living doing fundamental physics research? How else could the foundational equations of electromagnetic theory have been discovered except by that sort of subsidy? No one had any idea what those equations would be good for when Maxwell first formulated them, and it was at least fifty years later, some years after Maxwell himself passed away, that its prediction of electromagnetic radiation found application in the form of radio. There was no immediate profit to be had from the equations: that only came much much later. I doubt that private, profit-driven enterprises could have made that kind of discovery because the cycle between discovery and application is far too long, and such enterprises need to soon turn up a profit somehow.
      --
      Numquam ponenda est pluralitas sine necessitate.
      • (Score: 1) by khallow on Saturday June 03 2017, @10:17PM (6 children)

        by khallow (3766) Subscriber Badge on Saturday June 03 2017, @10:17PM (#519997) Journal

        My favourite rebuttal to this is Maxwell's Equations. What would have happened had Queen Victoria's government not seen fit to endow an institution like King's College London with enough funding such that someone like James Clerk Maxwell could make a living doing fundamental physics research?

        Someone else would have. It's worth noting here that universities existed at the time in the absence of government subsidy and similarly, people were investigating this important field in the absence of government subsidy as well. Further, Maxwell's equations were well on their way to being discovered due to past work on electric and magnetic field interactions. It was just a matter of putting the pieces together.

        No one had any idea what those equations would be good for when Maxwell first formulated them, and it was at least fifty years later, some years after Maxwell himself passed away, that its prediction of electromagnetic radiation found application in the form of radio.

        EM research already had considerable value and considerable money had already been spent on it. And Maxwell found an elegant reformulation of the theory that made all existing EM research more valuable. And radio came out less than 30 years later, not 50 (Maxwell eqns in 1861-62, radio waves discovered in late 1880s). Finally, for the last eight years of Maxwell's life, he was privately funded by a relative of Henry Cavendish.

        I doubt that private, profit-driven enterprises could have made that kind of discovery because the cycle between discovery and application is far too long, and such enterprises need to soon turn up a profit somehow.

        There's also private non profit-based research. For example, a fair number of US astronomical observatories have been built with private donations.

        • (Score: 2) by kaszz on Sunday June 04 2017, @01:41AM (5 children)

          by kaszz (4211) on Sunday June 04 2017, @01:41AM (#520053) Journal

          with reliable funding research can be done more efficiently and more and faster results can be had with a another level of quality. Which lets industry exploits this faster (for free..) and with more certainty. And while the delay between discovery and application might been far in the 1900ths. It's way faster these days, usually. Which makes the ROI case even more compelling these days. Then it's the question if important science should be beholden to the private sphere. In the end I think publicly funded research benefits the society in many less than obvious ways.

          • (Score: 1) by khallow on Sunday June 04 2017, @03:22AM (4 children)

            by khallow (3766) Subscriber Badge on Sunday June 04 2017, @03:22AM (#520074) Journal

            with reliable funding research can be done more efficiently and more and faster results can be had with a another level of quality.

            I disagree. That could happen in theory with public funding, but in practice it doesn't happen that way because there's no incentive to do that.

            A particularly egregious example (which I might add spurred my skepticism of publicly funded basic science research in the first place) is space science and manned space exploration, which has huge problems with one-off missions (which prioritize dead end technology development over doing space science, exploration, or development), missions decided on the basis of who gets funding rather than what the supposed purpose of the mission is (such as substantially increasing the cost of the International Space Station so that it uses the Space Shuttle and sources Russian space parts), kitchen sink design (throwing in tons of additional features, which have tremendous negative synergy when it comes to the cost and complexity of the mission) and spending staggering sums of money and consuming the lives of some of the best and brightest to little consequence (a space scientist who gets one research mission every 5-10 years could be doing a lot more, even in space science).

            • (Score: 2) by kaszz on Sunday June 04 2017, @07:46AM (3 children)

              by kaszz (4211) on Sunday June 04 2017, @07:46AM (#520134) Journal

              That is a problem with perverted incentives. Guess what people complain about at NASA, administrators! which is the same old again, bureaucrats, HR department, bosses with a few hairs (PHB) that decides with too little clue etc. It's the death-by-MBA in the public funding version. Some universities seems more like a corporation with a big tax exempt and expensive administration than a learning and research institution. I'll suggest the perverted incentives are fixed instead of killing all funding.

              The problem with a lot of research is that it takes a lot of (uninterrupted) time. It can be as cheap as a person sitting at a desk, or more expensive with a particle accelerator etc. And the outcome may either never happen or show up much later where it never were intended. So stable funding is a necessity.

              A comparison can be made with research in the 1800-1900 vs 1945-1990.

              • (Score: 1) by khallow on Sunday June 04 2017, @08:54AM (2 children)

                by khallow (3766) Subscriber Badge on Sunday June 04 2017, @08:54AM (#520148) Journal

                That is a problem with perverted incentives.

                Exactly. A subsidy for "intellectual curiosity" so frequently turns out to be something else, such as a subsidy for "death-by-MBA" because ultimately, that is the perverse incentive of the subsidy - to not only do the minimal behavior required to get the subsidy, but to politically game the system so that the subsidy ends up being about something very different from its expressed purpose. I'm not going to claim here that Reagan was grasping the full nuances of public funding of research or we are grasping the full nuances of Reagan's quote. But a key problem with this kind of thing is that it devolves into being another political tool focused on completely unrelated purposes, such as bureaucratic empire-building or vote garnering, rather than its expressed purpose.

                There's really only two advantages to public funding. First, it's bigger than almost any other approach. It's the easiest way to rig massive funding and diversion of a society's resources into research. You just need to get the necessary political support. Second, it's relatively nonpartisan in the generic sense which is important for highly disruptive things like nuclear weapons or generating research necessary for regulation creation and enforcement.

                The key disadvantage is that you can't simply cut funding when things go off the rails. A private NASA with the decades of problems the current one has would have been at least been partially cut off or reformed long ago. Thus, there really isn't a point to having a massive publicly funded system that is grossly inefficient. It actually hurts scientific research more than it helps by diverting resources, such as the efforts of scientists, to unproductive routes (such as spending considerable time and effort running on the bureaucratic wheel merely to obtain more funding) and discouraging private efforts (which tend to be much more effective) from attempting research that is already dominated by publicly funded projects (such as space science or fusion research).

                • (Score: 2) by kaszz on Sunday June 04 2017, @09:02AM (1 child)

                  by kaszz (4211) on Sunday June 04 2017, @09:02AM (#520150) Journal

                  One idea, let researchers select the management? and of course limit them to max 5% of funding or so. And only active researchers may have a say.
                  Exclude humanities from the process of course ;)

                  • (Score: 1) by khallow on Sunday June 04 2017, @09:54AM

                    by khallow (3766) Subscriber Badge on Sunday June 04 2017, @09:54AM (#520160) Journal

                    One idea, let researchers select the management? and of course limit them to max 5% of funding or so. And only active researchers may have a say.

                    The point is that any such process can be corrupted, even by the researchers themselves (who let us note are collectively rather cheap to corrupt). A public system doesn't have any means of correcting corruption except by convoluted political processes. I gather Reagan's saying, for example, comes from one such attempt.