where from + where to
The search for our origins
The universe seems to have been made just for us. Had the constants of nature been only slightly different, human life might never have emerged; this prompts us to wonder about where we came from.
Humans have a long period of development behind them on Earth, but the evolution of life on our planet is a relatively young process. We are now searching for our roots in space as well as on Earth, and this search is leading us to look further and further into the past. Life on Earth began with the first primitive organisms 3.5 billion years ago. They had the ability to absorb substances from their environment and to reproduce. Their constituents, the first complex molecules, either formed on Earth or arrived on our planet with comets.
Before that, the building blocks from which everything is made emerged in space over a period of billions of years. Humans, animals, plants, earth and air - are all made of the “ash” of stars that became extinct a long time ago. Through astronomical observations, mathematical models and sophisticated experiments we now know what the most important constituents of matter are. Light elements, such as hydrogen and helium, were created during the Big Bang more than 13 billion years ago. Heavy elements, like carbon and oxygen, formed in stars or were created when stars met their explosive end. Today, physicists recreate some of these extreme conditions in complex machines here on Earth, and thus look into the very heart of matter.
Observation and experiments have taught us about elementary particles and to understand the forces that act between them. However, this “normal” matter makes up only 4 percent of the universe. What about the rest? Astronomical observations allow cosmologists to very precisely define some parameters of our universe. Effects on the gravity of stars and galaxies show us that there must be around four times more matter than can be seen; we call this “dark matter”. The accelerating expansion of the universe can only be explained by “dark energy”, but at the moment, it is only possible to speculate about its nature.
Nor are there any answers to the question: Where are we going?