Imagination is more Imagination is more important than knowledgeimportant than knowledge

Knowledge is limited.Knowledge is limited. Imagination encircles the Imagination encircles the

worldworld

www.gsi.de/~wollewww.gsi.de/~wolle

The Brandenburg Gate at 95 percent of the speed of lightThe Brandenburg Gate at 95 percent of the speed of light

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Flight to Saturn with 99 percent of the speed of flightFlight to Saturn with 99 percent of the speed of flight

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Flight to the Eiffel Tower with 99 percent of the speed Flight to the Eiffel Tower with 99 percent of the speed of lightof light

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This video visualizes the apparent geometry only. This video visualizes the apparent geometry only. The observer is moving with 90 percent of the The observer is moving with 90 percent of the speed of lightspeed of lightwww.tat.physik.uni-tuebingen.de/~weiskopf/gallery

Flight of the Enterprise at 95 percent of the speed of lightFlight of the Enterprise at 95 percent of the speed of light

www.gris.uni-tuebingen.de/gris/proj/scivis.html

Edwin Abbott Abbott (1838-1926)Edwin Abbott Abbott (1838-1926)

Isaac Newton:Isaac Newton:„„clockwork universe“clockwork universe“

Albert Einstein:Albert Einstein:

„„space-time relation“space-time relation“

A sundial - Constant time ?A sundial - Constant time ?

Moving clocksMoving clocks

run slowrun slow

Relativity before EinsteinRelativity before Einstein

The train revisitedThe train revisited

The velocity of the ball The velocity of the ball relative to Dave is relative to Dave is 40 40 ft/sft/s

The velocity of Dave The velocity of Dave relative to Nolan is relative to Nolan is 50 50 ft/sft/s

So the velocity of the So the velocity of the ball relative to Nolan is ball relative to Nolan is 90 ft/s90 ft/s

The 300,000,000 meters, The 300,000,000 meters, relative to Dave, is not relative to Dave, is not really 300,000,000 meters really 300,000,000 meters relative to Nolan.relative to Nolan.

One second for Dave is not One second for Dave is not one second for Nolan.one second for Nolan.

As long as two persons remain at rest relative to each other, As long as two persons remain at rest relative to each other, both agree that each other´s clock tick-tocks at the same rate both agree that each other´s clock tick-tocks at the same rate as their own.as their own.

Time and moving clocksTime and moving clocks

Since the speed of light is constant, the person at rest Since the speed of light is constant, the person at rest thinks it takes longer for the moving person´s clock to tick-thinks it takes longer for the moving person´s clock to tick-tock than its owntock than its own

Time and moving Time and moving clocksclocks

Percentage of thespeed of light

Amount time isdilated by

10% 0.99520% 0.98030% 0.90040% 0.90850% 0.89360% 0.80070% 0.71480% 0.60090% 0.436

99.9% 0.045

The universal speed limitThe universal speed limit

Distances shrink in the direction of motionDistances shrink in the direction of motionMass (appears to) increase with speedMass (appears to) increase with speedNothing can travel faster than lightNothing can travel faster than light

The Doppler EffectThe Doppler Effect

As the police car approaches As the police car approaches the sound waves are the sound waves are compressed and the pitch rises.compressed and the pitch rises. As it recedes As it recedes the sound waves the sound waves are stretched and the pitch are stretched and the pitch decreases.decreases.

Relativistic Doppler and Searchlight Effects for v/c=0.1Relativistic Doppler and Searchlight Effects for v/c=0.1

v/C=0.0v/C=0.0

v/c=0.1v/c=0.1

scene aheadscene ahead

v/c=0.1 scene behindv/c=0.1 scene behind

Riding a tram at near-light speeds:Riding a tram at near-light speeds:

the head-light effect brightens the scene ahead and darkens the the head-light effect brightens the scene ahead and darkens the scene behindscene behind

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E = energy (measured in joules, J)E = energy (measured in joules, J)

m = mass (measured in kilograms, m = mass (measured in kilograms, kg)kg)

c = the speed of light (metres per c = the speed of light (metres per second)second)

chemical chemical energyenergythermal energythermal energykinetic energykinetic energy

If we use this energy to power a 100 If we use this energy to power a 100 Watt light bulb how long could we Watt light bulb how long could we keep it lit for?keep it lit for?

sun mass: 2 10sun mass: 2 103030 [kg] [kg]

75% hydrogen (75% hydrogen (HH), 25% helium ), 25% helium ((HeHe))

H -> He 7 10H -> He 7 101111 [kg/s] [kg/s]

energy output: 4 10energy output: 4 102626 [Ws] [Ws]

1,4 [kWs/m1,4 [kWs/m22] reach the earth] reach the earth

mass difference: 0,050 10mass difference: 0,050 10-27-27 [kg] [kg]

energy gain: 0,45 10energy gain: 0,45 10-11 -11 [J] [J]

energy gain: 28,3 [MeV]energy gain: 28,3 [MeV]

Typically, a uranium Typically, a uranium alpha decayalpha decay produces 4.3 MeV of produces 4.3 MeV of energyenergy

We can calculate the mass We can calculate the mass which has been turned into which has been turned into energy in accordance with energy in accordance with E=mcE=mc22

m=0.000,000,000,000,000,000,000,000,000,007,m=0.000,000,000,000,000,000,000,000,000,007,600 kg600 kg

Typically, in the case of Typically, in the case of 235235U U fission around 200 MeV of fission around 200 MeV of energy (0.000,000,000,032 energy (0.000,000,000,032 J) is released.J) is released.

A very tiny amount of A very tiny amount of energy?energy?

However, it is about a million times However, it is about a million times more energy than is released by more energy than is released by the burning of one molecule of the burning of one molecule of petrol (gas) in a car´s engine. petrol (gas) in a car´s engine.

Put another way, if you currently Put another way, if you currently use a tank of petrol each week but use a tank of petrol each week but could use the energy provided by could use the energy provided by one tank of one tank of 235235U fission instead, U fission instead, you wouldn´t need to refill your car you wouldn´t need to refill your car

for over 19,000 years!for over 19,000 years!

In case of In case of 1000 kg1000 kg of of 235235U fission a mass of 1 kg is released into U fission a mass of 1 kg is released into energy.energy.

E=9 10E=9 101616 J = 2.5 10 J = 2.5 101010 kWhkWh

2.8 102.8 1099 kg kg coalcoal is needed to produce the same is needed to produce the same energy.energy.

If we plunge through the tram, all of ist parts If we plunge through the tram, all of ist parts Terrel rotate independently making it appear to Terrel rotate independently making it appear to turn inside out.turn inside out.www.anu.edu.au/Physics/Searle