Home Science & Technology “New Study Challenges Theory: Can Black Holes Form Directly from Light?”

“New Study Challenges Theory: Can Black Holes Form Directly from Light?”


If you pack enough material into one area, space-time itself will pucker up in a sweet cosmic kiss known as a black hole.

According to Einstein’s calculations, that “material” includes massless electromagnetic radiation. Thanks to E=mc², which illustrates the equivalence of mass and energy, even the energy contained in light theoretically has the potential to create a black hole if it’s concentrated enough in one spot.

But before you start aiming high-powered lasers at the universe’s floorboards, researchers from Spain’s Complutense University of Madrid and Canada’s University of Waterloo want you to consider something called the Schwinger effect, which might make the whole idea impossible before you even get started.

Einstein’s general theory of relativity describes how space and time distort in response to energy, like that contained in mass. If you concentrate enough mass in one spot, the distortion becomes so extreme that not even light can escape.

In the mid-1950s, American theoretical physicist John Wheeler discovered that Einstein’s theory didn’t rule out the possibility that energy within a sufficiently concentrated gravitational or electromagnetic wave could warp space-time enough to trap those same waves in place.

He called this exotic object a geon and considered it a hypothetical, highly unstable particle.

Today, geons are relics from an era of scientific ponderings that also gave us wormholes and white holes; they’re theoretical toys that illustrate the limits of mathematical models more than they do physical reality.

Yet a form of geon that Wheeler referred to as a “kugelblitz” occasionally appears in science fiction as a fantastic power source. German for “ball lightning,” these proton-sized black holes were proposed to form in the intense focus of highly energetic beams of light, such as futuristic high-powered lasers.

While general relativity permits kugelblitze, quantum physics raises doubts. Therefore, theoretical physicist Álvaro Álvarez-Domínguez from Complutense University of Madrid and his team crunched the numbers on the behavior of electromagnetic fields as their energy levels rise to extremes.

The quantum landscape resembles a casino where waves of possibility ripple like non-stop roulette wheels. Small bets rarely pay off, but if you stack enough chips on any given table, you’re almost guaranteed a win.

Similarly, a powerful electromagnetic field in an otherwise empty space nearly guarantees pairs of electrons and positrons will emerge from the quantum whirl of endless possibilities.

In a paper awaiting peer review, Álvarez-Domínguez and his team demonstrated that this phenomenon, known as the Schwinger effect, would prevent the formation of kugelblitze ranging in size from nearly twice the size of Jupiter down to a fraction of the size of a proton.

In essence, concentrating all that light in one spot would provide the energy needed for pairs of charged particles to pop into existence and zoom away near the speed of light, thwarting the formation of a black hole-defining event horizon in the developing dimple of space-time.

“Our analysis strongly suggests that the formation of black holes solely from electromagnetic radiation is impossible, whether in a hypothetical laboratory setting or in naturally occurring astrophysical phenomena,” the team concluded in their analysis.

However, that’s not to completely rule out the possibility. The researchers acknowledge that conditions in the “exceptionally extreme” early universe might have been different.

Other forms of geons, such as those based on gravitational waves, remain an intriguing concept that may have existed billions of years ago in the early cosmos.

For those banking on a kugelblitz-powered spacecraft to transport them to the stars, it may be back to the drawing board for now.

The paper is available on the preprint server arXiv.