Editing Micro black hole (section)

== Primordial black holes ==
{{Main|Primordial black hole}}

=== Formation in the early Universe ===
Production of a black hole requires concentration of mass or energy within the corresponding [[Schwarzschild radius]]. It was hypothesized by Zel'dovich and Novikov first and independently by Hawking that, shortly after the [[Big Bang]], the Universe was dense enough for any given region of space to fit within its own Schwarzschild radius. Even so, at that time, the Universe was not able to collapse into a [[Gravitational singularity|singularity]] due to its uniform mass distribution and rapid growth. This, however, does not fully exclude the possibility that black holes of various sizes may have emerged locally. A black hole formed in this way is called a [[primordial black hole]] and is the most widely accepted hypothesis for the possible creation of micro black holes. Computer simulations suggest that the probability of formation of a primordial black hole is inversely proportional to its mass. Thus, the most likely outcome would be micro black holes.{{citation needed|date=May 2012}}

=== Expected observable effects ===
A primordial black hole with an initial mass of around {{val|e=12|u=kg}} would be completing its evaporation today; a less massive primordial black hole would have already evaporated.<ref name="carr" /> Under optimal conditions, the [[Fermi Gamma-ray Space Telescope]] satellite, launched in June 2008, might detect experimental evidence for evaporation of nearby black holes by observing [[gamma ray burst]]s.<ref>{{cite journal |title=Primordial black holes as a source of extremely high energy cosmic rays |first=A. |last=Barrau |journal=Astroparticle Physics |volume=12 |issue=4 |date=2000 |pages=269–275 |doi=10.1016/S0927-6505(99)00103-6 |arxiv = astro-ph/9907347 |bibcode = 2000APh....12..269B |s2cid=17011869 }}</ref><ref>{{cite news |title=Satellite could open door on extra dimension |first=M. |last=McKee |date=30 May 2006 |work=New Scientist |url=https://www.newscientist.com/article/dn9240-satellite-could-open-door-on-extra-dimension/ }}</ref><ref>{{cite web |url=http://fermi.gsfc.nasa.gov/help/tech/minibh.html |title=Fermi Gamma Ray Space Telescope: "Mini" black hole detection |access-date=2008-12-03 |archive-url=https://web.archive.org/web/20090117075633/http://fermi.gsfc.nasa.gov/help/tech/minibh.html |archive-date=2009-01-17 |url-status=dead }}</ref> It is unlikely that a collision between a microscopic black hole and an object such as a star or a planet would be noticeable. The small radius and high density of the black hole would allow it to pass straight through any object consisting of normal atoms, interacting with only few of its atoms while doing so. It has, however, been suggested that a small black hole of sufficient mass passing through the Earth would produce a detectable acoustic or [[Seismology|seismic]] signal.<ref>{{cite journal |first1=I. B. |last1=Khriplovich |first2=A. A. |last2=Pomeransky |first3=N. |last3=Produit |first4=G. Yu. |last4=Ruban |date=2008 |title=Can one detect passage of small black hole through the Earth? |journal=Physical Review D |volume=77 |issue=6 |pages= 064017 |doi=10.1103/PhysRevD.77.064017 |bibcode = 2008PhRvD..77f4017K |arxiv = 0710.3438 |s2cid=118604599 }}</ref><ref>{{cite journal |last1=Khriplovich |first1=I. B. |last2=Pomeransky |first2=A. A. |last3=Produit |first3=N. |last4=Ruban |first4=G. Yu. |date=2008 |title=Passage of small black hole through the Earth. Is it detectable? |url=https://arxiv.org/pdf/0801.4623 |journal=[[Cornell University]] |volume=0801 |pages=4623 |arxiv=0801.4623 |bibcode=2008arXiv0801.4623K |archive-url=https://web.archive.org/web/20240727072534/https://arxiv.org/pdf/0801.4623 |archive-date=27 July 2024 |access-date=18 April 2025}}</ref><ref>{{cite web |url=https://www.universetoday.com/1930/are-microscopic-black-holes-buzzing-inside-the-earth/ |last=Cain |first=Fraser |title=Are Microscopic Black Holes Buzzing Inside the Earth? |work=Universe Today |date=20 June 2007 }}</ref><ref group=lower-alpha>The Schwarzschild radius of a {{val|e=12|u=kg}} black hole is approximately {{val|148|u=fm}} ({{val|1.48|e=-13|u=m}}), which is much smaller than an atom but larger than an atomic nucleus.</ref>
On the moon, it may leave a distinct type of crater, still visible after billions of years.<ref>{{cite news |last1=O’Callaghan |first1=Jonathan |title=Lunar craters could reveal past collisions with ancient black holes |url=https://www.newscientist.com/article/mg25133540-800-lunar-craters-could-reveal-past-collisions-with-ancient-black-holes/ |access-date=6 October 2021 |work=[[New Scientist]] |date=29 September 2021}}</ref>