Black hole physicists have been excitedly discussing experiences that the LIGO and Virgo gravitational-wave detectors just lately picked up the sign of an unexpectedly monumental black gap, one with a mass that was considered physically unimaginable.
Seven consultants contacted by Quanta stated they’d heard that among the many 22 flurries of gravitational waves detected by LIGO and Virgo since April, one of many alerts got here from a collision involving a black hole of unanticipated heft — purportedly as heavy as 100 suns. LIGO/Virgo crew members would neither verify nor deny the rumored detection.
Black holes — dense, paradox-ridden spheres whose gravity traps all the pieces, even gentle — type from the contracting cores of fuel-spent stars. However, in 1967, three physicists on the Hebrew University in Jerusalem realized that when the core of a dying star could be very heavy, it won’t gravitationally collapse right into a black hole. As a substitute, the star will bear a “pair-instability supernova,” an explosion that absolutely annihilates it in a matter of seconds, leaving nothing behind. “The star is totally dispersed into space,” the three physicists wrote.
A pair-instability supernova occurs when the core grows so sizzling that light begins to convert into electron-positron pairs spontaneously. The light’s radiation strain had stored the star’s core intact; when the light transforms into the matter, the ensuing strain drop causes the core to quickly shrink and change into even hotter, additional accelerating pair manufacturing and inflicting a runaway impact. Finally, the core will get so sizzling that oxygen ignites. This absolutely reverses the core’s implosion, in order that it explodes as an alternative. For cores with a mass between about 65 and 130 occasions that of our sun (in line with current estimates), the star is totally obliterated. Cores between about 50 and 65 solar masses pulsate, shedding mass in a collection of explosions till they drop beneath the vary the place pair-instability happens. Thus there ought to be no black holes with masses within the 50-to-130-solar-mass range.