NEBULA
VOLUME 44 I ssue 2
PAGE 12
knew, therefore, that Saturn must
close by. It was only a few yards
away, slightly obscured by foliage.
To Eva, Saturn with its rings was
like a ship’s wheel.
Jupiter came by very quickly.
Pluto, by comparison is tiny.
Mars, Earth, Venus and Mercury
were so little a bike ride after that
as to almost seem to be on top of
one another. Also their sizes had
shrunk back down again. It’s very
evident when seeing these scale
models like this that the bulk of the
planetary mass is pretty much just
Saturn and Jupiter.
The ride was easy going and
good for Eva, at just her second
proper bike ride. For those without
a bike, or the means to transport
one, it is possible to hire a bike
from York train station.
Eva and Saturn (20.22 cm diameter)
The Sun was located just by the
A64 flyover. The planets’ scale
and distance from it made them
seem pretty much insignificant. To
think that with modern instruments
we can detect the gravitational
wobble of planets that are as far
away from their star (that is many
light years away from us) as de-
picted by this model is hard to
comprehend.
WHY I LOVE THE SKY DURING THE SUMMER MONTHS
by Robert Lewis (reflecting on the summer)
I always love the summer sky at
night. It’s early July and I love the
way the sun only sits just below the
horizon and its rays are still to be seen
around 11 p m and midnight. The sky
does not assume its inky darkness like
it does in winter. In Leeds, Yorkshire,
we are at a rather northern latitude.
Beyond the city lights, just above the
horizon, the redness of the evening
sky is still present and the sky above
that is a beautiful light- to mid-b lue.
The rays of the sun are still impinging
on the sky. It’s wonderful. I never
observed the sky to be so bright at that
time of night in Northampton. In
Somerset and Devon, the sky is darker
still and the stars appear to be brighter
and more nu merous there.
“Just look at the big sky”, sang Kate
Bush in one of her songs. Some stars
are still quite bright and diagonally
above me I could see Ursa Major, one
of my main reference points in the
night sky. It’s the phenomenon at the
lower altitude that interests me at this
particular time. It is reminiscent of the
Midnight Sun that occurs at the ex-
treme Northern latitudes, in particular
the Arctic Circle. Here the sun does
not set and remains above the horizon
at certain times of the year.
The sun is geometrically below the
horizon in what could be called night
according to the time but astronomical
twilight and/or civil twilight, accord-
ing to what imp inges on the senses.
Light rays are still passing through the
Earth’s atmosphere and being refract-
ed back to the observer. The blue af-
ter-glow in the sky is remarkab le be-
cause the sun is not present like during
the day or the sun set event. It’s as if
the sun is still illu minating the sky by
proxy. The sun constantly transmits its
rays (obviously) and those that im-
pinge on the atmosphere get scattered
equally in all direct ions by the mole-
cules of nitrogen and oxygen, giving
that blue colour.
While looking at the horizon I am of
course scanning for noctilucent clouds
which are not frequently present.
Their high altitude reflects sun light.
One supposes that if you were at that
height you would still see the sun.
If you haven’t gone to bed and
maybe wandering in fro m the pub or
simp ly happening to be looking at the
night sky through your window take
time to ponder this phenomenon. The
sun is still there, not quite asleep in
twilight of its own.
£96m investment in Engi-
neering & Physical Sciences
at University
Leeds University has approved
plans to create an international
Centre for Engineering and Phys i-
cal Sciences on the north eastern
part of campus. The £96m project
was approved by the University's
governing body in Oct 2016. It is
the largest, single-project invest-
ment ever to have been made on
campus.
The new Centre will bring to-
gether schools of Engineering,
Computing and Physics & Astron-
omy. Works should be completed
by 2020 .