Приклади вживання Primordial black holes Англійська мовою та їх переклад на Українською
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Currently, primordial black holes are merely hypothetical.
NASA's Fermi Gamma-ray Space Telescope satellite, launched in June 2008,was designed in part to search for such evaporating primordial black holes.
Primordial black holes with a mass of greater than 1015 g have remained virtually unchanged.
But even if we cannot harness the emission from these primordial black holes, what are our chances of observing them?
However, since primordial black holes are not formed by stellar core collapse, they may be of any size.
Stephen Hawking theorized in 1974 that large numbers of such smaller primordial black holes might exist in the Milky Way in our galaxy's halo region.
Primordial black holes(PBHs) are previous and comparatively small black holes that emerged quickly after the Big Bang.
Fermi data set up the limit that less than one percent ofdark matter could be made of primordial black holes with masses up to 1013 kg.
The team's results showed primordial black holes can contribute no more than 0.1 percent of all dark matter mass.
An international team of researchers has put a theory speculated by the late Stephen Hawking to its most rigorous test to date,and their results have ruled out the possibility that primordial black holes smaller than a tenth of a millimeter make up most of dark matter.
The team's results showed primordial black holes can contribute no more than 0.1 per cent of all Dark Matter mass.
If primordial black holes were abundant enough to account for the proposed dark matter, the researchers anticipated 1000 lensing events.
The Fermi Gamma-Ray Burst Monitor experiment found that primordial black holes cannot contribute importantly to the dark matter within the mass range 5 x 1014- 1017 kg.
Primordial black holes could have formed in the very early Universe(less than one second after the Big Bang), during the so-called radiation dominated era.
Since quantum radiationprocesses reduce the mass of a black hole, all primordial black holes with a mass of less than 1015 g should have evaporated by the present time.
For example, primordial black holes fall into a category of entities known as MACHOs, or Massive Compact Halo Objects.
One would also have expected the density fluctuations in such amodel to have led to the formation of many more primordial black holes than the upper limit that has been set by observations of the gamma ray background.
This limit means that primordial black holes could make up at most one millionth of the matter in the universe.
Primordial black holes with initial masses less than this figure would already have completely evaporated, but those with slightly greater masses would still be emitting radiation in the form of X rays and gamma rays.
However, if theoretical Hawkingradiation does not actually exist, such primordial black holes would be extremely difficult, if not impossible, to detect in space due to their small size and lack of large gravitational influence.
Primordial black holes with masses more than a thousand million tons(the mass of a large mountain) could be detected only by their gravitational influence on other, visible matter or on the expansion of the universe.
But since gravity would draw primordial black holes toward any matter, they should be much more common in and around galaxies.
Evaporating primordial black holes would have also had an impact on the Big Bang nucleosynthesis and change the abundances of light elements in the Universe.
On the other hand, as mentioned in Chapter 6,there might be primordial black holes with a very much smaller mass that were made by the collapse of irregularities in the very early stages of the universe.
These so-called primordial black holes were first proposed in the early 1970s by Stephen Hawking and collaborators but have never been detected-- it's still not clear if they exist at all.
So if we could determine how many primordial black holes there are now, we would learn a lot about the very early stages of the universe.
Depending on the model, primordial black holes could have initial masses ranging from 6992100000000000000♠10- 8 kg(the so-called Planck relics) to more than thousands of solar masses.
It has been also argued that if primordial black holes are regrouped in dense halos, the micro-lensing constraints are then naturally evaded.
It is possible that such quantum primordial black holes were created in the high-density environment of the early Universe(or big bang), or possibly through subsequent phase transitions.
Other problems for which primordial black holes have been suggested as a solution include the dark matter problem, the cosmological domain wall problem and the cosmological monopole problem.