Bah, humbug! ;-] Was: Re: [OT] Happy Holidays

[Colin Law]

On 26 December 2010 08:15, Dotan Cohen <dotancohen at gmail.com> wrote:
> On Sun, Dec 26, 2010 at 01:44, Cybe R. Wizard
> <cyber_wizard at mindspring.com> wrote:
>>> Newton is a unit of force, not mass!
>>>
>> But his seminal work involves forces existing between and affecting
>> masses, the alternate meaning of which [1] may come to involve the
>> entire world in the future.
>>
>
> Er, not really. Light has no rest mass, yet gravity affects it. Though
> I contend that it wasn't until Einstein that we knew that.

The fact that it has no rest mass is irrelevant as it is not at rest.
It has mass and therefore gravity affects it.

>
> I don't think that Newton really did think that gravity is a force
> that affects only objects with mass, though. He was heavily into the
> what we would call "black majic" and that is what led him to believe
> that one object could affect another without touching it. Considering
> that "black magic" was the impetus for the discovery of gravity, and
> that his particular form of "black magic" considered objects other
> than tangible objects as physical objects, it stands to reason that it
> was not the mass that Newton was concerned with as causing the
> gravity.

What Newton thought at the time does not change the fact that his
seminal work _did_ involve forces between masses.  He may not have
thought in quite those terms but we now know that that is what he was
dealing with.

Colin