← ASTRO PRECISE THE COSMIC CALENDAR · DEEP TIME, COMPUTED

13.8 billion years,
squeezed into one year.

If the whole history of the universe were a single calendar year — the Big Bang at midnight on 1 January, this moment at midnight on 31 December — everything you have ever heard of happens in the last few seconds. Every date below is computed live from the measured age of the universe. You can check the arithmetic.

AGE OF THE UNIVERSE: 13.787 ± 0.020 BILLION YEARS · SOURCE: PLANCK 2018 (ESA)
SCALE: COMPUTING…
ONE CALENDAR SECOND = REAL YEARS · PURE ARITHMETIC, NOTHING INVENTED
WHEN THINGS HAPPENED — ON THE COSMIC YEAR
EVENTREAL TIMEON THE CALENDARTHIS IS…
● MEASURED / COMPUTED   ● MODELLED (SOUND PHYSICS)   ● SCIENCE IS UNSURE — WE SAY SO
WHERE YOU FALL

Enter your date of birth. Nothing is uploaded — this is arithmetic in your browser.

AND YET — THE FIRST SECOND IS THE BIGGEST

A calendar hides something. Stretch time by powers of ten instead, and the very first second of the universe — from about the Planck time (~10⁻⁴³ s; more precisely 5.4×10⁻⁴⁴ s) to one second — spans about 43 factors of ten. Everything since, all 13.8 billion years, spans only about 18. On a logarithmic clock, the first second contains more distinct eras than the entire age of the universe that follows it. Both statements are true; they are just two honest ways to look at the same history.

10⁻⁴³ s → 1 s ≈ 43 orders of magnitude · 1 s → 13.787 Gyr ≈ 17.6 orders · RATIO ≈ 2.4×
WHAT'S REAL / WHAT ISN'T — THE HONEST SEAM

There is no photograph of the Big Bang. The oldest real image of the universe is the Cosmic Microwave Background — the light released ~380,000 years after the beginning, mapped by ESA's Planck and NASA's WMAP. That is a genuine measurement: the actual oldest light in existence.

Everything earlier than that — inflation, the first instant, the birth of matter — cannot be pictured, only modelled, and the very first slivers (before ~10⁻⁴³ s) are genuinely unknown, because the physics itself runs out. Where this page shows one of those, it is labelled MODELLED or UNSURE, never dressed up as a snapshot. That seam is the whole point.

This is the near end of a longer instrument. From here the plan is a corridor you can drag from tonight's real, computed sky all the way back — the planets and eclipses genuinely computed near the present, the deep past honestly modelled and cited. Start with your own sky →

COSMIC-CALENDAR DATES ARE COMPUTED LIVE FROM THE PLANCK-2018 AGE (13.787 GYR) BY PURE PROPORTION. EVENT EPOCHS ARE STANDARD SCIENTIFIC CONSENSUS VALUES (WIKIPEDIA "CHRONOLOGY OF THE UNIVERSE" / ESA COSMIC ERAS); WHERE VALUES ARE UNCERTAIN OR MODELLED WE SAY SO IN THE TABLE.
THE OBSERVATORY · THE 12 AUG ECLIPSE · WHY WE NEVER MAKE THINGS UP
© MMXXVI ASTRO PRECISE · COMPUTED, NEVER FABRICATED