Extinction
Dust clouds along the line of sight scatter and absorb light coming from distant objects. We therefore see these objects as dimmer and redder than they really are.
Extinction Events
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Extinction event
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Definition: extinction: The failure of a taxonomic group to produce direct descendants, causing its worldwide disappearance from the record at a given point in time.
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EXTINCTION
Atmospheric extinction is the reduction in brightness of stellar objects as their photons pass through our atmosphere.
atmospheric extinction
The reduction in the intensity of light from a celestial body due to absorption and scattering by Earth's atmosphere.
As for the other extinction events, while an asteroid impact almost certainly caused the demise of the dinosaurs, environmental factors such as climate variation, sea level change or intense geologic activity could have been the trigger instead.
Late Triassic The Late Triassic extinction occurred about 200 million years ago, and it killed about 50 percent of all marine species. It was belived to be caused by volcanism and global warming.
However, in the case of the Cretaceous-Tertiary (KT) extinction that killed the dinosaurs 65 million years ago, there is ample evidence of both an asteroid strike and catastrophic volcanic upheaval (the Deccan Traps).
Extinction
Starlight passing through a dust cloud can be affected in a couple of ways.
Extinction, atmospheric. The diminishing of light from astronomical objects due to the earth's atmosphere, in which molecules (air, dust, etc.) of the atmosphere absorb, reflect, and refract light before it reaches the ground.
Extinction- the apparent reduction in the brightness of a star or planet when low over the horizon because more of its light is absorbed by the Earth's atmosphere ...
Extinction Loss of light from an object as a consequence of absorption or scattering by an intervening medium. An example is the atmospheric extinction of light from stars near the horizon.
extinction
The dimming effect of the interstellar medium on starlight passing through it.
eyepiece
An optical instrument constructed of lenses which magnifies and focuses the incoming light gathered from a telescope.
Extinction
The dimming of light by intervening material; commonly, dimming by the interstellar medium.
Eyepiece ...
EXTINCTION - In astronomy, the dimming of starlight as it passes through the interstellar medium. Dust scatters some of the light, causing the total intensity of the light to diminish.
Extinction. The apparent reduction in brightness of a celestial object when it is low in the sky and much of its light is absorbed by Earth's atmosphere.
Extinction - The dimming of starlight due to absorption and scattering by interstellar dust particles.
Extinction
(a) Attenuation of starlight due to absorption and scattering by Earth's atmosphere, or by interstellar dust. The longer the path through the dust, and the denser the dust, the more the starlight is reddened.
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extinction The dimming of starlight as it passes through the interstellar medium.
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Extinction is inversely proportional to wavelength so red light is less affected than blue light. Distant stars thus appear more red than they actually are.
Extinction risk from climate change
The extinction risk of global warming is the risk species have of becoming extinct due to the effects of global warming.
Extinction
The apparent dimming of star or planet when low on the horizon due to absorption by the Earth's atmosphere.
Extragalactic
A term that means outside of or beyond our own galaxy.
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The extinction of the light is caused by interstellar dust grains located in the coldest, densest parts of larger molecular clouds. Clusters and large complexes of dark nebulae are associated with Giant Molecular Clouds.
MASS EXTINCTION
Mass extinction is the process in which huge numbers of species die out suddenly. The dinosaurs (and many other species) went extinct during the K-T extinction, which was probably caused by an asteroid colliding with the Earth.
3. Extinction is the _____ of starlight by interstellar _____. (Hint)
4. The density of interstellar matter can be characterized as being very _____. (Hint)
5. Interstellar gas is composed of 90 percent _____ and 9 percent _____. (Hint) ...
Atmospheric extinction is the term used for defining the absorption of starlight light by the earth's atmosphere. At an altitude of 52 degrees and higher, atmospheric extinction has a factor of zero.
interstellar extinction - (n.)
The obscuration of starlight by interstellar dust. Light is scattered off of dust grains, so that a distant star appears dimmer than it otherwise would.
Interstellar Extinction: As light from a star travels through interstellar space it encounters some amount of dust. This dust scatters some of the light, causing the total intensity of the light to diminish.
interstellar extinction: The dimming of starlight by gas and dust in the interstellar medium.
interstellar medium: The gas and dust distributed between the stars.
extinction (Galileo Project Glossary - JPL) The failure of a taxonomic group to produce direct descendants, causing its worldwide disappearance from the record at a given point in time.
Because of dust extinction, one always wants to use lines at the longest possible wavelength. As Susan Kleinmann once said, "I don't care if it's plastic, as long as it's in the infrared and you can see it".
ALVAREZ THEORY OF EXTINCTION
This theory is that a large asteroid, meteor, or comet hit the Earth 65 million years ago, causing huge atmospheric and geologic disruptions, leading to a mass extinction which killed the dinosaurs and many other species.
telephotometry The body of principles and techniques concerned with measuring atmospheric extinction using various types of telephotometer. Telescopium (abbr Tel, Tele) See constellation.
The last such eruption occurred some 65 million years ago (press release, Basu et al, 1993), created India's Deccan Traps, and -- in combination with the Chicxulub meteorite impact -- contributed to the extinction of the dinosaurs.
This is an extreme example of interstellar extinction which is the dimming of star light caused by the presence of interstellar material. In the dust lanes the extinction is complete. But in other regions it is only partial.
In 1980, physicist Luis Alvarez and coworkers reported finding a very high concentration of the element iridium in the sedimentary clay layer laid down at the time of the K-T extinction.
2 magnitudes of interstellar dust extinction as well as for a lot of ultraviolet light, gives a luminosity of 1980 times that of the Sun, a radius 7.
The answer lies in extinction by the carbon and iron whiskers that the QSSC uses to convert star light into CMB photons.
Typically, the particles have size about 1 µm but there must be a wide range of particle sizes present to explain the interstellar extinction curve.
Mexico's Chicxulub crater is believed to be the site of a meteorite impact so immense that the resulting environmental changes caused the extinction of the dinosaurs 65 million years ago.
To further confuse matters, remnants have been found of other major impacts that are not linked to any mass extinctions.
Paleontologists speculated and theorized for many years about what could have caused this mass extinction, known as the K-T event (Cretaceous-Tertiary Mass Extinction event).
Sharks, Atlantic cod, and Pacific sardines are tapped as particularly imperilled with extinction. The scientists recommend drastic measures to reduce ocean fishing. Nature, Environment News, BBC ...
The Death Star Theory refers to the fact that mass extinctions are periodic, and may be caused by the Earth's passing through a cloud of comets (the Oort cloud) every 26 million years.
An apparent 26 My periodicity to mass extinctions on Earth could be linked to climatic changes.
Atmospheric thermal currents also vary the amount of starlight passing through it and we call this atmospheric "extinction." Random intensity fluctuations of starlight passing through the atmosphere are called "scintillation.
When examining the Earth's geological record, it appears that about once every 30 million years a mass extinction of life on Earth has occurred.
Following the Cambrian explosion, about 535 Ma, there have been five major mass extinctions.
A pulsar is apparently the last stage in the life cycle before final extinction as a black hole, which is matter so dense that nothing, not even radiation, can escape from it.
Impacts may have delivered the key ingredients for life on Earth - and caused devastating extinctions.
produce impact craters such as Meteor Crater in Arizona in the southwestern United States, and one measuring roughly 10 km across (according to some, a comet nucleus rather than an asteroid) is believed responsible by many for the mass extinction of ...
The evidence for this star is the apparent 30 million year period of global catastrophes and consequent mass extinctions of species such as the dinosaurs, The theory suggests that Nemesis disturbs the Oort cloud, ...
Sixty-five million years ago the Earth was struck by a large asteroid or comet, an event which may have hastened the extinction of the dinosaurs.
The extinction of the dinosaurs is attributed to such a collision, its evidence detected by Walter Alvarez as a thin layer of iridium-rich deposit extending though Italian limestone.
Here is a recent study by some folks that link a mass-extinction that happened 450 million years to a large gamma-ray burst. Such events can severely damage the ozone layer and lead to strong disruptions to the food chain.
According to Greek myth, he almost died after being stung by the Scorpion (Scorpius) sent by Gaia to prevent Orion from hunting all aminals to extinction. Asclepius (Ophiuchus) saved Orion's life.
Many people believe that the great extinction at the end of the Cretaceous period was caused by a large asteroid hitting the Earth. The resulting dust cloud then cooled the Earth and caused many species to die out, including the dinosaurs.
 See also: Earth, Time, Light, Planet, Period
  
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