Ridley Scott, eat your heart out.
Like
terrified moviegoers seated on the edges of their seats and at the
mercy of their imaginations, astronomers expect this week to finally see
the monster: a supermassive black hole.
At
9 a.m. Eastern Time on Wednesday April 10, a group of astronomers who
run a globe-girdling network of radio telescopes called the Event Horizon Telescope are
expected to unveil their long awaited pictures of a pair of putative
black holes. One of the objects sits at the center of the Milky Way
galaxy, buried in the depths of interstellar dust and gas, and
equivalent in mass to 4.1 million suns that otherwise have disappeared
from the visible universe.
The
other target is in the heart of Messier 87, a giant galaxy in the
constellation Virgo, where a black hole 7 billion times the mass of the
sun is spewing a jet of energy thousands of light-years across space.
According
to calculations, and if all has gone well, either or both of the black
holes should appear as a tiny shadow backlit by the glow of radio energy
at the galactic center.
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They
might be circular, oval or some other shape entirely, depending on
whether they are rotating, or if the Einsteinian equations describing
them are slightly wrong, or if they are spitting flares of energy, which
is how quasars produce fireworks visible across the universe.
If,
in fact, astronomers have finally brought the monsters into view at
last. The Event Horizon team has been extremely tight-lipped. Nobody
knows for certain if either of these black holes, if any, has been
imaged.
Shep Doeleman, director of
the Event Horizon Telescope, was ebullient but guarded when reached last
week at the Harvard-Smithsonian Center for Astrophysics. “The team is
working exceptionally hard to quadruple-check all the results,” he said.
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But
he and his colleagues are acting as if they have something to
celebrate. The announcement of their results will take place
simultaneously in six places around the world, reflecting the vast
international nature of the collaboration. One news conference, at the
National Press Club in Washington, D.C. will be presided over by France
Córdova, head of the National Science Foundation. The team and their
friends have booked the National Air and Space Museum for a party that
evening.
The
European Southern Observatory’s La Silla facility in the Chilean
Atacama Desert. Scientists have measured stars in the heart of the Milky
Way, above, traveling much faster than anywhere else in the galaxy,
evidence of a black hole 4 million times the mass of our sun.CreditESO/B. Tafreshi
Image
The unveiling will take place almost exactly a century after images of stars askew in the heavens
made Einstein famous and confirmed his theory of general relativity as
the law of the cosmos. That theory ascribes gravity to the warping of
space and time by matter and energy, much as a mattress sags under a
sleeper, and allows for the contents of the universe, including light
rays, to follow curved paths.
General
relativity led to a new conception of the cosmos, in which space-time
could quiver, bend, rip, expand, swirl like a mix-master and even
disappear forever into the maw of a black hole.
To
Einstein’s surprise, the equations indicated that when too much matter
or energy was concentrated in one place, space-time could collapse,
trapping matter and light in perpetuity.
Einstein
disliked that idea, but the consensus today is that the universe is
speckled with black holes waiting to vacuum up their surroundings. Many
are the gravitational tombstones of stars that have burned up their fuel
and collapsed.
Any lingering doubts
as to their existence vanished three years ago when the Laser
Interferometer Gravitational-Wave Observatory, or LIGO, detected the collision of a pair of distant black holes, which sent a shiver through the fabric of space-time.
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Since
then, other collisions have been recorded, and black holes have become
so humdrum that astronomers no longer bother sending out news releases
about them.
Nonetheless, astronomers are thrilled at the prospect of finally, actually seeing the previously unseeable.
“Yes,
I’m definitely excited to see the image!” Daniel Holz, of the
University of Chicago, wrote in an email. “It’s not really rational,
since I know the math works and the theory has been thoroughly tested.
But still, this would be a picture of the real thing, up close and
personal. That is super cool.”
Priyamvada
Natarajan, a Yale astrophysicist who is not part of the project, said,
“It’s exciting, even just technically, to get this up close and personal
to a black hole.”
Especially when
the black hole is no run-of-the-mill stellar corpse, but one of the
behemoths that crouch in the centers of galaxies and direct cosmic
weather, launching thunderbolts across thousands of light-years.
Even
if the new images do not overthrow relativity, they will be invaluable
as astronomers’ first glimpses into the hearts of these entities and the
way they generate cosmically catastrophic energies.
The
center of the Milky Way, 26,000 light-years from Earth, coincides with a
faint source of radio noise called Sagittarius A* (pronounced A-star).
By tracking the orbits of stars around this hub, astronomers have
calculated that whatever sits at the center has the mass of four million
suns.
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But
it emits no visible or infrared light. If this is not a black hole, no
one knows what it could be. The only way to be sure is to peer through
the haze and record the shadow of oblivion.
Which
is no small job. According to the standard Einstein calculations, a
black hole with the mass of 4.1 million suns would be only about 24
million miles wide — a tiny area to observe clearly from this distance.
Luckily, the black hole’s gravity will magnify it to appear twice that
size. But discerning even that is like trying to spot an orange on the
Moon with the naked eye.
It takes a
big telescope to see something so small. Enter the Event Horizon
Telescope, named for a black hole’s point of no return; whatever crosses
the event horizon falls into blackness everlasting. The telescope was
the dream-child of Dr. Doeleman, who was inspired to study black holes
by examining the mysterious activity in the centers of violent radio
galaxies such as M87.
By
combining data from radio telescopes as far apart as the South Pole,
France, Chile and Hawaii, using a technique called very long baseline
interferometry, Dr. Doeleman and his colleagues created a telescope as
big as Earth itself.
The network has
gained antennas and sensitivity over the last decade. In April of 2017,
the network of eight telescopes, synchronized by atomic clocks, stared
at the Milky Way center and at the giant galaxy M87 off and on for 10
days.
Astronomers have taken the last
two years to reduce and collate the results. The data were too
voluminous to transmit over the internet, and so had to be placed on
hard disks and flown back to M.I.T.’s Haystack Observatory, in Westford, Mass., and the Max Planck Institute for Radio Astronomy, in Bonn, Germany.
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The
data from the South Pole could not arrive before December 2017, Dr.
Doeleman said, “because it was Antarctic winter, when nothing could go
in or out.”
An
image made from data from the European Southern Observatory’s extremely
sensitive Gravity instrument, showing gas swirling at 30 percent of the
speed of light in a circular orbit around a black hole.CreditAgence France-Presse — Getty Images
Image
Last
year the team divided into four independent groups to assemble images
from the data dump. To stay objective and guard against bias, the teams
had no contact with each other, Dr. Doeleman said.
In
the meantime, the telescope kept growing. In April 2018, a telescope in
Greenland was added to the collaboration. Another observation run was
made of the Milky Way and M87, and captured twice the amount of data
gathered in 2017.
“We’ve hitched our
wagon to a bandwidth rocket,” Dr. Doeleman said. The new observations
won’t be included in Wednesday’s reveal, but they will allow the
astronomers to check the 2017 results and to track changes in the black
holes as the years go by.
“The plan
is to carry out these observations indefinitely,” said Dr. Doeleman,
embarking on his new career as a tamer of extragalactic beasts, “and see
how things change.”
Dennis
Overbye joined The Times in 1998, and has been a reporter since 2001.
He has written two books: “Lonely Hearts of the Cosmos: The Story of the
Scientific Search for the Secret of the Universe” and “Einstein in
Love: A Scientific Romance.” @overbye
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