Reading Passage 1

Electroreception
A Open your eyes in sea water and it is difficult to see much more
than a murky, bleary green colour. Sounds, too, are garbled and difficult to
comprehend. Without specialised equipment humans would be lost in
these deep sea habitats, so how do fish make it seem so easy? Much of
this is due to a biological phenomenon known as electroreception – the
ability to perceive and act upon electrical stimuli as part of the overall
senses. This ability is only found in aquatic or amphibious species because
water is an efficient conductor of electricity.

B Electroreception comes in two variants. While all animals (including

humans) generate electric signals, because they are emitted by the
nervous system, some animals have the ability – known as passive
electroreception – to receive and decode electric signals generated by
other animals in order to sense their location.

C Other creatures can go further still, however. Animals with active

electroreception possess bodily organs that generate special electric
signals on cue. These can be used for mating signals and territorial
displays as well as locating objects in the water. Active electroreceptors
can differentiate between the various resistances that their electrical
currents encounter. This can help them identify whether another creature
is prey, predator or something that is best left alone. Active
electroreception has a range of about one body length – usually just
enough to give its host time to get out of the way or go in for the kill.

D One fascinating use of active electroreception – known as the

Jamming Avoidance Response mechanism – has been observed between
members of some species known as the weakly electric fish. When two
such electric fish meet in the ocean using the same frequency, each fish
will then shift the frequency of its discharge so that they are transmitting
on different frequencies. Doing so prevents their electroreception faculties
from becoming jammed. Long before citizens’ band radio users first had to
yell “Get off my frequency!” at hapless novices cluttering the air waves, at
least one species had found a way to peacefully and quickly resolve this
type of dispute.

E Electroreception can also play an important role in animal defences.

Rays are one such example. Young ray embryos develop inside egg cases
that are attached to the sea bed. The embryos keep their tails in constant
motion so as to pump water and allow them to breathe through the egg’s
casing. If the embryo’s electroreceptors detect the presence of a
predatory fish in the vicinity, however, the embryo stops moving (and in
so doing ceases transmitting electric currents) until the fish has moved
on. Because marine life of various types is often travelling past, the
embryo has evolved only to react to signals that are characteristic of the
respiratory movements of potential predators such as sharks.

F Many people fear swimming in the ocean because of sharks. In

some respects, this concern is well grounded – humans are poorly
equipped when it comes to electroreceptive defence mechanisms.
Sharks, meanwhile, hunt with extraordinary precision. They initially lock
onto their prey through a keen sense of smell (two thirds of a shark’s brain
is devoted entirely to its olfactory organs). As the shark reaches proximity
to its prey, it tunes into electric signals that ensure a precise strike on its
target; this sense is so strong that the shark even attacks blind by letting
its eyes recede for protection.

G Normally, when humans are attacked it is purely by accident. Since

sharks cannot detect from electroreception whether or not something will
satisfy their tastes, they tend to “try before they buy”, taking one or two
bites and then assessing the results (our sinewy muscle does not compare
well with plumper, softer prey such as seals). Repeat attacks are highly
likely once a human is bleeding, however; the force of the electric field is
heightened by salt in the blood which creates the perfect setting for a
feeding frenzy. In areas where shark attacks on humans are likely to
occur, scientists are exploring ways to create artificial electroreceptors
that would disorient the sharks and repel them from swimming beaches.

H There is much that we do not yet know concerning how

electroreception functions. Although researchers have documented how
electroreception alters hunting, defence and communication systems
through observation, the exact neurological processes that encode and
decode this information are unclear. Scientists are also exploring the role
electroreception plays in navigation. Some have proposed that salt water
and magnetic fields from the Earth’s core may interact to form electrical
currents that sharks use for migratory purposes.
Reading Passage 1

Fair games?
For seventeen days every four years the world is briefly arrested by the
captivating, dizzying spectacle of athleticism, ambition, pride and
celebration on display at the Summer Olympic Games. After the last
weary spectators and competitors have returned home, however, host
cities are often left awash in high debts and costly infrastructure
maintenance. The staggering expenses involved in a successful Olympic
bid are often assumed to be easily mitigated by tourist revenues and an
increase in local employment, but more often than not host cities are
short changed and their taxpayers for generations to come are left
settling the debt.

Olympic extravagances begin with the application process. Bidding alone

will set most cities back about $20 million, and while officially bidding only
takes two years (for cities that make the shortlist), most cities can expect
to exhaust a decade working on their bid from the moment it is initiated to
the announcement of voting results from International Olympic Committee
members. Aside from the financial costs of the bid alone, the process ties
up real estate in prized urban locations until the outcome is known. This
can cost local economies millions of dollars of lost revenue from private
developers who could have made use of the land, and can also mean that
particular urban quarters lose their vitality due to the vacant lots. All of
this can be for nothing if a bidding city does not appease the whims of IOC
members – private connections and opinions on government conduct
often hold sway (Chicago’s 2012 bid is thought to have been undercut by
tensions over U.S. foreign policy).

Bidding costs do not compare, however, to the exorbitant bills that come
with hosting the Olympic Games themselves. As is typical with large-scale,
one-off projects, budgeting for the Olympics is a notoriously formidable
task. Los Angelinos have only recently finished paying off their budget-
breaking 1984 Olympics; Montreal is still in debt for its 1976 Games (to
add insult to injury, Canada is the only host country to have failed to win a
single gold medal during its own Olympics). The tradition of runaway
expenses has persisted in recent years. London Olympics managers have
admitted that their 2012 costs may increase ten times over their initial
projections, leaving tax payers 20 billion pounds in the red.

Hosting the Olympics is often understood to be an excellent way to update

a city’s sporting infrastructure. The extensive demands of Olympic sports
include aquatic complexes, equestrian circuits, shooting ranges, beach
volleyball courts, and, of course, an 80,000 seat athletic stadium. Yet
these demands are typically only necessary to accommodate a brief influx
of athletes from around the world. Despite the enthusiasm many
populations initially have for the development of world-class sporting
complexes in their home towns, these complexes typically fall into disuse
after the Olympic fervour has waned. Even Australia, home to one of the
world’s most sportive populations, has left its taxpayers footing a $32
million-a-year bill for the maintenance of vacant facilities.

Another major concern is that when civic infrastructure developments are

undertaken in preparation for hosting the Olympics, these benefits accrue
to a single metropolitan centre (with the exception of some outlying areas
that may get some revamped sports facilities). In countries with an
expansive land mass, this means vast swathes of the population miss out
entirely. Furthermore, since the International Olympic Committee favours
prosperous “global” centres (the United Kingdom was told, after three
failed bids from its provincial cities, that only London stood any real
chance at winning), the improvement of public transport, roads and
communication links tends to concentrate in places already well-equipped
with world-class infrastructures. Perpetually by-passing minor cities
creates a cycle of disenfranchisement: these cities never get an injection
of capital, they fail to become first-rate candidates, and they are
constantly passed over in favour of more secure choices.

Finally, there is no guarantee that an Olympics will be a popular success.

The “feel good” factor that most proponents of Olympic bids extol (and
that was no doubt driving the 90 to 100 per cent approval rates of
Parisians and Londoners for their cities’ respective 2012 bids) can be an
elusive phenomenon, and one that is tied to that nation’s standing on the
medal tables. This ephemeral thrill cannot compare to the years of
disruptive construction projects and security fears that go into preparing
for an Olympic Games, nor the decades of debt repayment that follow
(Greece’s preparation for Athens 2004 famously deterred tourists from
visiting the country due to widespread unease about congestion and
disruption).

There are feasible alternatives to the bloat, extravagance and wasteful

spending that comes with a modern Olympic Games. One option is to
designate a permanent host city that would be re-designed or built from
scratch especially for the task. Another is to extend the duration of the
Olympics so that it becomes a festival of several months. Local businesses
would enjoy the extra spending and congestion would ease substantially
as competitors and spectators come and go according to their specific
interests. Neither the “Olympic City” nor the extended length options
really get to the heart of the issue, however. Stripping away ritual and
decorum in favour of concentrating on athletic rivalry would be preferable.

Failing that, the Olympics could simply be scrapped altogether.

International competition could still be maintained through world
championships in each discipline. Most of these events are already held
on non-Olympic years anyway – the International Association of Athletics
Federations, for example, has run a biennial World Athletics Championship
since 1983 after members decided that using the Olympics for their
championship was no longer sufficient. Events of this nature keep world-
class competition alive without requiring Olympic-sized expenses.
Reading Passage 1

Time Travel

Time travel took a small step away from science fiction and toward
science recently when physicists discovered that sub-atomic particles
known as neutrinos – progeny of the sun’s radioactive debris – can exceed
the speed of light. The unassuming particle – it is electrically neutral,
small but with a “non-zero mass” and able to penetrate the human form
undetected – is on its way to becoming a rock star of the scientific world.

Researchers from the European Organisation for Nuclear Research (CERN)

in Geneva sent the neutrinos hurtling through an underground corridor
toward their colleagues at the Oscillation Project with Emulsion-Tracing
Apparatus (OPERA) team 730 kilometres away in Gran Sasso, Italy. The
neutrinos arrived promptly – so promptly, in fact, that they triggered what
scientists are calling the unthinkable – that everything they have learnt,
known or taught stemming from the last one hundred years of the physics
discipline may need to be reconsidered.

The issue at stake is a tiny segment of time – precisely sixty nanoseconds

(which is sixty billionths of a second). This is how much faster than the
speed of light the neutrinos managed to go in their underground travels
and at a consistent rate (15,000 neutrinos were sent over three years).
Even allowing for a margin of error of ten billionths of a second, this
stands as proof that it is possible to race against light and win. The
duration of the experiment also accounted for and ruled out any possible
lunar effects or tidal bulges in the earth’s crust.

Nevertheless, there’s plenty of reason to remain sceptical. According to

Harvard University science historian Peter Galison, Einstein’s relativity
theory has been “pushed harder than any theory in the history of the
physical sciences”. Yet each prior challenge has come to no avail, and
relativity has so far refused to buckle.

So is time travel just around the corner? The prospect has certainly been
wrenched much closer to the realm of possibility now that a major
physical hurdle – the speed of light – has been cleared. If particles can
travel faster than light, in theory travelling back in time is possible. How
anyone harnesses that to some kind of helpful end is far beyond the scope
of any modern technologies, however, and will be left to future
generations to explore.

Certainly, any prospective time travellers may have to overcome more

physical and logical hurdles than merely overtaking the speed of light.
One such problem, posited by René Barjavel in his 1943 text Le Voyageur
Imprudent is the so-called grandfather paradox. Barjavel theorised that, if
it were possible to go back in time, a time traveller could potentially kill
his own grandfather. If this were to happen, however, the time traveller
himself would not be born, which is already known to be true. In other
words, there is a paradox in circumventing an already known future; time
travel is able to facilitate past actions that mean time travel itself cannot
occur.

Other possible routes have been offered, though. For Igor Novikov,
astrophysicist behind the 1980s’ theorem known as the self-consistency
principle, time travel is possible within certain boundaries. Novikov argued
that any event causing a paradox would have zero probability. It would be
possible, however, to “affect” rather than “change” historical outcomes if
travellers avoided all inconsistencies. Averting the sinking of the Titanic,
for example, would revoke any future imperative to stop it from sinking –
it would be impossible. Saving selected passengers from the water and
replacing them with realistic corpses would not be impossible, however, as
the historical record would not be altered in any way.

A further possibility is that of parallel universes. Popularised by Bryce

Seligman DeWitt in the 1960s (from the seminal formulation of Hugh
Everett), the many-worlds interpretation holds that an alternative pathway
for every conceivable occurrence actually exists. If we were to send
someone back in time, we might therefore expect never to see him again
– any alterations would divert that person down a new historical trajectory.

A final hypothesis, one of unidentified provenance, reroutes itself quite

efficiently around the grandfather paradox. Non-existence theory suggests
exactly that – a person would quite simply never exist if they altered their
ancestry in ways that obstructed their own birth. They would still exist in
person upon returning to the present, but any chain reactions associated
with their actions would not be registered. Their “historical identity” would
be gone.

So, will humans one day step across the same boundary that the
neutrinos have? World-renowned astrophysicist Stephen Hawking believes
that once spaceships can exceed the speed of light, humans could feasibly
travel millions of years into the future in order to repopulate earth in the
event of a forthcoming apocalypse. This is because, as the spaceships
accelerate into the future, time would slow down around them (Hawking
concedes that bygone eras are off limits – this would violate the
fundamental rule that cause comes before effect).
Hawking is therefore reserved yet optimistic. “Time travel was once
considered scientific heresy, and I used to avoid talking about it for fear of
being labelled a crank. These days I’m not so cautious.”