40 Chapter 1 Is Earth the Center ofthe Universe?
A Heliocentric Model Was Proposed 2,300 Years Ago
The Grk scholar Aristarchus,
whowas born in the third century BC
(the era after Aristole), first tried to
explain the universe with a geocentric
th eo ry.
Aristarchus (about 310230 BC)
Ancient Grk astronomer and
mathematician
However, as he continued
to make observations,
this theory smed to
have one problem...
He noticed that the
waxing and waning of
the Mn oued
because of the angle of
the light from the Sun.
What do
you mean?
Like this!!!
Stop it!
For example, when
there is a half mn,
the Sun is shining
from a location that
is aroximately at
a right angle to
the mn, relative
toearth.
Bam!
A Heliocentric Model Was Proposed 2,300 Years Ago 41
It lks
like this.
Oh!
As long as we know this
angle, we can determine
the exact relationship
betwn the distances
from earth to the
mnand the sun.
cLEVER!
Gloria...that
was amazing!
Thanks! I’m prey
gd at math.
Aristarchus had the
same idea, and he
determined this angle
to be 87°.
It is actuay
89.8, but he did the
best he could do with
the observational
technology of
thosetimes.
What's
going
on?
Okay, but how are
the positions of
the Mn and Sun
related to...
...a geocentric
or heliocentric
model?
Let's take it
one step at
a time...
How dierent in
size do the Sun
and Mn aear
to be?
They lk
about the
same.
You can prey much
hide each of them with
one finger.
That's right. They
both aear to be
aroximately the
same size, from
ourperspective.
Based on this
fact, lets make
our diagram a bit
more aurate.
You mean redraw
the diagram using a
protractor?
Yes, that's
right.
A Heliocentric Model Was Proposed 2,300 Years Ago 43
Earth
Squeak
Let’s s,
this is
Earth...
And here is
the Mn.
Since the Sun is
oset from the
Mn by 90°, with
an interior angle
of 8...
Squeak
Huh?
Ack, there's
not enough
paper
Squeak
Yamane! More
paper!
Wi two
shts be
enough?
The lines are sti
almost parael!
Earth
Ha
What's the
maer?
Mn
Mn
44 Chapter 1 Is Earth the Center ofthe Universe?
I always s
things through, no
maer what may
stand in my way!
I' plot a
course to the
Sun by drawing
this line at the
spd of light!!
Iencountered a
staircase along
the way, so I didn't
make it a the way
to the sun. Miion
aborted, sir.
We, now you
should clean
up the marker
you drew
everywhere.
You made
a great
eort...
But you can use
trigonometric
functions to obtain
a ratio of the
lengths of the
triangle’s sides,
instead of drawing
a huge diagram.
Did you
hurt
your
head?
What?
Quit it!
Shut up!
Reporting
in, sir!
Bump
Bump
Bump
Crash!
F
w
o
o
o
s
h
!

Get The Manga Guide to the Universe now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.