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The [[Saturday Night Live season 34|thirty-fourth season]] of the [[Variety show|variety]] series [[Saturday Night Live]] began airing in [[2008 in television|2008]] and is expected to conclude in [[2009 in television|2009]] on [[NBC]]. The season is expected to consist of 22 episodes, in attempt to compensate for episodes lost during the [[2007–2008 Writers Guild of America strike]]. This would make it the longest season since the show's [[Saturday Night Live (Season 2)|second season]].
{{Citations missing|date=January 2008}}
In addition to the regular episodes, three thirty-minute episodes are scheduled to air Thursdays in October in the weeks leading up to the [[United States presidential election, 2008|2008 United States presidential election]].<ref name=autogenerated1>[http://www.cinemablend.com/television/New-NBC-Series-SNL-Thursday-Night-Live-Fall-2008-9791.html UNew NBC Series: SNL Thursday Night Live - Fall 2008 - Blend Television]</ref> The season began on [[September 13]], [[2008]] on NBC, with Olympic swimming gold medalist [[Michael Phelps]] as host and [[Tina Fey]] appearing as Republican vice presidential candidate [[Sarah Palin]] and [[Amy Poehler]] as [[Hillary Clinton]]. The show scored its highest-rated premiere since September 2001 and is the second most-watched ''SNL'' ever.<ref>[http://www.wopular.com/node/1259825 Tina Fey leads SNL in 2nd best premiere ever]</ref> The season premiere date of September 13 was earlier than the premiere date for previous seasons, which typically have started during the final weekend of September or in early October. This is [[Amy Poehler]]'s final season as she will be leaving in November after the election for maternity leave and will then go on to star in the as-of-yet untitled ''[[The Office (US TV series)|Office]]'' spinoff.<ref>[http://www.film.com/features/story/amy-poehler-confirms-she-leaving/21839551 Amy Poehler Confirms She Is Leaving Saturday Night Live - Film.com]</ref> With the exception of Amy Poehler's departure and the hiring of new feature player [[Bobby Moynihan]] (who, like Casey Wilson, was a member of the Upright Citizens Brigade stage troupe), there have been no major cast changes so far this season.


==SNL Thursday Night Live==
[[Image:Tycho_crater_on_the_Moon.jpg|thumb|300px|The prominent impact crater [[Tycho (crater)|Tycho]] on the [[Moon]]. ''[[NASA]]&nbsp;photo.'']]
Saturday Night Live will air three special [[prime time]] half-hour episodes on Thursdays starting October 9th. These specials, entitled [[SNL Thursday Night Live]], will focus on the [[United States presidential election, 2008|presidential election]].<ref name=autogenerated1 />
{{Redirect|Meteor crater|the crater in Arizona|Meteor Crater}}


{| class="wikitable" border="1"
In the broadest sense, the term '''impact crater''' can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with larger body. In most common usage, the term is used for the approximately circular [[depression (geology)|depression]] in the surface of a [[planet]], [[natural satellite|moon]] or other solid body in the [[Solar System]], formed by the [[hypervelocity|hyper-velocity]] [[collision|impact]] of a smaller body with the surface. This is in contrast to the [[pit crater]] which results from an internal collapse. Impact craters typically have raised rims, and they range from small, simple, bowl-shaped depressions to large, complex, multi-ringed, impact basins. [[Meteor Crater]] is perhaps the best-known example of a small impact crater on the Earth.
|-
! Episode Number
! Original Air Date
! Notes
|-
| Episode 1
| [[October 9]], [[2008]]
|
*[[Bill Murray]] and [[Chris Parnell]] made cameo appearances in the 2nd Presidential Debate sketch.
|-
| Episode 2
| [[October 16]], [[2008]]
| Confirmed Below
|-
| Episode 3
| [[October 23]], [[2008]]
| Confirmed Below
|-
|}


==Cast==
Impact craters provide the dominant landforms on many solid Solar System objects including the [[Moon]], [[mercury (planet)|Mercury]], [[Callisto (moon)|Callisto]], [[Ganymede (moon)|Ganymede]] and most small moons and [[asteroid]]s. On other planets and moons that experience more-active surface geological processes, such as [[Earth]], [[Venus]], [[Mars]], [[Europa (moon)|Europa]], [[io (moon)| Io]] and [[Titan (moon)|Titan]], visible impact craters are less common because they become [[erosion|eroded]], buried or transformed by [[tectonics]] over time. Where such processes have destroyed most of the original crater topography, the terms [[impact structure]] or astrobleme are more commonly used. In early literature, before the significance of impact cratering was widely recognised, the terms [[cryptoexplosion]] or cryptovolcanic structure were often used to describe what are now recognised as impact-related features on Earth.


;Repertory players
In the early Solar System, rates of impact cratering were much higher than today. The large multi-ringed impact basins, with diameters of hundreds of kilometres or more, retained for example on Mercury and the Moon, record a period of [[Late Heavy Bombardment|intense early bombardment]] in the inner Solar System that ended about 3.8 billion years ago. Since that time, the rate of crater production on Earth has been considerably lower, but it is appreciable nonetheless; Earth experiences from one to three impacts large enough to produce a 20 km diameter crater about once every million years on average. This indicates that there should be far more relatively young craters on the planet than have been discovered so far.
*[[Fred Armisen]]
*[[Will Forte]]
*[[Bill Hader]]
*[[Darrell Hammond]]
*[[Seth Meyers]]
*[[Amy Poehler]] (final: November)
*[[Andy Samberg]]
*[[Jason Sudeikis]]
*[[Kenan Thompson]]
*[[Kristen Wiig]]


;Featured players
Although the Earth’s active surface processes quickly destroy the impact record, about 170 terrestrial impact craters have been identified. These range in diameter from a few tens of meters up to about 300 km, and they range in age from recent times (e.g. the [[Sikhote-Alin Meteorite|Sikhote-Alin craters]] in [[Russia]] witnessed in 1947) to more than two billion years, though most are less than 200 million years old because geological processes tend to obliterate older craters. They are also selectively found in the [[craton|stable interior regions of continents]]. Few under sea craters have been discovered because of the difficulty of surveying the sea floor, the rapid rate of change of the ocean bottom, and the [[subduction|subduction of the ocean floor]] into the Earth's interior by processes of [[plate tectonics]].
*[[Bobby Moynihan]]
*[[Casey Wilson]]


==History==
==Listings==
* '''September 13, 2008 ''[[Michael Phelps]]/[[Lil Wayne]]'' (34.1, live)'''
* '''September 20, 2008 ''[[James Franco]]/[[Kings of Leon]]'' (34.2, live)'''
* '''September 27, 2008 ''[[Anna Faris]]/[[Duffy (singer)|Duffy]]'' (34.3, live)'''
* '''October 4, 2008 ''[[Anne Hathaway]]/[[The Killers]]'' (34.4, live)'''
* '''October 11, 2008''' ''[[Michael Phelps]]/[[Lil Wayne]]'' (34.1, repeat)<ref>[http://nbcumv.com/entertainment/program_detail.nbc/saturdaynightlive.html NBCUMV]</ref>
* '''October 18, 2008 ''[[Josh Brolin]]/[[Adele (singer)|Adele]]'' (34.5, live)'''
* '''October 25, 2008 ''[[Jon Hamm]]/[[Coldplay]]'' (34.6, live)'''


==Episodes==
<!-- Commented out because image was deleted: [[Image:MeteorCraterPanorama.jpg|thumb|left|300px|[[Meteor Crater]] in Arizona]] -->
{| class="wikitable"
[[image:Eugene_Shoemaker.jpg|thumb|left|250px|Eugene Shoemaker, pioneer impact crater researcher, here at a stereoscopic microscope used for asteroid discovery]]
|-
! Episode Number
! Date
! Host
! Musical Guest
! Remarks
|-
| 637
(34.1)
| [[September 13]], [[2008]]
| [[Michael Phelps]]
| [[Lil Wayne]]
|
*Senator [[Barack Obama]] was scheduled to make a second cameo appearance in this episode.<ref name="TV Guide">[http://community.tvguide.com/blog-entry/TVGuide-News-Blog/Todays-News/Barack-Obama-Saturday/800046555 Live from New York, It's Obama on SNL!]</ref> However, due to the results of [[Hurricane Ike]], Obama pulled out. <ref>[http://www.breitbart.com/article.php?id=080913104404.qqkvqu6h&show_article=1 Obama tones it down as Hurricane Ike looms] </ref> Therefore, his appearance will be rescheduled for a later date.<ref>[http://community.tvguide.com/blog-entry/TVGuide-News-Blog/Todays-News/Barack-Obama-Cancels/800046643 Rain Check? Obama Nixes SNL Visit Due to Hurricane]</ref>[[Chuck Norris]] was also scheduled to make a cameo appearance, but pulled out for the same reason.<ref>[http://snltranscripts.jt.org/08/08a.phtml SNL Transcripts]</ref>
*[[William Shatner]], Michael Phelps' mother Debbie and [[Jared Fogle]] make cameo appearances
*[[Guy Fierei]] was part of the front-row stage while Shatner was speaking.
*[[Tina Fey]] appeared as [[Sarah Palin]] in [[A Nonpartisan Message from Governor Sarah Palin & Senator Hillary Clinton]]
*[[Lil Wayne]] performed "[[Got Money]]" and "[[Lollipop (Lil Wayne song)|Lollipop]]"
*[[Bobby Moynihan]]'s first episode as a featured cast member
|-
| 638 (34.2)
| [[September 20]], [[2008]]
| [[James Franco]]
| [[Kings of Leon]]
|
* [[Cameron Diaz]] reprised her role in "The Cougar Den" sketch.
* ''[[Gossip Girl (TV series)|Gossip Girl]]'''s [[Blake Lively]] made a cameo appearance in the [[SNL Digital Shorts|SNL Digital Short]].<ref>[http://www.imdb.com/news/ns0000002/#ni0570238 Diaz Plays 'Cougar' on TV Show]</ref>
* [[Kings of Leon]] performed "[[Sex on Fire]]" and "Use Somebody"
|-
| 639 (34.3)
| [[September 27]], [[2008]]
| [[Anna Faris]]
| [[Duffy (singer)|Duffy]]
|
* Tina Fey returned as Gov. Sarah Palin in the cold open.
* [[Chris Parnell]] made a cameo appearance in a debate sketch as [[Jim Lehrer]].
* [[Duffy]] performed "[[Mercy (Duffy song)|Mercy]]" and "[[Stepping Stone (Duffy song)|Stepping Stone]]".
|-
| 640 (34.4)
| [[October 4]], [[2008]]
| [[Anne Hathaway]]
| [[The Killers]]
|
* [[Queen Latifah]] appeared as [[Gwen Ifill]] and Tina Fey returned as Sarah Palin in a parody of the Vice Presidental Debate.
* [[The Killers]] performed "[[Human (The Killers song)|Human]]" and "Spaceman".
* An edited version of the sketch parodying the economic bailout was posted on NBC.com, removing references to Herbert and Marion Sandler's (played by Darrell Hammond and Casey Wilson, respectively) corrupt activities and removing the graphic labeling the couple as "people who should be shot". [[Lorne Michaels]] admitted he did not know the Sandlers were a real couple, and that he believed they were simply characters written for the sketch. <ref>http://seattlepi.nwsource.com/tvguide/382363_tvgif8.html</ref>
|-
| 641
(34.5)
| [[October 18]], [[2008]]
| [[Josh Brolin]]<ref name="packed">[http://nbcumv.com/entertainment/release_detail.nbc/entertainment-20080929000000-nbc039s34satu.html NBC'S 'SATURDAY NIGHT LIVE' PREPARES A PACKED OCTOBER]</ref>
| [[Adele (singer)|Adele]]<ref name="packed"/>
|-
| 642<ref>[http://nymag.com/daily/entertainment/2008/09/don_draper_to_host_snl.html?loc=interstitialskip Don Draper to Host ‘Saturday Night Live’]</ref>
(34.6)
| [[October 25]], [[2008]]
| [[Jon Hamm]]
| [[Coldplay]]<ref>[http://www.coldplay.com/newsdetail.php?id=132&page=0]</ref>
|
* Governor [[Sarah Palin]] is rumored to be making a cameo appearance as herself.<ref>{{cite news |first=Cindy |last=Adams |authorlink= coauthors= |title=Golly, Palin To Play Herself on ''SNL'' |url=http://www.nypost.com/seven/10102008/gossip/cindy/golly__palin_to_play_herself_on_snl_132932.htm |work= |publisher=''[[The New York Post]]'' |date=2008-10-10 |accessdate=2008-10-10 }}</ref>
|-
| 643
(34.7)
| [[November 1]], [[2008]]
| TBA
| TBA
|-
|}


{{start box}}
[[Daniel Barringer (geologist)|Daniel Barringer]] (1860-1929) was one of the first to identify an impact crater, [[Meteor Crater]] in [[Arizona]]; to crater specialists the site is referred to as [[Barringer Crater]] in his honor. Initially Barringer's ideas were not widely accepted, and even when the origin of Meteor Crater was finally acknowledged, the wider implications for impact cratering as a significant geological process on Earth were not.
{{succession box | title=[[Saturday Night Live]]<br> Season 34 | before=[[SNL: Season 33|Season 33]] | after= | years=}}
{{end box}}


{{Saturday Night Live}}
In the 1920s, the American geologist [[Walter H. Bucher]] studied a number of sites now recognized as impact craters in the USA. He concluded they had been created by some great explosive event, but believed that this force was probably [[volcano|volcanic]] in origin. However, in 1936, the geologists [[John D. Boon]] and [[Claude C. Albritton Jr.]] revisited Bucher's studies and concluded that the craters that he studied were probably formed by impacts.

The concept of impact cratering remained more or less speculative until the 1960s. At this time a number of researchers, most notably [[Eugene M. Shoemaker]], conducted detailed studies of a number of craters and recognized clear evidence that they had been created by impacts, specifically identifying the shock-metamorphic effects uniquely associated with impact events, of which the most familiar is [[shocked quartz]].

Armed with the knowledge of shock-metamorphic features, [[Carlyle S. Beals]] and colleagues at the [[Dominion Observatory]] in [[Victoria, British Columbia]], [[Canada]], and [[Wolf von Engelhardt]] of the [[University of Tübingen]] in [[Germany]] began a methodical search for impact craters. By 1970, they had tentatively identified more than 50. Although their work was controversial, the American [[Apollo program|Apollo]] Moon landings, which were in progress at the time, provided supportive evidence by recognizing the rate of impact cratering on the [[Moon]]. Processes of erosion on the Moon are minimal and so craters persist almost indefinitely. Since the Earth could be expected to have roughly the same cratering rate as the Moon, it became clear that the Earth had suffered far more impacts than could be seen by counting evident craters.

== Crater formation ==
[[Image:Impact movie.ogg|frame|A laboratory simulation of an impact event and crater formation]]
Impact cratering involves high velocity collisions between solid objects, typically much greater than the [[speed of sound|velocity of sound]] in those objects. Such hyper-velocity impacts produce physical effects such as [[melting]] and [[Evaporation|vaporization]], that do not occur in familiar sub-sonic collisions. On Earth, ignoring the slowing effects of travel through the atmosphere, the lowest impact velocity with an object from space is equal to the gravitational [[escape velocity]] of about 11 km/s. The fastest impacts occur at more than 70 km/s, calculated by summing the escape velocity from Earth, the escape velocity from the Sun at the Earth's [[orbit]], and the motion of the Earth around the Sun. The [[median]] impact velocity on Earth is about 20 to 25 km/s.

Impacts at these high speeds produce [[shock wave|shockwaves]] in solid materials, and both impactor and the material impacted are rapidly [[physical compression|compressed]] to high density. Following initial compression, the high-density, over-compressed region rapidly depressurizes, exploding violently, to set in train the sequence of events that produces the impact crater. Impact-crater formation is therefore more closely analogous to cratering by [[explosive material|high explosives]] than by mechanical displacement. Indeed, the [[energy density]] of some material involved in the formation of impact craters is many times higher than that generated by high explosives. Since craters are caused by [[explosion]]s, they are nearly always circular – only very low-angle impacts cause significantly elliptical craters.

It is convenient to divide the impact process conceptually into three distinct stages: (1) initial contact and compression, (2) excavation, (3) modification and collapse. In practice, there is overlap between the three processes with, for example, the excavation of the crater continuing in some regions while modification and collapse is already underway in others.

=== Contact and compression ===

In the absence of [[atmosphere]], the impact process begins when the impactor first touches the target surface. This contact [[acceleration|accelerates]] the target and decelerates the impactor. Because the impactor is moving so rapidly, the rear of the object moves a significant distance during the short-but-finite time taken for the deceleration to propagate across the impactor. As a result, the impactor is compressed, its density rises, and the [[pressure]] within it increases dramatically. Peak pressures in large impacts exceed 1 [[Tera|T]][[Pascal (unit)|Pa]] to reach values more usually found deep in the interiors of planets, or generated artificially in [[nuclear explosions]].

In physical terms, a [[supersonic]] shockwave initiates from the point of contact. As this shockwave expands, it decelerates and compresses the impactor, and it accelerates and compresses the target. Stress levels within the shockwave far exceeds the strength of solid materials; consequently, both the impactor and the target close to the impact site are irreversibly damaged. Many crystalline minerals can be transformed into higher-density phases by shockwaves, for example the common mineral quartz can be transformed into the higher-pressure forms [[coesite]] and [[stishovite]]. Many other shock-related changes take place within both impactor and target as the shockwave passes through, and some of these changes can be used as diagnostic tools to determine whether particular geological features were produced by impact cratering.

As the shockwave decays, the shocked region decompresses towards more usual pressures and densities. The damage produced by the shockwave raises the temperature of the material, and in all but the smallest impacts this increase in temperature is sufficient to melt the impactor, and in larger impacts to vaporize most of it and to melt large volumes of the target. As well as being heated, the target near the impact is accelerated by the shockwave, and it remains moving away from the impact behind the decaying shockwave.

=== Excavation ===

Contact, compression, decompression, and the passage of the shockwave all occur within a few tenths of a second for a large impact. The subsequent excavation of the crater occurs more slowly, and during this stage the flow of material is largely sub-sonic. During excavation, the crater grows as the accelerated target moves away from the impact point. The motion is initially downwards and outwards, and with time this evolves to becomes outwards and upwards. The flow initially produces an approximately hemispherical cavity. The cavity continues to grow, eventually producing a paraboloid (bowl-shaped) crater in which the centre has been pushed down, a significant volume of material has been ejected, and a topographically elevated crater rim has been pushed up. When this cavity has reached its maximum size, it is called the transient cavity.

[[Image:Mimas moon.jpg|thumb|right|250px|[[Herschel (crater on Mimas)|Herschel Crater]] on Saturn's moon [[Mimas (moon)|Mimas]]]]

The depth of the transient cavity is typically a quarter to a third of its diameter. [[Ejecta]] thrown out of the crater does not include material excavated from the full depth of the transient cavity - typically the depth of maximum excavation is only about a third of the total depth. As a result, about one third of the volume of the transient crater is formed by the ejection of material, and the remaining two thirds is formed by the displacement of material downwards, outwards and upwards, to form the elevated rim. For impacts into highly porous materials, a significant crater volume may also be formed by the permanent compaction of the pore space. Such compaction craters may be important on many asteroids, comets and small moons.

In large impacts, as well as material displaced and ejected to form the crater, significant volumes of target material may be melted and vaporized together with the original impactor. Some of this impact melt rock may be ejected, but most of it remains within the transient crater, initially forming a layer of impact melt coating the interior of the transient cavity. In contrast, the hot dense vaporized material expands rapidly out of the growing cavity, carrying some solid and molten material within it as it does so. As this hot vapor cloud expands, it rises and cools much like the archetypal mushroom cloud generated by large nuclear explosions. In large impacts, the expanding vapor cloud may rise to many times the scale height of the atmosphere, effectively expanding into free space.

Most material ejected from the crater is deposited within a few crater radii, but a small fraction may travel large distances at high velocity, and in large impacts it may exceed [[escape velocity]] and leave the impacted planet or moon entirely. The majority of the fastest material is ejected from close to the centre of impact, and the slowest material is ejected close to the rim at low velocities to form an overturned coherent flap of ejecta immediately outside the rim. As ejecta escapes from the growing crater, it forms an expanding curtain in the shape of an inverted cone; the trajectory of individual particles within the curtain is thought to be largely ballistic.

Small volumes of un-melted and relatively un-shocked material may be [[spall]]ed at very high relative velocities from the surface of the target and from the rear of the impactor. Spalling provides a potential mechanism whereby material may be ejected into inter-planetary space largely undamaged, and whereby small volumes of the impactor may be preserved undamaged even in large impacts. Small volumes of high-speed material may also be generated early in the impact by jetting. This occurs when two surfaces converge rapidly and obliquely at a small angle, and high-temperature highly shocked material is expelled from the convergence zone with velocities that may be several times larger than the impact velocity.

=== Modification and collapse ===

In most circumstances, the transient cavity is not stable: it collapses under gravity. In small craters, less than about 4 km diameter on Earth, there is some limited collapse of the crater rim coupled with debris sliding down the crater walls and drainage of impact melts into the deeper cavity. The resultant structure is called a simple crater, and it remains bowl-shaped and superficially similar to the transient crater. In simple craters, the original excavation cavity is overlain by a lens of collapse [[breccia]], ejecta and melt rock, and a portion of the central crater floor may sometimes be flat.

[[Image:Valhalla crater on Callisto.jpg|thumb|left|250px|Multi-ringed impact basin Valhalla on Jupiter's moon [[Callisto (moon)|Callisto]]]]

Above a certain threshold size, which varies with planetary gravity, the collapse and modification of the transient cavity is much more extensive, and the resulting structure is called a ''complex crater''. The collapse of the transient cavity is driven by gravity, and involves both the uplift of the central region and the inward collapse of the rim. The central uplift is not the result of ''elastic rebound'' which is a process in which a material with elastic strength attempts to return to its original geometry; rather the collapse is a process in which a material with little or no strength attempts to return to a state of gravitational equilibrium.

Complex craters have uplifted centers, and they have typically broad flat shallow crater floors, and terraced walls. At the largest sizes, one or more exterior or interior rings may appear, and the structure may be labeled an ''impact basin'' rather than an impact crater. Complex-crater morphology on rocky planets appears to follow a regular sequence with increasing size: small complex craters with a central topographic peak are called ''central peak craters'', for example [[tycho (crater)|Tycho]]; intermediate-sized craters, in which the central peak is replaced by a ring of peaks, are called ''peak-ring craters'', for example [[schrodinger (crater)|Schrodinger]]; and the largest craters contain multiple concentric topographic rings, and are called ''multi-ringed basins'', for example [[mare orientale|Orientale]]. On icy as opposed to rocky bodies, other morphological forms appear which may have central pits rather than central peaks, and at the largest sizes may contain very many concentric rings – [[Valhalla (crater)|Valhalla]] on Callisto is the type example of the latter.

== Identifying impact craters ==
[[Image:Azuara-impact-structure-Shocked breccia.jpg|thumb|Shocked polymictic [[breccia]] from the [[Azuara impact structure]], Spain.]]
[[Image:Wells creek shatter cones 2.JPG|thumb|right|Close-up of shatter cones developed in fine grained [[dolomite]] from the [[Wells Creek crater]], USA.]]
Some volcanic features can resemble impact craters, and [[breccia]]ted [[clastic rocks|rocks]] are associated with other geological formations besides impact craters. Non-explosive volcanic craters can usually be distinguished from impact craters by their irregular shape and the association of volcanic flows and other volcanic materials. An exception is that impact craters on Venus often have associated flows of melted material.

The distinctive mark of an impact crater is the presence of rock that has undergone shock-metamorphic effects, such as [[shatter cone]]s, melted rocks, and crystal deformations. The problem is that these materials tend to be deeply buried, at least for simple craters. They tend to be revealed in the uplifted center of a complex crater, however.

Impacts produce distinctive "shock-metamorphic" effects that allow impact sites to be distinctively identified. Such shock-metamorphic effects can include:

* A layer of shattered or "[[breccia]]ted" rock under the floor of the crater. This layer is called a "breccia lens".
* [[Shatter cone]]s, which are chevron-shaped impressions in rocks. Such cones are formed most easily in fine-grained rocks.
* High-temperature rock types, including laminated and welded blocks of sand, [[spherulite]]s and [[tektite]]s, or glassy spatters of molten rock. The impact origin of tektites has been questioned by some researchers; they have observed some volcanic features in tektites not found in impactites. Tektites are also drier (contain less water) than typical impactites. While rocks melted by the impact resemble volcanic rocks, they incorporate unmelted fragments of bedrock, form unusually large and unbroken fields, and have a much more mixed chemical composition than volcanic materials spewed up from within the Earth. They also may have relatively large amounts of trace elements that are associated with meteorites, such as nickel, platinum, iridium, and cobalt. Note: it is reported in the scientific literature that some "shock" features, such as small shatter cones, which are often reported as being associated only with impact events, have been found in terrestrial volcanic ejecta.
* Microscopic pressure deformations of minerals. These include fracture patterns in crystals of quartz and feldspar, and formation of high-pressure materials such as diamond, derived from graphite and other carbon compounds, or stishovite and [[coesite]], varieties of [[shocked quartz]].

Craters can also be created from underground [[nuclear weapon|nuclear explosions]]. One of the most crater-pocked sites on the planet is the [[Nevada Test Site]], where a number of craters were purposely made during its years as a center for [[nuclear testing]] (see, for example, [[Operation Plowshare]]).

== Lunar crater categorization ==
In 1978, Chuck Wood and Leif Andersson of the Lunar & Planetary Lab devised a system of categorization of lunar impact craters. They used a sampling of craters that were relatively unmodified by subsequent impacts, then grouped the results into five broad categories. These successfully accounted for about 99% of all lunar impact craters.

The LPC Crater Types were as follows:

* ''ALC'' &mdash; small, cup-shaped craters with a diameter of about 10&nbsp;km or less, and no central floor. The [[archetype]] for this category is '[[Albategnius (crater)|Albategnius C]]'.
* ''BIO'' &mdash; similar to an ALC, but with small, flat floors. Typical diameter is about 15&nbsp;km. The lunar crater archetype is [[Biot (crater)|Biot]].
* ''SOS'' &mdash; the interior floor is wide and flat, with no central peak. The inner walls are not [[wiktionary:terrace|terrace]]d. The diameter is normally in the range of 15-25&nbsp;km. The archetype is [[Sosigenes (crater)|Sosigenes]].
* ''TRI'' &mdash; these complex craters are large enough so that their inner walls have slumped to the floor. They can range in size from 15-50&nbsp;km in diameter. The archetype crater is [[Triesnecker (crater)|Triesnecker]].
* ''TYC'' &mdash; these are larger than 50&nbsp;km, with [[wiktionary:terrace|terrace]]d inner walls and relatively flat floors. They frequently have large central peak formations. [[Tycho (crater)|Tycho]] is the archetype for this class.

Beyond a couple of hundred kilometers diameter, the central peak of the TYC class disappear and they are classed as basins.

==Lists of craters==
{{col-begin}}

{{col-1-of-2}}
* [[List of impact craters on Earth]]
* [[List of craters on Mercury]]
* [[List of craters on the Moon]]
* [[List of craters on Mars]]
* [[Phobos (moon)#Named_geological_features|List of geological features on Phobos]]
* [[List of geological features on Jupiter's smaller moons]]
* [[List of craters on Europa]]
* [[List of craters on Ganymede]]
* [[List of craters on Callisto]]
* [[List of geological features on Saturn's smaller moons]]
* [[List of geological features on Mimas]]
* [[List of geological features on Enceladus]]
{{col-2-of-2}}
* [[List of geological features on Tethys]]
* [[List of geological features on Dione]]
* [[List of geological features on Rhea]]
* [[List of geological features on Iapetus]]
* [[List of craters on Puck]]
* [[List of geological features on Miranda]]
* [[List of geological features on Ariel]]
* [[List of craters on Umbriel]]
* [[List of geological features on Titania]]
* [[List of geological features on Oberon]]
* [[List of craters on Triton]]
{{col-end}}

===Notable impact craters on Earth===
{{main|List of impact craters on Earth}}

{{col-begin}}

{{col-1-of-2}}
* [[Aorounga crater|Aorounga Crater]] (Chad)
* [[Barringer Crater]], aka Meteor Crater (Arizona, US)
* [[Beyenchime-Salaatin crater]] (Russia, Far East)
* [[Bosumtwi crater]] (Ghana)
* [[Chesapeake Bay impact crater]] (Virginia, US)
* [[Chicxulub Crater|Chicxulub, Extinction Event Crater]] (Mexico)
* [[Clearwater Lakes]] (Quebec, Canada)
* [[Connolly Basin crater]] (Western Australia)
* [[Deep Bay crater]] (Saskatchewan, Canada)
* [[Gosses Bluff crater]] (Australia)
* [[Haughton impact crater]] (Nunavut, Canada)
* [[Kaali crater]] (Estonia)
* [[Kara-Kul crater]] (Tajikistan)
* [[Kebira crater]] (Libya/Egypt)
* [[Lonar crater]] (India)
* [[Mahuika crater]] (New Zealand)
* [[Manicouagan Reservoir]] (Quebec, Canada)
* [[Manson crater]] (Iowa, US)
* [[Mistastin crater]] (Labrador, Canada)

{{col-2-of-2}}
* [[Morokweng crater]] (South Africa)
* [[Nördlinger Ries]] (Germany)
* [[Panther Mountain (New York)|Panther Mountain]] (New York, US)
* [[Popigai crater]], (Siberia)
* [[Rio Cuarto craters]] (Argentina)
* [[Rochechouart crater]] (France)
* [[Roter Kamm crater]] (Namibia)
* [[Shoemaker crater]] (Western Australia)
* [[Shunak crater]] (Kazakhstan)
* The [[Lake Siljan|Siljan Ring]] (Sweden)
* [[Silverpit crater]] (North Sea off the United Kingdom)
* [[Sudbury Basin]] (Ontario, Canada)
* [[Vredefort crater]] (South Africa)
* [[Weaubleau-Osceola structure|Weaubleau-Osceola impact structure]] (Missouri, US)
* [[Wilkes Land crater]] (Antarctica)
* [[Wolfe Creek crater]] (Western Australia)
* [[Woodleigh crater]] (Western Australia)
* [[Yarrabubba crater]] (Western Australia)

{{col-end}}

See the [[Earth Impact Database]],<ref>[http://www.unb.ca/passc/ImpactDatabase/essay.html Impact Cratering on Earth<!-- Bot generated title -->]</ref> a website concerned with over 170 identified impact craters on the Earth.

===Some extraterrestrial craters===

* [[Caloris Basin]] (Mercury)
* [[Hellas Basin]] (Mars)
* [[Mare Orientale]] (Moon)
* [[Petrarch crater]] (Mercury)
* [[Skinakas Basin]] (Mercury)
* [[South Pole-Aitken basin]] (Moon)
* [[Herschel (crater on Mimas)|Herschel crater]] (Mimas)

===Largest named craters in the Solar System===
# [[South Pole-Aitken basin]] - Moon - Diameter: 2,500&nbsp;km
# [[Hellas Basin]] - Mars - Diameter: 2,100&nbsp;km
# "[[Skinakas Basin]]" - Mercury - Diameter: ~1,600&nbsp;km
# [[Caloris Basin]] - Mercury - Diameter: 1,550&nbsp;km
# [[Mare Imbrium]] - Moon - Diameter: 1,100&nbsp;km
# [[Isidis Planitia]] - Mars - Diameter: 1,100&nbsp;km
# [[Mare Tranquilitatis]] - Moon - Diameter: 870&nbsp;km
# [[Argyre Planitia]] - Mars - Diameter: 800&nbsp;km
# [[Mare Serenitatis]] - Moon - Diameter: 700&nbsp;km
# [[Mare Nubium]] - Moon - Diameter: 700&nbsp;km
# [[Beethoven (crater)|Beethoven]] - Mercury - Diameter: 625&nbsp;km
# [[Valhalla (crater)|Valhalla]] - Callisto - Diameter: 600&nbsp;km, with rings to 4,000&nbsp;km diameter
# [[Hertzsprung (crater)|Hertzsprung]] - Moon - Diameter: 590&nbsp;km
# [[Apollo (crater)|Apollo]] - Moon - Diameter: 540&nbsp;km
# [[Huygens (crater)|Huygens]] - Mars - Diameter: 470&nbsp;km
# [[Schiaparelli (Martian crater)|Schiaparelli]] - Mars - Diameter: 470&nbsp;km
# [[Menrva (crater)|Menrva]] - Titan - Diameter: 440&nbsp;km
# [[Korolev (lunar crater)|Korolev]] - Moon - Diameter: 430&nbsp;km
# [[Dostoevskij (crater)|Dostievskij]] - Mercury - Diameter: 400&nbsp;km
# [[Odysseus (crater)|Odysseus]] - Tethys - Diameter: 400&nbsp;km
# [[Tolstoj (crater)|Tolstoj]] - Mercury - Diameter: 390&nbsp;km
# [[Goethe (crater)|Goethe]] - Mercury - Diameter: 380&nbsp;km
# [[Mare Orientale]] - Moon - Diameter: 350&nbsp;km, with rings to 930&nbsp;km diameter
# [[Epigeus (crater)|Epigeus]] - Ganymede - Diameter: 340&nbsp;km
# [[Gertrude (crater)|Gertrude]] - Titania - Diameter: 320&nbsp;km
# [[Asgard (crater)|Asgard]] - Callisto - Diameter: 300&nbsp;km, with rings to 1,400&nbsp;km diameter
# [[Vredefort crater]] - Earth - Diameter: 300&nbsp;km
# [[Mead (crater)|Mead]] - Venus - Diameter: 270&nbsp;km
There are approximately twelve more impact craters/basins larger than 300&nbsp;km on the Moon, five on Mercury, and four on Mars.<ref>[http://planetarynames.wr.usgs.gov/ USGS Astrogeology: Gazetteer of Planetary Nomenclature<!-- Bot generated title -->]</ref> Large basins, some unnamed but mostly smaller than 300&nbsp;km, can also be found on Saturn's moons Dione, Rhea and Iapetus.

==See also==
* [[Caldera]]
* [[Cretaceous–Tertiary extinction event]]
* [[Impact event]]
* [[Impact depth]]
* [[Nemesis (star)|Nemesis]]
* [[Rampart crater]]
* [[Ray system]]

==Notes==
{{reflist}}


==References==
==References==
{{Reflist}}
* Charles A. Wood and Leif Andersson, ''[http://adsabs.harvard.edu//full/seri/LPSC./0009//0003669.000.html New Morphometric Data for Fresh Lunar Craters]'', 1978, Proceedings 9th Lunar and Planet. Sci. Conf.
* Bond, J. W., "The development of central peaks in lunar craters", ''Moon and the Planets'', vol. 25, Dec. 1981.
* Melosh, H.J., 1989, Impact cratering: A geologic process: New York, Oxford University Press, 245 p.
* Baier, J., ''Die Auswurfprodukte des Ries-Impakts, Deutschland'', in ''Documenta Naturae'', Vol. 162, 2007. ISBN 978-3-86544-162-1

==External links==
{{CommonsCat|Impact craters}}
*[http://scsn.seis.sc.edu/Publications/GRLFinalDraft(web).pdf Study of a South Carolina crater]
*[http://www.unb.ca/passc/ImpactDatabase/ The Geological Survey of Canada Crater database, 172 impact structures]
*[http://www.spacedaily.com/news/deepimpact-02k.html A recent news report about tektites]
*[http://www.ottawa.rasc.ca/articles/odale_chuck/earth_craters/index.html Aerial Explorations of Terrestrial Meteorite Craters]
*[http://bbs.keyhole.com/ubb/download.php?Number=71111 Google Earth Placemarker based on the Geological Survey of Canada Crater database (KML)]
*[http://www.thinklemon.com/pages/ge/ All 172 confirmed meteor impact sites on earth, viewable in Google Earth (Largest, Most recent, Per continent, Including size indicator)]
*[http://www.somerikko.net/old/geo/imp/impacts.htm Impact sites, with individual bibliographies]
*[http://www.solarviews.com/eng/tercrate.htm Solarviews: Terrestrial Impact Craters]
*[http://www.unb.ca/passc/ImpactDatabase Earth Impact Database]
*[http://www.space.com/scienceastronomy/060601_big_crater.html Giant Crater Found: Tied to Worst Mass Extinction Ever]
* [http://www.doir.wa.gov.au/GSWA/594A90F2EB2643BCA0B9D5EB66505AEC.asp WA Geological Survey Meteorite Impacts in Western Australia]
*[http://www.lpi.usra.edu/publications/slidesets/craters/ Terrestrial Impact Craters]

{{Impact cratering on Earth}}

[[Category:Craters]]
[[Category:Impact events]]
[[Category:Planetary science]]
[[Category:Lunar science]]
[[Category:Depressions]]
[[Category:Astroblemes]]
[[Category:Articles containing video clips]]
<!-- The below are interlanguage links. -->


[[Category:Saturday Night Live seasons| season 34]]
[[als:Einschlagkrater]]
[[ar:فوهة صدمية]]
[[be-x-old:Ударны кратэр]]
[[bs:Krater]]
[[bg:Ударен кратер]]
[[ca:Cràter d'impacte]]
[[cs:Impaktní kráter]]
[[da:Nedslagskrater]]
[[de:Einschlagkrater]]
[[es:Cráter de impacto]]
[[eo:Alfrapa kratero]]
[[eu:Talka krater]]
[[fa:دهانه برخوردی]]
[[fr:Cratère d'impact]]
[[gl:Cráter (astronomía)]]
[[ko:충돌구]]
[[hr:Udarni krater]]
[[id:Kawah tabrakan benda luar angkasa di Bumi]]
[[it:Cratere meteoritico]]
[[lt:Smūginis krateris]]
[[hu:Becsapódási kráter]]
[[nl:Inslagkrater]]
[[ja:クレーター]]
[[nn:Nedslagskrater]]
[[pl:Krater uderzeniowy]]
[[pt:Cratera]]
[[ru:Ударный кратер]]
[[sk:Impaktný kráter]]
[[sl:Udarni krater]]
[[fi:Törmäyskraatteri]]
[[sv:Nedslagskrater]]
[[uk:Астроблеми]]
[[zh-yue:隕石坑]]
[[zh:撞击坑]]

Revision as of 17:25, 13 October 2008

The thirty-fourth season of the variety series Saturday Night Live began airing in 2008 and is expected to conclude in 2009 on NBC. The season is expected to consist of 22 episodes, in attempt to compensate for episodes lost during the 2007–2008 Writers Guild of America strike. This would make it the longest season since the show's second season. In addition to the regular episodes, three thirty-minute episodes are scheduled to air Thursdays in October in the weeks leading up to the 2008 United States presidential election.[1] The season began on September 13, 2008 on NBC, with Olympic swimming gold medalist Michael Phelps as host and Tina Fey appearing as Republican vice presidential candidate Sarah Palin and Amy Poehler as Hillary Clinton. The show scored its highest-rated premiere since September 2001 and is the second most-watched SNL ever.[2] The season premiere date of September 13 was earlier than the premiere date for previous seasons, which typically have started during the final weekend of September or in early October. This is Amy Poehler's final season as she will be leaving in November after the election for maternity leave and will then go on to star in the as-of-yet untitled Office spinoff.[3] With the exception of Amy Poehler's departure and the hiring of new feature player Bobby Moynihan (who, like Casey Wilson, was a member of the Upright Citizens Brigade stage troupe), there have been no major cast changes so far this season.

SNL Thursday Night Live

Saturday Night Live will air three special prime time half-hour episodes on Thursdays starting October 9th. These specials, entitled SNL Thursday Night Live, will focus on the presidential election.[1]

Episode Number Original Air Date Notes
Episode 1 October 9, 2008
Episode 2 October 16, 2008 Confirmed Below
Episode 3 October 23, 2008 Confirmed Below

Cast

Repertory players
Featured players

Listings

Episodes

Episode Number Date Host Musical Guest Remarks
637

(34.1)

September 13, 2008 Michael Phelps Lil Wayne
638 (34.2) September 20, 2008 James Franco Kings of Leon
639 (34.3) September 27, 2008 Anna Faris Duffy
640 (34.4) October 4, 2008 Anne Hathaway The Killers
  • Queen Latifah appeared as Gwen Ifill and Tina Fey returned as Sarah Palin in a parody of the Vice Presidental Debate.
  • The Killers performed "Human" and "Spaceman".
  • An edited version of the sketch parodying the economic bailout was posted on NBC.com, removing references to Herbert and Marion Sandler's (played by Darrell Hammond and Casey Wilson, respectively) corrupt activities and removing the graphic labeling the couple as "people who should be shot". Lorne Michaels admitted he did not know the Sandlers were a real couple, and that he believed they were simply characters written for the sketch. [10]
641

(34.5)

October 18, 2008 Josh Brolin[11] Adele[11]
642[12]

(34.6)

October 25, 2008 Jon Hamm Coldplay[13]
  • Governor Sarah Palin is rumored to be making a cameo appearance as herself.[14]
643

(34.7)

November 1, 2008 TBA TBA
Preceded by Saturday Night Live
Season 34 		Succeeded by

References

  1. ^ a b UNew NBC Series: SNL Thursday Night Live - Fall 2008 - Blend Television
  2. ^ Tina Fey leads SNL in 2nd best premiere ever
  3. ^ Amy Poehler Confirms She Is Leaving Saturday Night Live - Film.com
  4. ^ NBCUMV
  5. ^ Live from New York, It's Obama on SNL!
  6. ^ Obama tones it down as Hurricane Ike looms
  7. ^ Rain Check? Obama Nixes SNL Visit Due to Hurricane
  8. ^ SNL Transcripts
  9. ^ Diaz Plays 'Cougar' on TV Show
  10. ^ http://seattlepi.nwsource.com/tvguide/382363_tvgif8.html
  11. ^ a b NBC'S 'SATURDAY NIGHT LIVE' PREPARES A PACKED OCTOBER
  12. ^ Don Draper to Host ‘Saturday Night Live’
  13. ^ [1]
  14. ^ Adams, Cindy (2008-10-10). "Golly, Palin To Play Herself on SNL". The New York Post. Retrieved 2008-10-10. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
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