As esoteric as they may seem from this brief description, cosmic rays are actually quite impactful to our daily lives, our environment and to life itself. Examples include: major effects on the Earth's climates, corruption of our DNA (DNA corruption is critical for evolution - it could be that without cosmic rays intelligent life would not have evolved), flipped bits in our electronic devices, the existence of lightning, and cosmogenic nuclear transmutation (e.g.: the creation of carbon-14 from nitrogen).
Flipped Bits
Have you ever had to reboot your computer or cell phone in order to get it work right? It's likely your device was on the blitz because a cosmic ray had flipped a bit and, in doing so, had corrupted a key part of the OS code. Cosmic rays constantly zip around and through us and our electronic devices. Being of high energy, they occasionally zap a zero and change it to a one, or vice verse (reference). Cosmic ray mischief wreaked upon electronics in space, where flux rates are 1000x what they are here at the earth's surface, is a major nuisance.
Cloud Nucleation and Global Temperatures
Some of the cosmic rays that bombard our atmosphere trigger nucleation of water vapor into droplets. This leads to early cloud formation. With more clouds, solar heating of the earth's surface is reduced. Over the long term this reduces global temperatures. Cosmic ray levels, and thus cloud levels and weather, rise and fall due to solar activity, changing magnetic fields and several other natural phenomena. Nir Shaviv has argued that climate signals on geological time scales are attributable to changing positions of the galactic spiral arms of the Milky Way Galaxy, and that cosmic ray flux variability is the dominant "climate driver" over these time periods. (see role in climate change)
DNA Mutations
According to NASA (source article): Cosmic rays can seriously damage DNA. If DNA damage cannot be repaired by the cell, the cell could die. If the damage is copied into more cells, then a mutation could occur. (e.g.: Dr. David Banner ;-) - a natural source of gamma rays is secondary radiation from atmospheric interactions with cosmic ray particles.) Exposure to large amounts of cosmic rays could increase the risks for cancer, cataracts and neurological disorders. Long term exposure to cosmic rays, or short intense bursts, could affect the evolution of life on Earth.
Lightning (cool stuff)
Have you ever wondered why lightning bolts are jagged? Simple answer - cosmic rays. The electrical current that is lightning seeks the path of lowest resistance, or highest conductivity. That path turns out to be ion trails created by cosmic rays. Only by extreme coincidence would the ion trails exactly follow the point-to-point shortest distance between the maximum cloud-to-cloud or cloud-to-earth potentials (also the cosmic particles and their trails are aften suddenly terminated due to collisions with air molecules), so the lightning follows not one trail, but a series of trails blazed by numerous cosmic particles - hence the zigs and zags in the bolts. cosmic rays and lightning.
By the way, have you ever heard of the remote area in Venezuela where huge lightning storms light the skies every night? It has been hypothesized that the Relampago del Catatumbo is driven by an unusually high flux of cosmic particles in the region.
Cosmogenic Isotopes (beyond cool - sick)
Many of the cosmic rays are of such high energy that when they collide with molecules they precipitate nuclear reactions. Tritium occurs naturally due to cosmic rays interacting with atmospheric gases. In the most important reaction for the natural production of tritium, a fast neutron (which must have energy greater than 4.0MeV[10]) interacts with atmospheric nitrogen:
- A similar cosmic ray interaction is responsible for all naturally occuring carbon-14:n + 14N → p + 14C
Reaction products of primary cosmic rays,radioisotope half-lifetime, and production reaction.[41]· Tritium (12.3 years): 14N(n, 3H)12C (Spallation)· Beryllium-7 (53.3 days)· Beryllium-10 (1.39 million years): 14N(n,p α)10Be (Spallation)· Carbon-14 (5730 years): 14N(n, p)14C (Neutron activation)· Sodium-22 (2.6 years)· Sodium-24 (15 hours)· Magnesium-28 (20.9 hours)· Silicon-31 (2.6 hours)· Silicon-32 (101 years)· Phosphorus-32 (14.3 days)· Sulfur-35 (87.5 days)· Sulfur-38 (2.8 hours)· Chlorine-34 m (32 minutes)· Chlorine-36 (300,000 years)· Chlorine-38 (37.2 minutes)· Chlorine-39 (56 minutes)· Argon-39 (269 years)· Krypton-85 (10.7 years)
Health Effects
Your body receives about 2.4 mSv (milliSieverts) of radiation caused by the effects of cosmic rays every year. For comparison, it takes about 1 Sievert of radiation in a short time to cause nausea, and about 2-6 Sieverts to cause death (source). Cosmic rays are cause for concern to individuals who spend a lot of time in jet aircraft. At the cruising altitudes of commercial aircraft cosmic radiation is 100 to 300 times more intense than at sea level (source and more on this). In space, the health threat from cosmic rays is one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft.
And More
For those interested, here is some random information on cosmic rays (primary source - Cosmic ray):
- Cosmic rays are particles - these are usually small atoms stripped of their electrons. Specifically, 90% of cosmic rays are protons (hydrogen nuclei) and 9% are alpha particles (helium nuclei, 2 protons+2 neutrons). This means they typically have atomic masses of 1 or 4.
- They are high energy due to their high speeds. Most galactic cosmic rays have energies between 100 MeV (corresponding to a velocity for protons of 43% of the speed of light) and 10 GeV (corresponding to 99.6% of the speed of light) [R A Mewaldt].
- UHECRs, the most energetic ultra-high-energy cosmic rays have been observed to approach 3 × 1020 eV,[5] about 40 million times the energy of particles accelerated by the Large Hadron Collider.[6] At 50 J,[7] the highest-energy ultra-high-energy cosmic rays have energies comparable to the kinetic energy of a 90-kilometre-per-hour (56 mph) baseball.
- The vast majority coming to earth meet their end in the atmosphere as they collide with molecules
- On passing through the earth's atmosphere, "primary" cosmic rays are consumed and "secondary" ones created (source):
- At the earth's surface the flux of cosmic rays is 1000-10,000 times lower than in the earth's upper atmosphere. Note - in the plot below protons give the best indication of the relative flux levels of primary cosmic rays.
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| Flux levels of Cosmic Rays and Particles from Cosmic ray Collisions |
- Cosmic rays of energy levels 1 GeV (200 million times the energy needed to rip apart a DNA molecule) strike your body at the rate of 1000 per second. At 1 TeV the rate is 1 particle per square meter per second. At 10 PeV there are only a few particles per square meter per year. Particles above 10 EeV arrive only at a rate of about one particle per square kilometer per year, and above 100 EeV at a rate of about one particle per square kilometer per century
- As they pass through matter (gas, solid or liquid) they leave behind trails of ionized molecules.
- They can penetrate dense solid materials (such as gold) to depths of several centimeters
- More yet:
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