A cultural observance on March 21 celebrating the Planck mission's cosmic microwave background map and the scientific evidence confirming the Big Bang theory and the universe's age of approximately 13.8 billion years.
Last updated February 26, 2026 · by the
Holiday Calendar Team
The observance commemorates the European Space Agency's release of the Planck Collaboration's first all-sky map of cosmic microwave background radiation on March 21, 2013. No specific person or organization is credited with formally establishing it.
March 21 marks the day of one of the most explosive events in history – Big Bang Day! This day celebrates the creation of the universe as we know it, with a massive burst of energy and matter that led to the formation of stars, planets, and galaxies. It's a fascinating concept to wrap our minds around and scientists continue to study and learn more about the origins of our universe. So on this special day, let's marvel at the wonders of nature and appreciate how far we have come in understanding our existence. Get ready for an out-of-this-world celebration!
TIMELINE
GET INVOLVED
EDITOR'S PICK
WATCH
CREATE
DRESS
HAVE
WHY THIS DAY MATTERS
Big Bang Day is a global event that connects people all around the world through their shared interest in science and astronomy. It's an opportunity for communities to come together and appreciate the beauty and complexity of our universe.
Big Bang Day is a day to commemorate and celebrate one of the most important theories in cosmology. It recognizes the incredible progress made in our understanding of the universe and highlights the importance of science in our lives.
The Big Bang theory is a complex concept, but it encourages us to ask questions, think critically, and constantly seek new knowledge. On Big Bang Day, we can embrace our inner curiosity and dive deeper into the wonders of the universe.
Explore the cosmos from the comfort of home this Extraterrestrial Culture Day; dive into sci-fi, stargaze, or even hunt for UFOs!
Peek beyond our world on International Astronomy Day! Discover the wonders of the universe and satisfy your celestial curiosity!
An appreciation day on March 14 honoring the contributions and achievements of scientists in advancing knowledge, improving lives, and exploring the natural world.
Get ready to explore and discover the wonders of the universe during Global Astronomy Month - with events, workshops, and stargazing opportunities for all!
