eyes wide to long-discussed mysteries.
What are the processes by which the
twisting magnetic fields caught in such
maelstroms manage to expel, in powerful jets, a portion of the shattered stars,
planets, dust and gas drawn toward the
black hole’s grasp? Does a black hole
even behave as theory suggests? By witnessing extreme gravity at work — from
hundreds to hundreds of thousands of
times stronger than gravity at Earth’s
surface, slowing time and warping space
so that even photons can go into orbit
around a black hole — humankind might
see behavior that does not obey the predictions of the general theory of relativity. It would mark the first refutation of
Albert Einstein’s theory, and would offer
guides toward more complete, truer laws
of the universe.
The group has given its dream
machine a name: the Event Horizon
Telescope. The hope is to put it in operation some time around 2020.
“It would only cost a few tens of millions of dollars, not really so much at all,”
says Sheperd Doeleman of MIT’s Haystack Observatory. Doeleman and 22 of
his colleagues last year sent a white paper
to a National Research Council committee that listed, as part of a decadal review,
priorities for public astronomy funding
(SN: 9/11/10, p. 10). Compared with the
billions of dollars for space telescopes
and the hundreds of millions for large
conventional devices on the ground,
the price is small change. In August, the
Event Horizon Telescope was included
by the review committee in a list of
smaller but worthy projects. That is no
Signals that span the globe
Through a process called very long baseline interferometry,
the event horizon Telescope would combine data from more
than a dozen instruments operating in sync around the world,
from arizona to spain to the south pole.
guarantee federal agencies and Congress
will actually provide any or all of its costs,
but so far, so good.
This Arizona dish will operate alongside
others in the Event Horizon Telescope.
One scope from many
For the money, the project promises
the highest resolution in the history of
astronomy. It would bring distant objects
into focus 5,000 times more clearly than
the Hubble Space Telescope can.
Makers of telescopes have two basic
ways to get a very sharp focus and thus
the ability to see small details at great
distance: Make the telescope wider (or
the distance greater between instruments that make up the overall device)
or shorten the wavelength at which it
operates. Better yet, do both.
Astronomers proposing the telescope
plan to use the whole Earth as a plat-
form. And because of a fortunate break,
one specific class of telescopes already
spread out widely on the planet can oper-
ate at just the right wavelengths — from
0.8 to 1. 3 millimeters — between the far
infrared and microwave regions. This
narrow window of radiation not only
can provide the focusing power needed
for a telescope of such size, but is also
where the environs of black holes glow
the brightest. Earth’s mountaintops
and mesas where the observatories sit
are just high enough for the select wave-
lengths to arrive before atmospheric
water vapor absorbs and distorts them.