Are some black holes wormholes in disguise? Gammaray blasts may shed clues.
Unusual flashes of gamma rays could reveal that what appear to be giant black holes are actually huge wormholes, a new study finds.
Wormholes are tunnels in spacetime that can theoretically allow travel anywhere in space and time, or even into another universe. Einstein's theory of general relativity suggests wormholes are possible, although whether they really exist is another matter.
In many ways, wormholes resemble black holes. Both kinds of objects are extremely dense and possess extraordinarily strong gravitational pulls for bodies their size. The main difference is that no object can theoretically come back out after crossing a black hole's event horizon — the threshold where the speed needed to escape the black hole's gravitational pull exceeds the speed of light — whereas any body entering a wormhole could theoretically reverse course.
Video: Last 500 years around Milky Way's supermassive black hole
Assuming wormholes might exist, researchers investigated ways that one might distinguish a wormhole from a black hole. They focused on supermassive black holes with masses millions to billions of times that of the sun, which are thought to dwell at the hearts of most, if not all, galaxies. For example, at the center of our Milky Way galaxy lies Sagittarius A*, a monster black hole that is about 4.5 million solar masses in size.
Anything entering one mouth of a wormhole would exit out its other mouth. The scientists reasoned that meant that matter entering one mouth of a wormhole could potentially slam into matter entering the other mouth of the wormhole at the same time, a kind of event that would never happen with a black hole.
Any matter falling into a mouth of a supermassive wormhole would likely travel at extraordinarily high speeds due to its powerful gravitational fields. The scientists modeled the consequences of matter flowing through both mouths of a wormhole to where these mouths meet, the wormhole's "throat." The result of such collisions are spheres of plasma expanding out both mouths of the wormhole at nearly the speed of light, the researchers said.
"What surprises me most of all is that no one has proposed this idea before, because it is rather simple," study lead author Mikhail Piotrovich, an astrophysicist at the Central Astronomical Observatory in Saint Petersburg, Russia, told Space.com.
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The researchers compared the outbursts from such wormholes with those from a kind of supermassive black hole known as an active galactic nucleus (AGN), which can spew out more radiation than our entire galaxy does as they devour matter around them, and do so from a patch of space no larger than our solar system. AGNs are typically surrounded by rings of plasma known as accretion disks and can emit powerful jets of radiation from their poles.
The spheres of plasma from wormholes can reach temperatures of about 18 trillion degrees Fahrenheit (10 trillion degrees Celsius). At such heat, the plasma would produce gamma rays with energies of 68 million electronvolts.
In contrast, "accretion disks of AGNs don't emit gamma radiation, because their temperature is too low for that," Piotrovich said. Moreover, although jets from AGNs can emit gamma rays, these would mostly travel in the same direction as the jets — any traveling out in a sphere might suggest they came from a wormhole, he noted.
In addition, if an AGN resided in a kind of galaxy known as a Type I Seyfert — one in which hot gas was expanding rapidly — prior work suggested it would likely not generate many gamma rays with energies of 68 million electronvolts. If astronomers did see an AGN in a Type I Seyfert galaxy with a significant peak of such rays, that could mean that seeming AGN was actually a wormhole, the researchers said.
The scientists detailed their findings online Aug. 21 in a study accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.
Follow Charles Q. Choi on Twitter @cqchoi. Follow us on Twitter @Spacedotcom and on Facebook.

TorbjornLarsson " Einstein's theory of general relativity suggests wormholes are possible,".Reply
But only if there are added dimensions. And we now know our universe is on average flat on sufficient large scales so large wormholes are excluded. (And measurements of putative added gravity from hidden small dimensions have so far excluded small wormholes too, come to think of it.)
Which nicely explains the current absence of such more permanent spherical Xray sources. 
danr2222 The proclivity of nature for equipotential surfaces suggests to me, by analogy, that wormholes simply don't exist. Where did you ever see someone blow a soapbubble with a connecting tube from one part of the bubble to the other; where do you see toroidal droplets?Reply
The only environment where the ab initio energy conditions for a 4space manifold wormhole getting formed that I can possibly conceive of would be in the primordial Guthian expansion. But real surfaces have no mathematical topological formal constraints, apart from the nointersection axiom: those wormholes would rapidly pull their two ends together and the multiorder surface would quickly degenerate to a genus0 sphere. 
Xinhang Shen Don't waste resources on such nonsense any longer because there is nothing called spacetime in nature, not to mention the existence of its singularities. Einstein's relativity is totally wrong because our physical time is absolute and independent of the 3D physical space. He made a fatal mistake in his special relativity. He assumed that the speed of light should be the same relative to all inertial reference frames, which requires the change of the definition of space and time. But he never verified that the newly defined time was still the time measured with physical clocks. This leads to many mathematicians and theoretical physicists believe that time is like a playdough which can be freely compressed/stretched to fit their fantacies. Actually our physical time measured with physical clocks is stiff and absolute, which won't change with the change of the definition of the space and time. Einstein's newly defined relativistic time is no longer our physical time, but a mathematical variable without physical meaning, which can be easily verified as follows:Reply
We know physical time T has a relationship with the relativistic time t in Einstein's special relativity: T = tf/k where f is the relativistic frequency of the clock and k is a calibration constant, that is, a clock uses the change of the status of a physical process to indirectly measure time. Now We would like to use the behavior of our physical time in Lorentz Transformation to demonstrate that the relativistic time t defined by Lorentz Transformation is no longer our physical time T.
If you have a clock (clock 1) with you and watch my clock (clock 2) in motion and both clocks are set to be synchronized to show the same physical time T relative to your inertial reference frame, you will see your clock time: T1 = tf1/k1 = T and my clock time: T2 = tf2/k2 = T, where t is the relativistic time of your reference frame, f1 and f2 are the relativistic frequencies of clock 1 and clock 2 respectively, k1 and k2 are calibration constants of the clocks. The two events (Clock1, T1=T, x1=0, y1=0, z1=0, t1=t) and (Clock2, T2=T, x2=vt, y2=0, z2=0, t2=t) are simultaneous measured with both relativistic time t and clock time T in your reference frame. When these two clocks are observed by me in the moving inertial reference frame, according to special relativity, we can use Lorentz Transformation to get the events in my frame (x', y', z', t'): (clock1, T1', x1'=vt1', y1'=0, z1'=0, t1'=t/γ) and (clock2, T2', x2'=0, y2'=0, z2'=0, t2'=γt), where T1' = t1'f1'/k1 = (t/γ)(γf1)/k1 = tf1/k1 = T1 = T and T2' = t2'f2'/k2 = (γt)(f2/γ)/k2 = tf2/k2 = T2 = T, where γ = 1/sqrt(1v^2/c^2). That is, no matter observed from which inertial reference frame, the events are still simultaneous measured with physical time T i.e. the two clocks are always synchronized measured with physical time T, but not synchronized measured with relativistic time t'. Therefore, our physical time and the relativistic time behave differently in Lorentz Transformation and thus they are not the same thing. The change of the reference frame only makes changes of the relativistic time from t to t' and the relativistic frequency from f to f', which cancel each other in the formula: T = tf/k to make the physical time T unchanged i.e. our physical time is still absolute in special relativity. Therefore, based on the artificial relativistic time, special relativity is wrong, so is general relativity. For more details, please check: https://www.researchgate.net/publication/297527784_Challenge_to_the_Special_Theory_of_Relativity