When the light of the cosmic background was emitted about 13.8 billion years ago it was only 42 million light years away, but because of the expansion of the Universe that horizon is now more than 46 billion light years away.

 When the light of the cosmic background was emitted about 13.8 billion years ago it was only 42 million light years away, but because of the expansion of the Universe that horizon is now more than 46 billion light years away.