The main speaker was engineer Dario Kubler of the Asimov association, who was able to attract the audience’s attention with his speech: “Monna Lisa Pathfinder: discovering a new universe”.
To complete the evening the students of the classes 4A and 5B of Sereni High School in Luino showed the projects they developed during the previous school year inside their work-linked training.
Class 4A students introduced their project “Physics in sport” carried out together with the Science and High Technology department of Insubria University in Como.
A short video clearly illustrated the topics of their research project, whose aim was to investigate the laws of physics that can be applied to sports and, in particular, to swimming, basketball, table tennis and rowing; these laws include the principles of dynamics, mechanical energy conservation, the impact theory, the impulse-momentum theorem, and the levers.
In fact they explained, for instance, how a body can float in the water; what the forces that slow down a swimmer are due to; how a perfect shot in basketball can be scored; what happens in the impact of a small ball against a tennis table; how water friction affects rowing and so on.
Doctor Kubler’s speech was very interesting.
Mr Kubler showed a short video to the audience to share with them his satisfaction for a recent successful event, that is, the first trial flight of the microsatellite Alsat 1 on September 15th .
The satellite, lifted by a helium balloon, left at 11 am from Ceriano Laghetto and reached a height of over 40000 metres.
It landed near Brescia, but the technicians took 4 hours to detect its position.
The satellite name has been chosen in memory of the astronaut Alfred Worden, pilot of the command module of Apollo 15, which was orbiting around the moon while the other astronauts stepped on the moon ground.
Then Mr Kubler approached the issue of gravitational waves.
The first theory about their existence was developed by Einstein in 1916 but the definitive evidence was only found about one hundred years later: in 2015, in fact, the satellite Lisa (Laser Interferometer Space Antenna) Pathfinder was launched with the aim of detecting experimental evidence of the existence of gravitational waves following the formation and evolution of massive and supermassive black holes, but also of investigating compact binary systems and of discovering what there was before the Big Bang.
The gravitational waves are generated by the impact of two huge masses, for instance two black holes, exactly as Albert Einstein theorised in 1916.
They are extremely difficult to detect because the space-time ripple they produce dramatically reduces during the billions of years they take to reach the Earth.
To notice them it is therefore necessary to use very sensible devices called Interferometers, as well as considering the various interferences caused by Earth elements. For instance, the devices must be isolated from seismic events to avoid any disturbance. If they are placed near the sea, they are affected by tides.
For this reason the next Interferometer will be located in space.
Today there are only three of them: two are in the USA and the third is in Italy, in Pisa, and it is possible to visit it.
These devices are extremely sensitive: for example, they are able to measure the shift of an atom nucleus in the distance between the Earth and the Sun.
Something new and exceptional happened on August 17th: the Interferometers Ligo (USA) and Vigo (Italy) registered a one minute long signal. A really extraordinary event since all previous signals lasted only a few seconds.
Just two seconds after the arrival of the gravitational-wave signal, two space stations also detected another signal, but this signal referred to gamma rays.
From the Earth it was possible to see something optically.
It is the first time that a gamma-ray station and a gravitational-wave station have recorded something at the same time.
A new frontier called “multimessenger” opened: in fact the “messages” arrived on Earth were (a combination of light and sound, two completely different types of information.
Two objects that are not black holes but two Pulsar stars crashed in the sky (a pulsar is a neutron star which emits impulses that are detectable on Earth): a kilonova was created through their crash.
For the first time it is possible to explain the origin of some heavy elements of the periodic table such as gold and platinum.
At the end of his speech, Mr Kubler underlined that if we now know what observing the gravitational waves means and we are ready to observe them from the space too, the close observation of a black hole is still missing.
At the end of the event class 5B described their project concerning work-linked training. Its title is: “The physicist in medicine: their involvement in the world of Humanitas”.
During the school year they investigated medical physics and they studied its practical applications, such as radiotherapy.
The meeting was also attended by the astronomical association M42 and the astronomical station of Monteviasco. The experts should have observed the sky with their telescopes, but, unfortunately, it was cloudy.
Francesca Ronconi (5ALF)
