Okay so 100 million years seems like a big mistake on the part of Astronomers, but in the astronomical community its a small adjustment.
Today the most detailed map of the CMBR ever captured was released by the Planck telescope group at the ESA. Based on 15.5 months of data, it shows the tiny temperature variations that were present when the universe had a temperature of 2700 degrees Celsius and an age of just 380,000 years (trust me that’s small on astronomical scales). This is the point when the dense soup of protons and electrons formed hydrogen atoms, and the universe became transparent.
As the universe has expanded the light has stretched out to microwave wavelengths and now has a temperature of 2.7 degrees above absolute zero, -270 Celsius The tiny temperature fluctuations on the order of millionths of degrees visibly correspond to the structure that would eventually map out the structure of galaxies and galaxy clusters throughout the universe.
The estimate of the age of the universe is now more precise as well, since the CMBR measurements give precise constraints to the Hubble constant, used in the Lambda-CDM model of the universe to generate the time passed since the big bang. The adjustment brings the universe’s age to 13.82 billion years, 100 million years older than previously thought. This seems like a large difference, but as I said before, on astronomical scales we were in the right zone so its not too surprising.
However, some surprise did arise from the new map, pointing to the (known) conclusion that we do not understand the universe on larger scales. On small scales the standard model is correct, which says that CMBR temperature differences are caused by random quantum fluctuations, but on large scales this model falls short, suggesting that there is more to the big picture of understanding the universe. One such shortcoming is that a cold spot in the CMBR is much larger than expected from the standard model.
This is not a big surprise however, as physicists are aware that more theory is needed to explain the universe, since the standard model can’t explain either dark matter or dark energy, the two largest sources of’stuff’ in the universe.
Let’s think about that for a second. We have no clue what most of the universe is made of. And we don’t even have a really complete picture of the stuff we do know. Astronomy and Cosmology are still wide open fields.