# Explore Observatory Hawaii, Keck Observatory and more!

When we meet aliens, it won’t be a friendly encounter nor a conquest: it will be a gold rush. Can we make sure it’s ethical?

"Joules of the Universe". Diagram depicting all energy levels in the universe, beginning with a single photon, then progressing up to the energy of a hydrogen atom, the energy of an atomic bomb, the yearly output of the sun, and finally the total energy output of the universe. Memorable steps along the way include the energy in a ton of coal, and the energy of a bumblebee traveling at half the speed of light.

A Thin Sheet of Reality: The Universe as a Hologram. 2011 World Science Festival panel discussion on the holographic principle.What we touch. What we smell. What we feel. They're all part of our reality. But what if life as we know it reflects only one side of the full story? Some of the world's leading physicists think that this may be the case. They believe that our reality is a projection—sort of like a hologram

Topology "In der modernen Kosmologie stellt sich die Frage nach der Topologie des Universums." General Relativity classifies geometry, the FLRW Model maintains curvature of the universe as a constant, as a sphere - but this places constraints on the Riemann surface. There are 3 distinct ways to describe relations in space: k = 0 Euclidian k = -1 hyperbolic (Bolyai-Lobatschewski) k = +1 elliptic (Riemann)

Paul Steinhardt is a theoretical physicist who is best known for his work with the theory of cosmic inflation. He introduced the concept of quintessence, a time-varying form of dark energy to explain the current accelerating expansion of the universe. His recent work has been on brane cosmology, especially the ekpyrotic and cyclic models. The cyclic theory of the universe is a radical alternative to big bang/inflationary cosmology in which the evolution of the universe is periodic.