Why it is these cataclysmic events are always SO far away?

Quasars, gamma ray bursters, etc. They never seen closer than a
couple billion light years.

From Sky and Tel:

On Christmas Day, 2010, a flash of gamma rays set off an alarm aboard
NASA’s Swift satellite. The alarm is triggered whenever intense, high-
energy flares arrive from violent, faraway explosions. In a matter of
seconds, these brief gamma-ray bursts (GRBs) unleash more energy than
the Sun can radiate over its entire 10-billion-year lifetime. But the
Christmas Day burst, technically known as GRB 101225A, didn’t last
mere seconds — it lasted 30 minutes.

Barely a year later, Santa came early with another history-making GRB.
On December 9, 2011, GRB 111209A erupted, lasting at least seven hours
and becoming the most energetic cosmic explosion ever observed. The
two bursts lie 7 billion and 6 billion light-years away, respectively.

On 20/04/2013 04:27, RichA wrote:
Quasars, gamma ray bursters, etc. They never seen closer than a
couple billion light years.

From Sky and Tel:

On Christmas Day, 2010, a flash of gamma rays set off an alarm aboard
NASA’s Swift satellite. The alarm is triggered whenever intense, high-
energy flares arrive from violent, faraway explosions. In a matter of
seconds, these brief gamma-ray bursts (GRBs) unleash more energy than
the Sun can radiate over its entire 10-billion-year lifetime. But the
Christmas Day burst, technically known as GRB 101225A, didn’t last
mere seconds — it lasted 30 minutes.

Barely a year later, Santa came early with another history-making GRB.
On December 9, 2011, GRB 111209A erupted, lasting at least seven hours
and becoming the most energetic cosmic explosion ever observed. The
two bursts lie 7 billion and 6 billion light-years away, respectively.

The young universe was a lot more violent than it is today. The nearest
object with anything like the sort of activity of way back then is the
huge radiogalaxy Cygnus A third brightest object in the radio sky after
the sun and the SNR Cass A but it is at redshift 0.056 or 600Mly.

http://hubblesite.org/explore_astron..._mod1_q12.html

It wouldn't be good to have something like that too much closer!

It was the evidence from the number of radio galaxies in the universe
increasing very rapidly as a function of brightness that provided the
experimental nail in the coffin of Steady State cosmology. There was a
battle royal over this in Cambridge with Hoyle versus Ryle.

--
Regards,
Martin Brown

On Apr 20, 8:38*am, Martin Brown
wrote:

It was the evidence from the number of radio galaxies in the universe
increasing very rapidly as a function of brightness that provided the
experimental nail in the coffin of Steady State cosmology. There was a
battle royal over this in Cambridge with Hoyle versus Ryle.

--
Regards,
Martin Brown

Yet again,the furthest galaxies,at least in the minds of the
empiricists, are the youngest galaxies in an old Universe or what
amounts to the same thing - they are the oldest galaxies in a young
Universe which leads to the hilarious conclusion by extended logic
that the nearest galaxies are the youngest galaxies in an old
Universe.The idea that any human can visibly watch the evolutionary
timeline of the Universe directly by a spurious use of Roemer's
assertion that light has a finite speed through the electromagnetic
background is a form of intellectual laceration.

Who,for goodness sake,would go out of their way and force themselves
to believe that the present,past and future are different to what they
experience of it in their daily lives and that the celestial arena is
any different.The original assertion of Roemer has to do with
positional displacement and the very fact that he used the equation of
time tables means that he was operating off the 365/365/365/366
convention which affects all observations from Earth and certainly
would have shown an anomaly in the motion of Io.

I can't believe that it is over a decade since I dealt with this
material and even tried to accommodate empirical viewpoints which saw
glimpses of the difficulties but simply didn't know how to handle them
and shame the books no longer exist online -


" 27. In the Opticks published first in 1704, NEWTON has two
direct references to the velocity of light. In the first of these, at
the very start of the book he mentions that most people consider light
to be propagated instantaneously and so initially he defines rays,
refractions, etc. in accordance with that belief.

' But by an Argument taken from the Aequations of the times of the
Eclipses of Jupiter's Satellites, it seems that Light is propagated in
time, spending in its passage from the Sun to us about seven Minutes
of time: And therefore I have chosen to define Rays and Refractions in
such general terms as may agree to Light in both cases.'[Newton]

Was NEWTON just "playing safe"? It seems not. In so far as the
materials treated in Book I were concerned, it did not much matter
whether be assumed the propagation to be instantaneous or gradual.
NEWTON merely wished to avoid commitment to one point of view or the
other as long as possible. (It will be remembered with what dread
NEWTON viewed controversies.) But when he had reached that part of the
book where "the last proposition depended on the velocity of Light,"
he introduced the proposition that "Light is propagated from luminous
Bodies in time, and spends about seven or eight Minutes of an
Hour in passing from the Sun to the Earth." He adds that this "was
observed first by ROEMER, and then by others, by means of the Eclipses
of the Satellites of Jupiter," and after explaining how one derives
the fact of "mora luminis" from these eclipses, notes that -

'Some inequalities of time may arise from the Excentricities of the
Orbs of the Satellites; [etc.]... But this inequality has no respect
to the position of the Earth, and in the three interior Satellites is
insensible, as I find by computation from the Theory of their
Gravity.' [Newton]

It should be noted that the time is no longer given as ten minutes (as
in the first edition of the Principia) but as seven or eight minutes.
Whether this resulted from his own computation or from that of HALLEY
or FLAMSTEED, we have no way of knowing. Of course, once ROEMER had
described his method, it was a simple matter for anyone else to repeat
his work: all that was needed was a set of tables. Newton was
consistent with regard to the amount of time and in the second edition
of the Principia (revised by himself) the statement quoted in § 25
becomes "Namque Lucem successive propagari & spatio quasi septem vel
octo minutorum primorum a Sole ad Terram venire, ... " (94)."

http://web.mit.edu/dibner/

The cataclysm is in the heads of mathematicians and subsequently a
societal thing as the world now follows something as dismaying as the
anti-intellectual 'big bang' which forces people to dwell on a topic
they shouldn't have to and draws attention away from genuinely
intricate facets of astronomy that are more manageable.

People like Brown and his colleagues have reputations and salaries by
keeping things unstable and contrived and may even think they are
providing a public service by giving people the excuse not to think
about astronomy and the celestial arena because of the 'mathematical'
difficulty.Great scam if you can get away with it,even for a century
or so because in Newton's era it wasn't money but pretension/
reputation.

On 4/19/13 8:27 PM, RichA wrote:

They never seen closer than a couple billion light years.

Weak Anthropic Principle.

On 4/19/13 10:27 PM, RichA wrote:
Quasars, gamma ray bursters, etc. They never seen closer than a
couple billion light years.



Ancient bacteria may show evidence of supernova

http://blogs.physicstoday.org/newspi...-of-supernova/


Natu Iron-60 is produced in tiny amounts by cosmic rays and in
large amounts by supernovae. Given that 60Fe does not form naturally
on Earth, any significant concentration of the isotope is most likely
have come from a past supernova. In 2004 researchers found 60Fe in a
sample of deep-ocean crust 2.2 million years old and attributed it to
a nearby supernova. Now, Shawn Bishop of the Technical University of
Munich and his colleagues believe they have found further evidence of
the supernova in fossilized bacteria. From core samples dating to
between 1.7 million and 3.3 million years ago, they took samples from
strata formed roughly 100 000 years apart.

On Apr 19, 9:27*pm, RichA wrote:
Quasars, gamma ray bursters, etc. *They never seen closer than a
couple billion light years.

They are rare events. We only see them at all because the Universe is
so large.

Also, why tempt fate? Bad things _could_ be coming our way from
Betelgeuse...

John Savard

Would you like to see a supernova 10 light years away? :-)

On Apr 19, 11:27*pm, RichA wrote:
Quasars, gamma ray bursters, etc. *They never seen closer than a
couple billion light years.

From Sky and Tel:

On Christmas Day, 2010, a flash of gamma rays set off an alarm aboard
NASA’s Swift satellite. The alarm is triggered whenever intense, high-
energy flares arrive from violent, faraway explosions. In a matter of
seconds, these brief gamma-ray bursts (GRBs) unleash more energy than
the Sun can radiate over its entire 10-billion-year lifetime. But the
Christmas Day burst, technically known as GRB 101225A, didn’t last
mere seconds — it lasted 30 minutes.

Barely a year later, Santa came early with another history-making GRB.
On December 9, 2011, GRB 111209A erupted, lasting at least seven hours
and becoming the most energetic cosmic explosion ever observed. The
two bursts lie 7 billion and 6 billion light-years away, respectively.