The Expanding Universe In 1998, astrophysicists discovered a baffling phenomenon: the Universe is expanding at an ever-faster rate. Either an enigmatic force called dark energy is to blame or a reworking of gravitational theory is in order. In this new Science Bulletins video, watch a Fermilab team assemble the Dark Energy Camera, a device that could finally solve this space-stretching mystery.
Content of the Universe
WMAP data reveals that its contents include 4.6% atoms, the building blocks of stars and planets. Dark matter comprises 23% of the universe. This matter, different from atoms, does not emit or absorb light. It has only been detected indirectly by its gravity. 72% of the universe, is composed of "dark energy", that acts as a sort of anti-gravity. This energy, distinct from dark matter, is responsible for the present-day acceleration of the universal expansion. WMAP data is accurate to two digits, so the total of these numbers is not 100%. This reflects the current limits of WMAP's ability to define Dark Matter and Dark Energy. Credit: NASA / WMAP Science Team