This illustration summarises the almost 14-billion-year long history of our Universe. It shows the main events that occurred between the initial phase of the cosmos, where its properties were almost uniform and punctuated only by tiny fluctuations, to the rich variety of cosmic structure that we observe today: stars and galaxies.

The series of panels on the right side of the illustration zooms into the cosmic large-scale structure to reveal first a cluster of galaxies, then a spiral galaxy similar to our own Milky Way Galaxy, and finally, the Solar System.

Click the illustration to see a larger, more legible version.

Planck History of the Universe
Image Copyright ESA – C. Carreau


Alternatively, the illustration below provides a summary of the almost 14 billion-year history of the Universe, showing in particular the events that contributed to the Cosmic Microwave Background, or CMB.

Click the illustration to see a larger, more legible version.

History of the Universe and the CMB
Image Copyright ESA

The timeline in the upper part of the illustration shows an artistic view of the evolution of the cosmos on large scales. The processes depicted range from inflation, the brief era of accelerated expansion that the Universe underwent when it was a tiny fraction of a second old, to the release of the CMB, the oldest light in our Universe, imprinted on the sky when the cosmos was just 380 000 years old; and from the ‘Dark Ages’ to the birth of the first stars and galaxies, which reionized the Universe when it was a few hundred million years old, all the way to the present time.

Tiny quantum fluctuations generated during the inflationary epoch are the seeds of future structures: the stars and galaxies of today. After the end of inflation, dark matter particles started to clump around these cosmic seeds, slowly building a cosmic web of structures. Later, after the release of the CMB, normal matter started to fall into these structures, eventually giving rise to stars and galaxies.

The inserts below show a zoomed-in view on some of the microscopic processes taking place during cosmic history: from the tiny fluctuations generated during inflation, to the dense soup of light and particles that filled the early Universe; from the last scattering of light off electrons, which gave rise to the CMB and its polarisation, to the reionization of the Universe, caused by the first stars and galaxies, which induced additional polarisation on the CMB.


Source:  ESA