Technology

CAN high-resolution satellite

images increase international

pressure on Burma’s ruling junta?

After almost two weeks of

protests, led by monks, against the

dictatorship and at least 13 deaths,

it remains difficult to determine

what is going on. People used

the internet and cellphones to

transmit reports and photos,

but the junta responded by

cutting off internet access.

Now the American Association

for the Advancement of Science

Geospatial Technologies project

in Washington DC has requested

images from satellite companies.

Human rights groups will use

them to amass evidence of

violence used to quash protests.

They hope to deter the junta from

further atrocities and hold them

to account. “It will give them a

sense that the world is watching,”

says Lars Bromley of the AAAS.

A POSITION-finding device that

uses the Earth’s magnetic field

could take over from GPS when

no satellites are in view.

Because the angles at which

magnetic field lines intersect the

Earth’s surface are different at

every point on the planet, they can

be used for location. Previous

magnetic sensors were too large to

carry by hand and needed liquid

29per cent of Americans say they will not eat food that has been enhanced with ingredients engineered using nanotechnology

Using hydrogen to power vehicles

could free us from our reliance on fossil

fuels, and water is its obvious source,

but how to get one from the other? Now

a semiconductor has been discovered

that uses energy from sunlight to do

this efficiently.

The usual way to get hydrogen

from water is by splitting the water

molecules with an electric current, but

this is inefficient and expensive. For

years researchers have hoped to harness

sunlight to do the job , using a process

analogous to photosynthesis.

Some light-sensitive semiconductors

can do this, but they, too, are very

inefficient. Now Martin Demuth and

colleagues at the Max Planck Institute

for Bioinorganic Chemistry in Mülheim,

Germany, have found a solar-powered

water splitter that does this more

efficiently . It still uses only 4 per cent of

the visible light that hits it, but that is

double previous attempts, says Demuth.

What’s more, it absorbs the hydrogen it

produces, solving the problem of how

to store the gas once it is produced.

When Demuth’s team suspended the

semiconductor titanium disilicide (TiSi2)

in water and exposed it to lights that

simulate sunlight, they produced

hydrogen and oxygen (Angewandte

Chemie, DOI: 10.1002/anie.200701626).

Both gases were initially absorbed by

the TiSi2 but could be released by

heating. Because the hydrogen is

released at a lower temperature than

the oxygen, it can be extracted in pure

form using gentle heat.

“This may prove to be a significant

advance,” says photochemist James

Durrant of Imperial College London.

GREEN GAS MADE BY THE SUN

nitrogen to keep cool, but now

researchers at Virginia Tech in

Blacksburg have created a device

just 10 centimetres across ( Applied

Physics Letters, vol 91, p 12,3513 ).

At its heart is a piezoelectric

layer (PZT) stuck to a material

called Metglas, which changes

length in response to a magnetic

field. The Metglas pulls the PZT

with it, generating a voltage. Three

perpendicular sensors mean that

all components of the Earth’s

magnetic field can be combined

to give the angle of the field lines.

Games designed to relax their players can now be played on the go thanks to the

Personal Input Pod , created by Vyro Games of San Jose, California. Squeezing the

thumb-sized pod allows it to measure the electrical conductivity of your skin, which

increases with stress. The results are sent via Bluetooth to a phone running games

software. The higher the stress, the harder the game, encouraging you to relax.

IRobot, the Massachusetts-based maker of the robotic vacuum cleaner Roomba

and mop Scuba , has launched two more household robots. Controlled over the

internet, ConnectR roams the home and lets you point its webcam at the kids or the

cat to make sure things are OK. It also allows you to chat via its phone. Meanwhile,

remote-controlled Looj will clean your gutter, so you needn’t climb ladders.

GIZMO

Thru

st (

mil

lin

ewto

ns)

NEXT(NASA)

236 mN

92mN

70 mN

20 mN

NSTAR(NASA)

SMART-1(ESA)

Hayabusa(Japan)

250

200

150

100

50

0

RECORD-BREAKING ROCKET

The NEXT engine has set an endurance record

for ion motors by firing at 236 mN for 500 days

Kunimasa Hamaoka of Transcosmos, a Japanese company that has launched Meet Me, a buttoned-down, sex-free online world that is set in a virtual

version of Tokyo. Transcosmos is banking on the Japanese rejecting Second Life’s lawless, anything-goes culture (Associated Press, 27 September)

“Japanese people aren’t going to take to the culture of Second Life”

–If only they made hydrogen…–

PLA

INPI

CTU

RE

SOU

RCE

: W

OO

DR

OW

WIL

SON

CEN

TER

SOU

RCE

: N

ASA

, ESA

Burma, the whole

world is watching

Magnetic stand-in

fills GPS gap

www.newscientist.com 6 October 2007 | NewScientist | 29

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