[Music throughout] Hi, I'm Tom Essinger-Hileman.
I'm an astrophysicist at NASA's Goddard Space Flight Center
in the Observational Cosmology Laboratory.
I use sensitive microwave telescopes to try to understand
the composition, origins and history of our universe.
This image is our first baby picture of the universe, taken
by the Cosmic Background Explorer, or COBE satellite.
Really, I think what's so interesting about this is it gives you an idea
of what you would see if you looked out of the sky with microwave eyes.
We look out at the sky and we see a bunch of stars.
Maybe we see our galaxy.
But if you had the ability to look out at microwave wavelengths,
this is the sort of image that you would see, you’d see a very uniform sky
with these slight bright and dim patches.
You'd be looking back
to some of the earliest moments in the history of our universe.
COBE operated from 1989 to 1993,
and COBE revolutionized our understanding of the universe by
observing the cosmic microwave background that you're seeing here — the CMB.
The CMB is remnant
light from just 380,000 years after the Big Bang,
when the universe was transitioning from a hot, dense plasma
to a cooler neutral gas of predominantly hydrogen and helium.
At this early time, galaxies and stars hadn't formed.
What we're seeing in this image of the CMB
is the seeds of future galaxies,
the red and blue patches in this map of the sky
represent more and less dense regions
in that early universe, and the more dense regions clumped together
to form the galaxies that we see in the universe today.
This was a first of its kind measurement
of tiny fluctuations in the microwave brightness of the sky.
The DMR instrument very precisely measured
these tiny differences at wavelengths from 3 to 10 millimeters.
that's around where your cellphone operates.
The CMB is remarkably uniform;
these fluctuations are just one part in 100,000
of the overall 2.7 Kelvin temperature of the CMB.
And they're on very large angular scales, on very large physical scales in our universe.
Future measurements
were able to look at this map of the sky
in greater detail, and with greater angular resolution.
The universe when this was emitted
was about a thousand times smaller, and about a thousand times hotter.
So when the cosmic microwave background was emitted,
this light peaked up in the visible.
The universe as a whole has been expanding and cooling, and the cosmic
microwave background has been cooling along with it.
the light has shifted to longer wavelengths: into the microwave
and closer to the radio part of the spectrum.
The idea that you can answer fundamental questions about the history
of our universe with a map like this that we're seeing here is just amazing.