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. These effects are known as extinction and interstellar reddening respectively.
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Extinction, Scattering, and Absorption
Astronomers who specialize in photometry need to compensate for atmospheric extinction: the reduction in a celestial object's apparent brightness when its light passes through the atmosphere. This depends on three factors: ...
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.
Starlight passing through a dust cloud can be affected in a couple of ways. The light can be totally blocked if the dust is thick enough or it can be partially scattered by an amount that depends on the color of the light and the thickness of the dust cloud.
~, 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.
~- 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
Eyepiece- a set of lenses used to magnify the image produced by a telescope's objective ...
~ Loss of light from an object as a consequence of absorption or scattering by an intervening medium. An example is the atmospheric ~ of light from stars near the horizon.
The dimming effect of the interstellar medium on starlight passing through it.
An optical instrument constructed of lenses which magnifies and focuses the incoming light gathered from a telescope.
The dimming of light by intervening material; commonly, dimming by the interstellar medium.
~ and survival
Crocodilians, pterosaurs, dinosaurs, and champsosaurs survived the Triassic-Jurassic ~ event
Triassic-Jurassic ~ event ...
~ - 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. It is important to take this effect into account when measuring the apparent brightness of stars.
~. 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.
~ - The dimming of starlight due to absorption and scattering by interstellar dust particles.
Fabry- Perot Etalon - A nonabsorbing, multireflecting device, similar in design to the Fabry-Perot interferometer, that serves as a multilayer, narrow-bandpass filter.
(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. The normal relation is AV = 0.8 mag per kpc.
Mass ~ by Moroccan Desert Meteorite
Lesotho Poltergeist May Have Been a Meteorite
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~ The dimming of starlight as it passes through the interstellar medium.
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~ is inversely proportional to wavelength so red light is less affected than blue light. Distant stars thus appear more red than they actually are. This interstellar reddening must be compensated for in trying to determine the true colour and brightness of a star.
The apparent dimming of star or planet when low on the horizon due to absorption by the Earth's atmosphere.
A term that means outside of or beyond our own galaxy.
The ~ 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. Isolated small dark nebulae are called Bok globules.
Mass ~ is the process in which huge numbers of species die out suddenly. The dinosaurs (and many other species) went extinct during the K-T ~, which was probably caused by an asteroid colliding with the Earth.
ELE = ~ Level Event as far as i know
@Gray (No.12): Yes, that's pretty much it. The light from Betelgeuse takes 600 years to reach us, so any event we can see from Earth happened 600 years ago.
3. ~ 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 ~ 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 ~ has a factor of zero.
The K-T mass ~ obliterated the dinosaurs , pterosaurs, plesiosaurs, mosasaurs, ammonites, some families of birds and marsupial mammals, over half the plankton groups, many families of teleost (bony) fishes, bivalves, snails, sponges, sea urchins and others.
interstellar ~ - (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 ~: 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. The more dust, the dimmer the star will appear.
The dimming of starlight as it passes through the interstellar medium.
Gas and dust in interstellar space.
~ (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.
~ The attenuation of light; that is, the reduction of illuminance of a collimated beam of light as the light passes through a medium wherein absorption and scattering occur.
Because of dust ~, 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".
exosphere Outermost fringe of Earth's atmosphere. expanding cosmological model exploding galaxy Galaxy in which powerful explosions are occurring in its central region and which is emitting nonthermal radiation. ~ extragalactic ...
ALVAREZ THEORY OF ~
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 ~ which killed the dinosaurs and many other species.
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 ~ of the dinosaurs.
This is an extreme example of interstellar ~ which is the dimming of star light caused by the presence of interstellar material. In the dust lanes the ~ 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 ~.
2 magnitudes of interstellar dust ~ as well as for a lot of ultraviolet light, gives a luminosity of 1980 times that of the Sun, a radius 7.6 solar, a mass of about 5 1/2 solar, and confirmation that the star is indeed a subgiant and is about to give up core hydrogen fusion.
The answer lies in ~ 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 ~ curve.
An apparent 26 My periodicity to mass ~s on Earth could be linked to climatic changes. Possible external causes include variability of the , aging of the , orbital and obliquity changes, dust-releasing vulcanism, comet impacts, a companion star to the ("Nemesis"), and galactic plane dust.
Atmospheric thermal currents also vary the amount of starlight passing through it and we call this atmospheric "~." 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 ~ of life on Earth has occurred. The most well-known of those mass ~s is of course the dinosaur ~ some 65 million years ago.
Following the Cambrian explosion, about 535 Ma, there have been five major mass ~s.
Nemesis was proposed to explain some regularities of the great ~s of life on Earth. The theory says that Nemesis creates periodical perturbations in the asteroids and comets of the solar system causing a shower of large bodies and some of them hit Earth causing destruction of life.
Stars in the Milky Way at Mid-Infrared Wavelengths (free from dust ~ - NASA/IRAS Image).
Warm Dust in the Milky Way (NASA/IRAS Image)
Multiwavelength Milky Way
Request a free copy of the Multiwavelength Milky Way poster. COBE Infrared view.
This event resulted in the ~ of over 50% of the species living at the...
4 years ago
What is the price per ounce or gram of a meteorite ...
atmospheric absorption or ~
The decrease in light caused by passage through the atmoshpere.
atmospheric escape ...
Searching, finding and tracking asteroids and comets is important, probably more than any other natural threat, they are the most likely to cause a mass-~ event here on our humble planet.
The evidence for this star is the apparent 30 million year period of global catastrophes and consequent mass ~s of species such as the dinosaurs, The theory suggests that Nemesis disturbs the Oort cloud, ...
The ~ 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-~ 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.
- Every few tens of millions of years, on average, an asteroid 10 km or so in size hits Earth. The last one caused the ~ of the dinosaurs and many other species.
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 ~. Asclepius (Ophiuchus) saved Orion's life. Mortal enemies ever since, Orion and Scorpius are never seem together in the sky.
Many people believe that the great ~ 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.
The impact of a near-Earth object 65 million years ago in what is today the Caribbean region, as depicted in an artist's conception. Many scientists believe that the collision of a large asteroid or comet nucleus with Earth triggered the mass ~ of the dinosaurs and many other species near ...
A gamma-ray burst, for instance, may have caused the Ordovician ~ which killed 60% of all marine invertebrates 450 million years ago. No need to worry, though, as Scientists have put the chances of a gamma ray burst occurring in our galaxy at less than 1 in 10 million.
Some examples are the 1908 Siberian Tunguska impact by a comet or an asteroid and the asteroid that struck Earth 65 million years ago, which may have led to the ~ of the dinosaurs and other species of the Cretaceous-Tertiary era.
In 2267, James T. Kirk and his crew made contact with Apollo, the last of the Greek gods, who had waited for his worshipers to develop space travel and seek him out. The encounter resulted in the death of Apollo and the ~ of his species. (TOS: "Who Mourns for Adonais?") ...
Two wave trains of light from a double slit produce interference, an effect that is visible on a screen as a pattern of alternating dark and light bands caused by intensification and ~ at points at which the waves are in phase and out of phase, respectively.
1940s, Turner says, and those forests have mostly disappeared because they were heavily logged during the first half of the 20th century. The wood was in high demand for fuel during World War II. "[This was] believed to be a classic case of people driving a large charismatic species to ~ by ...
nucleus of a comet with a large city would probably destroy the city but the probability of such an event occurring is exceedingly small. Some scientists suggest, however, that collisions have taken place in the astronomical past and may even, for example, have had a climatic role in the ~ ...
Some scientists believe that just such an impact in the area of the Yucatan Peninsula in Mexico started the chain of events which led to the ~ of the dinosaurs here on Earth.
See also: What is the meaning of Earth, Astro, Planet, Sun, Orbit?