‘I read very, very little
fiction as a kid. All the books I can remember are junior science books.’
These
are the words of English writer Mark Haddon (1962-), whose award-winning 2003 novel
The Curious Incident of the Dog in the
Night-Time captivated my younger son, both in print and in a recent stage
production. It is a story to which my son can readily relate, for he and the
novel’s young protagonist share a defining trait: Asperger’s syndrome. My son
even bought a commemorative Curious
Incident pencil case, bearing the phrase: ‘I like Maths and being on my
own.’
For
this reason alone, and writing from a scientist’s angle, it gives me tremendous
pleasure to see that science museums the world over are now laying great
emphasis on interactive exhibits designed to captivate ‘Aspie’ youngsters, who
see their world in extraordinary detail, identify patterns where their peers
see only randomness, and generally analyse everything to the nth degree.
There
are around fifty such science museums in Britain alone. Alongside these are
play facilities aimed primarily at children, such as The Puzzling Place, in
Keswick and Techniquest (Figure 93.1), based in Cardiff. I took Junior to the
latter this Easter weekend. The interactive exhibits, demonstrating sound,
optics, anatomy and magnetism, kept us occupied for hours. One particular piece
practically mesmerized him. It was, at first view, a plastic bowl with two
identical holes at its deepest points (Figure 93.2). Kids of all ages took
turns dropping plastic balls into the bowl, watching carefully as each one
swirled round and round, often circling one hole before switching, at the last
moment, to the other. To the unscientific eye, the eventual destination of each
ball was random. It was simply fun to watch a moving object with (apparently) a
will of its own.
Figure
93.1: Further details are available at: http://www.techniquest.org
Copyright
© 2016 Techniquest
Figure
93.2: Watching the ‘magic’ of gravity
Copyright
© 2016 Paul Spradbery
Junior,
to his credit, saw things his own way. After studying the sweeping movements of
ball after ball, he remarked: ‘Dad, why is it, when they slow down a bit, they sometimes
start going round like a number eight?’
It
was an astute observation. Of all the questions he might have asked, though, this
was perhaps the most difficult for me to answer. Still, as Einstein once said: ‘If you can’t explain it to an eight-year-old, then you don’t
understand it yourself.’
So
here goes. Whenever a ball rolled deep into one of the holes, it would move
along a circular path, round and round, in a downward spiral, until it
disappeared from view. However, if a ball were moving with sufficient speed at
a high enough point, then it might have the energy required to roll across to
the other hole. Then, if it had lost too much energy by so doing, it would stay
there and eventually drop through that hole. If sufficient energy remained, it
might be able to switch back again, and so forth until its energy finally ran out.
This two-hole arrangement is called a ‘binary system’ and plays a crucial role in gravitational physics.
Why
a figure-of-eight? If a ball were to ‘escape’ from one orbit in, say, a
clockwise movement, it would necessarily join the other orbit in an
anticlockwise movement (Figure 93.3).
Figure
93.3: This simple graphic shows a figure-of-eight orbital pathway operating within
a binary system.
Copyright
© 2005 Pearson Prentice Hall, Inc.
The
so-called Roche lobe is a region around a star, within a binary system, where
the orbiting object is gravitationally attracted to that star. The lobe is
shaped like a teardrop, and, when conjoined to its corresponding lobe, forms a
figure-of-eight. The orbit takes its path along a line of equal gravitational
potential, which is analogous to a geographical contour line or a
meteorological isobar. The crossover point from one Roche lobe to the other is
called the L1 Lagrangian point of the orbital system.
Perhaps
– just perhaps – many years from now, there will be a banknote bearing the
image of a world-renowned scientist whose inspiration stemmed from playing with
a toy of such supreme scientific elegance.
Copyright
© 2016 Paul Spradbery