-
2164 - The Universe is 13.8 billion years
old. We know how fast it has been
expanding. We know that the Universe is
31 % matter of which is only 5% is Ordinary Matter. We know that the other 23% matter is invisible
Dark Matter that we know is there but we do not understand what it is. The rest is energy of some sort that remains
another mystery that is creating and accelerating the expansion, we call it Dark
Energy.
-
-
-
------------------ 2164
- CMB - What did it tell us?
-
- The Big Bang
started the Universe with a unique signature.
Astronomical Probes are making measurements that unravel how our
Universe began. This Review will start
with the conclusions and then look at how we learned from COBE, WMAP, and
PLANCK probes that did the exploring.
-
- About 380,000
years after the Big Bang started, the expansion cooled and expanded enough for
electrons and protons to combine to form neutral atoms. Seeing this today after 13.8 billion years of
expansion is studying radiation energy that has expanded and cooled from 3,000
to 2.725 degrees Kelvin.
-
- From the
measurements collected astronomers have concluded that the Universe is 13.8
billion years old. We know how fast it
has been expanding. We know that the
Universe is 31 % matter of which is only 5% is Ordinary Matter. The only ordinary stuff we think we know and
understand. We know that the other 23%
matter is invisible Dark Matter that we know is there but we do not understand
what it is. The rest is energy of some
sort that remains another mystery that is creating and accelerating the
expansion, we call Dark Energy.
-
- The Cosmic Microwave
Background , CMB, is stretched out radiation wavelengths and lowest Kelvin
temperature because it has been expanding and cooling for 13,800,000,000 years.
Much has been learned when we were able
to study this microwave afterglow with precision instruments measuring down to
the millionth of a degree.
-
- The Universe
started with a primordial soup of subatomic particles. When the soup cooled after 380,000 years
atomic nuclei of hydrogen and helium formed , with trace amounts of lithium.
When the temperature had cooled to 3,000 Kelvin the free electrons latched on
to the hydrogen nuclei to form the neutral atoms.
-
- When the
Universe was mostly neutral hydrogen the light photons could escape from the still
expanding soup. The photons started out
as gamma rays but have now stretched out to the microwave wavelengths.
-
- The COBE
satellite measured the intensity of this microwave energy at wavelengths from
0.1 to 10 millimeters. The measurements
prove that the CMB had a very specific intensity signal peaked at 2 millimeters
wavelength. This wavelength corresponds
to a temperature of 2.725 Kelvin.
-
- The wavelength
of light is directly related to temperature.
The redder the light the less the energy. The bluer the light the higher the
temperature.
-
- At first view
the temperature would look like a solid color, with no variations. But, when the resolution of the measurements
could see down to 0.00002 Kelvin the hotter and cooler patchwork became
"visible". The COBE satellite
could map these hot and cold spots to within 7 angular degrees across the
sky.
-
- Another
satellite, the WMAP, could expand this resolution down to 0.5 angular
degrees. And the PLANCK satellite
brought the resolution down to 0.16 angular degrees. These two satellites swept their measurements across the entire sky to map the
Universe CMB in every direction.
-
- The signal
strengths plotted across the sky revealed the Universe's age, its composition,
its expansion rate, and even when the first stars lit up out of the atomic
soup.
-
- Computer
models were created until the model results matched the measured data. Calculations made to match the models were
able to tell astronomers the composition of the Universe. From this astronomers have a "standard
model of cosmology".
-
- Students
today are studying this model to explore and learn even more about the Universe
they occupy. There is plenty left to
learn with nearly 95% of the Universe still remaining "unknown".
-
- We pickup
only pebbles of knowledge on the beach with a whole ocean of unknown before us.
-
- November 12, 2018. An Index of recent Reviews is available.
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to
whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for
copies or Index of all reviews
--- to:
------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
- https://plus.google.com/u/0/ -- www.facebook.com -- www.twitter.com
--------------------- Monday, November 12, 2018 -------------------------
-----------------------------------------------------------------------------------------
No comments:
Post a Comment