On Mar 26, 9:22 am, Bill <
brogers31...@gmail.com> wrote:
> On Mar 26, 8:21 am, T Pagano <
not.va...@address.net> wrote:
> > On Sun, 25 Mar 2012 16:41:46 -0700, John Harshman
> > <
jharsh...@pacbell.net> wrote:
> > >T Pagano wrote:
> > I find it hard to believe that Harshman doesn't think one medium sized
> > star (our Sun) can't be balanced considering the billions upon
> > billions of other masses in the ENTIRE Universe. The Milky Way Galaxy
> > alone has 100 billion stars. And Broccoli offered this wonderful
> > graphic of the Universe's super clusters:
> >
http://en.wikipedia.org/wiki/File:Superclusters_atlasoftheuniverse.gif
> > Notice in the graphic that the Virgo Super Cluster is in the center
> > where the Earth happens to be. The graphic depicts clusters of
> > galaxies surrounding the Earth with each galaxy containing approx 100
> > billion stars. And Harshman thinks it stretches credulity that all
> > that can't balance out one medium sized star in the Milky Way?
> > Pleeezzze.
> Indeed, Pleeeze, Tony. The rest of the stars in the Milky Way cannot
> possibly balance out the gravitational effect of the Sun on the Earth.
> Not even close. There are perhaps 400 x 10^9 stars in the Milky Way.
> The Milky way is about 100,000 light years in diameter. So, for ease
> of calculation, assume that
> (1) the average mass of each of those stars is equal to 10 times the
> mass of the sun (biasing things in your favor)
> (2) all of the mass of all of those stars is piled up at a point
> exactly opposite the sun and 50,000 light years away.
> Note that 50,000 light years is about 3 x 10^9 times farther from
> earth than is the sun.
> Therefore the gravitational force exerted by all those 400 billion
> stars would be
> 400 x 10^9 x 10 / 9 x 10^18 or about 4 x 10^-7, about 4 ten-millionths
> of the gravitational force exerted on the earth by the sun.
> Not even remotely strong enough to balance out the gravitational force
> of the sun.
> And pay attention to all the ways in which I biased the calculation in
> your favor. I assumed all the stars in the Milky way are 10 times as
> massive as the sun. I used a linear average of the distance based on
> the diameter of the Milky Way, rather than weighting it according to
> the inverse square law. Most importantly, I assumed that all of the
> mass of all the stars was collected at a point opposite the Sun - in
> reality, many of the stars will be on the same side of earth as the
> sun. The gravitational pull of the rest of the universe cannot account
> for the alleged orbit of the Sun around a fixed Earth.
> And, Tony, you need to balance out the gravitational effect of the
> sun, if you want the earth to stand still. You can invoke the Center
> of Mass until the cows come home, but unless you think Newton's law of
> gravitation is incorrect, you'd better find some actual mass to cancel
> out the gravitational force of the sun on the earth. The stars in the
> Milky Way don't come close. The galaxies further out are too far away
> and too symmetrically distributed to help you.
Let me add one thing. Perhaps you think the total mass of the
universe
would be enough. Nope. Not even close.
The estimate of the mass of the universe, including the dark matter
on
which you like to heap scorn, is about 6 x 10^52 kg or about 3 x
10^22
solar masses.
The diameter of the universe is on the order of 40-50 billion light
years.
So, lets take ALL of that mass, and pile it up at a point a mere 10
billion light years from the earth and sun, much closer than most of
it is on average.
10 billion light years is about 6 x 10^14 times the distance between
the earth and the sun. So the gravitational force of all the mass in
the universe piled up 10 billion light years away would be -
3 x 10^22/ 3.6 x 30^29 or still less than one ten millionth of the
gravitational force exerted on the earth by the sun.
And remember, this assumes that the entire mass of the universe is
conveniently piled up right where it would be most effective in
balancing the gravitational force from the sun.
Swoooooosh.