Starship Asterisk*

The object that excavated the crater was a nickel-iron meteorite about 50 meters (54 yards) across, which impacted the plain at a speed of several kilometers per second.

Objects of diameters of over 50 meters strike the Earth approximately once every thousand years, producing explosions comparable to the one observed at Tunguska in 1908.

emc wrote:After seeing this image I decided to trade my red vehicle for a blue one.

emc wrote:http://apod.nasa.gov/apod/ap090811.html



http://antwrp.gsfc.nasa.gov/apod/ap021118.html

After seeing this image I decided to trade my red vehicle for a blue one. It appears meteors are attracted to red vehicles, besides the police seem to be attracted to red also… or is it movement that attracts the police?? It is evidently not movement that attracts meteors since the red car was parked at the time... so I suspect it was the car’s coloring that attracted the meteor. Meteors don’t care if their target is moving or parked. Anyway, if police are attracted to red and movement, that would mean the police would easily spot the red fire ball of a meteor and if the meteor is attracted to red vehicles… well, then, my point is that I think it’s best to own a blue vehicle.

geckzilla wrote:Man, I'd trade an old car for a good sized meteor like that any day. Just as long as I'm not in it when it happens.

orin stepanek wrote:The bumper held up pretty good though. 8)

http://antwrp.gsfc.nasa.gov/apod/ap081001.html wrote:
Explanation: A new chapter in space flight began on 1950 July with the launch of the first rocket from Cape Canaveral, Florida: the Bumper V-2. Shown above, the Bumper V-2 was an ambitious two-stage rocket program that topped a V-2 missile base with a WAC Corporal rocket. The upper stage was able to reach then-record altitudes of almost 400 kilometers, higher than even modern Space Shuttles fly today. Launched under the direction of the General Electric Company, the Bumper V-2 was used primarily for testing rocket systems and for research on the upper atmosphere. Bumper V-2 rockets carried small payloads that allowed them to measure attributes including air temperature and cosmic ray impacts. Seven years later, the Soviet Union launched Sputnik I and Sputnik II, the first satellites into Earth orbit. In response in 1958, 50 years ago today, the US created NASA.

neufer wrote:Well....it never Wacked the Bumper

http://en.wikipedia.org/wiki/Canyon_Diablo_(meteorite) wrote:
<<The Canyon Diablo meteorite impacted at Barringer Crater (Meteor Crater), Arizona and is known from fragments collected around the crater, and nearby Canyon Diablo which lies about 3 to 4 miles west of the crater.


7.1% Ni; 1% C; 1% S; 0.46% Co; 0.26% P; 320ppm Ge; 80ppm Ga; 1.9ppm Ir
Total Known Weight (TKW) 30,000 kg.

The meteoroid fell about 50,000 years ago. The meteorite has been known and collected since the mid 1800s and was known and used by pre-historic Native Americans. The Barringer Crater, from the late 19th to the mid-20th century, was the center of a long dispute over the origin of craters that showed little evidence of volcanism. That debate was settled in the 1950s thanks to Eugene Shoemaker's study of the crater.>>

http://en.wikipedia.org/wiki/Clair_Cameron_Patterson wrote:
<<Harrison Brown of the University of Chicago developed a new method for counting lead isotopes in igneous rocks, and assigned it to Cameron Patterson as a dissertation project in 1948. During this period he operated under the assumption that meteorites are left-over materials from the creation of the Solar System, and thus by measuring the age of one of these rocks the age of the Earth would be revealed. Gathering the materials required time, and in 1953, Patterson had his final specimens from the Canyon Diablo meteorite. He took them to the Argonne National Laboratory, where he was granted time on a late model mass spectrograph. In a meeting in Wisconsin soon afterward, Patterson revealed the results of his study. The definitive age of the Earth is 4.550 billion years (give or take 70 million years). This number still stands although the margin of error is now down to about 20 million years.>>

neufer wrote:

http://en.wikipedia.org/wiki/Canyon_Diablo_(meteorite) wrote:7.1% Ni; 1% C; 1% S; 0.46% Co; 0.26% P; 320ppm Ge; 80ppm Ga; 1.9ppm Ir

apodman wrote:

neufer wrote:

http://en.wikipedia.org/wiki/Canyon_Diablo_(meteorite) wrote:7.1% Ni; 1% C; 1% S; 0.46% Co; 0.26% P; 320ppm Ge; 80ppm Ga; 1.9ppm Ir

Would it have hurt them to have mentioned it's mostly Iron (Fe)?

geckzilla wrote:Wow, how could I have never heard that joke before? I love it. There are a surprising amount of ferrous wheel designs out there too.

http://en.wikipedia.org/wiki/Ferris_wheel wrote:The original Ferris wheel was designed by George Washington Gale Ferris, Jr., as a landmark for the 1893 World's Columbian Exposition in Chicago. The term Ferris wheel later came to be used generically for all such rides.

History

... Ferris ... began his career in the railroad industry and then pursued an interest in bridge building. Ferris understood the growing need for structural steel and founded G.W.G. Ferris & Co. in Pittsburgh, a firm that tested and inspected metals for railroads and bridge builders.

Ferris designed and built the Chicago Wheel for the 1893 World's Columbian Exposition in Chicago, Illinois. The wheel was intended as a rival to the Eiffel Tower, the centerpiece of the 1889 Paris Exposition. It was the largest attraction at the Columbian Exposition, with a height of 80 metres (260 ft), and was powered by two steam engines. There were 36 cars, accommodating 60 people each (40 seated, 20 standing), giving a total capacity of 2,160. It took 20 minutes for the wheel to make two revolutions - the first to make six stops to allow passengers to exit and enter; the 2nd, a single non-stop revolution - and for that, the ticket holder paid 50 cents. When the Exposition ended, the wheel was moved to north side, next to an exclusive neighborhood. William D. Boyce filed an unsuccessful Circuit Court action against the owners of the wheel, to have it moved. It was then used at the St. Louis 1904 World's Fair and eventually destroyed by controlled demolition in 1906. At 70 tons, its axle was the largest steel forging of the time. It was 26 stories tall, only a quarter of the Eiffel Tower's height.

Sections of the Chicago Wheel were used to construct a bridge across the Kankakee River, about 45 miles (72 km) south of Chicago, just north of Tefft, Indiana.

apodman wrote:

http://en.wikipedia.org/wiki/Octahedrite wrote:
<<Octahedrites are the most common class of iron meteorites. They are composed primarily of the nickel-iron alloys:

• Kamacite - low nickel content, and
  Taenite - high nickel content.

Due to a long cooling time in the interior of the parent asteroids, these alloys have crystallized into intermixed millimeter-sized bands (from about 0.2 mm to 5 cm). When polished and acid etched the classic Widmanstätten patterns of intersecting lines of lamellar kamacite, are visible.

Widmanstätten pattern in NiFe octahedrite meteorite


In gaps between the Kamacite and Taenite lamellae [the KT boundary?], a fine-grained mixture called plessite is often found. An iron nickel phosphide, schreibersite, is present in most nickel-iron meteorites, as well as an Fe, Ni, Co-carbide, cohenite. Graphite and troilite occur in rounded nodules up to several cm in size.>>

neufer wrote:Bumper , n. [A corruption of bumbard, bombard, a large drinking vessel.]
A cup or glass filled to the brim, or till the liquor runs over,
particularly in drinking a health or toast.

apodman wrote:When I learned to drive, I was taught that the best way to avoid apprehension was to follow a red Corvette through a speed trap. Later I was taught that the authorities had become wise to that trick and switched their focus to the car immediately after the red Corvette. So now I drive two cars behind the red Corvette. And I will no longer own a green car because the subconscious mind of the oncoming driver sees me as part of the scenery and doesn't direct that driver to get back off of my side of the double yellow line on a country road. I'm not sure any of this advice helps with meteorites.

• Little red corvette
  Baby youre much 2 fast, yes u r
  Little red corvette
  U need 2 find a love thats gonna last

http://en.wikipedia.org/wiki/Barringer_Crater wrote:
<<The object that excavated [Barringer Meteor Crater] was a nickel-iron meteorite about 50 meters across, which impacted the plain at a speed of several kilometers per second. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at a speed of up to 20 kilometers per second (45,000 mph), but more recent research suggests the impact was substantially slower, at 12.8 kilometers per second. It is believed that about half of the impactor's 300,000 tonnes (metric tons) bulk was vaporized during its descent, before it hit the ground.>>

http://www.planetary.org/blog/article/00002047/ wrote: Are we doing enough to detect and track asteroids?

Finding: Congress has mandated that NASA discover
90 percent of all near-Earth objects 140 meters in diameter or greater by 2020.
The administration has not requested and Congress has not appropriated new funds to meet this objective.

Finding: The current near-Earth object surveys cannot meet the goals of the 2005 NASA Authorization Act
directing NASA to discover 90 percent of all near-Earth objects 140 meters in diameter or greater by 2020.

neufer wrote:

http://en.wikipedia.org/wiki/Barringer_Crater wrote:The object that excavated the crater was a nickel-iron meteorite about 50 meters (54 yards) across ... It is believed that about half of the impactor's 300,000 tonnes (metric tons) bulk was vaporized during its descent, before it hit the ground.

http://en.wikipedia.org/wiki/Barringer_Crater wrote:Barringer, who in 1894 was one of the investors who made $15 million in the Commonwealth silver mine in Pearce, Arizona in Cochise County, Arizona, had ambitious plans for the iron ore. He estimated from the size of the crater that the meteorite had a mass of 100 million tons. The current estimate of 300,000 tons for the impactor is only three-tenths of one percent of Barringer's estimate.

neufer wrote:

http://en.wikipedia.org/wiki/Canyon_Diablo_(meteorite) wrote:The Canyon Diablo meteorite impacted at Barringer Crater (Meteor Crater), Arizona and is known from fragments collected around the crater ... Total Known Weight (TKW) 30,000 kg.

apodman wrote:First, the back-of-the-envelope density calculation: A 50 meter sphere is about 65,450 cubic meters or 65,450,000,000 cubic centimeters. If it has a mass of 300,000 metric tons or 300,000,000 kilograms or 300,000,000,000 grams, it has a density of about 4.6 grams per cubic centimeter. This is less than the 7 or 8 grams per cubic centimeter I've seen quoted for iron-nickel meteorites, but it's close enough that the quoted size and quoted mass are in the same ballpark. Of course, if the 50 meter size is supposed to go with the 150,000 kilogram reduced mass, the discrepancy is greater.

apodman wrote:Second, Barringer's number was a lot bigger than 300,000 metric tons (by a factor of more than 300), so "wow", that's quite a revision from the initial estimate to the current one.

http://en.wikipedia.org/wiki/Daniel_Barringer_(geologist) wrote:
<<In 1902 Daniel Moreau Barringer (1860 – 1929) learned of the existence of a large (1.5 km in diameter) crater, located 35 miles east of Flagstaff, Arizona. Upon hearing of the existence of the crater and the meteoritic iron, Barringer became convinced that the crater was of meteoritic origin. With both scientific and monetary aims in mind, Barringer created the Standard Iron Company [SIC] in order to mine the crater for the iron that he assumed must be buried under the surface. The Standard Iron Company conducted drilling operations in and around the crater between 1903 and 1905, and concluded that the crater had indeed been caused by a violent impact. They were unable to find the meteorite, however. The mining of the crater continued until 1929 without ever finding the ten-million ton meteorite that Barringer assumed must be hidden. At this time the astronomer Forest Ray Moulton performed calculations on the energy expended by the meteorite on impact, and concluded that the meteorite had most likely vaporized when it landed. By this point Barringer had spent over $600,000 in mining the crater, nearly bankrupting him, with no iron profits to show for it. Barringer died of a heart attack on November 30, 1929, shortly after reading the very persuasive arguments that no iron was to be found. By the time of his death, Barringer had convinced most of the scientific community that his impact theory was correct. The theory has been further confirmed with new evidence since then, most notably by Eugene Shoemaker in the 1960s.>>

apodman wrote:Third, 150,000 metric tons (if half of the 300,000 ton impactor vaporized before impact with the solid ground as stated above) is a lot higher (by a factor of 5,000) than the Total Known Weight (30,000 kilograms or 30 metric tons) quoted in the other article. So I guess the Total Known Weight doesn't reflect the total estimated weight of the meteorite (which they didn't explain in the article so I would notice). So what does the 30,000 kilogram figure represent? I'm guessing it's total weight found and recovered, which might be useful for small meteorites but sounds like a less than useful number to give a hint of the mass of a large object that is mostly buried and/or melted into the Earth's crust.

http://en.wikipedia.org/wiki/Hoba_meteorite wrote:
<<Hoba (also known as Hoba West) (pron. "HOE-bah") is a meteorite that lies on the farm "Hoba West", not far from Grootfontein, in the Otjozondjupa Region of Namibia. It has been uncovered but, because of its large mass, has never been moved from where it fell. The main mass is estimated at over 60 tons, and it is the largest known meteorite (as a single piece) and the most massive naturally-occurring piece of iron known at the Earth's surface.

The Hoba meteorite is thought to have landed less than 80,000 years ago. It is inferred that the Earth's atmosphere slowed the object down to the point that it fell to the surface at terminal velocity, thereby remaining intact and causing little excavation. The meteorite is unusual in that it is flat on both major surfaces, possibly causing it to have skipped across the top of the atmosphere in the way a flat stone skips on water.



The Hoba meteorite left no preserved crater and its discovery was a chance event. The owner of the land is said to have encountered the object while ploughing one of his fields with an ox. During this task, the farmer heard a loud metallic scratching sound, before his plough came to a sudden stop. The meteorite was excavated soon after and identified and described by scientist Jacobus Hermanus Brits, whose report was published in 1920. This report can be viewed at the Grootfontein Museum in Namibia.

Hoba is a tabloid body of metal, measuring 2.7 by 2.7 metres by 0.9 meters. In 1920 its mass was estimated at 66 tons. Erosion, scientific sampling and vandalism have reduced its bulk over the years. The remaining mass is currently estimated at just over 60 tons. The meteorite is composed of about 84% iron and 16% nickel, with traces of cobalt. It is classified as an ataxite iron meteorite belonging to the nickel-rich chemical class IVB. A crust of iron hydroxides is locally present on the surface, owing to weathering.

The Hoba meteorite in 1967.

In the attempt to control vandalism, the Government of Namibia (then South West Africa), declared the Hoba meteorite to be a National Monument on March 15, 1955 with permission of Mrs. O. Scheel who was the owner of the farm at that time. In 1985, Rossing Uranium Ltd. made resources and funds available to the Namibian Government to provide additional protection against vandalism. In 1987 Mr. J. Engelbrecht, the owner of Hoba West farm, donated the meteorite and the site where it lies to the State for "educational" purposes. Later that year, the Government opened a tourist centre at the site. As a result of these developments, vandalism of the Hoba meteorite has ceased and it is now visited by thousands of tourists every year.>>