So what IS the Cosmic Microwave Background, anyway? A few hundred thousand years after the Big Bang, things cooled down enough (to about 2,700 ˚C) that neutral matter like hydrogen and helium began to condense from a sea of charged protons and electrons. This released photons that have been propagating through space since that very moment. Of course, we know that the universe is expanding, right? Those photons are expanding along with it. We are detecting them at a distance in light years almost equal to the age of the universe itself, as they have been stretched and cooled to just above absolute zero (a few degrees Kelvin).  Why “microwave”? The photon wavelengths have expanded so much during the expansion of the universe that they now sit in the microwave range, like extending a Slinky into a single, straight wire! Check out this cool feature from Space.com to find out even more about the CMB, including how pigeon poop helped us figure out it even existed.
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So what IS the Cosmic Microwave Background, anyway?

A few hundred thousand years after the Big Bang, things cooled down enough (to about 2,700 ˚C) that neutral matter like hydrogen and helium began to condense from a sea of charged protons and electrons. This released photons that have been propagating through space since that very moment.

Of course, we know that the universe is expanding, right? Those photons are expanding along with it. We are detecting them at a distance in light years almost equal to the age of the universe itself, as they have been stretched and cooled to just above absolute zero (a few degrees Kelvin). 

Why “microwave”? The photon wavelengths have expanded so much during the expansion of the universe that they now sit in the microwave range, like extending a Slinky into a single, straight wire!

Check out this cool feature from Space.com to find out even more about the CMB, including how pigeon poop helped us figure out it even existed.

Planck-in’ on Billions and Billions I’m amazed that in 2013, we can still be smacked upside the head and reminded of how little we know about our universe. Even the most basic things about it. Like, how old it is. The European Space Agency’s Planck space telescope has collected 15.5 months worth of data on the Cosmic Microwave Background, or CMB (What’s that? Click here), and today they released the most detailed map ever of those oldest remnants of the Big Bang. It says that our universe is almost perfect. Almost.  The highlights from this new map include the finding that the universe is almost certainly 13.81 billion years old, about 100 million years older than previous estimates. And we got better estimates for the stuffness of stuff: 4.9 percent normal matter, 26.8 percent dark matter, and 68.3 percent dark energy. The universe is expanding, which is the whole reason that the CMB even exists, but this new map says it’s expanding slower than we thought.  The coolest part, though? The “almost perfect” part. The radiation that became the CMB was just sort of randomly splattered out, like we’d expect (and the randomness of the dots on the map above show that). But those little fluctuations aren’t the same everywhere! The universe appears to be slightly lopsided, and even rather cold in one part. The ESA folks say we may need “new physics” to explain why. Nice to know you cosmologists of the future will have something to work on :) Of course, all of this just goes for the observable universe. The rest, whatever it may be (or not be), has NO EDGE. Just like Hank Green reminds us. Phil Plait has tons more dirty details behind the Planck news at Bad Astronomy.
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Planck-in’ on Billions and Billions

I’m amazed that in 2013, we can still be smacked upside the head and reminded of how little we know about our universe. Even the most basic things about it. Like, how old it is.

The European Space Agency’s Planck space telescope has collected 15.5 months worth of data on the Cosmic Microwave Background, or CMB (What’s that? Click here), and today they released the most detailed map ever of those oldest remnants of the Big Bang. It says that our universe is almost perfect. Almost. 

The highlights from this new map include the finding that the universe is almost certainly 13.81 billion years old, about 100 million years older than previous estimates. And we got better estimates for the stuffness of stuff: 4.9 percent normal matter, 26.8 percent dark matter, and 68.3 percent dark energy. The universe is expanding, which is the whole reason that the CMB even exists, but this new map says it’s expanding slower than we thought. 

The coolest part, though? The “almost perfect” part. The radiation that became the CMB was just sort of randomly splattered out, like we’d expect (and the randomness of the dots on the map above show that). But those little fluctuations aren’t the same everywhere! The universe appears to be slightly lopsided, and even rather cold in one part. The ESA folks say we may need “new physics” to explain why. Nice to know you cosmologists of the future will have something to work on :)

Of course, all of this just goes for the observable universe. The rest, whatever it may be (or not be), has NO EDGE. Just like Hank Green reminds us. Phil Plait has tons more dirty details behind the Planck news at Bad Astronomy.