When looking at the night sky, many people often wonder what remains invisible.
Our glittering starry sky contains only a few visible galaxies.
Thanks to the capabilities of modern observatories, much more becomes clear.
In the Milky Way alone there are between 200 and 400 billion stars.
Many have sun-like properties: they are rich in heavy elements and have rich planetary systems.
Our Local Group – dominated by the Milky Way and Andromeda – contains over 100 known galaxies.
A look into the deepest depths of space reveals the cosmic history of stars and galaxies.
Modern, massive galaxies are formed by the accumulation and merging of earlier, smaller and more primitive galaxies.
In the earliest times, all galaxies were small and had low mass compared to today.
Meanwhile, star formation reached its peak about 11 billion years ago.
It reached this peak from a starless state and has been slowly declining since then.
Today there are between 6 and 20 trillion galaxies in the universe.
However, only about 100 billion are large and massive.
And these ~100 billion “most massive” galaxies contain over 99% of our cumulative 2.21 × 1021 (2.21 sextillion) stars.
The earliest stars and the galaxies with the lowest mass have the greatest uncertainties.
Most stars are in galaxies similar to the Milky Way, but most galaxies are not like ours.
“Mostly Mute Monday” tells an astronomical story in pictures, graphics and no more than 200 words.