New Scientist - USA (2019-10-05)

5 October 2019 | New Scientist | 17

Archaeology

Entomology Materials science

Gigantic planet

orbiting tiny star

Some 31 light years away,

a planet at least half the

mass of the gas giant

Jupiter is orbiting a star just

12 per as massive as our

sun. Modelling suggests

this world couldn’t have

formed around such a small

star in the way we think

most planets take shape

(Science, doi.org/db2p).

Coated paper can

store secret letters

Paper can now be turned

into a tool for spies by

adding a manganese

coating. Secret messages

that can be read only

under UV light are printed

on the paper using water.

Destroying any trace of the

message is a cinch too – the

recipient just has to blow it

with a hairdryer (Matter,

doi.org/db2r).

Male infertility

linked to cancer

A study of more than

35,000 men in Sweden

who had children via

fertility treatments

suggests that men who

need IVF to conceive have

a 33 per cent higher risk of

developing prostate cancer.

The risk was 64 per cent

higher in men whose sperm

had to be injected into

eggs, a treatment known

as ICSI (BMJ, doi.org/db26).

Clue to fall of ancient

society in vast halls

MYSTERIOUS megastructures in

ancient Europe were hubs of social

and political decision-making, but

their role in centralising control

may have doomed these societies.

The big buildings were part of

Tripolye culture, which spread

from modern-day Moldova and

Romania into Ukraine. Its large

settlements were each home

to up to 10,000 inhabitants.

These “towns” emerged

around 4100 BC and appear to

A RECENTLY discovered parasitic

wasp appears to have extraordinary

abilities – it can take over at least

seven other species.

It was thought that each species

of parasite could influence the

behaviour of only one host, or

at least only very closely related

species. For example, the

crypt-keeper wasp Euderus set

(pictured), which was only identified

in 2017, is known to parasitise the

gall wasp Bassettia pallida.

Gall wasps lay eggs in plants,

triggering abnormal growths called

galls inside which the larvae feed

and grow, eventually chewing their

way out of the gall. When Anna

Ward at the University of Iowa and

her colleagues looked at 23,

galls from 10 kinds of oak trees they

found that at least seven of 100

species of gall wasp they collected

were parasitised by E. set (Biology

Letters, doi.org/dbzq).

The crypt-keeper wasp seeks out

oak galls and lays an egg in them.

Its larva attacks a gall wasp larva

and takes control of it. Infected gall

wasps start chewing their way out,

but stop when the hole is small and

block the exit with their head.

When the crypt-keeper turns into

an adult after a few days, it chews

through the head of the gall wasp

to get out. MLP

have stopped being built around

3600 BC. Archaeologists recently

discovered megastructures up to

65 metres long and 10 metres wide

in a giant Tripolye settlement in

Ukraine, called Maidanetske, but

their purpose was unclear.

An analysis by Robert Hofmann

at Kiel University in Germany

and his colleagues has found they

occupied important positions, for

example open plaza-like spaces

(PLoS One, doi.org/dbzp). They

look like community centres that

serve several purposes in other

cultures, including economic and

political decision-making and

Hitch-free way to

make a liquid knot

FLUIDS are a little too slippery to be

tied in knots – but it can be done. A

special liquid has been coaxed into

knots that can then form crystals.

Earlier attempts to do this have

had trouble creating stable knots

or getting the knots to take on

a crystalline structure. Finally,

Jung-Shen Tai and Ivan Smalyukh

at the University of Colorado,

Boulder, have cracked it.

They started with a liquid

crystal. These can flow like a liquid,

but the molecules within them

line up in ordered arrays, instead

of being jumbled up as in a regular

fluid. Liquid crystals are already

used in some flat-screen TVs.

Then Tai and Smalyukh mixed

in chiral molecules, which have

an asymmetric “handedness” –

think of them like screws, which

can only be tightened by turning

them one way. The researchers

used electric fields to create little

whirlpools of these molecules,

which tied themselves into knots

and spontaneously assembled

into ordered lattices.

These are similar to existing

liquid crystal materials. They could

be used for storing information,

where different knots at various

locations have specific meanings,

or in very energy-efficient displays

(Science, doi.org/db25). Leah Crane

religious functions, says Hofmann.

But the team found a shift in the

Maidanetske structures over time.

Around 4100 BC, multiple smaller

versions existed, to cater to varied

segments of the community, says

Hofmann. Towards the end of the

Tripolye culture, only the largest

megastructures persisted. This

suggests that the collapse of these

town-like settlements by 3600 BC

followed strong centralisation of

decision-making, says Hofmann.

Maybe such centralisation was

dysfunctional or the population

didn’t accept that model of society,

he says. Ruby Prosser Scully

Grisly insect can control the

minds of many other species

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Really brief

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