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Starts With A Bang

For The Last Time: The LHC Will Not Make An Earth-Swallowing Black Hole

No matter what Martin Rees or anyone else says, physics dictates that the world is safe.


The Large Hadron Collider is the world’s most powerful particle accelerator.

An aerial view of CERN, with the Large Hadron Collider’s circumference (27 kilometers in all) outlined. (MAXIMILIEN BRICE (CERN))

Inside, protons collide head-on at top speeds of 299,792,455 m/s: 99.99999896% the speed of light.

The particle tracks emanating from a high energy collision at the LHC in 2014. The detector tracks are what we use to reconstruct what was created at the collision point.

With a maximum of 13 TeV of energy available for new particle creation, it can make everything we predict exists.

The particles and antiparticles of the Standard Model have now all been directly detected, with the last holdout, the Higgs Boson, falling at the LHC earlier this decade. All of these particles can be created at LHC energies, and the hope is that there are additional particles or entities that may be created at the LHC as well, although there is not presently direct evidence for them. (E. SIEGEL / BEYOND THE GALAXY)

If physics works the way we think it does, this energy is insufficient to make a black hole.

The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. But outside the event horizon, the black hole is predicted to emit radiation. Hawking’s 1974 work was the first to demonstrate this, and it was arguably his greatest scientific achievement. (NASA; JÖRN WILMS (TÜBINGEN) ET AL.; ESA)

All black holes decay, via Hawking radiation, on timescales dependent on their mass/energy.

The simulated decay of a black hole not only results in the emission of radiation, but the decay of the central orbiting mass that keeps most objects stable. For a black hole at the LHC’s energies, the decay timescales are 10^-83 seconds. (THE EU’S COMMUNICATE SCIENCE)

An energy of 13 TeV equates to decay times of 10^-83 seconds: 40 orders of magnitude below nature’s observability threshold.

Black holes are not isolated objects in space, but exist amidst the matter and energy in the Universe, galaxy, and star systems where they reside. They grow by accreting and devouring matter and energy, but also lose energy over time due to the competing process of Hawking radiation. If you were to use those same calculational tools to determine the lifetime of an LHC-created black hole, you’d find its existence was entirely impossible under the currently known laws of physics. (NASA/ESA HUBBLE SPACE TELESCOPE COLLABORATION)

If extra dimensions exist, however, that decay time could be increased up to 10^-23 seconds.

The decay of a black hole, via Hawking radiation, should produce observable signatures of particles and antiparticles that would be unique, and distinct from a scenario where no black hole was formed. (ORTEGA-PICTURES / PIXABAY)

Under that scenario, the LHC could conceivably create a black hole whose products could be detected.

Hawking radiation is what inevitably results from the predictions of quantum physics in the curved spacetime surrounding a black hole’s event horizon. At present, the minimum mass a black hole can have and still be a black hole is 0.00002 grams: about 15 orders of magnitude stronger than what the LHC can achieve. (E. SIEGEL)

To prevent decay, new, unknown physics — for which no evidence exists — must be invoked.

If extra dimensions exist, they must be very small in size. Even with the largest values allowed, the decay time of a black hole created at the LHC would still only be increased to a tiny fraction of a second. (FERMILAB TODAY)

Even if the newly created black hole were stable, it could not devour the Earth.

This artist’s impression depicts a Sun-like star being torn apart by tidal disruption as it nears a black hole. For an LHC-mass black hole, these forces are inconsequential, as they’re negligibly small. (ESO, ESA/HUBBLE, M. KORNMESSER)

The maximum rate it could consume matter is 1.1 × 10^–25 grams-per-second.

Black holes will devour whatever matter they encounter. Even if they are created on Earth’s surface and zip through the planet’s core, colliding with protons, neutrons, and electrons along the way, the black hole’s rate-of-growth is so small that it has no chance of threatening Earth. (X-RAY: NASA/CXC/UNH/D.LIN ET AL, OPTICAL: CFHT, ILLUSTRATION: NASA/CXC/M.WEISS)

It would take 3 trillion years to grow to a mass of 1 kg.

The Earth as viewed from a composite of NASA satellite images from space in the early 2000s. The Earth is 6 x 1⁰²⁴ kg in mass; it would take an LHC-mass black hole on the order of 1⁰³⁶ years to swallow the entire Earth. (NASA / BLUE MARBLE PROJECT)

Under no circumstances is Earth in danger, even if black hole creation at the LHC is possible.


Mostly Mute Monday tells the scientific story of an object, image, or phenomenon in the Universe in visuals and no more than 200 words. Talk less; smile more.

Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.

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