John Dobson died in Burbank last week,
and when I read his obituary in the Los Angeles Times, I remembered him as the
first person to stun me with the size of the universe. My brief encounter with
him changed the way I see the world, influenced what I studied at university,
and it still affects me to this day.
Dobson
founded the Sidewalk Astronomers in San Francisco, an amateur group of
astronomers who built homemade reflective telescopes out of whatever they could
find, including gigantic cardboard shipping tubes, metal rings, and discarded
timber.
I saw the planet Saturn for the first
time through a Dobsonian telescope that was painted with whorls of bright
colors, on the roof the California Academy of Sciences in San Francisco. John
Dobson himself was hosting the viewing party, and I was twelve years old.
I
was interested in the cosmos, so my parents signed us up for a mid-winter,
mid-week astronomy class. Every Wednesday we’d get in the car and drive into
Golden Gate Park and attend a lecture at the California Academy of Sciences, in
the Morrison Planetarium. It’s a round theater with a raised platform in the
middle, on which stands a star projector, which recreates the stars of the
night sky on the domed ceiling above you.
The professor would speak --
This
is what the stars in the Northern Hemisphere look like on the first day of
summer...
--
And the machine would whir and click into place and project the exact array
of stars in the sky for that night. I would stare at the mechanical marvel in
front of me, and then stare at the projected stars above me, amazed by both.
To
this day, I still remember how to find the visible planets in the night sky,
and I know some of the secrets hidden in the constellations, like the middle
star in the three star dagger that hangs from Orion the Hunter’s Belt is
actually the Crab Nebula.
On
one moonless Wednesday night, the professor invited us to climb to the roof of
the Academy building, where the Sidewalk Astronomers had set up a 12-foot long
reflective telescope pointed at Saturn. I loved that we were allowed up there
on the tar and gravel, and I could see over a mile in every direction. I
remember that there were several astronomers up there, including Mr. Dobson
himself. He was a tall and lanky guy with glasses and long brown hair, sort of
a tall hippie version of Bill Gates.
It
was finally my turn to put my eye up to the lens. When I looked inside I saw
the planet Saturn, floating perfectly in black space. It looked like a
Kodachrome slide from science class, it looked so perfect. As I looked in the
lens, it seemed to be about as big as my thumb. The planet and its rings were
mostly black and white but there was yellow and brown mixed in, and it was in
sharp focus, and I could actually see the separate rings. I was convinced it
was a trick, and that the man had just stuck slide behind the lens
somehow.
This
is an approximate recreation of my conversation with Dobson, from several
decades ago:
Is
that really Saturn?
Yes,
it’s really Saturn.
It
looks like a picture. It’s so clear.
It’s
a clear dark night, and earth’s orbit is fairly close to Saturn’s right now.
How
close is that?
About
900 million miles.
How
far is 900 million miles?
I’ll
show you.
Dobson
then gestured for my parents and I to follow him close to the edge of the
building, which was about 600 feet long.
Imagine
that the sun is a ball about a foot in diameter, which is a little bit bigger
than a basketball, and we put it on the edge of the building. The earth is
about 100 feet away from that basketball, so that’s about 30 steps for me.
My
dad, my mom, and I then followed John Dobson as he walked his 30 steps, and we
were about 100 feet away the edge, and about a fifth of the length of the
entire building. John Dobson held up his fingers and made a pinching motion in
front of us.
This
distance is about the radius of earth’s orbit, about 93 million miles, and our
Earth is smaller than a pea.
We
were so stunned, that we could only giggle. He then pointed off into the
distance, past the building, and towards the dark trees of Golden Gate Park.
Saturn is about ten times further away,
which is almost twice the length of this building. It’d be in those trees over
there, and it’s the size of a small plum.
At
this point, I was beyond words. I stared into the trees in the distance,
imagining an orbiting plum out there somewhere. It didn’t seem conceivable that
a plum would feel the tug of gravity and orbit a basketball a thousand feet
away. Even more mysterious is how we, on our pea, could even see that plum. I
think he saw that he was blowing my mind, and he smiled and then launched me
into infinity.
And guess how far away the nearest star,
Alpha Centari, is?
I
shrugged.
It’s a beach ball in Japan.
To
this day, it’s hard to conceive of scale this way. When I read his obituary, I
fondly remember that night on the roof when John Dobson exploded my mind.
To explode your own mind, check out
this website, and enter in some numbers of your own to get a sense of the scale
of the universe. It’s courtesy of the Exploratorium:
I later
learned that the distances between the atoms in our body (when you increase
their electrons and nuclei to the size to plums and basketballs) are just as
vast and empty. Go big or small, most of the universe is empty. Yet there are
more cells in our bodies than in our own galaxy. They estimate we have 3.72 x
10(13) cells in our body (that’s 3,720,000,000,000,000 cells) and our galaxy
has about 10 (12) stars. However, our universe as 10 (12) galaxies, maybe more.
And if certain math and physics models are correct, there may be that many
“universes” beyond our own. We may be part of a multi-verse. That’s a lot to
think about, sitting on our tiny orbiting pea.
Around
the same time, I discovered what became another great influence on how I view
the universe -- Monty Python. Life is silly, and the more you embrace that, the
happier and wiser you will be. John Cleese and Michael Palin may be the
absurdist comic geniuses behind some of their best writing, but the composer
and lyricist for their best songs is Eric Idle. His Galaxy Song sums it up for me, and I have these words laminated and
pinned to the bulletin board in my office at home. It’s a constant reminder of
who I am, where I am, and how to put it all into perspective...like John Dobson
first did for me when I was 12 years old. Thank you John Dobson. Your sidewalk
astronomy lessons worked on me.
THE GALAXY SONG -- by Eric Idle and John
Du Prez
Just remember that
you're standing on a planet that's evolving
And revolving at
nine hundred miles an hour.
That's orbiting at
ninety miles a second, so it's reckoned,
A sun that is the
source of all our power.
The sun, and you
and me, and all the stars that we can see,
Are moving at a
million miles a day,
In an outer spiral
arm, at forty thousand miles an hour,
Of a galaxy we
call the Milky Way.
Our galaxy itself
contains a hundred billion stars;
It's a hundred
thousand light-years side to side;
It bulges in the
middle sixteen thousand light-years thick,
But out by us it's
just three thousand light-years wide.
We're thirty
thousand light-years from Galactic Central Point,
We go 'round every
two hundred million years;
And our galaxy
itself is only one of millions of billions
In this amazing
and expanding universe.
The universe
itself keeps on expanding and expanding,
In all of the
directions it can whiz;
As fast as it can
go, the speed of light, you know,
Twelve million
miles a minute and that's the fastest speed there is.
So remember, when
you're feeling very small and insecure,
How amazingly
unlikely is your birth;
And pray that
there's intelligent life somewhere out in space,
'Cause there's
bugger all down here on Earth!
Check out these two links on Mr. John
Dobson:
http://www.universetoday.com/108150/john-dobson-inventor-of-the-popular-dobsonian-telescope-dead-at-98/
No comments:
Post a Comment