Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Magnitude


Related Topics
PVO

In the News (Sun 22 Nov 09)

  
  Apparent magnitude - Wikipedia, the free encyclopedia
The absolute magnitude, M, of a star or galaxy is the apparent magnitude it would have if it were 10 parsecs away; that of a planet (or other solar system body) is the apparent magnitude it would have if it were 1 astronomical unit away from both the Sun and Earth.
Magnitude is complicated by the fact that light is not monochromatic.
For this purpose the UBV system is widely used, in which the magnitude is measured in three different wavelength bands: U (centred at about 350 nm, in the near ultraviolet), B (about 435 nm, in the blue region) and V (about 555 nm, in the middle of the human visual range in daylight).
en.wikipedia.org /wiki/Apparent_magnitude   (1178 words)

  
 Richter magnitude scale - Wikipedia, the free encyclopedia
The diminution of amplitude due to distance between the earthquake epicenter and the seismometer is corrected for by subtracting the common logarithm of the expected amplitude of a magnitude 0 event at that distance.
Richter arbitrarily chose a magnitude 0 event to be an earthquake that would show a maximum combined horizontal displacement of 1 micrometre on a seismogram recorded using a Wood-Anderson torsion seismometer 100 km from the earthquake epicenter.
By the beginning of the 21st century, most seismologists considered the traditional magnitude scales to be largely obsolete, being replaced by a more physically meaningful measurement called the seismic moment which is more directly relatable to the physical parameters, such as the dimension of the earthquake rupture, and the energy released from the earthquake.
en.wikipedia.org /wiki/Richter_scale   (844 words)

  
 Apparent magnitude Info - Encyclopedia WikiWhat.com   (Site not responding. Last check: 2007-10-21)
The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, its brightness without regard to the object's distance from a point of observation.
The brightest stars were said to be of first magnitude (m = +1), those which were only half as bright were of second magnitude, and so on up to sixth magnitude (m = +6), the limit of human visual perception (without a telescope or the like).
For this purpose the UBV system is widely used, in which the magnitude is measured in three different wavelength bands: U (centred at about 350 nm, in the near ultraviolet), B (about 435 nm, in the blue region) and V (about 555 nm, in the middle of the human visual range).
www.wikiwhat.com /encyclopedia/a/ap/apparent_magnitude.html   (802 words)

  
 Magnitude - Wikipedia, the free encyclopedia
In physics, the magnitude of a vector is a scalar in the physical sense, i.e.
In astronomy, magnitude refers to the logarithmic measure of the brightness of an object, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.
In seismology, the magnitude is a logarithmic measure of the energy released during an earthquake.
en.wikipedia.org /wiki/Magnitude   (206 words)

  
 The Richter Magnitude Scale, Alaska Science Forum
In the examples shown, a magnitude 2 earthquake would produce a deflection of 0.1 millimeter from an earthquake 100 kilometers away, or a deflection of 2 millimeters if it were only 20 kilometers distant.
Magnitude scales in general often seem to be devised with a devilish intent to mislead.
The magnitude of a disaster, for instance, goes up as the disaster becomes worse, but the magnitude of a star goes down as the intrinsic brightness becomes greater.
www.gi.alaska.edu /ScienceForum/ASF7/701.html   (800 words)

  
 Stellar Magnitudes
The former is a convolution of the true brightness and the effect of distance on the observed brightness, because the intensity of light from a source decreases as the square of the distance (the inverse square law).
However, the apparent magnitude is not so useful because it mixes up the intrinsic brightness of the star (which is related to its internal energy production) and the effect of distance (which has nothing to do with the intrinsic structure of the star).
The apparent magnitude of various objects determined using light from the visible part of the spectrum is given in the adjacent table.
csep10.phys.utk.edu /astr162/lect/stars/magnitudes.html   (802 words)

  
 Absolute magnitude - Wikipedia, the free encyclopedia
In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us.
Many stars visible to the naked eye have an absolute magnitude which is capable of casting shadows from a distance of 10 parsecs; Rigel (−7.0), Deneb (−7.2), Naos (−7.3), and Betelgeuse (−5.6).
In this case, the absolute magnitude is defined as the apparent magnitude that the object would have if it were one astronomical unit (au) from both the Sun and the Earth and at a phase angle of zero degrees.
en.wikipedia.org /wiki/Absolute_magnitude   (842 words)

  
 Troubled Times: Magnitude
The scale is logarithmic, so, a difference in magnitude of 8 (between the actual and apparent magnitude of the 12th) consists in a factor of nearly 3000.
A magnitude of 10 is reasonable for an object the size and distance of the 12th planet.
Hence, telescopes, designed to measure magnitude by assuming that light is emanating from the full area of a sphere, classify it as magnitude 11.0, and the actual magnitude from the vantage point of earth is 11.0, regardless of whether certain faint, irregular hisps of light occasionally make it to earth with magnitude 2.0 brightness.
www.zetatalk.com /theword/tword03k.htm   (780 words)

  
 USGS Earthquake Hazards Program-FAQ - Frequently Asked Questions
The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded on a seismogram at a certain period.
The idea of a logarithmic earthquake magnitude scale was first developed by Charles Richter in the 1930's for measuring the size of earthquakes occurring in southern California using relatively high-frequency data from nearby seismograph stations.
In that case, the different assigned magnitudes are a result of the slight differences in the instruments and their locations with respect to the earthquake epicenter.
earthquake.usgs.gov /faq/meas.html   (2978 words)

  
 eSky: Magnitude
A star of magnitude +5.0 is dim, and hardly visible to the naked eye, while a star with a magnitude close to 0.0 (such as Capella in Auriga) is very bright indeed.
For example, Alpha Centauri (with a magnitude of very nearly 0.0) is one hundred times brighter than Marfik in Hercules, one of the faintest named stars with a magnitude of exactly +5.0.
The magnitude scale is calibrated to the brightnesses of about a hundred specific stars, all lying within a few degrees of the Northern Celestial Pole and thus termed the North Polar Sequence.
www.glyphweb.com /esky/concepts/magnitude.html   (655 words)

  
 FAQs on Pacific Northwest Earthquakes
Magnitude is determined from measurements made from seismograms and not on reports of shaking or interpretations of building damage.
The Richter magnitude of an earthquake is calculated by measuring the amplitude of the maximum wave motion recorded on the seismogram.
The magnitude 6.5 April 29, 1965, Seattle-Tacoma earthquake produced intensity VII to VIII damage near its epicenter, intensity V damage 150 kilometers away, and intensity I and 11 (barely felt) 300 to 500 kilometers from the epicenter.
www.geophys.washington.edu /SEIS/PNSN/INFO_GENERAL/faq.html   (2932 words)

  
 Magnitude
Apparent magnitude is the brightness of an object as it appears to an observer on Earth.
Pogson proposed that a 6th magnitude star should be 1/100 of the brightness of a star of the 1st magnitude.
Photographic magnitude is the magnitude measured by a standard photographic emulsion, which responds chiefly to the blue and violet part of the spectrum (although different photographic materials have very different colour responses).
www.historyoftheuniverse.com /magnitude.html   (618 words)

  
 Absolute Visual Magnitude - Hutchinson encyclopedia article about Absolute Visual Magnitude
In astronomy, measure of the intrinsic brightness of a celestial body in contrast to its apparent brightness or magnitude as seen from Earth.
For a non-self-luminous body, such as an asteroid, the absolute magnitude is the magnitude it would appear to have if it were one astronomical unit (149.6 million km/92.6 million mi) from both the Sun and the Earth with the phase angle zero.
For a self-luminous body, such as a star or galaxy, the absolute magnitude is the magnitude it would appear to have if it were at a distance of 10 parsecs or 32.616 light years.
encyclopedia.farlex.com /Absolute+Visual+Magnitude   (162 words)

  
 ABAG On Shaky Ground - Magnitude   (Site not responding. Last check: 2007-10-21)
Magnitude is a measure of overall earthquake size.
Thus, one principal factor in determining shaking hazard is the magnitude of the earthquake.
The moment magnitude is proportional to the area of the fault surface that has slipped.
www.abag.ca.gov /bayarea/eqmaps/doc/big.html   (185 words)

  
 Glossary
There are many different ways that magnitude is measured from seismograms because each method only works over a limited range of magnitudes and with different types of seismometers.
A magnitude for distant earthquakes based on the amplitude of Rayleigh surface waves measured at a period near 20 sec.
Based on the moment of the earthquake, which is equal to the rigidity of the earth times the average amount of slip on the fault times the amount of fault area that slipped.
earthquake.usgs.gov /recenteqsww/glossary.htm   (1535 words)

  
 Star Magnitudes
Sixth magnitude stars were assigned to stars that were barely visible to the unaided eye under favorable conditions.
For example, a first magnitude star is 100 brighter than a sixth magnitude star or the sixth magnitude star is 1/100 or.01 dimmer that a first magnitude star.
Second example, a fifth magnitude star is 2.512 times brighter than a sixth magnitude star or the sixth magnitude star is 1/2.512 or.40 dimmer that a fifth magnitude star.
www.stargazing.net /david/constel/magnitude.html   (638 words)

  
 Measurement
Magnitude does not depend on population and effects to ground structures, but rather on wave amplitude and distance.
This magnitude scale is logarithmic, meaning each step in magnitude is exponentially greater than the last.
These magnitude scales differ by the type of wave amplitude that is measured from the seismogram and the mathematical formula used to determine the magnitude.
scign.jpl.nasa.gov /learn/eq8.htm   (492 words)

  
 SPACE.com -- Time to View Planet Mercury is Now
On the evening of March 4, Mercury will be shining at magnitude —1.1, which means that only one other object in that same evening sky will be brighter: Sirius (the brightest of all stars).
Magnitude is the standard by which astronomers measure the apparent brightness of objects that appear in the sky.
Negative magnitudes are reserved for the most brilliant objects: the brightest star is Sirius (-1.4); the full Moon is -12.7; the Sun is -26.7.
www.space.com /spacewatch/050304_mercury_guide.html   (1105 words)

  
 Zoom Astronomy Glossary: M
Magnitude is a measure of brightness of celestial objects.
Lower numbers represent brighter objects than higher numbers; very bright star are 1st magnitude, less bright stars are 2nd magnitude, etc. The magnitude scale is logarithmic; a difference in magnitude of 5 is a 100-fold increase in brightness (the difference in each successive magnitude is a factor of about 2.512 times).
Miras are pulsating red giants that vary in magnitude as much as a factor of many hundred (by 6 or 8 magnitudes).
www.enchantedlearning.com /subjects/astronomy/glossary/indexm.shtml   (4064 words)

  
 What Is Visual Magnitude?   (Site not responding. Last check: 2007-10-21)
"Visual magnitude" is a scale used by astronomers to measure the brightness of a star.
This means a difference in magnitudes of 5 units (from magnitude 1 to magnitude 6, for example) corresponds to a change in brightness of 100 times.
Absolute magnitude is defined as how bright a star would appear if it were exactly 10 parsecs (about 33 light years) away from Earth.
liftoff.msfc.nasa.gov /academy/universe/MAG.HTML   (385 words)

  
 Magnitude   (Site not responding. Last check: 2007-10-21)
The brightest stars were given a magnitude of 1 and the dimmest stars a magnitude of 6.
A range of magnitude of 1 to 6 is actually quite a large variation.
Since a jump from magnitude 6 to magnitude 1 is an increase in brightness of 100 times, each step, represented by x must be multiplied (5 times) to go from a magnitude 6 to a magnitude 1, so:-
freespace.virgin.net /gareth.james/astro/alevel/magnitude.html   (580 words)

  
 Properties of Stars
The other intervals of magnitude were based on the 19th century belief of how the human eye perceives differences in brightnesses.
On the quantified magnitude scale, a magnitude interval of 1 corresponds to a factor of 100
times brighter than 4th magnitude stars, etc. (See the math review appendix for what is meant by the terms ``factor of'' and ``times''.) Notice that you raise the number 2.512 to a power equal to the difference in magnitudes.
www.astronomynotes.com /starprop/s4.htm   (1223 words)

  
 USGS Earthquake Hazards Program: The Richter Magnitude Scale   (Site not responding. Last check: 2007-10-21)
The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes.
The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs.
For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3.
wwwneic.cr.usgs.gov /neis/general/richter.html   (650 words)

  
 Sacramento Peak: Magnitude   (Site not responding. Last check: 2007-10-21)
A difference of five magnitudes corresponds to a brightness ratio of exactly 100: a star of magnitude 0 is 100 times as bright as a star of magnitude 5, and 10,000 (= 100 times 100) times as bright as a star of magnitude 10.
The limiting magnitudes are as seen from the Earth: the Hubble Space Telescope in space might gain another 1.5 magnitudes because it does not have to look through an atmosphere that blurs and scatters light.
How long one has to expose a picture to record a very faint object depends on the magnitude of the object, on the optical quality of the instrument, on the length of the exposure, on the efficiency of the recording device, and on whether the object is point-like or extended.
www.sunspot.noao.edu /sunspot/pr/answerbook/magnitude.html   (1988 words)

  
 Stellar Magnitude
The magnitude scale, like the sensitivity of the naked eye, is logarithmic and, by convention, defined so that brighter stars have smaller magnitude values.
Thus a first magnitude star is very bright, a sixth magnitude star is at the limit of normal vision.
Absolute magnitude is the apparent magnitude that a star would have if it were located at a standard distance of 10 parsecs from the Earth.
www.peripatus.gen.nz /Astronomy/SteMag.html   (454 words)

  
 Determination of the limiting magnitude | International Meteor Organization   (Site not responding. Last check: 2007-10-21)
The limiting magnitude (which is defined as being the magnitude of the faintest star near the zenith that the observer can detect using the slightly averted naked eye) defines both the condition of the sky's clarity and the quality of the observer's eyes.
Determine the limiting magnitude at the start of the watch, and then every 30-45 minutes, even if there is no considerable change.
Magnitude gaps of about 0.3 or more occurring for magnitudes fainter than +5.5 are marked by italic numbers.
www.imo.net /visual/lm.html   (490 words)

  
 Curious About Astronomy: What is apparent magnitude?
Thus, you might have expected that if the magnitude scale were set up "correctly", the difference in brightness between a magnitude 1 and magnitude 2 star would be the same as the difference in brightness between a magnitude 2 and magnitude 3 star -- this would be a so-called linear brightness scale.
That is, a magnitude 2 star is around 2.5 times fainter than a magnitude 1 star, while a magnitude 3 star is around 2.5 times fainter than a magnitude 2 star and therefore 2.5 x 2.5 = 6.3 times fainter than a magnitude 1 star.
Therefore, the magnitude of each star also depends on the color of the light, so we have to define exactly what type of light we're looking at when we quote a star's magnitude.
curious.astro.cornell.edu /question.php?number=569   (929 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.