The canopy of the night sky is both immense and awe-inspiring.
The Milky Way, as seen at La Silla observatory, is a stunning, awe-inspiring sight to anyone, and offers a spectacular view of a great many stars in our galaxy. Although there are definitely regions, like towards our galactic center, that are denser in stars than others, the average “square degree” on the sky contains ~10 million stars from the Milky Way. (: ESO/Hakon Dahle)
All told, cumulatively, the full sky contains 41,253 square degrees.
In this photo of the night sky over the Very Large Telescope at Paranal, an arm and hand is shown for angular scale. The circled pinkie nail takes up about one square degree on the sky, while the angular separation between the pinkie and index finger is about 12 degrees: the amount that the Moon appears to shift in the sky from night-to-night. (: ESO/Y. Beletsky; modifications: E. Siegel)
If you hold your hand at arm’s length, your pinkie finger’s nail covers about 1 square degree.
Artist’s logarithmic scale conception of the observable universe. The Solar System gives way to the Milky Way, which gives way to nearby galaxies which then give way to the large-scale structure and the hot, dense plasma of the Big Bang at the outskirts. Each line-of-sight that we can observe contains all of these epochs. (: Pablo Carlos Budassi; Unmismoobjetivo/Wikimedia Commons)
Behind every single square degree, there’s a portion of the Universe that unveils its entire story.
Gaia’s all-sky view of our Milky Way Galaxy and neighboring galaxies. The maps show the total brightness and colour of stars (top), the total density of stars (middle) and the interstellar dust that fills the Galaxy (bottom). Note how, on average, there are approximately ~10 million stars in each square degree, but that some regions, like the galactic plane or the galactic center, have stellar densities well above the overall average. (: ESA/Gaia/DPAC)
The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.
