From dark energy and string theory to the end of the Universe, these are the unanswered cosmic conundra that are still baffling scientists.
Dark Matter and Dark Energy: The Mystery Explained (Infographic)
Birth of Universe
How do you know this vase is blue? This takes a while to sink in. :P
La quinta dimensión
The second largest component of the universe is dark matter. The truth is, we understand little of what it is, and more of what it is not.
Black hole? Or wormhole in disguise? | CosmOnline
La odisea de los viajes temporales
Alternative à la théorie du Big Bang