Universe

The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. According to this theory, space and time emerged together 13.787±0.020 billion years ago, and the universe has been expanding ever since the Big Bang. While the spatial size of the entire universe is unknown, it is possible to measure the size of the observable universe, which is approximately 93 billion light-years in diameter at the present day. The earliest cosmological models of the universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the center. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the center of the Solar System.

Read more in the app

The James Webb May See the First Stars to Appear in the Universe

Déjà Vuniverse: Why some physicists believe we could be living in a Groundhog Day universe

Cosmic Breakthrough: Accurate New Map of All the Matter in the Universe Released

New map of the universe's matter reveals a possible hole in our understanding of the cosmos

‘Less clumpy’ universe may suggest existence of mysterious forces

The bubbling universe: A previously unknown phase transition in the early universe

Scientists release newly accurate map of all the matter in the universe

New cosmic map reveals the universe's matter isn't as 'clumpy' as it should be

Scientists Reveal The Most Precise Map of All The Matter in The Universe

Unearthing Clues to the Evolution of the Universe – Measuring the Hidden Energy of Gamma-Ray Bursts

Astronomers Suggest More Galaxies Were Formed in the Early Universe Than Previously Thought

The universe is slightly hotter than it should be. 'Dark photons' could be to blame.

ALMA Confirms Discovery of Oxygen-Rich Galaxy in Very Early Universe

Neil Turok on the case for a parallel universe going backwards in time

Were galaxies much different in the early universe?

Titan’s Dragonfly Test, New Nuclear Rocket, Shadow Universe

Why This Universe? Maybe It’s Not Special—Just Probable

Revealing the Start of Time Itself: Ripples in the Fabric of the Universe May Peer Back to the Beginning of Everything We Know

Ripples in fabric of universe may reveal start of time

Ancient humans and their early depictions of the universe: “It is no exaggeration to say that astronomy has existed as an exact science for more than five millennia,” writes the late science historian John North.