from the world's big
The outer edges of a black hole might be "fuzzy" instead of neat and smooth.
- A recent study analyzed observations of gravitational waves, first observed in 2015.
- The data suggests, according to the researchers, that black holes aren't bounded by smooth event horizons, but rather by a sort of quantum fuzz, which would fit with the idea of Hawking radiation.
- If confirmed, the findings could help scientists better understand how general relativity fits with quantum mechanics.
ESO, ESA/Hubble, M. Kornmesser<p>In the 1970s, Stephen Hawking famously proposed that black holes aren't truly "black." In simplified terms, the theoretical physicist reasoned that, due to quantum mechanics, black holes actually emit tiny amounts of black-body radiation, and therefore have a non-zero temperature. So, contrary to Einstein's view that black holes are neatly defined and are not surrounded by loose materials, Hawking radiation suggests that black holes are actually surrounded by quantum "fuzz" that consists of particles that escape the gravitational pull.</p><p>"If the quantum fuzz responsible for Hawking radiation does exist around black holes, gravitational waves could bounce off of it, which would create smaller gravitational wave signals following the main gravitational collision event, similar to repeating echoes," Afshordi said.</p>
Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman<p>A new study from Afshordi and co-author Jahed Abedi could provide evidence of these signals, called gravitational wave "echoes." Their analysis examined data collected by the <a href="http://www.virgo-gw.eu/" target="_blank">LIGO and Virgo gravitational wave detectors</a>, which in 2015 detected the first direct observation of gravitational waves from the collision of two distant neutron stars. The results, at least according to the researchers' interpretation, showed relatively small "echo" waves following the initial collision event.</p><p>"The time delay we expect (and observe) for our echoes ... can only be explained if some quantum structure sits just outside their event horizons," Afshordi told <em><a href="https://www.livescience.com/black-hole-echoes-unsettle-einstein-relativity.html" target="_blank">Live Science</a>.</em></p>
Afshordi et al.<p>Scientists have long studied black holes in an effort to better understand fundamental physical laws of the universe, especially since the introduction of Hawking radiation. The idea highlighted the extent to which general relativity and quantum mechanics conflict with each other. </p><p>Everywhere — even in a vacuum, like an event horizon — pairs of so-called <a href="https://www.scientificamerican.com/article/something-from-nothing-vacuum-can-yield-flashes-of-light/" target="_blank">"virtual particles"</a> briefly pop in and out of existence. One particle in the pair has positive mass, the other negative. Hawking imagined a scenario in which a pair of particles emerged near the event horizon, and the positive particle had just enough energy to escape the black hole, while the negative one fell in.</p><p>Over time, this process would lead black holes to evaporate and vanish, given that the particle absorbed had a negative mass. It would also lead to some interesting <a href="https://en.wikipedia.org/wiki/Black_hole_information_paradox#Recent_developments" target="_blank">paradoxes</a>.</p><p>For example, quantum mechanics predicts that particles would be able to escape a black hole. This idea suggests that black holes eventually die, which would theoretically mean that the physical information within a black hole also dies. This violates a key idea in quantum mechanics which is that physical information can't be destroyed.</p><p>The exact nature of black holes remains a mystery. If confirmed, the recent discovery could help scientists better fuse these two models of the universe. Still, some researchers are skeptical of the recent findings.</p><p>"It is not the first claim of this nature coming from this group," Maximiliano Isi, an astrophysicist at MIT, <a href="https://www.livescience.com/black-hole-echoes-unsettle-einstein-relativity.html" target="_blank">told</a> Live Science. "Unfortunately, other groups have been unable to reproduce their results, and not for lack of trying."</p><p>Isi noted that other papers examined the same data, but failed to find echoes. Afshordi told <em>Galaxy Daily</em>:</p><p>"Our results are still tentative because there is a very small chance that what we see is due to random noise in the detectors, but this chance becomes less likely as we find more examples. Now that scientists know what we're looking for, we can look for more examples, and have a much more robust confirmation of these signals. Such a confirmation would be the first direct probe of the quantum structure of space-time."</p>
This discovery finally points to the source of Earth's precious heavy elements, also proves Einstein correct in more ways than one.
Last September, scientists at a special observatory announced that they detected a gravitational wave for the first time. The detection took place in September, 2015, but wasn’t announced until last year. The observatory is known as the Laser Interferometer Gravitational-Wave Observatory (LIGO). It registered ripples in space-time formed from the collision of two black holes. Apparently, the fabric of the universe ripples just as water does.
These scientists scooped up the Nobel by detecting a ripple in space-time.
Officials in Sweden have just announced the 2017 Nobel Prize in Physics. Three American scientists won for detecting, for the very first time, gravitational waves or ripples in space-time, which were first predicted by Einstein back in 1916. Rainer Weiss of MIT, and Barry Barish and Kip Thorne of Caltech were this year’s recipients.
LIGO and Virgo reveal a gravitational wave was detected on two different continents. Here's what that means and why it matters.
The twin Laser Interferometer Gravitational-Wave Observatory (LIGO) is a collaborative effort. It’s basically a group of scientists who use specialized equipment to study gravitational waves. There are currently two such observatories in the US, one in Hanford, Washington and the other in Livingston, Louisiana. They use an interferometer, or a laser-based instrument, to detect even the minutest ripples in space-time as it relates to gravitational waves. The instrument is so delicate, it can pick up distortions one proton in width.
Get ready for a decade of scientific revelations. Thanks to gravity waves, we have a completely new way to explore the universe.
Alex Filippenko is a Hertz Foundation Fellow and recipient of the prestigious Hertz Foundation Grant for graduate study in the applications of the physical, biological and engineering sciences. When the discovery of gravitational waves was announced in February 2016, Filippenko was awed. The researchers at LIGO (Laser Interferometer Gravitational-Wave Observatory) managed to prove a key prediction of Einstein's general theory of relativity: his theory of gravity. Here, Filippenko explains the mind-boggling way they did it, and the scope of discoveries that this hyper-precise technology will reveal to us over the next decade. With the support of the Fannie and John Hertz Foundation, Filippenko pursued a PhD in astronomy at the California Institute of Technology.