[ExI] Discontent with the path physics is taking

[Kelly Anderson]

On Wed, Aug 17, 2011 at 2:03 PM, Adrian Tymes <atymes at gmail.com> wrote:
> On Wed, Aug 17, 2011 at 12:56 PM, Kelly Anderson <kellycoinguy at gmail.com> wrote:
>> While it's cool that the math for CAT scans was worked out in the
>> 1920s, would it have hurt if they had waited to develop it until the
>> 1970s when they needed it?
>
> 1) What else was it used for in the mean time?

Nothing, that I am aware of.

> 2) Would the last little bits that came together in the 1970s, have
> come together if the math hadn't already generally been out there
> from some time previous?

The preexisting math was discovered after the idea of reconstruction
from slices was considered, as I understand the story. The CAT scan
was patented in 1975, just as computers were beginning to become
powerful enough to do the reconstruction. Indeed, according to
Wikipedia... "At the time, Hounsfield was not aware of the work that
Cormack had done on the theoretical mathematics for such a device."

Additionally, "In terms of mathematics, the method is based upon the
use of the Radon Transform invented by Johann Radon in 1917. But as
Cormack remembered later,[29] he had to find the solution himself
since it was only in 1972 that he learned of the work of Radon, by
chance."

So the work of Radon had zero effect on the invention of the CAT scan,
even though the work had been done much earlier.

Similarly, there is no evidence that Darwin was aware of the work of
Mendel (according to Dawkins), but the two ideas were combined
sometime around 1905... even though the work with the peas predated
Darwin's publication of the Origin of Species.

-Kelly