nge of human hearing: 20 Hz – 20,000 Hz nsitivity reshold for hearing: 110 -12 Watt/ ncrease of pressure on eardrum 0.00003 Pascals (N/m 2 ) above normal atmospheric pressure: 1 atm = 101,300 Pa ibrating air molecules displaced n amplitude of ~110 -10 m / 10 the diameter of an air molecul reshold for pain: 1 Watt/ 9 Pa above atmospheric pressure mplitude of vibrations 110 -5 m ot perceived as 10 12 times “as loud”
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Range of human hearing: 20 Hz – 20,000 Hz Sensitivity Threshold for hearing: 1 10 -12 Watt/m 2 Increase of pressure on eardrum 0.00003 Pascals (N/m 2.
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Range of human hearing:
20 Hz – 20,000 Hz
SensitivityThreshold for hearing: 110-12 Watt/m2
•Increase of pressure on eardrum0.00003 Pascals (N/m2) abovenormal atmospheric pressure: 1 atm = 101,300 Pa
•vibrating air molecules displaced by an amplitude of ~110-10 m 1/10 the diameter of an air molecule!
Threshold for pain: 1 Watt/m2
•29 Pa above atmospheric pressure•Amplitude of vibrations 110-5 m
Source: Garrels, MacKenzie and Hunt: Chemical cycles. 1975
Distribution of Elements in the Human Body (by weight)
Element Atomic no. Percentage Role
oxygen 8 65.0cellular respiration, component of water
carbon 6 18.5 basis of organic molecules
hydrogen 1 9.5component of water & most organic molecules, electron carrier
nitrogen 7 3.3component of all proteins and nucleic acids
calcium 20 1.5component of bones and teeth, triggers muscle contraction
phosphorus 15 1.0component of nucleic acids, important in energy transfer
potassium 19 0.4min positive ion inside cells, important in nerve function
sulfur 16 0.3 component of most proteins
sodium 11 0.2main positive ion outside cells, important in nerve function
chlorine 17 0.2 main negative ion outside cells
magnesium 12 0.1essential component of many energy-transferring enzymes
iron 26 traceessential component of hemoglobin in the blood
copper 29 trace component of many enzymes
molybdenum 42 trace component of many enzymes
zinc 30 trace component of some enzymes
iodine 53 trace component of thyroid hormone
Solar system massesSun 1.981030 kgJupiter 1.901027 kgEarth 5.981024 kg
Absorption “lines”
• First discovered in spectrum
of Sun (by an imaging scientist
named Fraunhofer)• Called “lines” because they
appear as dark lines super-
imposed on the rainbow of the
visible spectrum
Sun’s Fraunhofer absorption lines
(wavelengths listed in Angstroms; 1 A = 0.1 nm)
The Solar Spectrum
Emission line spectra
Insert various emission line spectra here
Emission line images
Planetary nebula NGC 6543
Green: oxygen; red: hydrogen(blue: X-rays)
Orion Nebula
The optical emission line spectrum of a young star
The Nuclear pp cycle
4 protons 4He + 6+ 2e
26.7 MeV
July 1969 Apollo 11 astronauts trap cosmic ray particles on exposed aluminum foil, returned to earth for analysis of its elemental & isotopic composition. With no atmosphere or magnetic field of its own, the moon’s surface is exposed to a constant barrage of particles.
March 3, 1972 Pioneer 10 launched -on its flyby mission, studies Jupiter's magnetic field and radiation belts.
December 1972 Apollo 17’s lunar surface cosmic ray experiment measured the flux of low energy particles in space (foil detectors brought back to Earth for analysis.
October 26, 1973 IMP-8 launched. Continues today measuring cosmic rays, Earth’s magnetic field, and the near-Earth solar wind from a near-circular, 12-day orbit (half the distance to the moon).
October 1975 to the present GOES (Geostationary Orbiting Environmental Satellite) An early warning system which monitors the Sun's surface for flares.
1977 The Voyager 1 and 2 spacecraft are launched. Each will explore acceleration processes of charged particles to cosmic ray energies.
August 31, 1991 Yohkoh spacecraft launched - Japan/USA/England solar probe - studied high-energy radiation from solar flares.July 1992 SAMPEX (Solar Anomalous and Magnetospheric Particle Explorer) in polar orbit. By sampling inter- planetary & magnetospheric particles, contributes to our understanding of nucleosynthesis and the acceleration of charged particles.
July 1992 IMAX (Isotope Matter-Antimatter eXperiment) balloon- borne superconducting magnetic spectrometer measured the galactic cosmic ray abundances of protons, anti-protons, hydrogen, and helium isotopes.
August 25, 1997 Advanced Composition Explorer (ACE) was launched!
Hydrogen (H) 1 1.00 640
Helium (He) 2 6.8 10-2 94
Lithium, beryllium, boron 2.6 10-9 1.5
Carbon, Nitrogen, Oxygen 1.2 10-3 6
Iron (Fe) 26 3.4 10-5 0.24
All heavier atoms 1.9 10-6 0.13
ElementAtomic
Number (Z)
Solar SystemComposition
(relative number of atoms)
PrimaryCosmic Ray
Flux(particles/m-2 sec)
50m
Cosmic ray strikes a nucleuswithin a layer of
photographicemulsion
Primary cosmic ray
Mostly photons, electrons and muons at Earth’s surface
A 1019 eV Extensive Air Shower
100 billion particles
at sea level
89% photons10% electrons~1% muons
12 km
6 km6 km
The Cosmic Ray Energy Spectrum
(1 particle per m2-sec)
(1 particle per m2-year)
(1 particle per km2-year)
Cosmic Ray Flux
Energy (eV)
Refrigerator cold CO2 bubble (887 mph)
0.02 eV
Room temperature nitrogen N2 (1160 mph)
0.03 eV
Atoms in sun’s MILLION DEGREE surface0.50 eV
Energy given to each single electron whenaccelerated by AA battery 1.5 eV
Electrons accelerated by your televisionpicture tube (traveling ~1/3 speed of light)
30,000 eV
Fermi National Lab’s high energy protons 1,000,000,000,000 eV
Superball bounced over your house 4 x 1017 eV
Pitched baseball 4 x 1020 eV
Slammed hockey puck 1 x 1021 eV
Recall: 1 joule = 6.2 x 1018 eV
The highest energy Cosmic Rays areSUBATOMIC particles carrying theenergy of MACROSCOPIC objects!
4 x 1021 eV = 60 joules
The Cosmic Ray Energy Spectrum
FERMILAB’s protonsFERMILAB’s protons
Bounced Superball
Bounced Superball
Pitched baseballPitched baseball
Hockey PuckHockey Puck
Energy (eV)
Two possible sources of cosmic rays
Colliding galaxies
Active galacticnucleus
GZK Cutoff
1966 - K. Greisen - G.T.Zatsepin & V.A.Kuz’min
showed the recently discovered cosmic microwave background radiation (CMBR)effectively makes the universe opaque tosufficiently high energy cosmic particles.
GZK Cutoff
For example:
p *+0 p
++ n
and similar resonances yield attenuation lengths mere 10s of Mega parsecs for cosmic ray protons with E>1019 eV.
Center of (our) Virgo supercluster is approximately 20 Mpc away
All E>1019 eV primaries must originate within 100 Mpc of the earth