In the U.S., NASA scientists have once again reminded
people how big the universe - to show how small our Milky Way galaxy, if it is
placed in the newly discovered halo - a cloud of hot gas that extends for
hundreds of thousands of light years.
When is the estimated mass of the
halo is comparable to the mass of all the stars in the galaxy - is able to
detect by X-ray Observatory "Chandra". Estimate the size - is
important because it can explain the problem of "missing baryons" -
that is, the particles that make up 99.9% of the mass of all the atoms in the
universe.
Scientists believe that the
baryonic matter in the universe there is a very long time - now, when her age
was only a few billion years, and it accounts for one-sixth of the mass and
density of dark matter.
At least half of the dark matter
halo of the galaxy in the form of baryons owes its origin to the contribution
of low-mass stars and brown dwarfs. What is in the second half of the baryonic
component of dark matter and the nature of the components of the non-baryonic
dark matter remains a mystery.
NASA believe that beyond the Milky
Way, there are eight superhot and dense clouds of elements where there are
oxygen ions, which are hundreds of times hotter than the surface of the Sun and
from 1 to 2.5 million Kelvin. It goes halo colder - from 100,000 to 1 million
Kelvin.
Note, in 2008 an international team
of astronomers from the Netherlands, Germany and other countries used the data
obtained orbiting X-ray observatory XMM-Newton («Newton") of the European
Space Agency, in order to find the part of the dark matter in the universe.
This is not about the so-called "dark" matter, and an ordinary
(baryonic) matter consisting of atoms - nucleons, electrons - and other particles
already known to science that are simply not visible to ordinary telescopes.
Almost all of the matter in the
universe is collected in giant structures - a kind of invisible network, in the
most dense nodes of which, like spiders, "sit" galaxy clusters - the
largest structural units of the world. Astronomers have long suspected that
stretched from one site to the "thread" of the network laid gas
having a low density and high temperature (105-107 degrees Kelvin), which
allows them to emit X-rays. Unfortunately, the large sparse gas is still almost
insurmountable obstacle to its discovery.
It should also be said that in a
recent study, a team of five astronomers used the data "Chandra" and
"Newton" and space observatory "Suzaku" tried to set limits
on the temperature, volume and mass of the hot gas halo. Studies have shown the
presence of hot gas with a temperature of more than 1 million Kelvin.
This new study shows hot gas halo
enveloping the Milky Way is much more massive than the warm halo gas.
"We know about the gas clouds
around galaxies, and we know how hot it can be," said Ange Gupta, one of
the authors of the study, adding that another interesting question - how big
halo and how it massively. It turned out that quite large - from 10 to 60
billion solar masses, reports Daily Mail.
"Our work shows that under
reasonable parameters and reasonable assumptions, observations," Chandra
"show the huge amount of hot gas around the Milky Way" - added Mathur
co-Smith of the University of Ohio.
"In any case, its mass is very
large. Estimated weight is dependent on such factors as the amount of oxygen to
hydrogen - they dominate in the gas, "- he added.
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