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|To-do list for Impact event:|
- 1 Miscellaneous 2004-2006 comments
- 2 This is Correct
- 3 rate of earth impacts
- 4 Impact Events in Fiction
- 5 Improvement drive
- 6 War, near misses, etc.
- 7 Attention
- 8 point of confusion
- 9 List of doomsday scenarios
- 10 external links
- 11 Additional impact events worth noting
- 12 Mass Extinction Events
- 13 What if impact effects
- 14 Hypothesis -> Original Research
- 15 Science Fiction?
- 16 Shoolkid Hoax
- 17 Impact event on Jupiter last Sunday
- 18 FYI - proposed renaming for Category:Craters hierarchy of 76 impact crater-related categories
- 19 Caption for File:Impact event.jpg
- 20 I will do some work on this article
- 21 Delete two subsections?
- 22 Asteroid impact simulator
- 23 http://neo.jpl.nasa.gov/risk/
- 24 The only reported..
- 25 A fragmented comet that nearly hits Earth
- 26 Problematic Definition used in Lead Paragraph
- 27 Weird IP edit
- 28 Split article into sections about impact events involving Earth and other bodies
Miscellaneous 2004-2006 comments
Great work on the merge Bryan! --mav
- Thanks. :) Bryan
Note the recently raised possibility that the Permian and Cretaceous impact objects causing extinction events may have been massive molten rocks ejected from the flood basalt events which occurred at the same times rather than asteroid impacts -- Derek Ross
- I'd need some pretty good external references before I'd consider that a plausible theory, personally. Basalt flood eruptions are relatively sedate for their size, not like explosive volcanos. And the impacts proposed for these events are huge; Chicxulub Crater is either 180 or 300 kilometers in diameter (jury's not entirely decided yet) and the Bedout is about 200 kilometers in diameter, both of which suggest impactors about 10 kilometers across. An explosion that would hurl a mass that big out of Earth's atmosphere would be about as energetic as the explosion that would result when it falls back in, and I don't think anyone's ever proposed a volcanic eruption anywhere near that violent. The basaltic flood eruptions were dramatic enough as it is without proposing continent-sized explosions accompanying them. Bryan 07:37, 23 May 2004 (UTC)
There's no doubt that it's speculation at the moment based on computer modelling of the mantle. However the modelling has shown that the titanic explosions required to launch these huge masses are possible under the right circumstances (in the model at least). And there is some physical evidence to follow up. See New Scientist (8-May-2004). I just thought that I should make everyone aware of a possible alternative to the asteroid theory, so that we don't start saying is when we should be saying is thought to be. I'm certainly not saying "Drop the asteroid theory. Here's something better". It's early days yet for the "verneshot" theory and, as you say, it involves a major rethink on flood basalt eruptions. -- Derek Ross 19:17, 23 May 2004 (UTC)
I think this is a great article, and I'd like to see it nominated for feature status. There are however a few things that appear to be in need of elaboration; in particular, there ought to be some more info on the direct consequences of a major collision (some of which is mentioned in e.g. crater but should also be covered here).
Thoughts? Fredrik 12:50, 23 May 2004 (UTC)
I think it would need a better description of the first 4.5 billion years of Earth's history than "The current traditional Biblical view of history held that the Earth was created 6,000~10,000 years ago" Astronaut 19:04, 24 July 2006 (UTC)
regarding Derek's first comment above - what about the reverse possibility? - that flood basalts have been triggered by impact events? valkyree 00:28, 9 August 2012 (UTC) — Preceding unsigned comment added by Valkyree (talk • contribs)
This is Correct
I would have to say that, scientifically this assumption is correct. And can also be proven.
Ha! You senile liberals on the Wiki are a funny lot.
Partner, this absurd theory was debunked over the past two years. Despite all the lurid magazine covers, it was a rubbish idea and has been abandoned. The dinosaurs were not killed by an asteroid impact. Very theatrical stuff, though - unfortunately not science.
It is also unfortunate that Alvarez and Gould attacked half the scientists in the country who criticized the notion, destroyed their careers and got them dropped from tenure for daring to oppose the screamin' Alvarez brothers. What a shame. (Anonymously contributed by Anonymous User:220.127.116.11 whose contribution can also be enjoyed at Talk:Stephen Jay Gould.)
There is no solid evidence of impacts leading to the four other major mass extinctions, though many scientists assume that they are at least related to impacts. No, this is not a scientific assumption. Even a quick read through Wikipedia entries on Extinction events will correct this impression. I haven't removed this text, however. --Wetman 18:53, 27 Dec 2004 (UTC)
rate of earth impacts
This information is a bit out of date:
The late Eugene Shoemaker of the US Geological Survey came up with an estimate of the rate of Earth impacts, and suggested that an event about the size of the nuclear weapon that destroyed Hiroshima occurs about once a year.
[re: Tunguska] Shoemaker estimated that one of such magnitude occurs about once every 300 years.
See, for instance, Tunguska-type impacts less common than thought (no more than 50 metres in diameter). The quotes below are from _The flux of small near-Earth objects colliding with the Earth_ Brown et al. Nature, Volume 420, Issue 6913, pp. 294-296. (2002)
"The Earth is struck by an object with the energy of Tunguska (assumed to be 10 MT) every 1,000 years."
"We estimate that the Earth is on average struck annually by an object of energy ~5 kton (with a possible range of 2-10 kton), and struck each month by an object with 0.3 kt of energy. Every ten years, an object of energy ~50 kton impacts Earth."
--Mu301 14:43, 2 Jan 2005 (UTC)
Perhaps kinetic energy 50kt[x J] is dissipated in upper atmosphere before anything reach surface. If otherwise - seen in news ? :). —Preceding unsigned comment added by 18.104.22.168 (talk) 11:06, 28 June 2009 (UTC)
Impact Events in Fiction
I completely re-wrote this section in an effort to make the media references more mainstream and more centered around the books and movies which are specifically about impacts (also more consistent with other Wikipedia articles). One thing which is missing, though; I'm sure there are early sci-fi stories (in Astounding, etc.) about impact events, but I've not been able to find a specific citation. Could someone who collects 30's and 40's science fiction help out with stories of historical note? (i.e. the "first" impact story) Jberkus 18:42, 2 October 2005 (UTC)
War, near misses, etc.
This makes for a good story, but I doubt it is really true:
- It is very likely that a great many more near misses occur but are never detected. In addition to the danger of a strike, the possibility of war at a time of international tension due to a near miss triggering attack early warning systems, or a strike, is very real.
How would one estimate near misses that are never detected? Seems like a hard problem, and frankly I would be surprised if there are "many" near misses by hazardous asteroids (i.e. >100 m). Also, as there has never been a war by asteroid, and the things have speeds and trajectories much different than missles, I honestly think it unlikely that modern surveillance would have a "very real" risk of mistaking an asteroid for an attack to the point of creating an international incident. Please provide sources for both claims. Dragons flight 16:31, 6 March 2006 (UTC)
I have added the attention tag, particularly re the section on mass extinctions, but some concerns are of more general relevance. Most fundamentally, the article needs to directly cite assertions made in the text- including a (small) number of references at the bottom without direct links is not enough. Some of the key points made (ie the discovery of the Chicxulub crater) are at best only partially correct, and a general expansion is very much in order. The selection of material currently seems to be a little bit patchy and incomplete; it is not even approaching a holistic treatment of the subject. The article does currently read a bit like a school essay project (although to be fair I would probably give it a C+, or even a B!). Cheers, Badgerpatrol 16:02, 5 April 2006 (UTC)
- I fixed the majority of what I could based on what I think you meant was wrong with the article. I added some references, cited some, added some footnotes; I don't know if I did everything you wanted so please explain in detail if more is needed! For now, I'm going to remove the "cleanup tag" Kosmkrmr 00:01, 5 March 2007 (UTC)
point of confusion
The article states, "In the past 600 million years there have been five major mass extinctions that on average extinguished half of all species. The largest mass extinction to have affected life on Earth was in the Permian-Triassic, which ended the Permian period 250 million years ago and killed off 90% of all species. The last such mass extinction led to the demise of the dinosaurs and has been found to have coincided with a large asteroid impact; this is the Cretaceous-Tertiary (K-T) extinction event. There is no solid evidence of impacts leading to the four other major mass extinctions, though a recent report from Ohio State scientists stated that they have located a 483-km diameter impact crater beneath the East Antarctic Ice Sheet which may date back about 250 million years, based on gravity measurements, which might associate it with the Permian-Triassic extinction event."
Back in 2001, the AP reported, "The Permian-Triassic impactor, either an asteroid or comet, left behind subtle deposits of buckminsterfullerenes, or 'Buckyballs,' a form of carbon shaped like a volley ball with a hollow cage-like cavity inside" Recer, 2001). Is this research not yet deemed "solid evidence"? If it were, shouldn't this entry state that there's evidence (in additon to the Antartic crater, of course) that two out of five extinction events were caused by a large asteroid or comet?
Could use votes to save this article, thanks MapleTree 22:29, 28 September 2006 (UTC)
Hi. What about this site I found, which has an asteroid impact simulator, and other simulators. I know it seems a bit immature with all the "marvin the martian" stuff. Otherwise, dispite its innacuracies, it still is the only site I found providing simulations on impacts elsewhere in the solar system. It also has simulators about orbits and stars and such. Should this and other links be included? I don't think it would be spam. Thanks. AstroHurricane001(Talk+Contribs+Ubx) 20:43, 3 March 2007 (UTC)
Additional impact events worth noting
These three already have articles and should probably be mentioned here:
- Do we need to include every impact event? There are more than 120, not counting the meteorites and airbursts that happen once a month or so. The article is in danger of turning into a list. Pretty soon it might be appropriate to discuss which ones are significant enough to mention specifically and discuss generalities instead of listing the rest. Geogene (talk) 02:54, 1 July 2009 (UTC)
Mass Extinction Events
It is not neseccary to assume that impact events are directly responsible for mass extinctions, only that they are seemingly corilated. —Preceding unsigned comment added by Rdailey1 (talk • contribs) 01:53, 1 April 2008 (UTC) here's the problem:East Antarctic Ice Sheet which may date back about 250 million years, based on gravity measurements, which might associate it with the Permian-Triassic extinction event.
- I agree that there's very little evidence in the article of a causal link between impact events and mass extinctions; the subject is still very much under discussion. Furthermore, the vast majority of of impact events have not caused mass extinctions or indeed had any long-term far-reaching effects on our planet's ecosystems. For these reasons I feel that dedicating 50% of the lead to a largely speculative link between impacts and extinction gives undue weight to the subject, and I have deleted the reference and moved the "mass extinction" section down the article to a position below the more factual discussions. -- Timberframe (talk)
What if impact effects
A highly simplified calculation can be made using the web-based program by Collins et al.. This table assumes a density of 3.4 g/cm3, entry angle of 45 degrees and an entry velocity of 15 metres per second (can be from 11 to over 40 km/s):
|Name||Diameter||Energy lost||Airburst altitude||Airburst energy||Impact energy||Crater diameter||How often?|
|Great 1972 Fireball||3||1.3 kiloton||39 km||0.4 kiloton||none||none||8 months|
|2004 FU162||6||10 kiloton||33 km||3.8 kiloton||none||none||3.3 years|
|2004 FH||30||1.3 megaton||13 km||0.9 megaton||none||none||135.1 years|
|1996 JA1||300||1300 megaton||48 km begins breaking||no airburst||1200 megaton||4.67 km||28000 years|
- Robert Marcus, H. Jay Melosh, and Gareth Collins. Computing Effects of an Impact on Earth
- Collins, Gareth S. et al. Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth Meteoritics & Planetary Science 40, Nr 6, 817–840 (2005) "The curvature of the Earth is also ignored."
Hypothesis -> Original Research
Would it be appropriate to include my hypothesis entitled The Impact And Exit Event on this page? It can be 'googled', so if anyone could take a look and let me know I'd appreciate it. Thanks. —Preceding unsigned comment added by 22.214.171.124 (talk) 18:07, 27 December 2008 (UTC)
- I'm sure many editors will thank you for asking first. The short answer is "no, not yet". A self-published web site or book is a "primary source" - it comes from the originator. Until there are reliable sources, secondary sources independent of the originator, then any hypothesis would be considered original research and is therefore not (yet) acceptable for inclusion in the encyclopedia. Depending how long it takes to get reliable sources, you may need to be patient on the scale of years before Wikipedia is ready for a currently-self-published hypothesis. For now, make the most of your own web site and any ongoing effort you can use to further develop your research. I can provide a relevant example - I have not posted/submitted/etc on Wikipedia some research of my own about a possible remnants of a mostly-eroded impact crater at Nevada's Black Rock Desert, because it is still original research under Wikipedia's rules. Discover Magazine had a blurb about the research in an article about various research projects by amateur scientists the Dec 2008 issue. But that isn't a result - it just says the research is happening. Until the research progresses to a definitive result and that result is published in a reliable source, it won't go into Wikipedia. And even then, in my case I should provide it to other editors via a talk page because it would be a conflict of interest to add my own research myself. To me this isn't a problem - I'm not trying to promote this project any more than letting potential participants know about it. We have more than enough circumstantial evidence now to know we just need to keep looking. Ikluft (talk) 21:13, 27 December 2008 (UTC)
- I note that as of edit the original research has been inserted without citation. Since in the absence of citation the original objection to its inclusion is still valid, I am removing it. 126.96.36.199 (talk) 04:19, 7 April 2013 (UTC)
- My edit was automatically reverted. Somebody else can see to this if they wish. 188.8.131.52 (talk) 04:34, 7 April 2013 (UTC)
- I note that as of edit the original research has been inserted without citation. Since in the absence of citation the original objection to its inclusion is still valid, I am removing it. 184.108.40.206 (talk) 04:19, 7 April 2013 (UTC)
Is it necessary for the second sentence in an article on a scientific subject to mention that the topic has been used in SF? What does that have to do with geology? Astronomy? —Preceding unsigned comment added by Geogene (talk • contribs) 01:11, 4 June 2009 (UTC)
- Support. The lead should summarise the article, and the weight given to each aspect of the article in the lead should reflect the weight given in the article's main body gives. In this case more than 50% of the words in the lead are given over to the SF aspect while in the article it constitutes only some 15% (rough estimate by screenfuls). If nobody else raises any adverse comments here over the next few days I suggest that you act boldly and remove the SF reference from the lead; you could also consider bolstering the lead with a few more pertinent facts from the article. -- Timberframe (talk) 09:49, 4 June 2009 (UTC)
I removed the part about the German schoolkid that claims to have been hit by a "pea-sized" meteorite travling at "thousand of kilometers an hour" that grazed his hand, causing a scar, then hit the ground behind him, creating a crater four feet across. Oh, and his friends heard a sonic boom.
- Even though the details may have been muddled by the reporting, Ansgar Korte, director of Germany's Walter Hohmann Observatory, confirmed chemically that the rock which hit him really was from outer space.  Dragons flight (talk) 02:47, 20 June 2009 (UTC)
Angsar Korte has denied having seen the alleged meteorite, as reported on Phil Plait's "Bad Astronomy" blog at Discover Magazine. The MSNBC piece says Korte was mistranslated and he merely said it would be valuable if a real meteorite, and (MSNBC) quoted a meteorite expert who said that the scenario presented is physically impossible and that the kid is not telling the truth.  It is a physical impossibility that a meteorite the size of a pea, having a density between 3 and 5 g/cm^3 will be traveling at hypervelocity five feet off the ground. The pictures in the papers are not consistent with either a small hypervelocity crater or of the sort of gash somebody would get from something traveling many, many times faster than a rifle bullet. The "crater" shown in photographs is not a crater, but a worn spot on the pavement. . What else can be said? Obvious Hoax is obvious? The media should try fact-checking before they mindlessly spread such nonsense. Geogene (talk) 13:37, 21 June 2009 (UTC)
Impact event on Jupiter last Sunday
Apparently something hit Jupiter last Sunday night, CNN, SpaceWeather.com, New Scientist, and Skypub.com (Sky & Telescope magazine's site) are reporting a single, massive black spot (like those after SL9) that is bright in thermal infrared and contains a spectroscopic signature of ammonia, a gas normally found in deeper layers of Jupiter's atmosphere. It was first seen Sunday by an Australian amateur, now confirmed by JPL. 
Apparently SL9 is an example of a recurring phenomenon. There's an old magazine (S&T or Astronomy) article somewhere about black spots appearing on Jupiter before. Geogene (talk) 15:39, 21 July 2009 (UTC)
FYI - see the CFR renaming discussion. 76 categories with "craters" in their names, all part of the Category:Craters hierarchy, have been proposed to be renamed to use "impact craters" in their names. All the higher-level categories in the hierarchy have text instructions that they are for impact craters, not craters of volcanic or explosives origins. The renaming is intended to make their purposes more obvious and lead to less confusion. Ikluft (talk) 09:30, 22 August 2009 (UTC)
Caption for File:Impact event.jpg
Artist's impression of a major impact event. The collision between Earth and an asteroid a few kilometers in diameter may release as much energy as several million nuclear weapons detonating, one after another.
Would it not be more accurate to say: "as much energy as several million nuclear weapons detonating simultaneously" or "as much energy as the simultaneous detonation of several million nuclear weapons"?
Also, the comparison with the energy released by "several million nuclear weapons" seems to be quite non-specific. The explosive yield of a nuclear weapon can range from 0.01–0.02 kt (see Davy Crockett (nuclear device)) to 50 kt (see Tsar Bomba), which is 5,000 times greater. Could a different comparison be used, or perhaps even a different point emphasized?
- As no one objected, I changed the caption (diff) to use "simultaneously" instead of "one after another". -- Black Falcon (talk) 00:40, 23 March 2010 (UTC)
I will do some work on this article
Delete two subsections?
For me the article is not easy to read. It doesn't seem to stay on topic.
I'm wondering about completely deleting the "Modern impact events" because these events did not create impacts. Is there an article on near misses? Perhaps this information should be moved?
I'm also wondering about deleting all except this paragraph (in "Close approaches and forecasts):
- In 2004, a newly discovered 320 m (1,050 ft) asteroid, 99942 Apophis (previously called 2004 MN4), achieved the highest impact probability of any potentially dangerous object. The probability of collision on April 13, 2029 is estimated to be as high as 1 in 17 by Steve Chesley of NASA's Jet Propulsion Laboratory, though the previously published figure was the slightly lower odds of 1 in 37, calculated in December 2004. Later observations showed that the asteroid will miss the earth by 25,600 km (15,907 mi) (within the orbits of communications satellites) in 2029, but its orbit will be altered unpredictably in a way which does not rule out a collision on April 13 or 14, 2036 or later in the century. These possible future dates have a cumulative probability of 1 in 45,000 for an impact in the 21st century.
from the article. Again, in general, this section does not talk about actual impacts. The above paragraph seems relevant to me. Perhaps all except the one paragraph could be move to Near-Earth object?
- I need to refresh my memory on the article before I do anything!!
- I did copy-and-paste the "Close encounters and forecasts" to the discussion page of "Near-Earth object". The text is available if someone wants to incorporate into that article.
- I've finished my (modest) goals for this article. I did copyediting, removed one non-relevant section (discussion above), used the convert template, moved one sentence to lead and removed some overlinkings. There remains quite a bit of work to bring this up to standard, but several of us have a start. Bettymnz4 (talk) 02:40, 8 April 2010 (UTC)
Asteroid impact simulator
The folks at Purdue University have put together a really outstanding asteroid simulator. May be worth adding to the article somehow, external links or otherwise. I'll leave that to the authors who better know this page. Here's the link: [ImpactEarth Asteroid Impact Simulator]. Cheers. N2e (talk) 05:42, 9 February 2011 (UTC)
The only reported..
"The only reported fatality from meteorite impacts is an Egyptian dog that was killed in 1911 by the Nakhla meteorite, although this report is disputed. The meteorites that struck this area were identified in the 1980s as Martian in origin."
A fragmented comet that nearly hits Earth
Guys,i think we should add this into the article. Here's the info: Interpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the Earth -- Dino-Mario (talk) 17:20, 18 October 2011 (UTC)
Problematic Definition used in Lead Paragraph
The current definition in the lead states:
- An impact event is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet.
The problem I see with this is that it is too narrow for the scope of the article.
Reasoning is that the following things mentioned in the article do not fit the current definition:
- Comets plunging into the Sun are not "impact event"s as the Sun is clearly not a planet
- The Giant Impact Hypothesis was not an "impact event" as according to the theory the Earth was not at that time a planet (ie. it was a either a protoplanet or dwarf planet as it shared its orbit with the protoplanet Theia and therefore had not cleared its neighbourhood)
- P/2010 A2 with a smaller asteroid (this is clearly not an "impact event" as neither are planets)
- Major impact events occur on other objects. Rheasilvia, like the Giant Impact theories for example represents an "impact event" on a non-planetary object as does the South Pole–Aitken basin and the Big Spat theory of the lunar highland formation.
I propose that the reference to "another planet" be replaced with "another large celestial object".
It could possibly say "another celestial object" to include asteroid impacts, although this could probably broaden the scope too much.
Weird IP edit
Split article into sections about impact events involving Earth and other bodies
I propose creating a section to deal with the history of impact events with Earth and a section dealing with impact events elsewhere. Currently the article suffers from schizophrenia jumping around the Solar System and beyond, whereas the majority of the content is written in the context of Earth. I understand that impacts with Earth are the priority due to the threats they pose to life on our planet, but the subject should be considered holistically, from the context of their bearing on the history (and future) on planetary systems as a whole. --EvenGreenerFish (talk) 02:22, 27 May 2013 (UTC)