<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Good for science, as I love science, but sometimes, it has a little bit different dialect, sometimes. What would you say if there was no moon for earth? That is why I think, gravity is something like alive. It can move, relocate, manipulate physical features here on earth. If there was no gravity, from earth and moon, we'd see no tides. <br /> Posted by Aaupaaq</DIV></p><p>Gravity isn't alive -- in fact, gravity is remarkably constant. It doesn't change. Every bit of matter has a gravitational field. I think that's really cool, quite honestly.</p><p>Science doesn't have a different dialect, exactly, but it is clear that there is a language barrier here. I know English is not your first language, and would guess that your first language is something like Inupiaq, which is pretty darned cool too. ;-) Still, the concepts should apply.</p><p>Science is a discipline, not a set of beliefs or understandings. Science is a means of systematically exploring the world around us. It means not just running off on a tangent about any old thing. It means formulating questions as concrete, precise hypotheses which can be tested, and then testing them. After testing them, we either adjust the hypotheses and retest, or we discard them and start anew with a totally different hypothesis. The process repeats again and again, indefinitely. The advantage is that it helps us guard against mistakes and self-deception (which all humans are prone to).</p><p>Now, as to gravity and magnetism....</p><p>Gravity is the property of any two objects to attract one another. They attract one another with a force proportional to the product of their masses, and inversely proportional to the square of the distance between them. What causes gravity to be is not clear, but we can definitely observe the action of gravity, and so far it has been totally consistent with that basic law of gravitation. Gravity is the weakest of the known forces, but on large scales has really amazing effects, such as gravity lensing.</p><p>Magnetism can seem superficially similar, especially since it also obeys the inverse square rule (the force is inversely proportional to the square of the distance from the thing generating the field) but it's much more powerful. Take fridge magnets. Their magnetic fields are enough to stick themselves to most metals. But you can't stick them to a tree, or other non-magnetic surface. Their *gravitational* fields are absolutely insignificant, completely overwhelmed by more powerful forces.</p><p>You mention "what if there were no moon?" Scientists have long pondered that question. The ocean tides are not the only thing we'd lose. Tidal interactions between the Earth and Moon have slowed the Earth's rotation over the past few billion years, and it's also helped stabilize the Earth's axial tilt. It's hard to say for sure what life would be like without the Moon, and even whether or not there would *be* life on Earth. But things would definitely be very different. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>