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keeping a sense of perspective
October 1, 2007 / July 2, 2013





You see the bluish cloud. The bright star near the right end of the cloud (not at the end), named “Mira”
(named after some astronomer’s daughter?), is making the bluish tail, like a comet, as Mira speeds
through the Milky Way—through so many solar systems? Firstly, note tha
t our sun is the size of one of the tinier specs.

The tail of Mira is trillions of miles long. You’re looking at an image of something trillions (that’s plural) of miles long.
(Can anyone really comprehend even a billion?)

When you look at the whole expanse of the sky with your unaided eyes at night, you see a small segment
of our galaxay, equivalent to a tiny segment of this photo
, through the lens of our solar system's heliosphere
which protects our self-formative solar system from the cruel cosmos, revealed to us by Voyager which, you know,
is emblemized with a wave to the cruel cosmos
.

And that photo above is a segment of one galaxy. You know about galaxies: those tens of little swirls in Hubble telescope photos,
taking up a small percent of the surrounding space (each galaxy separated by trillions of trillions of miles)?




Yet, a Hubble photo is just a segment of the universe.

Below, each barely-discernible speck is a galaxy, in this wedge of our Hubble Volume (which is the surrounding
distance of light that has so far reached us from the expanding universe—expanding faster than the speed of light),
an image here from the Wilkinson Microwave Anisotropy Probe:





Below, the full cosmic microwave background is shown as a sphere with the galaxies, surveyed by the Sloan Digital Sky Survey (like the above), positioned inside it.

from Science, Jan. 4, 2008

If universes beyond our Hubble Volume are also expanding, we couldn’t know it,
but only infer the possibility from astrophysical anomalies at the limits of mathematics?
“With only one universe to study researchers may be hard pressed to say...
[how the] cosmos is strange in some way” (How Odd Is Our Universe?).



from Science, Jan. 4, 2008, captioned:
View of the expanding universe illustrating the evolving cosmic web.
Primordial fluctuations of quantum mechanical origin are stretched by an early superluminal
phase of expansion known as
inflation. Four hundred thousand years after the Big Bang,
these fluctuations imprint tiny anisotropies in the cosmic microwave background as electrons and protons
combine to form neutral hydrogen. As the universe continues to expand, these fluctuations grow
through the gravitational instability, eventually giving rise to the first stars and galaxies,
whose radiation reionizes the intergalactic medium, thereby ending the cosmological
dark ages.
The cosmic web sharpens as the universe becomes more mature and becomes visible in the Ly-alpha forest
(or specific type of cosmic absorption space for gases) and in the spatial distribution of galaxies.
http://www.sciencemag.org/cgi/content/full/319/5859/52