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On
the
Track
of
Modern
Physics
Is the black hole really black?
And how heavy is it?
And how is it made inside?
European Southern Observatory: http://www.eso.org
Black holes are probably quite colorful: quickly rotating
ionized gas, imploding towards the center contains heavy
atoms, like iron, and its emission lines are strongly
shifted by the Doppler effect.
Fig. Krzysztof Karwasz
Crab Nebula testifies the Supernova explosion in
1054AD, noted in Europe, China and by Indians in
New Mexico
Quasars - quasi-stellar radio sources, discovered in 1961,
now believed to be super-massive (billion of M☺) black
holes in centers of distant galaxies. The ionized gas
quickly falling inside the hole emits powerful radiowaves.
http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html
Crab Nebula in X-rays
Cygnus Loop in X-rays
Remnants of supernovae are sources of
radio signals and also of X-ray radiation.
Credits: NASA Goddard Space Flight Center
http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html
Evolution of stars depend on their mass. Those above 8 Solar
masses, at the end of the life, were all the termonuclear fuel is
burn into iron, first collapse, and then explode into supernova.
A part of the mass is expelled and the remnants form a core
of about 20 km diameter made of neutrons. The expelled
material contains heavy elements and can be re-cycled, to
form a system, like the Solar one.
The neutron ball is similar to a giant atomic nucleus with
Z=1057. With such a big compression, neutrons start to
"crowd-up", following the Pauli's rule, which does not allow
them to be in the same quantum state. It is energetically
useful to replace some neutrons with protons, or even by
isolated quarks.
It seems (A.R. Bodmer 1971 , E. Witten 1984) that the state
of the matter with a lowest possible energy level is a mixture
of the "normal" u and d quarks with strange quarks s. It is
solely the big mass of the s quark (30 times more than that of
u) which protects us from falling the nucleus of 58Fe, for
example, to a quark state.
Chandra X-ray observation of RX J1856.5-3754
(or the C58 pulsar), the remnants of a supernova
noted on Earth in AD 1181, reveal that the
neutron star in the core has a temperature much
lower than expected. This suggests that a new
state of nuclear matter might exist inside the star.
Pulsars - quickly rotating neutron stars
which flares the magnetic field around
the space. The first pulsar CP 1919+21
(1.3 s period of rotation) was
discovered in the constellation of
Cygnus (“Swan”) in 1967 by graduate
student Jocelyn Bell Burnell but the
"Cygnus." Wikipedia.
Nobel prize went to her supervisor.
Strange quark droplets are a possible form of
hadronic matter, containing approximately
equal (and potentially very large) numbers of
up, down, and strange quarks inside a single
hadronic bag.
strange
up
down
Credits:NASA/CXC/CfA/P.Slane et al.
http://chandra.harvard.edu/photo/2002/0211/index.html
Free quarks
Confined quarks
Left: 12C nucleus. Right: a strange matter droplet with A=12.
RX J1856 in Optical Light
This optical image of RX J1856.5-3754 portrays a
crowded region of star formation. In comparison, the
Chandra X-ray image shows that RX J1856 outshines
all of the other sources in the field, indicating it is both
extremely hot and very small.
The Grand Canyon
is 30 km wide. A
neutron star is about
20 km in diameter,
and a quark star is
about 12 km in
diameter.
Credit: European Southern Observatory Very Large Telescope
(Illustration: CXC/D. Berry)
Astronomers still discuss if a real
black hole has been discovered.
Sign-down these numbers and
check from time to time on internet,
if they are really BLACK:
X-ray transient XTE J1650-500
SS433 MilkyWay Star
Cygnus X1 and HDE 226868
Seyfert-1 galaxy NGC 4593
Seyfert galaxy MCG -6-30-15
Galaxy NGC 4486
See aslo: http://blackholes.stardate.org/