8-15 billion years BP (current estimate: 13 billion years BP)	Big Bang (George Gamow and Ralph Alpher, 1948) Click here for artist's representation of the big bang theory
Stars and star clusters start to form 1 billion years after the Big Bang. Recent finding indicates that stars formed as early as 300 mln. years after Big Bang Helium is generated from hydrogen in stars, carbon from helium Supernovae explosions generate the rest of the elements from the periodic table and distribute heavier atoms in space Our sun and planetary system form using heavier elements from the supernova explosion 11 billion years BP
4.5-5 billion years BP	Earth and Moon form. Here is an essay on the Age of Earth. Earth was quite different at that time from how it looks today: "Think of French onion soup with a skin of cheese floating on hot fluid below" [Eyles and Miall, "Canada Rocks", Fitzhenry and Whiteside, 2007]
4.03 billion years BP	Oldest rocks on Earth, located in Canada! (Acasta Gneiss, Northwest Territories). Go here and here for details on dating rocks. Some characteristics of these rocks indicate that 4.3 billion years ago the crust was already in contact with water, more here. 4.3 billion years old crustal rocks were found embedded in 3.49 billion years old rocks in Pilbara, Australia (news release and article).
about 4 billion years BP	Mare Imbrium was formed [Photo is from this NASA web site]
about 3.9 billion years BP	End (tail) of the Early Heavy Bombardment
3.85 billion years BP	Oldest known sedimentary rocks, indications for liquid water, rounded pebbles, and discrimination against heavy carbon isotopes is detectable in organic material (just like modern biochemical reactions). Oldest geological evidence for life is based on ¹³C discrimination (carbon derived from living systems often have lower delta ¹³C values than inorganic carbonates) [here]. The rocks are from Akilia island off the coast of Greenland, and severely altered by metamorphism. However, recently the evidence for that was reassessed.
3.5 billion years BP	For about a decade the oldest microfossils were considered to be about 3.5 Ga old (see here). The fossils (as interpreted by Bill Schopf) look like "modern" Cyanobacteria [bacteria that have O₂ producing photosynthesis]. However, recently the evidence for these fossils was questioned:
about 3.45 billion years BP	Formation of earth's magnetic field. Magnetic field is important for life forms, as it shields the planet against the solar wind and radiation. "Without such a magnetic field, the atmosphere would have been exposed to ionization and erosion by the charged particles in the solar wind, and any form of early life would have been irradiated by the intense x-ray and high-energy ultraviolet emission from the young Sun." [Source]
3.2 billion years BP	acritarchs from rocks of the Moodies Group of South Africa. Relatively large in size (300 micrometres) and it is not known from which domain of life they are (Javaux, 2010)
3.2 billion years BP	filamentous fossils, probably of thermophilic chemotrophic prokaryotes (Rasmussen, 2000)
2.7 billion years BP	probable biomarkers of cyanobacteria and of eukaryotes (Roger Summons, Roger Buick and Jochen Brocks)
3.5 (?) -1.5 billion years BP	microbial mats (-> stromatolites) dominate the biosphere [What are Stromatolites?]
2 billion years BP	Rise in atmospheric O₂
1.8 billion years BP	fossils from Gunflint formation: iron-loving bacteria and cyanobacteria
1.2 billion years BP	fossil red algae (bangiophytes) Fig. Comparison of fossil filaments (A to C) with modern Bangia atropurpurea (D to F) [Source]
750 million years BP	Possible "Snowball Earth" event: Illustration and Timing Scientific American article by Hoffman and Schrag on "Snowball Earth" - Ice entombed our planet hundreds of millions of years ago, and complex animals evolved in the greenhouse heat wave that followed." Also, a recent book is highly recommended: "Snowball Earth: The Story of the Great Global Catastrophe That Spawned Life As We Know It" by Gabrielle Walker, Crown Publishing Group, 2003 Recent criticisms (2010): here.
	Ediacaran Biota - A group of multicellular complex organisms (all extinct). More info: here and here Fig. "Pizza Disc", Mistaken Point, Newfoundland. [Source]
600 million years BP	Cambrian explosion -> origin of the different animal phyla

Scale of the Universe

The closest star to Earth (aside from our own Sun) is Proxima Centauri in Alpha Centauri system. It is 4.3 light-years away.
The closest galaxy to our Milky Way is Sagittarius Dwarf Elliptical Galaxy. It is 80,000 light-years away.
The closest spiral galaxy to our Milky Way is Andromeda, a galaxy much like our own Milky Way. It is 2.2 million light years away from us.
The visible Universe is 14 billion light-years. The map of the visible Universe is here

Timeline for the evolution of the universe

Scale of the Universe