Assembling the first global map of lunar hydrogen

Using data collected over two decades ago, scientists from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, have compiled the first complete map of hydrogen abundances on the Moon's surface. The map ...

Scientists find oldest Martian meteorite's original home

Scientists announced Tuesday they had found the crater from which the oldest known Martian meteorite was originally blasted towards Earth, a discovery that could provide clues into how our own planet was formed.

Discovery of extragalactic neutrino factories

Highly energetic and difficult to detect, neutrinos travel billions of light years before reaching our planet. Although it is known that these elementary particles come from the depths of our universe, their precise origin ...

Large Hadron Collider revs up to unprecedented energy level

Ten years after it discovered the Higgs boson, the Large Hadron Collider is about to start smashing protons together at unprecedented energy levels in its quest to reveal more secrets about how the universe works.

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Cosmic ray

Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, almost 10% are helium nuclei (alpha particles), and slightly under 1% are heavier elements and electrons (beta minus particles). The term ray is a misnomer, as cosmic particles arrive individually, not in the form of a ray or beam of particles.

The variety of particle energies reflects the wide variety of sources. The origins of these particles range from energetic processes on the Sun all the way to as yet unknown events in the farthest reaches of the visible universe. Cosmic rays can have energies of over 1020 eV, far higher than the 1012 to 1013 eV that man-made particle accelerators can produce. (See Ultra-high-energy cosmic rays for a description of the detection of a single particle with an energy of about 50 J, the same as a well-hit tennis ball at 42 m/s [about 94 mph].) There has been interest in investigating cosmic rays of even greater energies.

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