400 million years ago. 13.8 billion years ago. These are large numbers, and are difficult to make sense of and truly grasp. However, these large numbers are important because they tell us just how old our universe really is. In order to fully grasp this concept, astrologist Carl Sagen (1934-1996) has created what is known as “The Cosmic Calendar”. This analogy helps us to fully comprehend the grand scale of our origin timeline. The Cosmic Calendar shows the time-scale relationship of the universe and all events on Earth as plotted along a single 12-month, 365-day, year. On this scale, one second corresponds to 438 years; a minute is about 26,000 years; an hour is 1.6 million years; and a day is 38 million years.
In this analogy, “The Big Bang” happened at exactly midnight of a brand new year (January 1st). Our current life today is represented as exactly 11:59 of December 31st. If we condense the 13.8 billion years, which is scientist’s best guess of the age of the universe, into this one understandable concept of 1 year, we can more clearly understand our small place in time.
Table 1. Cosmic Calendar Time
Notes: Date in year calculated from formula
T(days) = 365 days * 0.100/13.797 ( 1- T_Gya/13.797 )
If we follow this analogy, it was only “May” when our galaxy, The Milky Way, was formed. Nearly equidistant in time from the Big Bang, to the Milky Way (4 months), our own solar system and life on it was formed in “September”. From there, life expands quite rapidly. Photosynthesis gives rise to oxygen in “October”, Eukaryotic cells are formed in “November”, and multicellular life begins in “December”. Isn’t that amazing? This means that all multicellular life from shells, to fish, to dinosaurs, and present day humans all have only existed in the most recent 1/12th of known time.
More than that, it has only been in the last “3 hours” of the last day in which humans began to walk upright. In fact, all of our recorded human history has only taken place in the last “1 minute” of this theoretical year. Buddha, Jesus, and Muhammad have all only arrived in the last 10 seconds.
Did this analogy help you to understand the timeline of our Universe? There will be many interesting things as you continue to explore the time of the universe.
Figure 1. A graphical view of the Cosmic Calendar, featuring the months of the year, days of December, and the final minute.
Table 2. Evolution of Life on Earth
Table 3. Human evolution
Sources:
https://en.m.wikipedia.org/wiki/Cosmic_Calendar
https://youtu.be/Ln8UwPd1z20
Edited by Alyssa Meyer