newearthscience©2012

How do you travel to the Moon?

No!

To take a trip to the Moon,

one must first imagine it.• And as you will recall, that’s just what

Kepler did—back in 1593. But it would take another 16 years to come to full realization.

• Now read the first item in your packet—Die Somnium. Answer the two questions at the end of the reading. You may be asked to share out your thoughts after 7 minutes.

Final Question for All

• How did Kepler propose one actually got to the Moon?

• Yeah, not very realistic. But, what else could he imagine?

Enter Sir Isaac Newton• Now turn the page of your packet. Examine this VUE of Newton’s influences.

This VUE is available on our website. Feel free to add to your VUE.

Want Moon? Find Rules.

• Actually getting to the Moon would eventually require powerful engines and great advancements in chemistry as well as physics.

• But for the anyone to imagine such a trip was actually possible, the physics had to come first.

• How to do it? Simply invent a new physics.

New Rules

• Newton first took Galileo’s inclined plane experiment and combined it with Kepler’s Laws of Planetary Motion.

• Knowing that the Universe seemed to behave not by some random whim of a spirit being, but of knowable and steady rules (perhaps according to a creator), Newton realized that all moving objects obeyed…

Three Laws of Motion

Newton: Laws of Motion

1A body at rest or in motion at a constant speed along a straight line remains in that state of rest or motion unless acted upon by an outside force.

Newton’s Laws of Motion

2The change in a body’s velocity due to an applied force is in the same direction as the force and proportional to it, but is inversely proportional to the body’s mass.

F = m a

F/ m = a

Newton’s Laws of Motion

3 For every applied force, a force of equal size but opposite direction arises.

Newton’s Laws of Motion

© 2004 Pearson Education Inc., publishing as Addison-Wesley

Newton’s Universal Law of Gravitation

Isaac Newton discovered that it is gravity which plays the vital role of determining the motion of the planets - concept of action at a distance.

…and seriously freaked some people out.

So, what was gravity?• For Newton’s contemporaries, it seemed a very

troubling prospect, almost like a form of “magick”. How could the action of one physical body affect another without them ever touching?

• Still, it became a law. Scientific laws tell us what nature will do given certain variables. A law also implies that you will get the same answer every single time you run the experiment or conduct the observation.

• Every. Single. Time.

What about the theory of gravity?

• Theories tell us why something happened. A theory will explain the essential nature of the phenomena being investigated.

• Laws are the rules by which theories operate.• "Two objects always attract in direct proportion of

their masses and in inverse proportion of the square of the distance between them."

Newton’s Universal Law of Gravitation

Between every two objects there is an attractive force, the magnitude of which is directly proportional to the mass of each object and inversely proportional to the square of the distance between the centers of the objects.

To Go to the Moon

• Requires you to pull away from the pull of the Earth’s gravity.

• Turns out, that requires a lot of power unknown in Newton’s time.

• Yet, he wrote the equation that would stipulate the amount of energy or force, required.

OK, Go!

Now, the tricky part!• How do you slow down or lose acceleration?• Use Newton’s Third Law.• It’s the same principle you use in a car.

Apply the brakes. But in a spaceship you must use the same kind of engines that got you off the Earth but now aim them down towards the mass of the Moon that is pulling you in.

• You must slow down from 23,000 mph to 0 mph in just the right amount of time.

• Or you die.• And if you’re Neil Armstrong, no one has

EVER done this before you. Good luck with that.

Calling Isaac Newton…• But hey Neil, if Newton was right

THREE HUNDRED years ago, you have nothing to worry about, eh?

• When you arrive, will you see with your flesh and blood eye what Kepler saw in his mind’s eye all those centuries ago?

Video of Lunar Excursion Module

(LEM) (LM)

• The mission of Apollo 11 would be the first in all of human history to land on another world.

• The rules of the voyage were written by Newton some 300 years before Apollo 11.

• Your astronomy teacher was 10 years old when it happened.

• Yes, it was just as exciting as you might think it was for him.

OK, now the videos• First,

testing to know that the engineering married the physics.

• Second, Neil Armstrong, in FAIL.• Step One.• Step Two.• Step Three. Ok, now you take if from

here. Next slide…

Now, it’s your turn, Johannes Kepler!

• What Kepler could not have known but Newton discovered, was that if one could precisely measure the force that held planets in place, one could leave Earth and fly and land on the Moon.

• For real.• Now, go to the simulation on this

week’s webpage and try your hand at landing on the Moon. Your lab procedure packet will be your guide.