©Planeterrella The polar light simulator
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First to Sixth grade

On the morning of Friday, May 4th, we went to the IPAG (Institute of Planetology and Astrophysics of Grenoble). There, we met Jean. He explained what he had made with his colleagues by replicating and improving the Terrella invented by Kristian Birkeland between 1896 and 1917. This is a magnetized sphere in a vacuum chamber with a pump that sucks air.
It was making light as aurorae. No other light was permitted otherwise it did not work.
It was very interesting and beautiful to see.

The Planeterrella is an auroral simulator. We had a presentation by video projection at the Institute of Planetology and Astrophysics of Grenoble.
These lights are curtains of colored lights which are formed by the magnetic fields of the sun falling into the Earth’s atmosphere. They are common in a rather dark night.
Finally, we were given to a demonstration. In a bell jar, one encloses two metal spheres and the vacuum is created inside. One sends to each a magnetic field and there is the creation of a light.
We can therefore create auroras.

The Planeterrella is an auroral simulator. It was created using the Birkeland Terrella which had a flaw: the planets were suspended and because of the strength of magnetization, they could touch, stand out and break. At IPAG, they found a way to rectify this: by putting them on pedestals. It is also found, by dint of research, a planet similar to Earth and also that 90% of global warming on Earth was due to man.

The solar wind is the power sent by the sun to the planets who receive it. Earth has an atmosphere that prevents the solar wind to hit it. The solar wind is transformed into light called aurora borealis and aurora australis in the north or south, or polar lights if we talk about the north and south.
There are 350 Northern Lights in Lapland against 2 in Saint Martin D’Heres.
As I do orienteering, I also held that the compass does not show the geographical but magnetic north.

I loved the visit to the IPAG as we were shown to experience the aurora with magnets as auroras are made through magnetism. There is an auroral oval at the South Pole and the North Pole.
We also learned that a compass shows the magnetic north pole.

We saw an aurora borealis simulator called Plannetterella. Jean has two spheres in a small jar without air. He also showed us that when he put the gas, that forms the Northern Lights. And he showed us a film where there is the place where Jean watches the aurora borealis.

We learned that the aurora showed themselves when it is dark, moonless. Apparently there are 350 in Lapland every year.
The Professor has made an experiment to show how Kristan Birkeland made to understand the mechanism of polar auroras. He made the same demonstration as K. Birkeland had made.
So he went to Lapland several times for this magnificent spectacle of nature.
To return to the experiment, it was fascinating, so I’ll explain: there were two spheres of different sizes. At times, the small sphere was a planet, and a small electric nozzle a star. You could see through the "solar wind" auroral oval to the north and south.
With the compass, he explained that it showed not really the north, but magnetic north.
Towards the end, he gave us a brochure "Planeterrella." There were photographs inside an observatory watching the northern lights, photographs of the experience. So we were left spellbound.

We left to the IPAG in Grenoble, we have seen images of the aurora borealis and Jean told us that the bears did not know how to go up on the stairs. He showed us two spheres in a jar without air in the dark. Then auroras appeared on the spheres. The tour ended at 11:30. Then we took the bus back to school.

I retained when the man said that the inventor was wrong in suspending the ball. But he almost was right. Tilting the electron gun with my little ball, it made a ring around the small ball.

I liked when he told us how the aurora borealis were created. He also explained that the sun produced light and electricity. It is called the solar wind. It is seen around stars like a crown. The solar wind creates polar lights. There may be all the planets with an atmosphere and a magnetic field.

Jean, astrophysicist, showed us a slideshow that showed the different colors of the aurora borealis. There were purple, blue, yellow, orange, red, green ...
We learned that Birkeland had invented the Terrella. We saw the Planeterrella. It consists of a large sphere with a tilted magnet like the Earth and a small sphere with a bar magnet.

Institut de Planétologie et d'Astrophysique de Grenoble (IPAG)