30 SKYNEWS •SEPTEMBER/OCTOBER 2019
but those observations stretched over sev-
eral days, and even within that time frame,
there are hints that the target changed
subtly. Data obtained a year later are still
being analyzed. “We’re all chomping at the
bit to compare,” says Broderick.
Meanwhile, astronomer Daryl Haggard
at Montreal’s McGill University is poring
over reams of additional data gathered by
other instruments operating in conjunction
with the EHT. Her aim is to build up a
comprehensive picture of the centre of M87
at many wavelengths to help connect the
black hole image to other observations.
For example, as Haggard notes, M87 is a
source of frequent X-ray flares. In future,
it may be possible to correlate the flares to
changes that the EHT observes. Being able
to do so will help interpret observations of
more distant active galaxies and set the
stage for the EHT’s highly anticipated look
at the black hole residing at the centre of
our own galaxy.
The scientific potential of the EHT to
answer fundamental questions about black
holes, galaxies and gravity itself is enormous.
But it all starts by wringing as much infor-
mation as possible from this first historicportrait. As Haggard says, “It’s the most
gorgeous look at the microcosm around a
black hole that you can get. And we’re going
to be mining it for a while.” ✦Ivan Semeniuk is a science reporter for The
Globe and Mail newspaper and recipient of
the 2017 Simon Newcomb Award from The
Royal Astronomical Society of Canada.AROUND THE BENDLight rays coming from many directions are bent by the gravity of a super-
massive black hole and sent on parallel paths, as depicted in this illustration. For an observer, the effect
creates the appearance of a bright ring around a dark centre. ILLUSTRATION COURTESY NICOLLE R. FULLER/NSFBIG PICTURENo single radio telescope can
hope to resolve something as compact as the
region around a black hole in a distant galaxy.
Instead, the Event Horizon Telescope combines
data from a global network of observatories.
They create baselines stretching from Europe to
Hawaii and include radio dishes in Antarctica,
above, Arizona, Mexico and Chile, as shown in
the inset illustration. Longer baselines give the
network greater resolution on the sky. The South
Pole Telescope (pictured) is unable to image
M87 itself, but observations it provided were
still crucial to the project’s ability to obtain the
first image of a black hole. PHOTO COURTESY DANIEL
MICHALIK/SOUTH POLE TELESCOPE. DIAGRAM: ESO/L. CALÇADA