Tuesday, February 26, 2013

London Science Museum

Used the holiday for a short trip to London. More specifically for a short trip to the science museum! I was amazed at the number of authentic items on display!
My favourite:

The Apollo 10 command module. This baby really flew around the moon. It is on lone form NASA. Let me repeat: this baby flew around the moon! Actually!! Not a mock up!

The original mirror of the 44 foot telescope from William Herschel. And even better: I'm reflected in it...
An original V2 rocket... Need I say more?

A Cray 1 Supercomputer...

One million volt particle accelerator from 1937. Wow....

Sunday, February 17, 2013


The mass estimates have gone up from 10000 kg to 10000000 kg (see:. nasa website). This seems like an absurd update, but in size it means that the object was only 10 times bigger than previous estimates (10 to the power 3 = 1000).
This also means that the equivalent energy released could be as high as 250 kiloton TNT.

This is equal to 17 Hiroshima bombs...

Why did we not see more destruction?

Several factors:
1) The energy was not released in 1 go. It was released during its flight...
2) The energy was released somewhere between 10 and 30 km above ground...

Saturday, February 16, 2013

A big meteor fell from the sky in Russia. Could we do some calculations on it?
Yes we can!

Based on simple calculations I've estimated the amount of kinetic energy the object had to be around 1/4 kiloton TNT. So approximately 50 times smaller than Hiroshima. Still a respectable amount of energy.

In addition a simulation of the results if the rock was a little bigger & a little faster... (actually an order of magnitude)

Please note: above simulation assumes all the energy is released at once several hundreds meters above amsterdam. In reality the results will be far less devastating. 

Tuesday, January 1, 2013

Next followup on the LHC (CERN), Any bright ideas?

Just visited the Roque de los Muchachos Observatory on la Palma. Or basically had a look from afar on a bunch of telescopes!

The telescope above is the Gran Telescopio Canarias, it is the world's largest single-aperture optical telescope (source : wiki). 

Lots of other interesting scopes too (the one on pillars is a dutch solar scope!):

The most interesting one is the magic telescope!

It looks for Cherenkov radiation (the light you get when very fast particles travel trough a medium with a speed which is higher than the speed of light in that medium). Cherenkov radiation is the blue light you also see in the water of a nuclear power plant.

The speed of light was the highest possible? And it was constant? How could it be depended on the medium? Did Einstein screw up? 
No! The answer is: in a medium the light is "hopping" from atom to atom. More precisely from electron to electron. In between those hops the electron "holds" the energy of the light for a short moment. When it is released again it travels with the same speed of light we know & trust : c! But the average speed of light in a medium is lower than c because of the time the electrons keep hold of the energy...

The Cherenkov radiation is generated when particle showers are created by very powerful cosmic rays.

This brings me to the point of this post!
The Large Hadron Collider at CERN accelerates particles to high speeds. This increases the energy of the particles. When they collide with a particle going the reversed direction the released energy creates new particles. These new particles give insight in new physics. The ultimate goal is to develop a Theory of Everything. The higher the energy of the particles, the more insight into the working of nature it gives. The cost of building accelerators increases enormously with each new generation (which is capable of producing higher energy particles).

Now back to the Magic telescopes. Did you know that the energy contained in cosmic rays can be as high as 1020 eV?

Distribution of energies coming from cosmic rays (source: wiki)

Is that a lot?
YES, that is a lot.
The Large Hadron Collider at CERN is designed to smash two beams of particles (protons or lead nuclei) with resulting energies of 14 TeV.
Well surely that must be much more than a measly 1020 eV?

NO! It is more than a million times less than the energy of some cosmic rays!!!
The energies contained in the more powerful cosmic rays are so high that we could not reproduce this with current accelerator technology even if it was 100.000 times better!

So my guess is:
1) We are going to abandon the path of CERN and start looking more seriously at the sky..


2) We have to invent something drastically different to accelerate particles...
which should be possible because the total energy levels we are talking about are still relatively small 
Source wiki:
6.24×1020 eV: energy needed to power a single 100 watt light bulb for one second.   
The difficulty is in putting that small amount of energy in 1! particle

Happy New Year!!!!

Tuesday, December 18, 2012

Simulating light sources? Interference...

You could simulate a mirror as several point sources of light. I've made an excel to do just that.

What you basicly do is calculate the distance to the point sources for each point and see what the contribution in each point is for the wave originating in respectiv point source.

The Bean, a great kite...

Trying to build a great kite?

Here you can find the calculator to calculate the shape of the sails:

ISS & Moon simulation

A simple Excel sheet to simulate the movements of the moon and the ISS. Nothing fancy, almost no commentary...