Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The Harvard Club of the Netherlandsinvites you to a popular lecture
by Nobel prize winnerProf. Dr. Gerard ’t Hooft
Science ≠ fiction
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Gerard ’t HooftUtrecht University
and
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007Cassini – Huygens mission
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Foundations ofModern Science
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
What modern science has taught us:
There are very strict rules
The rules can be derived from what is NOT possible:
● Energy is conserved: 1) No energy out of nothing2) No energy out of heat !
Unless there are temperature differences !
● All masses generate the same gravitational force
Anti-gravity is not possible !
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
● There are speed limits !
1) The speed of sound
2) The speed of light
Air: 344 m/secCopper: 3100 m/sec
Stone: 5971 m/sec
299 792 458 m/sec
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The speed of sound is approximately the limit of all velocities that can be obtained using chemical substances only:
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The Earth’s escape velocity isapproximately 11 km /sec
The exhaust velocity in most rockets is limitedby approx. 3 km/sec
To reach Earth orbit, you needabout 9 km/sec
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The same numbers are decisivefor the concept of a space elevator
The limiting factor is the strengthof a tether relative to its weight
It is expressed in terms of GigaPascal / specific weight, orNewton meter / kg
2 2Nm / kg kgm / sec m / kg (m / sec)
Steel: 154 kNM/kg = 392 m/sec ²
Nanotubes: 48,462 kNm/kg= 7 km/sec ²
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Consisting of carbon atoms only
Nano tubes
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The space elevator
tethered satellites
Catapulting spacecraft tohigher velocities
But never velocity differences much beyond the sound velocity of a few km / sec
Also the wheels of anautomobile would explode if you would drive faster than that ...
Applications of tethers:
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
To reach much greater velocities in space, you must use nuclear propellants (or solar energy if you can ...)
The characteristic velocities in nuclear reactions is one tenth of the speed of light ...
Freeman Dyson
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
A black hole
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Important restrictions:
Space travel: people will probably never be able to travel faster than approx. 1000 km/sec, a lot slower than light velocity ... !
“Space-warp” will remain fiction forever ....
Black holes are no “worm holes”
The mass would have to exceed 10 000 solar masses (so you can’t bring them along in your space ship), and even if ...
Communication and transport to other stars (than our sun) will remain
problematic.
Black hole diameter is proportionalto its massOne solar mass = 3 km.Velocity of light = 300 000 km / sec
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
What fantastic things can we still imagine without clashing with science ?
Information technology
Truly intelligent computers do not contradict any of our present knowledge –it is just difficult !
The IT revolution has only just started !
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The basic units in computer chips can still becomea lot smaller – and faster !
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Richard Feynman, 1959, APS CalTech:
“There is plenty of Room at the Bottom!”
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The information period has only barely begun
Computer software and hardware can become a lot better and faster
Computers can become intelligent, indeed a lot more intelligent than humans ...
Robots (automated machines, controlled by computers), may become tiny and universal, but:
if they are tiny, their vision will be very bad ... !
Moore’s Law
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Will NANO TECHNOLOGY determine our future?
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
A proteineand DNA
10 nm
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The Human
Genome
Genetic engineering offers fantastic possibilities in the future
Food
water
energy
space colonization
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
How will space be colonized ?
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The Solar System Can we go there ?
The Moon: 3 - 4 days Mars: 8 months
Asteroids: ~ 1 yearJupiter moons ~ 2 years ?Saturnus moons ~ 3 years ?
Then: Uranus, Neptune, etc. Pluto and beyond ?
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Our motives: curiosity and expansionism
But human colonization will onlyhappen if affordable !
SF authors perhaps underestimate:
the Media the Internet
To keep funding agencies interested
For essential information
remotely controlled machines (robots)
Human Colonization ...
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
The first colonies willbe small and under ground ...
Glass can be made onany planet
Ice is also a magnificent buildingmaterial
The Lunar hotel
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
John von Neumann:Robots can reproduce themselves.Robots can become semi-intelligent .
Self-reproduction and intelligence are not possible today
but not forbidden by science !
Neumannbots
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Travelling to the stars will take thousands or millions of years
But perhaps living oranisms can be spread and cultivated.
Humans of flesh and blood will not be interested in such long-lasting trips
To the stars ?
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Our science is also the science for intelligentcreatures elsewhere in the Universe
if these creatures exist at all, they will be subjectto the same limitations
therefore, we should not expect visits by creatures of flesh and blood
But their neumannbots might be able to reach us
they haven’t done so yet.
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Are neumannbots dangerous ?
Not if we adhere to some fundamental principles. Read Richard Dawkins
All “evolutions” must be orchestrated from one central point (on Earth)
Then all neumannbots will be genetically identical. They behave like termites. The “queen” stays on Earth.
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Cassini
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Atomic nucleus
electron
More than 10 000 x greater distance !
Matter as we know it: atoms
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007
Proton
Neutron
Quarks
Atomic nucleus
Harvard Club, Sociëteit de Witte, Den Haag, March 22, 2007