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A Hidden Galaxy Discovered

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posted on May, 13 2008 @ 09:11 AM
Sharing information relating to astronomy and the study of the universe is so important becauase we are part of it all. Astronomers be them professional or amateur whose information when supplied is so vital for our understanding on how the universe functions and how it is evolving constantly. The following is just a small piece of the puzzle but nevertheless important to add to our knowledge in understanding the cosmos.
Astronomers have made use of ESO's Very Large Telescope to detect for the first time in the ultraviolet the carbon monoxide molecule in a galaxy located almost 11 billion light-years away, a feat that had remained elusive for 25 years. This detection allows them to obtain the most precise measurement of the cosmic temperature at such a remote epoch.

Well-hidden galaxies can be discovered through the imprint their interstellar gas leave on the spectrum of an even more remote quasar. Interstellar clouds of gas in galaxies, located between the quasars and us on the same line of sight, absorb parts of the light emitted by the quasars. The resulting spectrum consequently presents dark 'valleys' that can be attributed to well-known elements and possibly molecules. In this schematic representation, the VLT observes (D) the features associated with three systems, located at different distances (A, B, and C), and whose light is therefore shifted by different amounts. The quasar, which acts as a beacon, is the bright object at the left of the image.

Using a quasar located 12.3 billion light-years away as a beacon, a team of astronomers detected the presence of molecular hydrogen in the farthest system ever, an otherwise invisible galaxy that we observe when the Universe was less than 1.5 billion years old, that is, about 10% of its present age. The astronomers find that there is about one hydrogen molecule for 250 hydrogen atoms. A similar set of observations for two other quasars, together with the most precise laboratory measurements, allows scientists to infer that the ratio of the proton to electron masses may have changed with time. If confirmed, this would have important consequences on our understanding of physics.

[those of you who have some understanding of physics can relate to this angelc01]

Spectrum of the quasar PSS J 1443+2724, revealing the otherwise invisible galaxy at a redshift of 4.224. The velocity profiles of selected transition lines from some rotational levels of H2 are shown. The best fit is superposed in red on the observed spectrum (in black).

Spectrum of a very distant quasar on which the footprints from a galaxy located almost 11 billion light-years away are seen. Various bands of carbon monoxide (CO), as well as bands of normal and deuterated molecular hydrogen (H2, HD) were identified by the astronomers. The different intensities of the CO bands allow the astronomers to infer the temperature of the Cosmic Background Radiation at this very remote epoch. The spectrum was obtained with UVES on ESO's VLT. It is the result of more than 8 hours of observations.

A composite infrared image of the X-ray luminous galaxy cluster XMMU J2235.3-2557 at redshift 1.4, one of the most distant galaxy clusters known.
The composite is made of 4 HAWK-I pointings in both J and Ks and covers 13.5 arc minutes on a side. The cluster is right in the middle of the frame and is difficult to see, given the large field of view, so a blow-up centred on the cluster is shown in the inset. As can be seen by eye, the core of the cluster is dominated by red galaxies with very similar colours. The stars in these galaxies are already very old. On average they formed when the Universe was only one billion years old. As one moves away from the center of the cluster, cluster galaxies become slightly bluer, suggesting that galaxies in the outskirts are either younger or have recently experienced a small amount of star formation (commonly called "frosting"). As one moves even further out, the authors hope to find small groups of galaxies that will, one day, merge with the core.
In the standard flat, lambda-dominated cosmology, the universe is 4.6 billion years old at redshift 1.4 and 1.1 billion years old at redshift 5. The universe at redshift 0 (today) is 13.7 billion years old.
At a redshift of 1.4, 10 arc minutes on the sky corresponds to a linear distance of 5 Mpc (15,000,000,000,000,000,000 km).
Authors: Chris Lidman, Piero Rosati, Masyuki Tanaka and the HAWK-I science verification team.

Any feedback or add on is welcome


[edit: added links and required external source tags]
Mod Edit: External Source Tags – Please Review This Link.

[edit on 13-5-2008 by 12m8keall2c]

posted on May, 13 2008 @ 10:11 AM
This is pretty interesting stuff. A find as important as the fact that proton/electron mass ratios change over time in the universe is huge!

I'm not super with quantum mechanics, and pretty crappy with general relativity, but I can translate a few highlights of the article for anyone interested without background knowledge.

Basically, when we view something really far away in a telescope, we're looking into the past (remember from grade school- light takes 8 minutes to travel from the sun to Earth). Using methods called spectroscopy that analyze what kind of light (essentially what colors) are absorbed by different materials like oxygen or carbon dioxide (or anything), scientists can tell what materials lie between a distant star and Earth. This way, we can effectively sample materials billions of light years away from us.

The fact that we can sample something billions of light years away from us using light means that we can look at something billions of light years away and billions of years ago. Looking at material from close to the birth of the universe can show us the differences between the universe in the era of man (the past 100,000ish years or 4,000 years, depending on what you believe) and the birth of the universe.

The proposition is that the relative sizes (or masses, rather; density changes could account for the mass changes instead of size changes) of electrons and protons (again, remember grade school if you're not up on sciences) changed since the dawn of the universe. Interesting.

A little "redshift" basics to understand the end: "redshift" is a doppler shift (change in frequency) due to, typically, a source (star) velocity relatively away from an observer (us). So redshift effect (light tends towards low energy red light and infrared) happens more when the star moves away from Earth faster, right? Right, but that's not really it. The speed of a star is not really what places the most new space between the star and Earth in a few billion years it takes light to reach us. The thing that shifts it the most is the expansion of the universe, which has more chance to shift the frequency the farther the star is from Earth. In other words, more redshift, contrary to initial thought, does not mean a faster star; more redshift means a farther away star. That's why "redshift 1.1" is associated with farther into the past than "redshift 0" (which is really Earth, not "now"), and more recent than "redshift 5".

I'm sure I was blurry on some things, ask me to explain if you're interested and I can help.

EDIT: Grats to angelc: good post on an interesting topic. I can relate to the excitement!

[edit on 13-5-2008 by pondrthis]

posted on May, 13 2008 @ 10:19 AM
reply to post by pondrthis
Thank you podthris for your response and you do have the basics down packed. We do not all have to be physicist to be able to grasp the idea that is shown or demonstrated to us via grphics, images and theories.
All we need is an open mind.

posted on May, 14 2008 @ 05:20 PM
Quite quite wonderful!

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