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RonPrice
2015-Feb-11, 10:48 AM
SWALLOWED BY A BLACK HOLE

Part 1:

In the southern hemisphere's summer of 2014-2015, the black hole at the centre of our Milky Way has been getting ready to feast. I was enjoying the first of the summers which I would have in my life during my 70s. I had taken an early retirement some 15 years before and I was also enjoying the intellectual feast that was prepared for me on the world-wide-web. My three children had all left the family nest, and grand-children occupied space out on the periphery of my universe. I served as the secretary and publicity-officer of the local Baha'i group, went for a walk everyday, and socialized in the main with my wife of 40 years.

A gas cloud three times the size of our planet was straying this summer within the gravitational reach of this our nearest super-massive black hole, and was about to be eaten-alive. Across the globe, telescopes were being trained on the heart of our Milky Way galaxy, some 27,000 light years from Earth. Astronomers were living in the expectation of observing this unique spectacle in the cosmos. For cosmic detectives across the Earth, it was a unique opportunity. For the first time in the history of science, they hoped to observe in action the awesome spectacle of a feeding super-massive black hole.

Part 1.1:

I had just finished my dinner which was about as far from an awesome spectacle as one could get in the evening of my life. I watched a program on SBS TV on 9/2/'15 at 7:30 p.m. entitled: Swallowed By A Black Hole. It helped to have some knowledge of both quasars and black holes to really appreciate this program. It also helped to know something about astronomy and physics, astrophysics and mathematics.

Part 2:

QUASARS

Quasars, or quasi-stellar radio sources, are the most energetic & distant members of a class of objects called active galactic nuclei (AGN). Quasars are extremely luminous and were first identified as being high red-shift sources of electromagnetic energy, including radio waves and visible light, that appeared to be similar to stars, rather than extended sources similar to galaxies. Their luminosity can be 100 times greater than that of the Milky Way. A quasar is a compact region in the center of a massive galaxy surrounding a central super-massive black hole. Its size is 1010,000 times what is called the Schwarzschild radius of the black hole. The energy emitted by a quasar derives from mass falling onto the accretion disc around the black hole. I leave it to readers with the interest to search-out the meaning of terms here which, in all likelihood, they do not understand.

Part 2.1:

It can be shown that quasars are between 600 million, and 29 billion light-years away. Because of the great distances to the farthest quasars and the finite velocity of light, we see them and their surrounding space as they existed in the very early universe. For more on quasars and AGN, as well as explanations of the many complex terms, go to: http://en.wikipedia.org/wiki/Quasar

Part 3:

BLACK HOLES

The idea of a body so massive that even light could not escape was first mentioned by John Michell in a letter written to Henry Cavendish in 1783 of the Royal Society. Black holes are mathematically defined regions of space-time exhibiting such a strong gravitational pull that no particle or electromagnetic radiation can escape from it. Black holes, defined and described as regions of space from which nothing can escape, was first published by David Finkelstein in 1958, and black holes became mainstream subjects of research.

Part 3.1:

After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, super-massive black holes of millions of solar masses may form. There is general consensus that super-massive black holes exist in the centers of most galaxies. The core of the Milky Way contains a super-massive black hole of about 4.3 million solar masses.

The theory of general relativity predicts that a sufficiently compact mass can deform space-time to form a black hole. For more on black holes go to:http://en.wikipedia.org/wiki/Black_hole This subject really requires some knowledge of physics, astrophysics, astronomy and mathematics. The layman and amateur like myself can only grasp the content to a limited extent.-Ron Price, Pioneering Over Five Epochs, 11/2/'15.

Part 4:

These are subjects which
the average person can't
get their head around; the
numbers are just too big
and the concepts behind
the numbers require the
study of astronomy and
physics, astrophysics, &
mathematics. The average
punter, occupied as he or
she is with the mundane
and the quotidian, with a
job and family life, with
an interest in gardening
and sport, perhaps, bush-
walking and swimming,
is just not on the money
for the complex, distant,
scientific phenomena at
the centre of our Milky
Way galaxy at a 27,000
light-year outpost, in a
state of utter remoteness.

Ron Price
11/2/'15.

NoChoice
2015-Feb-11, 11:20 AM
I'm not sure what you are trying to say?

Cougar
2015-Feb-11, 12:31 PM
It can be shown that quasars are between 600 million, and 29 billion light-years away. ...

I think maybe you should check your figures here.

RonPrice
2015-Feb-12, 01:20 AM
Thanks, folks, for your responses. I am just making some personal comments about black holes and quasars and the incredible distances involved. Wikipedia has the following about quasars, Cougar:

The luminosity of some quasars changes rapidly in the optical range and even more rapidly in the X-rays range. Because these changes occur very rapidly they define an upper limit on the volume of a quasar; quasars are not much larger than the Solar System. This implies an astonishingly high energy density. The mechanism of brightness changes probably involves relativistic beaming of jets pointed nearly directly toward us.

The highest redshift quasar known (as of June 2011) is ULAS J1120+0641, with a redshift of 7.085, which corresponds to a comoving distance of approximately 29 billion light-years from Earth (see more discussion of how cosmological distances can be greater than the light-travel time at Metric Expansion of Space). The Chandra X-ray image is of the quasar PKS 1127-145, a highly luminous source of X-rays and visible light about 10 billion light years from Earth.

According to the Wiley Online Library: "A team of astronomers has reported that it has ‘strong evidence’ that quasars are indeed tremendous distances from the earth. If their findings are confirmed, it could end a debate that has continued among scientists for years. Many astronomers have held that quasars are among the most distant objects in the universe—about 20 billion light years away. Others have contended that quasars are much closer—a few hundred million light years from earth.