The Hubble Deep Field

Hubble Deep Field
The Hubble Deep field courtesy the Space Telescope Science Institute

"The image, called the Hubble Deep Field (HDF), was assembled from 342 separate exposures taken with the Wide Field and Planetary Camera 2 (WFPC2) for ten consecutive days between December 18 and 28, 1995.

Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the HDF image covers a speck of the sky only about the width of a dime located 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space because the universe, statistically, looks largely the same in all directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1,500 galaxies at various stages of evolution.

Most of the galaxies are so faint (nearly 30th magnitude or about four-billion times fainter than can be seen by the human eye) they have never before been seen by even the largest telescopes. Some fraction of the galaxies in this menagerie probably date back to nearly the beginning of the universe."

--- Excerpt from STScI Press Release STScI-PR96-01

Visitor's Travel Instructions:

We are hard-put to try to describe our particular Universe to a being from a different manifold of the Multiverse.... Trouble is, we don't even know if other universes (and you) exist, so we don't quite know how to go about describing to you how ours is different and/or unique.

But since you're reading this, you must exist ... and we're fairly sure we do too .... so, by the anthropic principle, it might be prudent to suggest that you should look for a Universe similar to your own, with cosmic parameters and space-time conditions conducive to the generation and proliferation of life-forms.

Basically, search for a Universe that has existed for roughly 13-18 billion years* that is expanding at the rate of roughly 55 km/sec/Mpc, and appears to be "flat" (cosmologically speaking). We're a bit uncertain, but also look for one containing roughly 5% baryonic matter (of which 1/5th is associated with light-emitting bodies), 25% dark non-baryonic matter (don't ask us what this stuff is yet), and 70% field-stored energy (maybe the cosmological constant isn't zero). Also look for cosmic background radiation corresponding to a temperature of 2.73 kelvins, and very slightly lumpy (shaken but not stirred).

Please stop by and explain to us what all this means, OK?


Pioneer 10 Plaque * Some of our resident lifeforms will surely complain that we should utilize generic units of space and time rather than ones tied to, and defined by, our own planetary ecosystem. But hey, any pan-dimensional creature such as yourself really ought to be able to figure these things out from our electromagnetic broadcasts (be forwarned, however: any information that you pick up in the 1-5 gigahertz range is usually pretty stupid and highly unreliable!)

... and anyway, we've already spacemailed you specific directions ... twice. It's not our fault if you discarded our important advertisements as pornographic junk mail!

Milky Way Galaxy ... End of the Tour. Beyond here, there be Dragons!

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