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A
Hubble ultra­deep field discovery
galaxies.
The expansion of the universe causes light to be
stretched into longer and longer wavelengths so
what starts as ultraviolet light will be
“redshifted” to infra­red light by the time this
stronomers have found six, possibly
seven, new galaxies in the Hubble ultra­
deep field image. If the seventh galaxy is
confirmed, it will be the furthest known object
we’ve ever seen. When we look out into the
universe, we are in fact looking back in time
(since light has a finite speed) and so, the further
back we look, the closer we get to the first light
from the universe.
These galaxies therefore were around near the
start of the big bang. In fact, the seventh galaxy
found could be as far back as 380 million years
after the big bang in a period cosmologists call
the epoch of reionisation. This epoch describes
the period in which hydrogen has gone from
being neutral to being ionised (the reason it’s
called reionisation is because there was a period
between the big bang and the dark ages (when
the universe was made up of neutral hydrogen)
where the universe was ionised).
light reaches us. Hubble is able to measure this
light by exposure the instrument (the wide field
camera in this case) to hours of light. In fact,
Hubble has been building up this ultra­deep
field picture since 2003.
What they have found out about these galaxies
so far (the first six) is that these galaxies are
quite mature and already have a reasonable
amount of heavy elements. So Hubble has taken
us back to 5% of the Universe’s age and we are
still not seeing the first generation of stars.
This paves the way for the James Webb Space
Telescope to go even deeper with its bigger
mirror and better resolution in the infrared
region of the spectrum.
This is where the cosmologists expect to be able
to find the first objects in the universe. But we
will have to wait until at least 2018 before
JWST is launched.
In the meantime, Hubble can scan different parts
of the sky (this ultra­deep field image took up a
very small amount of space on the sky) to check
whether this discovery is rare or if
there are galaxies at this distance
seen everywhere.
In cosmology, we use a term called “redshift” to
measure the distance between us and these old
© Spacelink Learning Foundation 2012
David Shelton
1
December ­ Issue 12
Getting to know the Team ­ Robert Coombes,
Head Operational Planning
The project is still on­going and computer
education is now a subject in their national
curriculum. I then returned to the UK and
Broadwater School where I am still working as
a Deputy Headteacher.
I
In 1997 Frank Bell asked me to become
involved it what was then, the Millennium
Satellite project. This was an exciting time; I
was looking into and developing the educational
programme for the project, which when so very
near fruition was halted due to the loss of
promised lottery funding.
In 1987 I was given the opportunity to lead a
project for the introduction of Computer
Education in Pakistan. This was a fascinating
time, meeting Ministers of Education, setting up
the project, organising a team to train teachers
and introduce this subject in several of the
major cities in Pakistan. I also wrote the first
text book to be used by the project.
In 2010 Dr Norman White asked me to re­join
Spacelink as an educational consultant. I am
currently Chair of the Operational Planning
Committee and have the privilege of working
with a very talented group of people, sharing a
common interest, that of, inspiring young
students in STEM subjects though the exciting
media of space.
[email protected]
was educated at Lord Wandsworth College
in Long Sutton. From there I went to train
as a teacher at the University of London,
Goldsmiths College. In 1974 I started teaching
as a Design Technology teacher.
© Spacelink Learning Foundation 2012
2
December ­ Issue 12