Volume 2, Issue 7 July 2007

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Triton Fun Company Science Newsletter July 2007 Science Newsletter July 2007

Cosmic Collision: The Lake Cheko — Tunguska 1908 Bolide Event

T. Dockweiler

Special points of interest: Objects in space are colliding all Russian scientists, mostly unrec- the time. We don’t think about ognized for their significant ef- Cosmic collision them much. However, space ob- forts, have spent a century trying Triton Fun stuff ject collisions were brought to the to figure out this impact event. public’s awareness dramatically in Some of the speculations involved Superfluous questions 1994 with the collision of the 3- seismic events, or some “outside mile-wide Comet Shoemaker-Levy of the box” ideas, such as a mi- 9 with Jupiter in 1994. This comet cro-black hole impacting the broke into about 20 impacting bod- Earth, and others involving ies which produced Earth-sized “mirror matter”, that is, matter blast events which became appar- consisting of anti-particles. Many Trees flattened by Tunguska ent in Jupiter’s atmosphere as gray- astronomers believed that a small impact in 1908; the region ish dark spots. Such collisions comet, meteor, or small asteroid- still looks like this almost have occurred on Earth in its past, like object collided with the Earth 100 years later the most recent significantly nota- on that date. This was a bolide: a ble events being that produced by bright meteor or fireball that ex-

the Tunguska Space Body (TSB) plodes in the air and/or hits the The research details results of object in 1908 and the first video- Earth. Recent research over the an expedition at Lake Cheko in taped small impact event last year last decade indicates that a mete- central Siberia. Lake Cheko (02 May 2006) on the Moon. oroidal object may well be the may have been formed from a cause of the impact and subse- fragment of the impacting Many theories have been given quent devastation. body from this 1908 event. during the century since the 30 Previous research in 1960 of June 1908 event. [This is the date An interesting article will appear this lake yielded nothing due on our modern Gregorian calendar; in the August 2007 issue of the We are always looking to insufficient sensitivity of witness accounts use 17 June 1908 European multi-geoscience socie- for contributors to the instruments. Science Newsletter. If on the Julian calendar which was in ties’ journal Terra Nova [solid you would like to write effect at the time in Russia (a dis- earth and planetary sciences] per- The lake is about 5 miles (8 an article about a sci- placement of 13 days of accumu- taining to the 1908 bolide event km) north-northwest of the ence subject you are lated leap year days)]. On that day, over Siberia in Russia. This re- excited about, or con- event’s airburst epicenter. The something, presumably an impac- gion contains permafrost, thermo- tribute a superfluous impact produced a Richter tor of uncertain type, hit the Earth karst, taiga, and boreal forests. question, or if you magnitude 5 earthquake seis- and devastated the mostly uninhab- The recent research was con- would like to be on our mic shock wave through the ited forested area near Tunguska in ducted by scientists at the Institute mailing list for future ground and multiple air pres- newsletters, please the remote Russian wilderness. of Sea Biology of the University sure waves resulting in the e-mail us at: Significant luminescent night skies of Bologna of the National flattening of an estimated 80 were reported for days over Europe Research Council of Italy. million trees radiating from [email protected] and Scandinavia [you could read a the site for nearly 1,000 square book by it!]. miles. Science Newsletter

Cosmic Collision, continued Photos/Graphics: Institute of Sea Biology of the University of Bologna, National Research Council of Italy; Central Int Agency Fact Book; NASA/art by Don Davis; illustration is not to scale

The most massive meteor stream in the inner Solar System, the Taurid Me- teor/Asteroid Complex, has been identified to con- sist of 4 meteor streams (the night-time North Taurids, the night-time South Taurids, the day- time Beta Taurids, and the day-time Zeta Perseids) consisting of 2 major branches. The 5 mile wide (4 km radius) periodic Comet Encke (2P/ Encke) is a Jupiter family comet and is the cause of much of the Taurid meteoroidal com- plex stream. Comet Encke and the Taurid me- teor stream is thought to be a remnant of a lar- ger comet which disintegrated 20,000-30,000 years ago. The Beta Taurids daytime approach meteor shower, which can be detected by radio Map showing location of 1908 impact event and radar observations, appears to be the source of the Tunguska object. The core of this Taurid shower, one component of which produces the The hypersonic burst resulted in mass It is thought to have decreased in size known “Halloween fireballs”, appears to dis- macro-fires and literally wiped small (from atmospheric ablation) to play “wild skies” about every 3,000 years. towns and villages off the map with around 10-40 meters and traveled at Some researchers think it may have inspired the force equivalent of 1,000 times the an inclination of 3-15 degrees from Earthlings to create megalithic structures such energy of the first atomic bombs used over the horizon with a brightness as Stonehenge. Another interpretation is that at the end of World War II. The 164 greater than that of the Sun. Its true they were “The Star of Bethlehem”. The next foot deep (50 m) lake is shaped like bearing was 125 degrees from the core Taurid stream to approach Earth is ex- the conical funnel shape of the Odessa southeast towards the north- pected to occur in about 1,000 years. impact site in Texas. (That impact northwest. It is believed to be an from a meteor occurred around 25,000 object from the daylight meteor References: years ago; the meteor hit the Earth and shower of the Beta Taurids and im- (1.) A possible impact crater for the 1908 Tun- came in at a shallow angle, creating a pacted sometime shortly after 7 a.m. guska event, L. Gasperini, et al., Terra Nova, 7 weird and unusual-shaped crater near in the morning local time, after decel- pages, preprint, 2007 what is now Odessa, Texas.) Sonar erating from about a Mach 5 velocity (2.) Farinella P, et al., Probable asteroidal ori- and seismic wave analyses seem to (1,700 meters per second). It appar- gin of the Tunguska Cosmic Body, Astron. As- show a surviving meteorite in Lake ently split into pieces, most of which trop., 377, 1081 (2001) Cheko which is reflecting some of the ablated/evaporated in the Earth’s (3.) Foschini L, A solution for the Tunguska waves. The potential object or very atmosphere explosively, and was event , Astron. Astrop., 342, L1 (1999) compacted sedimentary layers 33 feet heard by distant surviving witnesses (4.) Klacka J, E.M. Pittich, Origin of the Taurid below the lake bed is to be explored who reported that it sounded like a meteor stream, Planet. Space Sci. 46, 881 by the same Italian team next year. military ballistic artillery barrage. (1998)

The progenitor object of the Tunguska Far left: Lake impact event is thought to be 60 me- Cheko as it looks ters across and is believed to have today exploded 5.3 miles (8.5 km) above the Left: Simulation ground. showing how Lake Cheko would look if top 40 meters of wa- ter was drained away; note crater shape Volume 2, Issue 7

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Superfluous Questions:

1. What year did women in America get the right to vote (by Congress passing the 19th Amendment) ?

a) 1898 b) 1915 c) 1920 d) 1925

2. In what movie did Danny Kaye play twins who were opposite in personality (one shy, one extroverted) ?

a) Knock on Wood b) On the Riviera c) Wonder Man d) The Kid from Brooklyn

3. Tirane is the capital of what country ?

a) Bulgaria b) Azerbaijan c) Albania d) Belarus

4. What spacecraft first detected the van Allen radiation belts in Earth’s magnetic field ?

a) Pioneer 1 b) Mariner 1 c) Explorer 1 d) Apollo 1

—-> ANSWERS in next months issue of the Science Newsletter ! <——-

** ANSWERS to June’s Superfluous Questions: 1. a) 1790 2. c) Barbara Barrie 3. d) subatomic particles 4. c) compound.. tin