The Gemini Paradox: Why are Galaxies in the Early Universe Old?

August 06, 2008

The Gemini Paradox: Why are Galaxies in the Early Universe Old?

Some of the faintest spectra in the universe raise a glaring question: Why do Galaxies in the early universe appear so old?

Until recently, astronomers have been nearly blind when looking back in time to survey an era when most stars in the Universe were expected to have formed. This critical cosmological blind-spot has been removed by a team using the Frederick C. Gillett Gemini North Telescope located on Mauna Kea, Hawaii, showing that many galaxies in the young Universe are not behaving as they would have expected some 8-11 billion years ago.

The surprise: these galaxies appear to be more fully formed and mature than expected at this early stage in the evolution of the Universe.

"Theory tells us that this epoch should be dominated by little galaxies crashing together," said Dr. Roberto Abraham (University of Toronto) who is a Co-Principal Investigator of the team conducting the observations at Gemini. "We are seeing that a large fraction of the stars in the Universe are already in place when the Universe was quite young, which should not be the case. This glimpse back in time shows pretty clearly that we need to re-think what happened during this early epoch in galactic evolution. The theoreticians will definitely have something to gnaw on!"

These observations are from a multinational investigation, called the Gemini Deep Deep Survey (GDDS), which used a special technique to capture the faintest galactic light ever dissected into the rainbow of colors called a spectrum. In all, spectra from over 300 galaxies were collected, most of which are within what is called the "Redshift Desert," a relatively unexplored period of the Universe seen by telescopes looking back to an era when the universe was only 3-6 billion years old.

These spectra represent the most complete sample ever obtained of galaxies in the Redshift Desert. By obtaining large amounts of data from four widely separated fields, this survey provides the statistical basis for drawing conclusions that have been suspected by past observations done by the Hubble Space Telescope, Keck Observatory, Subaru Telescope and the Very Large Telescope over the past decade.

Studying the faint galaxies at this epoch when the Universe was only 20-40% of its current age presents a daunting challenge to astronomers, even when using the light-gathering capacity of a very large telescope like Gemini North with its 8-meter mirror. All previous galaxy surveys in this realm have focused on galaxies where intense star formation is occurring, which makes it easier to obtain spectra but produces a biased sample. The GDDS was able to select a more representative sample including those galaxies which hold the most stars–normal, dimmer, and more massive galaxies–that demand special techniques to coax a spectrum from their dim light.

"The Gemini data is the most comprehensive survey ever done covering the bulk of the galaxies that represent conditions in the early Universe. These are the massive galaxies that are actually more difficult to study because of their lack of energetic light from star formation. These highly developed galaxies, whose star-forming youth is in fact long gone, just shouldn't be there, but are," said Co-Principal Investigator Dr. Karl Glazebrook (Johns Hopkins University).

"It is unclear if we need to tweak the existing models or develop a new one in order to understand this finding," said the survey's third Co-Principal Investigator, Dr. Patrick McCarthy (Observatories of the Carnegie Institution). "It is quite obvious from the Gemini spectra that these are indeed very mature galaxies, and we are not seeing the effects of obscuring dust. Obviously there are some major aspects about the early lives of galaxies that we just don't understand. It is even possible that black holes might have been much more ubiquitous than we thought in the early Universe and played a larger role in seeding early galaxy formation."

What is arguably the dominant galactic evolution theory postulates that the population of galaxies at this early stage should have been dominated by evolutionary building blocks. Aptly called the Hierarchical Model, it predicts that normal to large galaxies, like those studied in this work, would not yet exist and would instead be forming from local beehives of activity where big galaxies grew. The GDDS reveals that this might not be the case.

Caltech astronomer, Dr. Richard Ellis commented, "The Gemini Deep Deep Survey represents a very significant achievement, both technically and scientifically. The survey has provided a new and valuable census of galaxies during a key period in cosmic history, one that has been difficult to study until now, particularly for the quiescent component of the galaxy population."

Making observations in the Redshift Desert has frustrated modern astronomers for the last decade. While astronomers have known that plenty of galaxies must exist in the Redshift Desert, it is only a "desert" because we couldn't get good spectra from many of them. The problem lies in the fact that key spectroscopic features used to study these galaxies have been redshifted–due to the expansion of the Universe–into a part of the optical spectrum that corresponds to a faint, natural, obscuring glow in the Earth's nighttime atmosphere.

To overcome this problem, a sophisticated technique called "Nod and Shuffle" was used on the Gemini telescope. "The Nod and Shuffle technique enables us to skim off the faint natural glow of the night sky to reveal the tenuous spectra of galaxies beneath it. These galaxies are over 300 times fainter than this sky glow," explains Dr. Kathy Roth, an astronomer at Gemini who was also part of the team and obtained much of the data. "It has proven to be an extremely effective way to radically reduce the "noise" or contamination levels that are found in the signal from an electronic light detector."

Previous studies in the Redshift Desert have concentrated on galaxies that were not necessarily representative of mainstream systems. For this study, galaxies were carefully selected based upon data from the Las Campanas Infrared Survey in order to assure that strong ultraviolet emitting starburst galaxies were not oversampled.

"This study is unique in that we were able to study the red end of the spectrum, and this tells us about the ages of old stars," says Dr. Abraham. "We undertook incredibly long observations with Gemini–about ten times as long as typical exposures. This let us look at much fainter galaxies than is usually the case, and let us focus on the bulk of the stars, instead of just the flashy young ones. This makes it a lot easier for us to work out how the galaxies are evolving. We are no longer guessing at it by studying young objects and assuming the old objects were not contributing much to the story of galaxy evolution. It turns out that there are lots of old galaxies out there, but they're really hard to find."

The Gemini Multi-Object Spectrograph used on the Frederick C. Gillett Gemini Telescope on Mauna Kea to make the GDDS observations is one of two identical instruments, which are used on both Gemini telescopes. GMOS is primarily designed for spectroscopic studies where several hundred simultaneous spectra are required, such as when observing star and galaxy clusters. GMOS also has the ability to focus astronomical images on its array of over 28 million pixels.

The Gemini Observatory is an international collaboration that has built two identical 8-meter telescopes. The Gemini South telescope is located on Cerro Pachón in central Chile (Gemini South), and hence provide full coverage of both hemispheres of the sky. Both telescopes incorporate new technologies that allow large, relatively thin mirrors under active control to collect and focus both optical and infrared radiation from space.

Posted by Casey Kazan.

Comments

Simple. Everything else is wrong. There was no creation event, big bang or whatever. We are actually in the tiny pocket of an explosion event that was vast locally, but cosmically insignificant. This (big bang) event that created conditions that have led us to far too broad a conclusion about the universe. We have truly become the flea on the dog's back, describing with dubious authority the dog, its position in time and space and its velocity... makes us kinda laughable if you think about it. Images like these remind us that we should study the skin and hair of the dog to discover our own reality, rather than eying up the distant neighbors and imagining, well all sorts of things.
However, it is pleasant to imagine that we might well exist in our own celestiosphere, may be traveling somewhere interesting and are effectively protected from the greater knowledge that we, as human beings, would most likely abuse.
To assume anything too much about that which we cannot directly assess will make fools of many cosmologists in the fullness of time and it is just such a discovery that could do it. It could pay us to recall that time is a relative concept when pretending we can know what happened 14 billion years ago. We might be less surprised if we did and would certainly be the humbler for it.
I, meanwhile, am a very happy observer of the observers. Astronomy is really a sophisticated form of photography and we all know how the interpretation of a snapshot or two can lead to just about anywhere. Keep it up. It's very entertaining.

Posted by: Hamy | August 07, 2008 at 03:35 AM

My theory:

The speed of light is only relatively constant ( relative - as in from our perspective ), changing as forces known and unknown act upon and influence it, sometimes even in isolated pockets.

Einstein's model would seem to allow dense clusters of truly massive masses eclipsing each other in an orbit we likely can not adequately observe ( yet ), thus causing relative time-distortions, such as time-compression or acceleration ( depending upon perspective ).

This could easily mean that the oldest of the old existed in what we could view as a different time reality, and may in fact have evolved for much much longer before escaping the inner events occurring at the universal "source."

In short, those galaxies actually are old, and they were created in a dense environment with powerful currents, heat, and gravitational influences.

I would suspect a grouping of black holes at the "source." perhaps at max density, probably more than one orbiting the other. It only seems logical from here that one could theorize that the gravity and friction of these masses could cause violent ripples & tears on the actual "fabric" of the "universe" at the quantum level, creating patterns which will, given probability, ultimately create the building blocks of matter, which will then build, naturally, into matter. Dark matter, then, would simply be incomplete matter patterns.

Dis/Proving this would be a matter looking back in time and seeing mature galaxies ( done ;-) ), possibly observing a rate of rotation ( by observing any preferences in the direction of galactic flow at numerous distances from the "source" ), discovering the outer-most galaxies having a preference for a more unified flow pattern, outward from the "source," seemingly all heading to "the edge," creating matter by pulling a few strings in "dark matter," and many other possible ways.

Imagine, if you will, that the "edge" of the universe is, really, an edge, it may slowly push outward, but not at a particularly great rate. Galaxies at the edge are buffered by "dark matter," or these quantum patterns, these patterns influence the adjacent "universe fabric's" potential for excitation, thus changing states, with NEARLY zero energy loss ( but there is likely some ).

The inside of the universe has a current, a general direction of flow for galaxies, friction from the expanding "edge" of the universe normalizes the outer edge's flow until it hits a point in which those objects are outside the flow, but still being pushed outward ( but at a very constant rate, given enough time or a particularly violent early "eruption" from the "source", if I'm right ).

So pressure from the "source" and a little back-pressure at the "edge", the source is swirling and affecting what it spewed out for some time, but it spews more and more, pushing things outward & losing influence on those furthest away. Almost immediately a very slight friction is encountered, which is the rate of the quantum state relay race at the "edge."

This should be easily testable in the future, and adds at least a few questions, but may answer many others. The biggest questions?

Is there a cost in time or effect of the transference of quantum states to the adjacent quantum fabric's "strings" that, when expanded to the universe scale, would cause an aggregate loss of acceleration at the outer-extent of expansion?

Does the universe have a current / general flow?

If so, can we observe an attrition of flow towards the outer extent of the universe, perhaps even seeing beyond and to the oldest galaxies formed, and measure for a tendency of the outer-most galaxies to leave that flow and flow almost directly away from the "source?"

That would be pretty cool :-) And, actually, we already know that the outer-most galaxies have a near constant flow seemingly "attracted" to the "edge" of the universe.

Of course, it would be nice to see the effects of the flow on the innermost of the outermost galaxies.

--The loon, comments desired.

Posted by: looncraz | October 20, 2008 at 10:56 PM

As for the origin of the black holes:

String theory is best here, but we still don't know why there would be ripples in the sea.

First, one quick note, though, as an observation:

The Bible has God saying that he created the universe in an "ocean," which means that modern science could really be describing the ocean in which God placed creation. God would have emplaced the proper quantum state to create exactly what "he" wanted to create, but may well seem to be limited ( from our perspective ) to finite & subtle interactions on the quantum plane ( like Hawking thinks ), though that would not prevent God from much of anything as any intelligence smart enough to get this far, could probably go much farther - and, I mean, how many software developers integrate back-doors in their software?? Oh yeah - most of the good ones.

Naturally, that answer doesn't give any scientist anything to consider valid, so...

The question then would be: Where would God exist in relation to the universe?

For me, this all falls back to why anything would exist, at all, and the nature of time relativity itself.

See, the very basic inherent rule of all would be that "nothingness" can't exist simply because it is in conflict with being "nothing." You just can't have nothing, period. No voids whatsoever, just potential.

And, that potential will be realized unless something prevents it, if nothing exists to prevent it, then it will be realized.

So, because nothingness could never be, something always was, and always will be, and it will always, fundamentally, be that same something in on form or another.

That something would be an energy field organized from the perfect "on-switch," organizing the quantum level into every potential reality simultaneously ( remember there is no friction anymore, nothing to stop potential from becoming real - at this "low" level ), and it is one of these realities in which we reside, at one level or another, nested or otherwise, and bound to a specific set of rules.

What does that have to do with time relativity? Simple, infinity now becomes a time reality from which all others must be derived, by relationship. It is possible, is not likely that a single form would result from the initial starting point, expressive of the realization of the potential which never had the potential to not exist ( so, therefore, must ), on the time "plane."

Basically, time doesn't exist, but it still does because can't not exist, so it is infinite as nothing was present to prevent it.

Obviously there never was, then, a starting point. But a (good?) reason why there wasn't one.

Food for thought to whomever ever may read this little rant :-)

--The loon

Posted by: looncraz | October 20, 2008 at 11:36 PM