The Hubble eXtreme Deep Field
(XDF) was completed in September 2012 and shows the farthest galaxies
ever photographed. Except for the few stars in the foreground (which are bright and easily recognizable because only they have diffraction spikes
), every speck of light in the photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 2 trillion galaxies.
Cosmology (from the Greek κόσμος, kosmos "world" and -λογία, -logia "study of") is a branch of astronomy concerned with the studies of the origin and evolution of the universe, from the Big Bang to today and on into the future. It is the scientific study of the origin, evolution, and eventual fate of the universe. Physical cosmology is the scientific study of the universe's origin, its large-scale structures and dynamics, and its ultimate fate, as well as the laws of science that govern these areas.
The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff, in Cosmologia Generalis.
Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology.
The cosmic microwave background (CMB) is the thermal radiation assumed to be left over from the "Big Bang" of cosmology.
In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or "relic radiation." The CMB is a
cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination.
With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other
object. This glow is strongest in the microwave region of the radio spectrum.
Did you know...
- ... that space is flexible, and has been expanding at a measurable rate since the beginning of time?
- ... that most of the atoms in our bodies were created in stars through fusion?
- ... that the Earth isn't flat, but the universe is? Based on Einstein’s Theory of General Relativity, there are three possible shapes that the Universe may take: open, closed, and flat. Once again, measurements by WMAP on the CMBR have revealed a monumental confirmation – the Universe is flat.
- ... that the average density of visible matter in the universe is about 10−30 g/cm3?
- ... that the Earth is neither the center of the Universe nor the galaxy, because the universe has no center?
- ... that considering only the largest structures, the Universe is made up of filaments, voids, superclusters, galaxy groups and clusters? By combining galaxy groups and clusters, we come up with superclusters. Some superclusters in turn form part of walls, which are also parts of filaments.