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December
31, 2001 | Very early on a cold February morning in 1979
I looked with one of my highly astigmatic eyes through my first
professional telescope at a setting Jupiter. Even with my flawed
vision, the long white metal tube so finely manufactured it could
have been a piece of sophisticated medical equipment, let the cloud
bands of our solar system’s largest planet and the bright points
of a handful of its moons into my mind, making me feel a shadow
of the shock that Galileo must have felt when he saw the same sight
before any of us. The instrument belonged to a scientist visiting
to photograph the total solar eclipse that would be happening when
the sun and moon came up later that morning.
Twenty years later almost to the day, on Galileo's 435th birthday,
the European Southern Observatory flew me to Cerro Paranal in Northern
Chile to get a first hand look at the most important telescope in
the world – the VLT – Very Large Telescope. The name implies
that there is just one telescope, but actually the VLT is a system
of four cooperating telescopes (Five if you count the Hubble Space
Telescope which frequently acts as a finder scope for the more powerful
VLT.) Each of the four VLT unit telescopes has a primary mirror
of 8.2 meters. There is a system of interconnecting tunnels under
the telescopes that allow light to be collected from the four separate
telescopes and combined as if they were one 16 meter telescope –
making the VLT the largest optical telescope in the world.
If everything went well, my new job would be to become an intergalactic
taxi driver, "driving" the VLT wherever in the universe
an astronomer might wish to go.
My first stop at Paranal was the canteen, where the first words
out of the mouth of Roberto Gilmozzi, then the head of VLT Science
Operations and now Director of the observatory were, "Have
you heard about OWL?"
The VLT was still under construction, yet I could see the gleam
of the next telescope in the visionary eye of the VLT’s future
director. OWL, Gilmozzi told me, was short for "OverWhelmingly
Large," though he now prefers "Observatory at World Level."
The OWL will be the ultimate ground-based telescope, and at a mere
$1 billion a bargain of 1/3 the cost of the Hubble. This 100 meter
fully steerable skyscraper will be able to operate on the margin
between, and will be the first with a real chance of penetrating,
the barrier between astronomy and biology.
OWL will be able to detect and measure the spectra of extrasolar
planets directly, looking for signs of life. Its 100 meter segmented
primary mirror will have more collecting surface than every telescope
ever made combined. It will consist of about 1600 separate mass-produced
primary mirror segments, each segment financed, according to one
plan, by a different visionary corporation or individual. It will
subtract the effect of atmospheric turbulence with sophisticated
high speed computer controlled active optics systems, effectively
putting it in space. If the current plan holds, we could see the
OWL a reality before 2020.
Of course, while the OWL is still on the drawing board, some scientists
have their eye on the construction of something grander still –
a still nameless space telescope that works using the gravity of
the sun to bend and concentrate light instead of a mirror or lens.
The first account of the deflection of light by gravity was written
in 1804 by Johann Soldner - a German geodesist, mathematician and
astronomer then working at the Berlin Observatory. More than a century
later in 1913 Albert Einstein contacted the director of the Mt.
Wilson Observatory, George Ellery Hale, and asked him whether it
would be possible to measure positions of stars near the sun during
the day in order to establish the deflection effect of the sun.
Of course it was possible, but it would have to wait until the end
of World War I for Arthur Eddington to travel to the island of Principe,
and confirm the deflection of starlight near the sun during what
is now considered the most important total solar eclipse in history.
Eddington’s measurements helped confirm Einstein’s theory
of relativity and change our view of the universe.
At about 550 AU (Astronomical Units) from the Sun - 550 times the
mean distance between the Earth and the Sun - or about 51 billion
miles, lies the inner boundary of the solar foci. The solar foci
is a sphere surrounding the Sun where it's gravity focuses all electromagnetic
radiation passing it to a resolution beyond anything possible with
human engineering. One current plan for a mission to the solar foci
calls for a highly autonomous, 400 metric ton spacecraft (Hubble
is 11.2 metric tons) to be assembled in low Earth orbit and would
use nuclear electric propulsion to cruise for the years it will
require to leave the solar system and approach the solar foci.
Nuclear Electric Propulsion, in case you were wondering, uses a
nuclear reactor to produce large amounts of electrical power which
is used to run low thrust electric propulsion rocket engines. One
specific example of such a propulsor is an ion engine, which works
by electrically accelerating ionized fuel to tens of thousands of
meters per second. The high exhaust velocity translates into a high
fuel efficiency. And ion engines are simple – something very
important for a probe that has to operate so far from Earth. So
simple in fact, that a reasonable model can be constructed at home
using television tube parts by a junior high school student –
I know.
To give you an idea of how large the distances involved are, consider
that Voyager 1 - the most distant human artifact - was launched
in 1977 and has been heading out of the solar system at more than
38,000 miles per hour ever since. As of November 2001, Voyager had
only made it out to 130 AU. Fortunately, even a small telescope
placed at the solar foci would out perform any traditional terrestrial
or space telescope, including OWL. Such an instrument would be able
to not only take spectra of extrasolar planets, but also image large
surfaces features such as oceans, continents or ice caps or even
the impact of civilization on such features.
But how realistic is an OWL or a solar foci probe?
In November of this year, the European Southern Observatory successfully
tested adaptive optical systems capable of detecting and removing
atmospheric distortion, creating a virtual vacuum column above Cerro
Paranal and thus proving a key technology required by OWL. And just
a few days ago, NASA successfully concluded its test of Deep Space
1, the first space probe ever to fly with an ion engine under control
of artificial intelligence. The only real question for OWL is money,
and the only one for the solar foci probe other than money, is the
controversy surrounding placing a nuclear reactor in orbit.
We have the technology. Time and money and will, will do the rest.
All three giant telescopes, the VLT which I am now privileged to
drive, the OWL, and the unnamed solar foci probe, would have been
impossible for me to extrapolate from the reality of a cold February
morning in 1979. I can't help but wonder what will be the astronomical
vision on Galileo's birthday in 2020.
As always, the opinions expressed here are my own, and not necessarily
that of the European Southern Observatory.
Copyright 2002, Chris McKinstry
bio:
Chris
McKinstry is a Canadian living in Chile where he operates
the world's largest optical telescope for the European
Southern Observatory. He is also the creator of the Mindpixel
Digital Mind Modeling Project, the world's largest AI effort.
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