The Economist - USA (2021-02-20)

The Economist February 20th 2021 Science & technology 67

L

ike electriccars, electric boats are

not a new idea. In the early 1900s Clara

Ford preferred driving her electric car

around Detroit instead of one of the

noisy gasoline-powered Model Ts her

husband Henry had begun making.

Around the same time, posh electric

launches cruised silently along the River

Thames in Britain, using dockside stop-

offs to top up their batteries with elec-

tricity and their bars with champagne.

These days, thanks to worries about

climate change, electric cars are making

a comeback (in eco-minded Norway, they

account for more than half of new cars

sold). Now electric boats are following. A

number of manufacturers are vying to

become the marine equivalent of Tesla,

the Californian company which builds

some of the most fashionable and fastest

electric cars.

Rand, a Danish firm, has developed a

range of traditional-looking electric

motorboats. Zin Boats, a Seattle-based

company, has two electric models, a

tender and a five-seater speedboat. For

more leisurely cruising, Serenity Yachts,

a Cayman Islands boat-builder, offers a

19.4-metre hybrid with 30 solar panels on

the roof. In electric mode the panels will

power the craft along at a steady pace

provided, of course, the sun is shining.

Candela, a Swedish company, is tak-

ing a different approach. Its six-seater

Candela Seven (pictured) uses hydrofoils

to raise its hull completely out of the

water. This reduces friction, says Gustav

Hasselskog, Candela’s founder. That, in

turn, cuts energy use by around 80%,

which should help reassure any skippers

with range anxiety.

The hydrofoils also operate like the

ailerons on an aircraft’s wing. Computer

software similar to that which helps

pilots fly jet fighters automatically turns

the foils in different directions to stabil-

ise the boat and prevent it from tipping

over. The hydrofoils can be retracted

when the boat comes into dock or runs

up to a beach. 

With a top speed of 30 knots (56kph)

and little wake, the Candela Seven can

also be used for waterskiing. So far, 20 of

the 30 speedboats ordered have been

delivered. At €265,000 ($322,000) a pop,

this shows early adopters of electric

motorboats, like the buyers of the first

Teslas, are happy to pay premium prices.

Electric sailing

Of batteries and boats

A new generation of electric craft take to the water

Mixing water and electricity

an ancestor of the iconic woolly mam-

moth. It appeared to possess many of its

descendant’s features half a million years

earlier, suggesting the woolly mammoth’s

distinctive physiology evolved more slow-

ly than had been thought.

These are the sorts of insights into the

slow workings of evolution that very an-

cient dnacan offer. And, it seems, pro-

spects for collecting more such ultra-old

samples are good. Permafrost has existed

on Earth for the past 2.6m years. That puts

an upper limit on the age of sequenceable

dna, but one that still leaves a million

years more headroom. “I’m sure that in the

permafrost there are going to be samples

that have survived longer,” says Patricia

Pecnerova of the Swedish Museum of Nat-

ural History, and a co-author on the study.

Records, after all, are made to be broken. 

Sleep research

The interpretation

of dreams

D

reams areclearly important. All hu-

mans have them, as do animals from

cats to elephants. Neuroscientists believe

they are involved in the processing of me-

mories. Yet studying them is limited by the

fact that dreamers themselves cannot talk

to anyone while they are asleep. Research-

ers must rely on the unreliable recollec-

tions of people who have woken up. Now,

though, a team of scientists led by Ken Pall-

er, a neuroscientist at Northwestern Uni-

versity, think they may have found a way

around that problem.

Dr Paller's starting point was the fact

that lucid dreams—in which sleepers are

aware they are dreaming—seem to be asso-

ciated with only one kind of sleep, known

as "rapid eye movement" (rem) sleep. Dur-

ing remsleep, brain activity looks similar

to that seen during waking hours. Past re-

search has shown that it is possible for

people to be influenced by events taking

place in the outside world during rem

sleep. So Dr Paller speculated that it might

be possible to reach out to people in such

states, and to get answers back.

As described in Current Biology, Dr Pall-

er, along with colleagues in France, Germa-

ny and the Netherlands, gathered 35 volun-

teers. All were trained to be mindful of

their mental state, and to analyse whether

they thought they were awake or in a

dream. In some labs (though not all) that

training was accompanied by a distinctive

sound. That same sound was repeated, as a

cue, while the participants were in rem

sleep. Participants were also trained to

make distinct left/right eye movements to

indicate they were aware they were dream-

ing, and in response to questions. They

practised interpreting numbers conveyed

as flashes of light, taps on their arm, or

even as spoken words.

Thus prepared, the volunteers were

wired up with electrodes and sent back to

the land of Nod. Sometimes the research-

ers would initiate contact with their

dreamers by playing the sound cue and

waiting for an eye signal in response. At

other times, the participants themselves

sent an eye signal of their own accord.

Once it was clear that contact had been

made, the researchers asked their ques-

tions, and waited for answers.

Interviewed upon waking, the partici-

pants reported that the questions had been

incorporated into their dreams. One said

an audio question was heard through a car

radio; another that flashes of light sent by

the researchers manifested as a flickering

light. One of the numerical questions even

manifested as the street number of a

house. Intriguingly, participants occasion-

ally “remembered” a mathematics prob-

lem different from the one they had been

asked—despite having given the correct

answer, via eye movements, at the time.

The method often did not work. Partici-

pants signalled that they were engaged in

lucid dreaming in just 26% of the sessions.

Of that group, 47% answered at least one

question put to them correctly. But it

proves a point. Dr Paller and his colleagues

say their findings refute the notion that at-

tempting communication with dreamers

is pointless. And that, in turn, may help re-

searchers shed some light on what dreams

are for, and how they work. 

Dreamers can be asked questions.

Some will even give answers