The Early Universe t 1015 By

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The Early Universet 10-15 By
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Hubble Ultra Deep Space the Early Universe
Brief Expert Astronomer Explanation Within the
Hubble Ultra Deep Field there are approximately
10,000 discrete objects. The total field of view
represents only 1 ten millionth of the total sky.
Most of these objects are very small and likely
have masses in the range of 105 to 107 solar
masses. Note the mass of the Milky Way galaxy is
1012 solar masses. Thus, many of these objects
are pre-galactic size lumps of material which are
merging together to form larger galaxies. In this
sense, this image is very much like looking back
to our origins. Before there can be life, first
nature must assemble matter in discrete units
that we call galaxies. The different colors of
the objects represent how they appear to us on
earth. Those colors do not necessarily reflect
the intrinsic color of the object as many of
these objects are greatly redshifted. The likely
average redshift of a small object in this field
is 3-5, and thus we are seeing rest frame
ultraviolet emission, redshifted into the Hubble
filter set.
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Hubble Ultra Deep Space 2
There are also examples of fully formed galaxies
(i.e. regular spiral pattern). These are most
likely galaxies at a redshift of about 1. But
there are plenty of chaotic and odd looking
objects and as you scroll through pixels you will
see more and more diversity in the various
morphologies. You will also see lots of clumps of
individual objects which look like they are
merging into a single object. This supplies
strong evidence that galaxies are formed via the
gravitional merging of sub clumps. Finally, for
you cosmologists/experts out there this ultra
deep field is quite consistent with what was seen
in the original Hubble Deep Field in the sense
that the angular size distribution objects is
overwhelmed by small angular size objects.
Remember, in cosmology there is a minimum
redshift in the angular size diameter (somewhere
between 2 and 3 for reasonable cosmologies), so
high redshift objects (z 5) don't necessarily
have small angular diameters. Thus, the great
preponderance of small angular size objects in
this field is challenging to understand. Also
note that there are some diffuse/ low surface
brightness objects in this field. These may very
well be normal galaxies at relatively high
redshift and thus we are seeing the (1z)4
cosmological dimming.
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Globular Cluster
M13, also called the Great globular cluster in
Hercules', is one of the most prominent and best
known globulars of the Northern celestial
hemisphere. It was discovered by Edmond Halley in
1714, who noted that it shows itself to the
naked eye when the sky is serene and the Moon
absent.' According to Charles Messier, who
cataloged it on June 1, 1764, it is also reported
in John Bevis' "English" Celestial Atlas. At
its distance of 25,100 light years, its angular
diameter of 20' corresponds to a linear 145 light
years - visually, it is perhaps 13' large. It
contains several 100,000 stars Timothy Ferris in
his book Galaxies even says "more than a
million". Towards its center, stars are about
500 times more concentrated than in the solar
neighborhood. The age of M13 has been determined
by Sandage as 24 billion years and by Arp as 17
billion years around 1960 Arp later (in 1962)
revised his value to 14 billion years (taken from
Kenneth Glyn Jones).
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The famous globular cluster M13 in Hercules, seen
in a blue-light image taken with the Lowell
Observatory 1.1-meter telescope. The nonlinear
intensity mapping simultaneously shows stars with
a wide brightness range, from the brightest red
giants down to the main sequence.
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elliptical galaxy NGC 221
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Elliptical galaxy NGC 221
The brighter and closer elliptical companion of
the Andromeda galaxy, also known as NGC 221. This
is the inner half of a V-band CCD image taken in
twilight (15 seconds' exposure) at the prime
focus of the 4-meter Mayall telescope of Kitt
Peak National Observatory. North is at the top
and east to the left, for direct comparison with
a chart or eyepiece view. The center of M31 is to
the north. This area subtends 7.3 arcminutes, and
is shown with a logarithmic intensity mapping.
Even so, the bright nucleus of M32 (probably
the highest stellar density known in the entire
Local Group) saturates the display.
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our sun
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Spiral Galaxy
This is the nearby Sc spiral (in fact, perhaps
the textbook example of a luminous so-called
luminosity class I spiral) NGC 5457 or Messier
101, in Ursa Major. It has several extremely
luminous star-forming (H II) regions in the outer
spiral arms, some sporting their own NGC numbers.
It dominates a small group of galaxies, with some
of its neighbors such as NGC 5474 showing wear
and tear attributed to the tidal effects of M101.
M101 itself is further noteworthy for its
extensive and lopsided distribution of neutral
hydrogen gas, and for showing evidence of gas
falling into its disk at high speeds. Cepheid
variables suggest a distance of about 7
Megaparsecs (about 22 million light-years) at
that distance some can just be picked up from the
ground when the seeing cooperates, though the
definitive study had to await the availability of
HST. This color composite is from B and R
images (with synthetic V) taken during twilight
with a Tektronix 2048x2048 CCD at the prime focus
of the 4-meter Mayall telescope of Kitt Peak
National Observatory. North is at the top and
east to the left, for direct comparison with a
chart or eyepiece view. The image has been
block-averaged to 512x512 for this presentation,
which uses a logarithmic intensity transformation
to preserve information across a wide dynamic
range. The field is 14.3 arcminutes square. A few
of the brighter field stars saturated the CCD so
strongly that some of the electric charge bled
along columns, giving the vertical streaks from
several stars.
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Galactic Center
One of the busiest areas in our sky, this is the
region around the Galactic Center near the border
between Scorpius and Sagittarius. This is a
30-minute exposure on Ektachrome 400 taken from
Cerro Tololo, Chile (and scanned at fairly high
density), using a Canon 50mm lens wide open at
f/1.8 North is at the top in this view, which
spans an area about 27 by 40 degrees. This view
shows the intricate absorbing dust lanes which
block our view of the galactic center, and the
yellowish color of the old bulge stars (dimmed to
brownish when there's noticeable reddening by
interstellar dust). This film has a very strong
response to the red light of H-alpha from
emission nebulae, so that the many H II regions
in this direction show up well.
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Galactic Center - Labeled
Can't tell the players without a program? Have a
look at the labelled version of this picture,
which marks the 17 Messier objects in this area,
plus constellation lines and some of the more
prominent non-Messier clusters and nebulae to be
found here. They include the Eagle , Omega,
Lagoon, and Trifid nebulae, the globular clusters
M25, M22, M28, M54, M69, and NGC 6723, open
clusters M6, M7, M23, M21, and M18, plus the star
cloud M24. Also to be seen are the dark Pipe
Nebula (recently described by John Shibley as
part of the Dark Horse Nebula) and Baade's
Window, best known as the region with the
clearest optical view into the central bulge of
the Milky Way and therefore especially important
to our understanding of the structure and
evolution of our Galaxy. Studying this area from
Northern Hemisphere observatories can be
interesting - from the Crossley reflector at Lick
Observatory, I recall lying on the observing
floor looking up into the guiding eyepiece to get
a plate of Baade's Window.