COBE Dipole: Speeding Through the Universe
Our Earth is
not at rest. The Earth moves around the
Sun.
The Sun orbits the center of the
Milky Way Galaxy.
The Milky Way Galaxy orbits in the
Local Group. The Local Group falls toward the
Virgo Cluster of Galaxies.
But these speeds are less than the speed that all of these objects
together move relative to the
microwave background.
In the above all-sky map,
radiation in the Earth's direction of motion appears blueshifted
and hence hotter, while radiation on the opposite side of the
sky is redshifted and colder.
The map indicates that the Local Group moves at about 600 kilometers per
second relative to this primordial radiation.
This high speed was initially unexpected and its
magnitude is still unexplained. Why are we moving so fast?
What is out there?