July 18th, 2018: Galaxies

[xoxoxoBruce]

This is the sky, well part of the sky, and every little speck of infrared light is a galaxy, you insignificant worm.
Our galaxy, the Milky Way, is about 100,000 light-years across, and it’s packed with at least 100 billion stars.
It would make but a tiny dot on this image.

With that humbling realization in mind, take a look at this incredible image released by the ESA. It was captured by the Herschel Space Observatory’s Spectral and Photometric Imaging Receiver (SPIRE), and it shows a patch of sky near the constellation of Coma Berenices, or Berenice’s Hair, as seen from Earth’s northern hemisphere. This region of the night sky is far from the dense stellar disc of the Milky Way, so astronomers can gaze into the distance with an unhindered view of the cosmos.

The image shows the North Galactic Pole, and it covers some 180 square degrees of the sky. Interestingly, this area happens to contain a galaxy-rich cluster known as the Coma Cluster, which contributes at least 1,000 points of light to this image.
Each tiny mark on this map represents the heat emanating from dust grains lying between the stars of each galaxy. Most of the galaxies in this image produced their signatures well before our Solar System came into existence, but we’re only seeing them now, tens of billions of years later.

A couple of years ago, astronomers came to the startling realization that the Universe contains up to 10 to 20 times more galaxies than previously thought. The current best guess is that the universe contains somewhere between one and two trillion galaxies. This means the universe is absolutely packed with stars, somewhere on the order of 700 sextillion stars.

That’s 700,000,000,000,000,000,000,000 stars, and that’s only what we can see, not beyond... worm.

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