Cosmic microwave background radiation (CMB) as observed by Planck. The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old.
April 16, 2013 Scientists can't just agree to disagree. It's not because we are stubborn or ornery (OK, maybe we are). It's because science faces a fundamental problem when it can't agree on numbers like the value of the Hubble Constant. The whole point of science is to establish an understanding of the cosmos on which we can all agree.
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