The
top panel of this graphic is an artist's illustration that shows
what SN 2006gy may have looked like if viewed at a close distance.
The bottom left panel is an infrared image, using adaptive optics
at the Lick Observatory, of NGC 1260, the galaxy containing SN
2006gy. The panel to the right shows Chandra's X-ray image of the
same field of view, again showing the nucleus of NGC 1260 and SN
2006gy.
Credit:
Illustration: NASA/CXC/M.Weiss; X-ray: NASA/CXC/UC Berkeley/N.Smith
et al.; IR: Lick/UC Berkeley/J.Bloom & C.Hansen.
The
process that triggered the explosion in SN 2006gy: When a star is
very massive, its core can produce so much gamma-rays that some of
the radiation is converted into particle and antiparticle pairs.
The resulting drop in energy causes the star to collapse under its
own huge gravity. After this violent collapse, runaway
thermonuclear reactions ensue and the star explodes, spewing the
remains into space.
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Given
the brute fact that we are a carbon-based form of life slowly
evolved around a G-type star, there are some features of the
Universe, some constraints on physical constants, which can be
inferred quite straightforwardly. [...] But even if the constants
are fixed throughout the Universe we can observe, could there in
some sense be other universes where they are different? This idea
was outlined by a biologist, C.F.A. Pantin. He said "the
properties of the material universe are uniquely suitable for the
evolution of living creatures. If we could know that our universe
was only one of an indefinite number with varying properties we
could perhaps invoke a solution analogous to the principle of
natural selection, that only in certain universes, which happen to
include ours, are the conditions suitable for the existence of
life, and unless that condition is fulfilled there will be no
observers to note the fact."
If
someone walks into a clothing shop and buys a suit that is perfect
fit to his or her body, there are two possibilities. Either the
tailors who work in that shop have carefully measured that person’s
body and made a suit to fit it - bespoke tailoring - or the shop
has such a large range of closing available, in all shapes and
sizes, that the person in question has been fitted out from stock,
off the peg. The idea that the Universe is in some way constructed
for our benefit, or at least designed as a fit home for
intelligence, corre-sponds to the first possibility. In many ways,
the second alternative is more attractive; but it requires the
existence of a vast array of alternative universes from which we
have "chosen" by the fact of our existence. In this
picture, there are myriads of other worlds in which the laws of
physics and the constants of nature do differ, a little or a lot,
from those we know. In most of the universes, life - certainly
intelligent life - does not exist. Any universe in which our kind
of intelligent life can arise must look rather like our Universe,
since without the familiar coincidences and constants that life
would not be there. We believe our Universe
to be special because we inhabit it. But that does not mean that
it is special in any deeper sense of the word.
A
useful analogy is with a lottery. Suppose a million lottery
tickets are sold, and then one number out of that million is
selected. The holder of that number wins the prize, so that number
seems special. But in a deeper sense it is no more special than
any of the other numbers in the lottery. By the nature of the
lottery, somebody must win, and each of the numbers has an equal
chance of winning. It is only after the event that one number
gains a special status. The holder may feel lucky as a result; but
somebody had to get lucky!
Maybe
the world is like that. There may be a multitude of universes that
all start sterile. Intelligence appears in some (or perhaps only
one) of those universes as a result of the accumulation of random
coincidences ("luck"). But there is no meaning to the
coincidences, and that universe stands out from the rest as
special only with hindsight, once intelligence has appeared to
wonder over its own origins.
J.Gribbin
and M. Rees: Cosmic coincidences, Bantam Books, New York,
1989. |