Science Attack

Q: Dear 100 Hour Board:
(Continued from before)
3. Please explain in simple ways (so that we who are oh so stupid) why gravity is so weak and the 6 dimension.
4. Why are scientific books written in a demeaning and authoritative voice? They are really condescending as though they know all when in fact you get reading the book and there are so many questions unanswered. Do scientists think that if they right with absolute authority then they won't have to defend their theories?

Your Bro

A: Dear Bro,

Way to ask the scientific questions. I'll help you get down to the answers.
3. Gravity is somewhat mysterious, but can be explained and discussed in simpler ways. It doesn't need to be dark and scary. Gravity is actually very cool.
Gravitation is the realisation that all mass attracts each other. Gravity refers to the force some suppose causes gravitation. Why? What the 100 Hour Board can't answer is what exactly is the mechanism of gravity. Newton described gravitation as a force between two bodies - the force is gravity. This theory doesn't really work out perfectly, like for planets as an example. Einstein discussed the force as a bending of spacetime, and causing gravity as acceleration. This is a powerful theory but has some failures on the quantum level (i.e for really small particles). Quantum mechanics uses the theory that objects exchange gravitons (wave-particles, kind of like photons used in electricity) that cause a force of attraction (like two baseball players throwing balls back and forth). This is good too, but fails to completely describe things totally. So there is no perfect model for gravity.
What we do know is what we observe and how we approximate this in math. Several rules on the gravitational force: proportional to both masses (not weight - that's based on the pull of another mass), decreases proportionally to the inverse square of the distance (1/x^2) - ie. drops off quickly the farther you get away and is relatively weak compared to mass. The formula is Gravitational force = G x (m1 x m2) / d^2 (d is distance, m1 is mass 1 and m2 is mass 2). G is a constant that is calculated to fit (a smart guess) = 6.67 x 10E-8 dyne * cm2/gm2. Yes small! Electricity (and magnetism) have similar equations. But the constant for electricity is 1020 times larger than G. You can't compare them exactly, but to get anything strong with gravity you have to be close and one of the objects massive (ie. earth).
To let you know - electrons keep you from falling through the sidewalk when gravity is pulling you down! That's strong - b/c they are pretty tiny.
Why is this so? Can't really say - we don't totally understand. In quantum mechanics electrical forces are governed by spin 1 particles and gravity by spin 2 particles. Confused - so are physicists. If you can figure it out - unify forces - there is a Nobel prize for you. To make it worse, some people think that all forces are connected and actually stem from one electron that is wrapped around the universe millions of times. Freaky, huh?
Is the dimension a 2nd question? Because there are really 4 dimensions in classical relativity (3D in space and time). But millions of dimensions when you include other things (mass, brightness, electrical charge, etc. etc.) Just another way to describe things. nothing says that gravity is 'the 6th dimension.'

4. As for scientific books, I believe your question mostly stems from a matter of opinion - relative position. Let us understand about science. It is only theory. Science is based on observations, hypothesis and developing a model. It changes all the time. The best that can be said, is that current science is the best way we can describe life at this time. So no - any scientist that writes a book has no authority to be the end all authority.
But generally books are written for two audiences: the unscientific and colleagues. There are fantastic books written for 'unscientific' people, with calm, humble explanations for people who do not have all the background. Other books for colleagues generally are written with presupposed knowledge. If you read them and don't have this, it can come off condescending. But finally there is a phenomenon in scientific writing. A need to prove authority. Each writer is trying their best to show a 'bullet proof' theory, knowing their work will be heavily attacked by sceptics. Must they be condescending in their stance? No, but they usually are otherwise people will reject them. It's like trying to prove you are king of the jungle. So some good ones? The Universe on a T-Shirt (fantastic!), Brief History of Time and Universe in a Nutshell by Stephen Hawking, Brian Greene's works. There are some treasures there. So keep on reading.
100 Hour Board