Hello Space Fans and welcome to another edition
of Space Fan News.
This week, the European Space Agency released
the crown jewel of its Planck Space Telescope
Mission, the most detailed image of the early
universe ever taken.
Here is the culmination of its mission, this
is what the Planck Space Telescope was launched
for, this is the image it was designed to
take.
This is a picture of the universe when it
was only 380,000 years old in unprecedented
detail.
This is a finely detailed map of tiny temperature
variations across the the entire universe,
the red parts are very slightly warmer than
the blue parts and the patterns of these variations
are the blueprint, the backbone of the universe.
These temperature variations are not very
large, only 1 part in 100,000.
Along these patterns, galaxies and clusters
of galaxies will form.
This is the framework of all that will follow
and will form the basis of the large scale
structure of the cosmos.
The fluctuations arose almost immediately
after the Big Bang and were stretched out
by a period of rapid expansion, known as inflation.
This is a time when the universe got very
big, very fast; a time when vacuum energy
is pushing space-time apart exponentially.
During the inflationary period, the universe
doubles in size at least 100 times during
the period between 10^-33 and 10^-32 seconds
after the Big Bang.
The CMB is a snapshot of a time when the universe
was just entering a period known as recombination,
just after inflation.
The universe just prior to this was very hot:
about 2700 degrees Celsius and very dense,
photons could not travel very far with out
hitting something else and bouncing off, making
the universe opaque.
But as the universe expanded and cooled, photons
escaped and allowed atoms to form.
That is recombination and this is a picture
of that moment.
From this point on, the largest scales in
our universe were defined.
Galaxies would form along large tendrils creating
a web of structure we see today.
While Planck's results were considered to
support the standard model of cosmology, it
did uncover some anomalies not consistent
with the prevailing theories.
For example, the higher resolution images
revealed a hemispheric asymmetry and a cold
spot.
These anomalies had been found in Planck's
predecessor WMAP, but it wasn't possible to
confirm whether they were real or if they
were an artifact of data processing or foreground
emissions.
The fact that these anomalies are also present
in the more precise Planck data clears up
any doubt about their cosmic origin.
Without this picture, we couldn't even begin
to understand where we came from.
Amazing stuff and I couldn't be more excited
about these results.
Planck has done it's job exceedingly well.
This image is important.
And I would go so far as to say, it is the
second most important image ever taken.
Next, astronomers using ESA's Herschel Space
Telescope have detected emissions from the
base of black-hole jets for the first time.
While studying the black-hole binary system
GX 339-4 in a multi-wavelength observation
campaign, they noticed changes in the source's
X-ray and radio emissions which they say signals
the onset of powerful jets being released
from the black hole's vicinity.
Here's how it works:
When black holes collect matter from their
surroundings, they also trigger the release
of powerful jets of highly-energetic particles
that stem from the accretion disc into outer
space.
This phenomenon happens with any kind of black
hole, the stellar-mass black holes that result
from the death of massive stars in supernovae
and at the supermassive black holes at the
centers of galaxies.
Even though these jets have been studied for
decades and are easily seen in a variety of
wavelengths, from radio all the way across
the EM spectrum, astronomers still don't know
much about the physical mechanisms underlying
them.
The easiest black holes to study are the stellar
sized ones, especially the black holes in
orbit around a companion star in a binary
system.
These guys are pulling material off of the
nearby star and accreting mass around it and
the jets that are produced have properties
that change on relatively short time scales
- on the order of a few hours or day - and
this provides astronomers with a great opportunity
to study their evolution as well as the ignition
mechanisms that trigger them.
One of the best-studied stellar-mass black
holes is the one hosted in the binary system
GX 339-4: astronomers can monitor its evolution
quite closely because it gives rise to bright
outbursts every couple of years.
Now, while GX 339-4 has been studied extensively
at radio, NIR, optical and X-ray wavelengths,
astronomers had rarely observed it in the
vast portion of the spectrum between radio
and NIR wavelengths.
And this is where Herschel comes in.
The astronomers requested to observe GX 339-4
with Herschel after they detected changes
to its X-ray emission signalling that the
outburst phase of this source, which had been
going on for several months, was about to
cease.
They wanted to see what happened to those
jets as the black hole entered its quiescent
phase.
According to the science team: "It is the
first time that we could witness the onset
of compact jets and follow their evolution.
By combining radio observations with Herschel's
FIR data, we could probe the jet emission
down to the base, very close to the black
hole."
The Herschel data confirmed the current view,
which holds that these jets are synchrotron
radiation released by highly-energetic electrons.
In particular, the most energetic electrons,
present at the base of the jets, radiate at
FIR wavelengths, while the lower-energy ones,
which are more abundant at larger distances
from the black hole, give rise to radio emission.
Finally the Atacama Large Millimeter/submillimeter
Array (ALMA) - which officially came online
only this month is already making great discoveries.
This month, astronomers using ALMA announced
that they have found evidence that the most
vigorous burst of star formation in the cosmos
happened much earlier than previously thought.
According to the paper released in Nature
on March 14th, observations made with the
South Pole Telescope and later by ALMA, show
that the most rapid period of star birth in
the universe occurred 12 billion years ago,
a full one billion years earlier than previously
thought.
Now I thought this was curious because I thought
I heard news like this before.
You know, this idea that the period of high
star birth was older than we thought.
After some searching, I found what I was looking
for.
Back in January, 2011 there was a press release
from Hubble stating observations of UDFj-39546284
(a galaxy in the Ultra Deep Field) uncovered
evidence that the rate of star formation increased
by a factor of ten between 480 million years
to 650 million years after the Big Bang, which
is way earlier than what the ALMA observations
have found.
Was that the start of the period of rapid
star birth?
That's how I interpreted it.
So maybe the way to look at this announcement
is that these results are consistent with
those found in 2011.
We were already getting indications that rapid
star birth was very early in the life of the
universe - earlier than we thought.
Anyway, the ALMA team surveyed many galaxies
in the early universe and were surprised to
find that many of these distant dusty star-forming
galaxies are even further away than expected.
This meant that, on average, their bursts
of star birth took place 12 billion years
ago, when the Universe was just under 2 billion
years old — a full billion years earlier
than previously thought.
Two of these galaxies are the most distant
of their kind ever seen — so distant that
their light began its journey when the Universe
was only one billion years old.
What’s also very cool about this announcement
is that in one of these galaxies, water is
among the molecules detected, marking the
most distant observations of water in the
cosmos published to date.
So whether it's 650 million years after the
Big Bang or just under two billion, it looks
like we still have a lot to learn about this
important period in the history of our Universe.
Well, that's it for this week Space Fans,
thank you for watching and as always, Keep
Looking Up!
