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Ep. 38, Page 62
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Comic 2974 - Ep. 38, Page 62

28th Oct 2019, 10:02 PM in Episode 38 :: Save My Place | Load My Place
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Author Notes:

smbhax 28th Oct 2019, 10:02 PM edit delete
smbhax
Here's a pretty cool map of the night sky compiled from various surveys, where you can zoom in on part of the sky to see all the galaxies we've been able to see so far in it.

What's really amazing is when you zoom OUT, and turn on the constellation display overlay, to see what a tiny bit of the sky you were looking at with all those galaxies in it!

I got the link from a BBC article about DESI, a telescope that will conduct a detailed measurement of the distance to 35 million galaxies, using its 5000 robot-controlled optical fibers to take simultaneous spectrographic readings of many objects in the sky at once.

Primordial oscillation very early in the life of the universe, when the hot plasma that made up everything after the Big Bang began to cool, finally allowing light to travel freely, can still be seen today as a slight perturbation in the distribution of ancient (high redshift) galaxies; according to the DESI site, there is "a slight tendency for pairs of galaxies to be separated by the distance the waves traveled, which owing to the expanding Universe is about 500 million light-years today," and "with that, we can infer the distance to the galaxies. [...] DESI will [...] measure the relationship of distance to redshift over a wide range of redshifts with subpercent precision. This in turn allows us to infer the expansion history and the evolution of dark energy."

"Dark energy" is the name for whatever the heck is causing the observed acceleration of the expansion of the universe, which scientists don't yet know how to account for; the hope is that the DESI project will start to provide some new insights.