Timeline of the Universe

This is a timeline that attempts to show the best scientific estimates of the age of past events and predictions of the approximate timing of hypothetical future events with cosmological significance. Some locally significant events of interest to members of Homo sapiens are also included. See estimates of the date of Creation for alternative views based on religious tradition. (Note: in this context, billion means 1,000,000,000).

Table of contents

1 The distant past 2 The human era 3 The far future 4 Problems with estimating the age of the universe

The distant past

• 13.7 ± 0.2 billion years ago: Universe begins with Big Bang
  • Note: the Big Bang is dated according to NASA's Wilkinson Microwave Anisotropy Probe (WMAP) data
  • for details of what is believed to have happened immediately after the Big Bang, see timeline of the Big Bang
• 300 thousand years after the Big Bang, hydrogen nuclei capture electrons, forming the first atoms
• 600 million years after the Big Bang: formation of first galaxies, see Galaxy formation and evolution

• 5 billion years ago: formation of the Sun
• 4.5 billion years ago: formation of the Earth -- start of geologic timescale
• 3.5 billion years ago: first signs of single-celled life on Earth
• 600 to 500 million years ago: multicellular life evolves

• 2.5 to 2 million years ago: appearance of the genus "Homo" (see evolution of Homo sapiens)
• about 150,000 years ago: appearance of Homo sapiens
• for the past and present of mankind, see centuries
  • 12 to 10 thousand years ago: Homo sapiens invents agriculture; start of human civilization
  • 1961: men first orbit the Earth in spacecraft
  • January 15, 2001: Wikipedia project started

• 3 billion years from now: Milky Way and Andromeda collide
• 5 billion years from now: the Sun becomes a red giant

• Creation of the Universe for more on creation scenarios other than the Big Bang
• End of the Universe for theories about possible final fates for the Universe