#cerenkov

[andreaponza]

Doppler, Mach e il muro del suono | TuttoLogico

Il perché del botto quando un oggetto viaggia a velocità superiore a quella del suono. Effetto Doppler e il cono di Mach in poche semplici parole

Il muro del suono, Doppler, Mach 

[startswithabang]

Scientists Catch The Highest Energy Particles By Making Them Go Faster Than Light

“If you want to catch particles as they were before they ever reached Earth, you need to go to space to see them. But that's expensive; the Fermi gamma-ray telescope (which detects individual high energy photons, not cosmic rays directly) cost approximately $690 million total. For less than half that cost, you can catch the particles that result from cosmic rays hitting the atmosphere in more than 100 locations across the globe, all because we understand the physics of particles that move faster-than-light through the atmosphere. More than that, the science prospects include understanding the origin of relativistic cosmic particles, the acceleration mechanisms around neutron stars and black holes and might even improve astrophysical searches for dark matter.”

It’s true that nothing can move faster than the speed of light, but only if you’re in a vacuum. Once you’re in a material, like water, glass, or even the atmosphere, all you need to do is make your particles move faster than the speed of light in that medium and all the rules change. By moving faster than light, you force these relativistic particles to emit photons in all directions -- Cherenkov radiation -- which forces them to slow down. This Cherenkov radiation can be detected by an observatory designed to do exactly this! Since very high energy cosmic rays strike our world and move through the atmosphere, we can detect these Cherenkov photons as their signature, and work to reconstruct where they came from and what caused them.

Ground has been broken just this year on the first telescopes as part of the massive Cherenkov Telescope Array (CTA); come find out what science we’re poised to learn from this massive undertaking!

[fancityacireale]

Un nuovo telescopio sull'Etna, gioiello di tecnologia

  Il 24 settembre è stato inaugurato presso la sede di Serra la Nave dell’INAF-Osservatorio Astrofisico di Catania il telescopio SST (Small Size Telescope) realizzato nell’ambito di ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), un “Progetto Bandiera” dell’astrofisica italiana finanziato dal MIUR e condotto dall’INAF (Istituto Nazionale di Astrofisica).

Il telescopio verrà usato per il progetto internazionale CTA (Čerenkov Telescope Array), che sarà il primo gurppo di telescopi ad osservare i raggi gamma ad alta energia tramite la tecnica Cherenkov da terra.

Sarà formato nel suo sito sud da circa 100 telescopi, alcuni dotati di specchio principale grande ben 27 metri di diametro che saranno collocati al centro dell’array, una serie di altri (tra 20 e 25) di medie dimensioni (12 metri di diametro) e poi i tanti (circa 70) piccoli telescopi di 4 metri di diametro.

Quest’ultimo è proprio il settore in cui INAF vuole partecipare con la produzione di metà o più di questi piccoli telescopi. Il prototipo di ASTRI è proprio il capofila di questi telescopi che saranno distribuiti su un’area di 10 km quadrati e sarà rivolto ad osservare i segnali di energia più alta che si osservano con la tecnica Cherenkov, quelle che vanno da circa 2-3 tera elettronvolt fino a 100 e più TeV.

Un nuovo telescopio sull’Etna, gioiello di tecnologia was originally published on Fancity Acireale

[orintau]

"Cherenkov radiation is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium at a speed greater than the phase velocity of light in that medium."

[secretisque-blog]

  http://af.mil

[scutulatus-relatum-blog]

  http://inklineglobal.com

[scires-blog]

Tips for backpacking without a stove

 Backpacking without a stove is not only a good way to save money and weight, but can also be very funny. Before we go over some tips for cooking and preparing food without a stove let's look at two reasons that many people without a backpack stoves stove.Backpacking are one of the most expensive pieces of equipment for backpacking. Backpacking stoves also require a fuel source that will be addressed with more spending, spills as possible and at times can be difficult to find fuel. What many walkers who choose to go without a stove for these reasons in mind is the camping stove. A camping stove is both lightweight and economical. As the stove uses wood as fuel, the fuel should not be performed. Firestarting a block that can be cut into smaller pieces is useful to help a fire, but the small fire necessary for the operation of the stove is easy to work in most conditions. backpacking stoves can be bought cheaply and there are many sources of plans for building your own on the Internet. Some are nothing more than soup or coffee can be modified and others are more complex.However, even if the backpacking wood stove is not for you then you have two options. One is to cook or prepare food on the fire and the other is not to cook at all. If you are not going to cook at all (which is beneficial when you move quickly over long distances), then all you have to do is to plan well. Cooking on the stove requires some skill and materials, but can be quickly learned.A metal bowl (useful for boiling water), a small metal skewer (for food roast), and some aluminum foil make a good kit minimum cooking without a stove for backpacking. However, a pot and pan can make things much easier. An open cooking fire should not be great for preparing food. With the collection of wood no wider than a hot dog in a fire service can be done to cook meals and then be quickly extinguished in order to get back on track. These small cook fires are great for boiling water for use with prepackaged backpacking meals, making pasta and rice, and other fast-food cooking. The best way to learn the technique of feeding the fire only to meet your needs is through experience. So hit the track and gain experience of backpacking without a certain stove.Be before starting the journey that open fires are permitted for cooking. Fireplaces require that the backpacker pay attention to the flames and sparks as well as properly extinguish the fire before leaving.

http://popeater.com