University Lowbrow Astronomers

The Old Gray Universe, She Ain’t What She Used To Be.

by Lorna Simmons
Printed in Reflections: October, 2001.

When you are gazing out at the near Universe through your huge Super-Duper Mini-Keck Maxi-Scope with all of its highfalutin attachments, you are probably viewing the Universe through rose-colored filters.  There are no familiar shapes to greet your eyes farther out in the vast stretches where the denizens of the Hubble Deep Field lurk.  In the very-near universe, barred spirals are found in abundance, but barred spirals are more irregular in appearence the farther back you look in space and time beyond a redshift of z = 0.3.  As a result, beyond the redshift of 0.5, barred spirals have become remarkably chaotic and fail to appear clearly, if at all.  Even elliptical galaxies have their limit, eventually giving way to irregular wisps of nebulosity the deeper into space you look.  Deep, deep, deep in the Hubble Deep Field, irregular galaxies predominate.  Then again, farther back in the Hubble Deep Field, the viewing is so very difficult that, even with the Hubble Space Telescope, we can only guess about the galactic formations which might be found.  Using even the finest telescopes in existence, we are all back to faint fuzzies all over again -- astronomical deja vu!

The shapes of galaxies seem to change significantly and systematically, seemingly more orderly (in our way of thinking) the nearer one looks in the Universe.  There are a lot of elliptical galaxies with their jewel shapes glistening in the deep sky.  However, even these have an evolved condition from irregular to regular as the distance between them and us lessens.  Eventually, elliptical galaxies seem to return to spiral patterns after an extended period of time.  At least, that appears to be the way galaxies have gravitationally evolved in the Universe, from disorder to order, unstructured to structured.  For those of us who once memorized the Hubble Tuning Fork diagram, a long time ago, new ideas must now emerge to take its place.  Even the Hubble Tuning Fork diagram galaxies fail to appear clearly beyond a redshift of z = 1, traveling back in the Universe, away from us.  Beyond the redshift of z = 1, the Hubble Tuning Fork diagrams are meaningless for more than one-third of the galaxies found.

Right now, astronomers and astrophysicists are “working on it” and, perhaps, will come up with some answers to take the place of the Hubble Tuning Fork diagram.  At least the space density of the brighter galaxies has not changed, showing that the number of such galaxies has remained almost the same over time.  But, more likely, we must remain satisfied with the irregularities of the distant universe and get on with our scientific lives, accepting the astronomical and astrophysical uncertainties as facts of life.

So, hang onto your Mini-Kecks for a while, because things are not about to change radically or soon -- at least, not in the near universe.  Of course, it might help to cross your fingers for a while, just to make sure.  Then again, some telescope maker might create something much grander, so that you can renew your faith in the changed and changing structure of the Universe’s galaxies.  Perhaps we all must accept change as the way things should be and get on with our astronomical delights.

As the wise old saying goes:  “The more things change, the more they stay the same.”

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Copyright © 2013, the University Lowbrow Astronomers. (The University Lowbrow Astronomers are an amateur astronomy club based in Ann Arbor, Michigan).
This page originally appeared in Reflections of the University Lowbrow Astronomers (the club newsletter).
This page revised Sunday, March 9, 2014 4:30 PM.
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