stronomers have spotted 13 more of these
extragalacticlightflashes,knownasfastradio
bursts(FRB),andthenewhaulincludesthe
second repeating FRB ever discovered. “Knowing that
there is another [repeater] suggests there could be more
out there,” said Ingrid Stairs, an astrophysicist at the
University of British Columbia. “And with more sources for
studywemaybeabletounderstandthesecosmicpuzzles
–wherethey’refromandwhatcausesthem.”
FRBsarebriefbutincrediblypowerfulphenomena;the
millisecond emissions are energetically comparable to
thetotaloutputofourSunoveracentury.But,asStairs
noted, FRBs are as enigmatic as they are spectacular.
Astronomershaveofferedanumberofpossible
explanationsforthebursts,includingmergingneutron
stars and advanced alien civilisations. The discovery
team analysed observations by the Canadian Hydrogen
Intensity Mapping Experiment (CHIME), an advanced new
radiotelescopeinBritishColumbia'sOkanaganValley.Yet
thetelescopewasn'tevenfullyupandrunningwhenit
made the new detections.
AstronomersnowknowthatFRB“sourcescanproduce
low-frequency radio waves. Those low-frequency waves
canescapetheirenvironmentandarenottooscattered
to be detected by the time they reach the Earth,”
CHIMEteammemberTomLandeckersaid.“Thattells
us something about the environments and the sources,’
Landeckeradded.“Wehaven’tsolvedtheproblem,butit’s
several more pieces in the puzzle.”
Mysterious deep-space flashes
uncovered
ikethevastmajorityofstarsinourMilkyWay
galaxy, the Sun will eventually collapse into a
whitedwarf,anexoticobjectabout200,000-
timesdenserthanEarth.Toputthatinperspective,a
mere teaspoon of white dwarf material would weigh
about as much as an elephant if you could somehow
transport the stuff to our planet.
Half a century ago theorists predicted that white
dwarfs solidify into crystal over time – and new
research has found that this is indeed the case.
“All white dwarfs will crystallise at some point in
their evolution, although more massive white dwarfs
go through the process sooner,” study lead author Pier-
Emmanuel Tremblay, a physicist at the University of
Warwick in England, said. “This means that billions
of white dwarfs in our galaxy have already
completed the process and are essentially
crystal spheres in the sky,” Tremblay added.
“The Sun itself will become a crystal white
dwarf in about 10 billion years.”
Tremblay and his colleagues analysed
data gathered by the European Space
Agency's Gaia spacecraft which launched
in December 2013 to help researchersconstructthebest-ever3Dmap of the Milky Way. Gaia
does this by precisely monitoring the positions of huge
numbers of stars; the mission team aims to study 1
billion stars over the spacecraft's operational lifetime.
“Thisisthefirstdirectevidence that white dwarfs
crystallise, or transition from liquid to solid,” Tremblay
said. “It was predicted 50 years ago that we should
observe a pile-up in the number of white dwarfs at
certain luminosities and colours due to crystallisation,
and only now this has been observed.”Sunwillturnintogiant
crystalballafterdeath
A
L
Words by Mike Wall
Words by Mike WallThe first
FRB was
discovered
back in 2007(=(03()3, (;
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