skyandtelescope.com • NOVEMBER 2019 29eration is not cheap,” he says. “The science we can do can be
pretty incredible if we can fi nd a way to pay for it.” With PFI’s
resolution, astronomers could not only watch planets form,
but they could also see dust circling behemoth black holes in
other galaxies.
As for stars, researchers would no longer be limited to
nearby giants. Their vision could even extend beyond our
galaxy. Paladini says that PFI would allow her to study a star
like Pi^1 Gruis in the Magellanic Clouds, which are roughly
340 times farther away than Pi^1 Gruis itself.
But some interferometer plans are aiming even higher
— literally. “My dream interferometer would be in space,”
Roettenbacher says. Here, each telescope would get its own
spacecraft. A fl eet of these craft, relying on laser-based guid-
ance to maintain precision formation, would collect starlight
and focus it into a central mother ship, where the light from
the separate scopes would be combined. This fl otilla would get
above the blurring effects of Earth’s atmosphere and could be
quickly reconfi gured to meet science needs.
NASA has been tossing the idea around for nearly two
decades, but other missions keep stealing the spotlight. How-
ever, Ken Carpenter (NASA Goddard), who has been push-
ing for a space interferometer since the early 2000s, remains
optimistic.
“You have to go to interferometers at some point, because
you can’t make... telescopes large enough to do all the stuff
that you want to do,” he says. The next generation of inter-
ferometers, whether on the ground or in orbit, could reveal
details about many types of stars in various stages of their
lives. Those details could in turn put the Sun in context and
help astronomers better predict solar activity that meddles
with life and the environment on Earth.pCHILEAN BEAMS This illustration of the Very Large Telescope Inter-
ferometer in Chile shows light from the four 1.8-m Auxiliary Telescopes
(which are movable) traveling through tunnels to be combined in the
central laboratory. Astronomers can mix and match up to four ATs or
8.2-m Unit Telescopes (larger structures shown) as an interferometer.“It’s not just an abstract goal of understanding how stars
work,” says Carpenter. “It can actually have an impact on life
and the habitability of planets.”
Ultimately, all astronomy research is part of a quest to
understand where we came from and where we’re going.
Today’s fuzzy glimpses at the surfaces of stars may be just the
fi rst steps of a new generation of observatories that brings the
universe — and our place in it — into much sharper view.¢CHRISTOPHER CROCKETT is an astronomer-turned-sci-
ence-journalist who dabbles in theater production with his wife
(and three fur children) in the wilds of Washington, D.C.DELAY LINES The Very Large Telescope Interfer-
ometer in Chile moves mirror systems along under-
ground tracks to correct for differences in starlight’s
arrival time at each telescope in the array.
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