Ultra High Energy Cosmic Ray Particles

by Granite

Some cosmic rays have an almost unbelievable energy. The source of such high energy particles is still a mystery Suggested explanations include young neutron stars and active galactic cores.

Ultra high energy cosmic rays have an energy greater than 1 Exa electron volts (1 EeV), ie. 1018 eV or 0.16 Joules.

The “Oh-My-God” cosmic ray particle detected in 1991 Fly’s Eye experiment had an energy of (320 +/- 90)  Exa Electron Volts (EeV), that is 51 Joules.  Assuming it was a proton, this means it was traveling at 0.9999999999999999999999951 times the speed of light. [Wikipedia].

A 58 g tennis ball with kinetic energy of 51 joules would be a travelling at 42 metres per second or 150 km/h.  The average speed of a first serve by a professional tennis player is around the 190-200 km (https://tenniscreative.com/fastest-tennis-serve/).

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Nuclear Power Plants Under Construction

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As of 31 December 2022,  the IAEA Nuclear Power Reactors in the World, 2023 Edition lists 58 power reactors under construction where the first concrete for reactor has been poured.

Of the 58 power reactors under construction:

      • 1 is the 25 MWe Carem25, a small Pressurised Water Reactor (PWR) being built in Argentina,
      • 1 is the 100 MWe ACP100, the Linglong-1 PWR SMR  being built in China,
      • 1 is the 300 MWe Fast Breeder (FBR) BREST-OD-300 being built in Russia
      • 2 are 440 MWe pressurised water reactors (VVER-V-213) being built in Slovakia, and
      • 1 is the 500 MWe Prototype Fast Breeder Reactor (PFBR) being built in India,
      • 2 are 600 MWe CFR-600 Fast Reactors being built in China,
      • 3 are 700 MWe Pressurised Heavy Water Reactors (PHWR-700) being built in India,
      • 2 are 1300 MWe Advanced Boiling water Reactors (ABWR) being build in Japan but construction currently suspended,
      • 45 are large pressurised water reactor between 1000 and 1630 MWe being built in 15 countries.
        • Bangladesh 2, Belarus 1, Brazil  1, China 17, Egypt 2,  France 1, India 4, Iran 1, South Korea 3, Russia 2, Türkiye 4, UAE 1, UK 2, and USA 2.  Also 2 in Ukraine where construction is currently suspended.
        • Designs of large PWRs under construction are:
          • VVER – 12 under construction in Bangladesh, Egypt, India, Iran, Russia and Türkiye.
          • HPR1000 – 11 under construction in China and Pakistan.
          • APR1400 – 4 under construction in South Korea and UAE.
          • EPR – 3 under construction in France and UK
          • AP1000 – 2 under construction in USA
          • CAP1400 – 2 under construction in China
          • Pre KONOI – 1 in Brazil

Consumption of Hydrogen in the Sun

by Granite

Nuclear fusion in the Sun consumes about 5 million tonnes of hydrogen per second. Despite this enormous consumption of hydrogen, the sun has enough hydrogen to burn at this rate for the next 4 billion years.  The Sun is currently composed of about 90 percent hydrogen, 9 percent helium, and only 1 percent of all the other elements such as carbon, nitrogen, oxygen, silicon, and iron.  Ref: NASA

The temperature in the core of the Sun is about 15 million degC, the density 150 times that of water and the pressure over 200 billion times greater than atmospheric pressure on earth. https://www.wwu.edu/astro101/a101_sun.shtml

The mass of the sun s 1.99 x 1027 tonnes – about 333,000 times the mass of the Earth

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Neutrinos – present in vast numbers but barely interact with matter

by Granite

The sun emits vast numbers of neutrinos which can pass through the earth with little or no interaction. Solar neutrinos shine down on us during the day, and shine up on us during the night after passing through the earth almost no absorption. About 91% of solar neutrons are produced by the proton-proton fusion to produce deuterium.  Neutrinos from the proton-proton fusion have low energy up to 400 keV.  The flux of low energy neutrons is about 7 x 1010  neutrinos/cm2s, i.e 70 billion neutrinos per square cm per second.  A square centimetre is about the size of your small finger nail.  There are several other processes producing neutrinos up to 18 MeV (see figures below).

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Very High Energy Cosmic Gamma Rays Detected

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China’s Large High Altitude Air Shower Observatory (LHAASO) has detected two photons with energies exceeding 1 peta-electron-volt (quadrillion electron-volts or PeV).  The photon at 1.4 PeV is the highest energy photon ever observed. The largest accelerator on Earth (LHC at CERN) can only accelerate particles to 0.01 PeV. http://english.ihep.cas.cn/lhaaso/doc/4253.html

Aerial photograph of LHAASO

When a very high-energy particle strikes Earth’s atmosphere, it triggers a cascade of secondary particles. Ground-based detectors such as LHAASO record these air shower events and can then reconstruct the type, energy and trajectory of the primary particles.  Two of the photons detected from the Crab Nebular by LHAASO are the highest energy photons ever detected from the Crab Nebula: one at 0.88 PeV other at 1.1 PeV. https://www.scientificamerican.com/article/highest-energy-particles-yet-arrive-from-ancient-crab-nebula/
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Voyager 1 Spacecraft still talking to Earth

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The Voyager 1 spacecraft now at the immense distance of 18.5 billion kilometers (145 AU) from earth.  In 2017, thrusters were operated by NASA to adjust the orientation of the spacecraft; the signal from the spacecraft took 19 hours and 35 minutes to reach an antenna in Goldstone, California.

Voyager 2 launched on August 20, 1977, from Cape Canaveral, Florida aboard a Titan-Centaur rocket. On September 5, Voyager 1 launched, also from Cape Canaveral aboard a Titan-Centaur rocket.

The twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing on their more-than-39-year journey since their 1977 launches, they each are more that twice as far from Earth and the sun than Pluto.

Natural Radioactivity and Background Radiation

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Background radiation is a natural part of the environment. The largest source of background radiation exposure comes from the natural radioactivity in rocks and soil and the inhalation of naturally occurring radon that seeps from the ground into our buildings. We are also exposed to cosmic radiation and the natural radioactivity in food and in the body. On average, Australians are exposed to about 1.5 mSv each year from natural sources, although for some the dose might be more than double that. On average, we also receive about 1.7 mSv per year from medical diagnoses and treatment.
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Black holes and neutron star collisions

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The recent observations of gravitational waves from cosmic events opens a dramatic new window on the universe (first in 2015).  The first four events observed by gravitational waves were colliding black holes with masses between 7.5 and 35 solar masses. As black holes do not emit any radiation, there is no electromagnet radiation from the resultant black holes although the actual collision produces a gamma ray pulse which has been detected for one of the events. The amount of energy radiated away as gravitational energy from these black hole collisions is immense: between 1 and 3 solar masses of energy emitted in a short time of order or less than 100 seconds.

Even more interesting in terms of observations was the GW170817 event (published on 16 Oct 2017) which was caused by the collision of two neutron stars approximately 130 million years ago. 

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The Black Hole at the Centre of the Milky Way Galaxy

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Observations by the W. M Keck Telescopes provide clear evidence for the existence of a supermassive black hole at the centre of our Milky Way galaxy.  Because of dust, the galactic centre cannot be seen at visible, ultraviolet or soft x-rays wavelengths, but the W. M. Keck Telescopes have obtained incredible images of the stars and gas clouds at the centre of our Milky Way galaxy using infrared optics.

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