Julian Date: 2459191.16
2020-2021: LV
"Reminding ourselves of the great qualities we share with all human beings acts to neutralize the impulse to think we're bad or undeserving. Many Tibetans do this as a daily meditation practice. Perhaps that's why in Tibetan culture self-hatred never took hold."
From "The Art of Happiness"
His Holiness the Dalai Lama and Dr. Howard C. Cutler
THE DAILY ASTRONOMER
Monday, December 7, 2020
Remote Planetarium 129: Laniakea
This week we'll continue and then complete our progression through the cosmos. We'll begin this final stage with a rapid review of what we've seen so far.
Remember in March we started with the night sky: the comparatively minuscule region surrounding Earth. The ten thousand stars visible within that sky represent 0.0000025% of all the stars within the Milky Way Galaxy. (For comparison, imagine a sheet of 8.5" x 14" paper. On that sheet one could draw 10,000 small black dots. Each dot would represent one of these visible stars. In order to draw enough dots to represent every star in the galaxy, one would require a sheet of paper measuring 8.5" by 1500 miles)
Our Milky Way is part of the Local Group, a collection of at least 80 galaxies. This group is dumb-bell shaped, with the Milky Way at one lobe and the larger spiral galaxy of Andromeda at the other. A swarm of satellite galaxies surround both the Milky Way and Andromeda. That Local Group is, itself, a small part of an immensely large collection of galaxies called the Virgo Supercluster.
As a group of astronomers led by Richard Brent Tully at the University of Hawaii determined in 2014, the Virgo Supercluster is just part of a much larger structure known as Lanaikea, a name derived from the Hawiian term for "Immense Heaven."
Laniakea, also known as the Local Supercluster (colored yellow in the above image) consists of 100,000 galaxies. Apart from the Virgo Supercluster, Lanaikea contains the Hydra-Centaurus Supercluster, Centaurus Supercluster, and the Pavo-Indus Supercluster. The entire Local Supercluster extends over 520 million light years and contains more than 100,000 times the Milky Way Galaxy's mass.
Unlike other highly massive structures, Laniakea is bound together tenuously. Dark Energy should cause this Local Supercluster to disperse, albeit in billions of years from now.
Though its mass and extent are both impressive, Lanaikea is only a part of an even larger structure called the Pisces-Cetus Supercluster Complex, tomorrow's destination.
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