BBC Knowledge Asia Edition

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What is the function

of the golden foil that

covers space probes?

Some people think that the gold foil is

there to block electromagnetic radiation and

to protect the electronics

on the spacecraft. But the function is actually

thermal. Without the foil, heat would readily

escape from the space probe into the

coldness of space. In return, the Sun’s heat

would fry the equipment. The foil consists of

several aluminium sheets, each contributing

to better insulation. Sandwiched between the

thin metal sheets is thermally opaque plastic

spacer. GM

The Deep Impact

space probe was

launched in 2005

Could there be stars

and planets made

from antimatter?

It is a possibility. One of the greatest

mysteries of modern physics is why the

Universe is composed almost entirely of

ordinary matter with only a tiny fraction

of antimatter. The Big Bang should have

produced the same amount of each.

However, it has been suggested that

different regions of the Universe could be

dominated by one or the other, although

how this might come about is also a

mystery, and there is currently no evidence

that this is the case. AG

Can facial recognition software

differentiate between identical twins?

Identical twins are a particularly stringent

stress test for facial recognition systems. So

when Windows 10 launched, some wondered

whether twins could fool Windows Hello, the

authentication feature that uses facial and iris

recognition. An Australian newspaper tested it

with six pairs of identical twins. Though hardly a

scientific sample, the system did pass the test.

This suggested that biometrics technology for

consumers is clearing some big hurdles.

When it comes to identifying faces,

humans are better at subjective judgments

like whether someone looks happy, sad,

angry or just a bit shifty. But computers beat

us on the quantitative side of things such

as measuring the relative dimensions of the

features on a face. Windows Hello is built on

Intel technology that combines a webcam,

infrared camera and infrared laser projector.

This three-pronged approach shores up the

system’s rigidity, even when confronted with

identical twins. GM

Even identical

twins can’t outfox

facial recognition

PHOTO: NASA X2, CORBIS, ALAMY X2, GETTY, SHAUN R GARNER