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CMBR Dipole: Speeding Through the Universe

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CMBR 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 of Galaxies.

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
cosmic microwave background radiation (CMBR).

In the
above all-sky map from the COBE satellite, 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?

Note: Playing leading roles in the COBE
project, for their resulting discoveries
John C. Mather
(NASA, Goddard Space Flight Center ), and George F. Smoot (UC Berkeley)
were selected to receive the
2006 Nobel Prize in Physics.

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