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From Wikipedia -- Cosmic Rays

  Cosmic rays are immensely high-energy radiation, mainly
  originating outside the Solar System. They may produce
  showers of secondary particles that penetrate and impact the
  Earth's atmosphere and sometimes even reach the surface.
  Composed primarily of high-energy protons and atomic nuclei,
  they are of mysterious origin. Data from the Fermi space
  telescope (2013) has been interpreted as evidence that a
  significant fraction of primary cosmic rays originate from
  the supernovae of massive stars. However, this is not
  thought to be their only source. Active galactic nuclei
  probably also produce cosmic rays.


Track Cosmic Rays with Smartphone App

Observing Ultra-High Energy Cosmic Rays with Smartphones

Cosmic ray particle shower? There's an app for that.

  Every second, the Earth is being struck by cosmic rays, high
  energy particles that slam into the atmosphere.
  Understanding where they come from and how they're generated
  could provide information about some of the most energetic
  processes in the Universe. But Earth's atmosphere protects
  us from them, ensuring that they don't make it to the
  surface. Instead, we have to look for the shower of photons
  and particles that the cosmic rays create when they hit the

  Even large detectors, however, only capture a few traces of
  the high energy particles that reach the Earth, meaning that
  careful studies of their origin can take years, possibly
  even decades. So some researchers decided it might be
  possible to take advantage of a large population of
  non-specialized detectors that are pre-positioned all over
  the world: cell phone cameras.

  The researchers from the University of California have
  drafted a paper in which they describe testing whether a
  smartphone camera can detect high energy photons and
  particles of the sort produced by cosmic rays. Testing with
  radioactive isotopes of radium, cobalt, and cesium showed
  that the detector easily picked up gamma rays (and you
  didn't even have to point the phones at the source!). They
  also put a phone inside a lead box and showed that they
  could detect high energy particles. Finally, they took a
  phone up on a commercial flight and were able to obtain a
  particle track across the detector.

Cosmic ray observatory to expand

  The expansion will allow the next step aimed at identifying
  what objects in space produce ultrahigh-energy cosmic rays -
  subatomic particles so energetic that just one would feel
  like a lead brick if it hit your foot or a fast-pitched
  baseball to the skull. Ouch!

The Standard Model

  The Standard Model of particle physics is a theory
  concerning the electromagnetic, weak, and strong nuclear
  interactions, as well as classifying all the subatomic
  particles known. It was developed throughout the latter half
  of the 20th century, as a collaborative effort of scientists
  around the world.[1] The current formulation was finalized
  in the mid-1970s upon experimental confirmation of the
  existence of quarks. Since then, discoveries of the top
  quark (1995), the tau neutrino (2000), and more recently the
  Higgs boson (2013), have given further credence to the
  Standard Model.

  Every Particle that we have ever detected has been
  replicated by the Large Hadron Collider (LHC). So we expect
  that every particle is created in cosmic ray collisions.
  Cosmic Ray Collisions are 6-8 orders of magnitude more
  energetic than the LHC can muster.


Special Relativity

Time Dilation of Moving Particles

Cosmic Muons
  Let me illustrate time dilation AND length contraction with
  cosmic muons.