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NEWS & TECHNOLOGY Cosy cosmic pair

VADIM SAVITSKY/RUSSIAN DEFENCE MINISTRY PRESS OFFICE/TASS/ALAMY LIVE NEWS may cause radio

repeat bursts

TWO of the most extreme and
mysterious objects in the universe
might be getting cosy. And they’re
being flashy about it. The only
repeating fast radio burst we have
seen appears to be coming from a
neutron star beside a huge black hole.
Fast radio bursts (FRBs) are
powerful radio signals that flare from
distant space for milliseconds and
disappear. Their source is unclear, and
we’ve seen fewer than 30, but one is
Swarm ofdrones Do-it-yourself bombs that were special: FRB 121102 keeps repeating.
loaded onto home-made drones
Jason Hessels at the Netherlands
Institute for Radio Astronomy and
attacks airbase programmes, including missile- his colleagues have taken detailed
launched anti-tank swarms,
measurements of the light from
air-launchedPerdixmicro-drones, FRB 121102 and found a twist that
the ship-launched LOCUST project indicates the source of the bursts is a
David Hambling 50 kilometres away and the and the Gremlins programme to small, fast-rotating object within an
drones were guided by GPS. This take out air defences. extreme magnetic field – like the ones
ON THE night of 5 January and would require the coordinates of However, the largest military around supermassive black holes.
into the early hours of the next the target to be known in advance. swarm to date has been a group of Some of the bursts were extremely
day, Russian forces in Syria The source of the attack isn’t 119 drones flown in a test by the short, lasting only a few tens of
came under attack by a“massive known. Because the drones are China Electronics Technology microseconds (Nature, doi.org/ch8c).
application of unmanned aerial home-made, they can’t readily Group Corporation in June 2017. The only thing in our universe we
vehicles”, says the Russian be traced. Islamic State, which has The idea behind such projects know of that rotates fast enough to
Ministry of Defence. It is the first no bases in the area, has used such is that large numbers of small, beam light towards us and then away
announced use of a swarm of drone-carried bombs, and other cheap drones could overwhelm again so quickly is a neutron star.
drones in a military action, insurgent groups in Syria and Iraq defences that depend on single The team also found that the radio
but is unlikely to be the last. have used similar drones. Israeli large jets or a small group of waves were undergoing a process
According to reports, 13 small military intelligence website missiles. Incidents in Iraq and called Faraday rotation, where a
drones descended on Russian Debka.com quotes a Syrian source Syria have shown that small strong magnetic field causes the
forces, but none did significant as blaming Hayat Tahrir al-Sham, drones are difficult to shoot direction of the waves’ polarisation to
damage. Seven were destroyed down with machine guns. twist as they move through the field.
by anti-aircraft defences, and “This is the first known Most missiles can’t lock on to Magnetic fields that cause this
electronic countermeasures instance of a significant drones because of their weak degree of Faraday rotation are rare.
such as hijacking or jamming swarm used in a radar and heat signature. There is Hessels and his colleagues think FRB
the drone’s controls were used military conflict” no single effective way to combat 121102 may be next to a huge black
to land the others intact. swarms, but there are many hole, the source of the strongest
The captured aircraft seem a group linked to Al-Qaida, and projects developing jammers and magnetic fields in the universe.
crudely made, with a wooden a Twitter image from 1 January other devices to detect, track and Strong magnetic fields can also
undercarriage and plastic shows al-Sham fighters with a bring them down. cause plasma lensing, in which highly
sheeting, and are powered by similar drone. Flying large numbers of drones magnetised material acts as a sort of
a small liquid-fuel engine. DIY drones have been used in requires sophisticated software to magnifying glass for nearby light. This
Under their wings, they carried concert before in conflicts, but avoid collisions. Such programs process could allow us to see bursts
locally made bombs fitted with only in groups of three to five. will probably be available that would otherwise be too dim. The
3D-printed plastic fins. For example, in Mosul, Iraqi commercially soon, though, effect could mean that FRB 121102
Many drones carry a video forces reported ISIS quadcopters because swarms are increasingly isn’t so special after all. It could be that
camera and are piloted remotely dropping grenades. The Syrian used for light shows. Crowds at the all fast radio bursts are repeaters,
from just a few kilometres away. attack is the first known use of Consumer Electronics Show in Las but their light isn’t being boosted by
But Russia says this attack was a more substantial swarm. Vegas were mesmerised by Intel’s lensing, so we only see the very
launched from more than The US has many drone swarm 250-drone show, for example. ■ brightest flash. Leah Crane ■

12 | NewScientist | 20 January 2018