echidna

You've no idea how devastated that leaves me. Although at the same time I must thank you for breaking that rule to let me know.

I suppose it's an easier alternative to explaining why your consistently unsupported assertions aren't simply attempts at Cold Reading relying on the gullibility of believers. I mean it's not like we haven't offered you enough opportunities to demonstrate whether you're telling the truth or not ...

enrious

James Randi, in his book Flim Flam! points out four reasons why astrology is not science or anything other than make-believe.

1) The astrology symbols are arbitrary groupings of dots of light in the sky and given imaginative descriptions and shapes.

He reproduces a map of the night sky, with the various stars in them. He then challenges you to identify the various signs of the zodiac. He then points out how you can string together non "canon" stars to form other symbols, revealing the arbitrary nature of it. One man's scorpion is another man's Porche.

2) There's no scientific explanation for how the position of the stars can affect someone or how their position at the time of your birth could still have an effect.

This is further amplified by the fact that for most stars, where we see them in the night sky is *not* where they are today.

3) Assuming an argument were made that the stars (and planets) gravitational effect on you were the cause for such an effect, Randi points out something. If all of the planets and the sun were in perfect alignment with each other, and thus expected to exert the maximum gravitational effect on your body, do you know what it would take to counteract that effect using the Earth's gravitational effect on you?

Sit down.

Moving 12inches closer to the Earth is all that'd be required.

How much effect could the stars have on you again?

4) The arbirtrary nature is a clear indication of pseudo-science (or to put it another way, bullshit). There is no clear, consistent consensus of data for someone, using astrological methods.

By this, it's meant that if one person went to 10 seperate astrologers, the odds of the astrologers returning the same "diagnosis" does not exceed random chance.

And that's assuming they don't use equivicative/waffling language to hedge their bets.

Autonemesis

Yes yes, I know all that. It's still a con game. Come on, Volker, I know how to play it from your side. Think of me as a Junior James Randi when it comes to astrology. I know exactly what I need to do to be convincing with this happy horseshit. I bet I could fool every one of your customers into believing that a chart I made up out of whole cloth applies to them.

Shadowy Man

My understanding of astrology is that it is not the position of the stars that are important but the positions of the earth in its orbit and the positions of the planets relative to the earth. The stars just give a convenient backdrop to calculate these positions.

enrious

Yes, but even then they'd have to face the fact that the other planets do not affect us nearly as much as say...my laptop...or the table holding my laptop.

Shadowy Man

I don't believe in astrology, I'm an astrophysicist, but do yourself a favor and calculate the gravitational force on you by Jupiter at closest approach. I bet you'll be surprised.

enrious

Does it come close to the amount generated by the Earth?

Jesse

Jupiter's mass = 1.9 * 10^27 kg
Jupiter's distance from earth when the two are lined up: 6.3 * 10^11 meters

So, using the formula from Newtonian gravity, the force between a 1-kg mass on earth and Jupiter will be G*(1.9*10^27 kg)(1 kg)/(6.3*10^11 meters)^2 = (6.672*10^-11 Newtons meters^2 kg^-2)(1.9*10^27 kg^2)/(4.0*10^23 meters^2) = 3.2*10^-7 Newtons.

In comparison, the mass of the earth is about 6.0 * 10^24 kg, your distance from its center is about 6.4 * 10^6 meters, so the force on a 1-kg mass from the earth at its surface will be about 9.8 Newtons, about three million times larger.

If you have a 2000 kg car sitting 1 meter away away, the force on a 1-kg mass from the car would be 1.3 * 10^-7 Newtons, only about 2 1/2 times less than that of Jupiter.

Because of the way the equation for gravitational force works, the ratios between these different forces would be the same regardless of whether you use a 1-kg mass or, say, the mass of your own body.

edit: corrected a mistake in the value of G and the wrong answers for the forces that resulted

Lobstrosity

Wait, something's wrong here. gravitational acceleration on the surface of the Earth is approximately 9.8 m/s². The force on a 1-kg mass would then be F = ma = 9.8 kg m/s² = 9.8 N. You're off by two orders of magnitude, which seems to stem from the fact that the gravitational constant G is 6.672*10^-11 N m²/kg² (not 6E-13 as you state above). You comparisons should still be valid, however, as your error should cancel out when you take the ratios. In general I find it's better to talk about gravitational acceleration as opposed to gravitational force. All masses experience the same acceleration in a gravitational field, so why complicate things by making the scenario mass-dependent?

Jesse

Whoops, you're right about G...I got it from here but I must have copied it down wrong.