Everything is relative(or maybe not)

How physics changed our human perspective

Dap Hartmann

1 meter =• (1927) Length of the platinum ‘standard meter’ (at 0°C and 1

atm)accuracy: ?

• (1960) 1,650,763.73 wavelengths of the 605 nm Krypton-86 spectral line accuracy : 0.005 – 0.01 µm (10−8)

• (1983) Distance that light travels in a vacuum in 1 ⁄ 299,792,458 seconds

accuracy : 0.1 nm (10−10)

Length is relative

1 second =• (1956)   1 ⁄ 31,556,925.9747 of a ‘tropical year’

1 second is 1/60 of a minute 1 minute is 1/60 of an hour 1 hour is 1/24 of a day 1 day is 1/365.242347 of a year

= 365 days, 5 hours, 49 minutes and 1.114 seconds.

• (1967) 9,192,631,770 periods of a Cesium-133 hyperfine

transition = atomic clock

Time is relative

{Train: 100 km/h (w.r.t. the

observer) -5 km/h (w.r.t. the passenger)

Passenger: 5 km/h (w.r.t. the train)105 km/h (w.r.t. the observer)

Velocity is relative

5 km/h

100 km/h

Advantages of its finiteness:• Looking back in time

Disadvantages of its finiteness:• (Super) Computers• High Frequency Trading• “Hello, we are HERE!”

TV transmission of the 1936 Olympic Games in BerlinContact (1985) : Vega is at a distance of 25 light years.

• Interplanetary communicationAstronaut on Mars, 270 million km (= 15 light minutes)

from Earth

Speed of Light

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1 gram of matter is equivalent to 9 x 1013 J25 GWh

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