"It isn't exactly Rocket Science" The artsy science of rocket propulsion
Rocket Science Rocket Science Dr. Martin Hendry Glasgow University Reach for the Stars.
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Transcript of Rocket Science Rocket Science Dr. Martin Hendry Glasgow University Reach for the Stars.
Rocket Rocket ScienceScience
Dr. Martin Hendry
Glasgow University
ReachReachfor thefor theStarsStars
To ISS: £20 million
To Elgin: £20
Isaac Newton
Isaac Newton Galileo Galilei
How do things move?….How do things move?….
Aristotle’s Theory:
1. Objects move only as long as we apply a force to them
2. Falling bodies fall at a constant rate
3. Heavy bodies fall faster than light ones
How do things move?….How do things move?….
Aristotle’s Theory:
1. Objects move only as long as we apply a force to them
2. Falling bodies fall at a constant rate
3. Heavy bodies fall faster than light ones
Galileo’s Experiment:
1. Objects keep moving after we stop applying a force (if no friction)
2. Falling bodies accelerate as they fall
3. Heavy bodies fall at the same rate as light ones
v
Aristotle’s Theory:
1. Objects move only as long as we apply a force to them
2. Falling bodies fall at a constant rate
3. Heavy bodies fall faster than light ones
Galileo’s Experiment:
1. Objects keep moving after we stop applying a force (if no friction)
2. Falling bodies accelerate as they fall
3. Heavy bodies fall at the same rate as light ones
How do things move?….How do things move?….
Aristotle’s Theory:
1. Objects move only as long as we apply a force to them
2. Falling bodies fall at a constant rate
3. Heavy bodies fall faster than light ones
Galileo’s Experiment:
1. Objects keep moving after we stop applying a force (if no friction)
2. Falling bodies accelerate as they fall
3. Heavy bodies fall at the same rate as light ones
vHow do things move?….How do things move?….
Apollo 15 astronaut David Scott
Newton built on Galileo’s work and proposed 3 laws of motion:
1. A body moves in a straight line unless acted on by some force
How do things move?….How do things move?….
Newton built on Galileo’s work and proposed 3 laws of motion:
1. A body moves in a straight line unless acted on by some force
2. The acceleration of a body is proportional to the force on it
F = ma
How do things move?….How do things move?….
Newton built on Galileo’s work and proposed 3 laws of motion:
1. A body moves in a straight line unless acted on by some force
2. The acceleration of a body is proportional to the force on it
F = ma
3. To every action there is an equal and opposite reaction
How do things move?….How do things move?….
Isaac Newton:1642 – 1727 AD
The Principia: 1684 - 1686
Every object in the Universe attracts every other object with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them
Law of Universal GravitationLaw of Universal Gravitation
So to get into space, we need a lot of energy, to overcome the Earth’s gravity
Gravity lets the Gravity lets the Earth hold onto Earth hold onto its atmosphereits atmosphere
Gravity lets the Gravity lets the Earth hold onto Earth hold onto its atmosphereits atmosphere
Above 30km Above 30km there is there is nono atmosphereatmosphere
The Space Shuttle burns Oxygen,Just like a car engine!
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Car engine burns petrol, releases chemical energy
Applies a force to turn the car’s wheels – they push against the road surface
The car moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Getting from A to B…..Getting from A to B…..
Aircraft engine burns petrol, releases chemical energy, turns turbines
These draw air into engine, which gets compressed and heated – pushed out with great force and great speed
The plane moves forward
Gravity lets the Gravity lets the Earth hold onto Earth hold onto its atmosphereits atmosphere
Above 30km Above 30km there is there is nono atmosphereatmosphere
Gravity lets the Gravity lets the Earth hold onto Earth hold onto its atmosphereits atmosphere
There is no air There is no air to push againstto push against
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
NASA
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed Oxygen
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
NASA
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed
Newton’s 3rd Law: rocket pushed forwards
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
NASA
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed
Newton’s 3rd Law: rocket pushed forwards
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
NASA
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed
Newton’s 3rd Law: rocket pushed forwards
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed
Newton’s 3rd Law: rocket pushed forwards
Rockets move because of Rockets move because of thethe Reaction Principle Reaction Principle
Rocket engines burn oxygen; exhaust gas pushed backwards at enormous speed
Newton’s 3rd Law: rocket pushed forwards
Rockets can operate in space
A rocket reaches orbit and no longer needs to burn any more fuel.
No net force on rocket
A rocket reaches orbit and no longer needs to burn any more fuel
No net force on rocket
A rocket reaches orbit and no longer needs to burn any more fuel
No net force on rocket
A rocket reaches orbit and no longer needs to burn any more fuel
No net force on rocket
Gravity exactly balanced by rotation force:
Weightlessness!!
Moon’s orbit
Earth
This same balance explains why the Moon orbits the Earth…..
….and why planets orbit
the Sun
Orbit of the Moon Orbit of the Moon
The gravity of the Sun and the other planets makes the Moon’s orbit appear like a giant ‘Hula Hoop’: one complete cycle takes about 18 years.
Moon’s orbit
Earth
But how does the Moon know to orbit the Earth?
Moon’s orbit
Earth
But how does the Moon know to orbit the Earth?
How does gravity act at a distance across space?
Gravity in Einstein’s UniverseGravity in Einstein’s Universe
Einstein’s theory of gravity was General Relativity,published in 1916
Albert Einstein (1879-1955)
Extension of Einstein’s 1906 Special Theory of Relativity
300,000 kms-1
The speed of light is:-
Albert Einstein (1879-1955)
Extension of Einstein’s 1906 Special Theory of Relativity
Gravity in Einstein’s UniverseGravity in Einstein’s Universe
Gravity and acceleration are equivalent
Gravity is not a force acting through space and time, but the result of mass (and energy) warping spacetime itself
Gravity in Einstein’s UniverseGravity in Einstein’s Universe
“Spacetime tells matter how to move, and matter tells spacetime how to curve”
Gravity in Einstein’s UniverseGravity in Einstein’s Universe
vDifferences between Newtonian and Einsteinian
gravity are tiny, but can be detected in the Solar System – and Einstein always wins!
Hydrogen fusion – fuelling a star’s nuclear furnace
E = mc 2
H = HydrogenHe = Helium
Nuclear fusion is also the energy source in hydrogen bombs.
If we could control the energy release from fusion, it would make excellent rocket ‘fuel’
Nuclear fusion is also the energy source in hydrogen bombs.
If we could control the energy release from fusion, it would make excellent rocket ‘fuel’
But the thrust would be insufficient to ‘lift off’ from the Earth
Nuclear fusion is also the energy source in hydrogen bombs.
If we could control the energy release from fusion, it would make excellent rocket ‘fuel’
But the thrust would be insufficient to ‘lift off’ from the Earth
The ISS could be the launch pad for the fusion rockets of the future
Hydrogen fusion – fuelling a star’s nuclear furnace
E = mc 2
H = HydrogenHe = Helium
Solar sailing:
Using sunbeams to explore the Solar System
The stars are VERY far away. The nearest star (after the Sun) is about 40 million million km from the Earth. It takes light more than 4 years to travel this distance.
If the distance from the Earth to the Sun were the width of this screen, the next nearest star would be in Rome.
Einstein’s RelativityEinstein’s Relativity
Matter causes space Matter causes space to to curvecurve or or warpwarp
Gravity in Einstein’s UniverseGravity in Einstein’s Universe
‘Black Hole’: warps spacetime so much that even light can’t escape
Warping spacetime Warping spacetime
Wormholes in spacetime predicted by theories of quantum gravity, but these are unimaginably tiny, and unstable. How do we fit a spaceship through a wormhole?……
Could we use
To hold open wormholes?…