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By scrutinising
the Hubble Ultra Deep Field,

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the deepest image
of the sky ever made,

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the NASA / ESA
Hubble Space Telescope

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and the NASA
Spitzer Space Telescope

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have joined forces to
discover nine of the smallest,

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faintest, most compact galaxies

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ever observed
in the distant Universe.

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This is the Hubblecast.

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News and images from the
NASA / ESA Hubble Space Telescope.

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Travelling through time and space
with our host, Dr. J

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EPISODE 8: A step closer
to our origin...
a.k.a. Dr. Joe Liske.

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Hello and welcome
to the Hubblecast.

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One of the mos fundamental
questions that we all ask,

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astronomers and laypersons alike,

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is: where do we come from?

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We, the Earth, the Sun and
the rest of the Solar System

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are all part
of the Milky Way galaxy,

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and so the question of our
origin is closely linked

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to the birth
and evolution of galaxies.

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Now, the Spitzer and Hubble
Space Telescopes

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have joined forces to discover
nine of the faintest,

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youngest and most
compact galaxies

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ever observed in the
distant Universe.

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Conventional theories
of galaxy evolution

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predict that small galaxies
in the early Universe

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evolved into the massive
galaxies of today

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by merging together.

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The newly found young galaxies
offer important new insights

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into the Universe's
formative period,

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just 1 billion years
after the Big Bang.

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Hubble has detected
sapphire blue stars

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residing within
the nine pristine galaxies.

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Although they are glowing
with the light of millions of stars,

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each of the newly
discovered galaxies

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is actually a hundred
to a thousand times fainter

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than our own Milky Way.

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Now, usually
smaller things in space

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tend to be less interesting
to astronomers than the larger ones,

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but in this case
it's the opposite.

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Three of the new galaxies appear
to be slightly disrupted.

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Instead of being shaped
like rounded blobs,

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they appear to be stretched
into tadpole-like shapes.

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This is a sign that
they may be interacting

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and merging
with neighbouring galaxies

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to form larger,
cohesive structures,

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just as predicted by theory.

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The galaxies were observed
in the Hubble Ultra Deep Field

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with Hubble's Advanced
Camera for Surveys

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and the Near Infrared
and Multi-Object Spectrometer

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as well as Spitzer's
Infrared Array Camera

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and the European
Southern Observatory's

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Infrared Spectrometer
and Array Camera.

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In today's Hubblecast
we have a special guest,

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Dr. Martin Kümmel, from the European
Hubble group in Munich.

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- Welcome Martin
- Hello Dr, J

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You and your colleagues
are responsible

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for the particular
instrument mode on Hubble

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that was used
by the scientists.

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Can you tell us
a little bit about that?

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The so called Grism mode

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in the Advanced
Camera for Surveys

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spreads the different colours
emitted by the galaxies

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into short "trails".

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This is an example
of such a grism.

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One can see the rainbow colors
as the light is spread out.

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So how was that used
by the scientists?

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Well, the analysis
of these short trails

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allows the detection of emission
from glowing hydrogen gas,

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giving the distance
as well as an estimate

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of the rate
at which stars are formed.

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But could that not be done
in a different way?

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Finding and analysing
these small and faint galaxies

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at such great distances
is at the very limit

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of the capabilities of
the most powerful telescopes.

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The grisms on board Hubble
are the only instruments

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that can make
this kind of discovery.

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By finding these nine tiny

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and exceedingly faint
galaxy building blocks

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we followed another branch
of our galactic family tree

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and moved a small
but important step closer

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to understanding
our cosmic roots.

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We already know about the
existence of much more massive

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and therefore considerably
brighter galaxies

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at similarly great distances.

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How these monsters were assembled
so quickly after the Big Bang

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remains a real puzzle
for astronomers.

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But that's a story
for another day...

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With these small
galaxy building blocks

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we are basically witnessing
galaxy formation in action.

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Something that is important
if we want to understand

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our origin
on the cosmic scale.

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This is Dr. J
signing off for the Hubblecast.

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Once again, nature has surprised us
beyond our wildest imagination...

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Hubblecast is produced
by ESA / Hubble

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at the European
Southern Observatory in Germany.

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The Hubble mission is a project
of international cooperation

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between NASA and
the European Space Agency.