The Sky is Falling! Save the Mantis Shrimp!

Remember the recent, very devastating meteoric event in March of 2013, during which a large bolide entered Earth’s atmosphere over the city of Chelyabinsk in Russia, cutting a swath of sonic shock destruction as it went? As it traveled, it blew off its outer shell until the rock was down to its jammies, shattered windows in buildings and vehicles, set off car alarms, knocked down newly-built brick walls, and generally scared the pants off some observers. There were side effects of injuries from buildings that were damaged just by the shock wave alone.

The Russian people have a penchant for dashboard cams, which makes recovery of the trajectory and explosions easy to find.  It was a bolide, a large meteor weighing many tons, breaking up as it traveled, and finally ending up in several chunks, one of which was found in a frozen lake outside of Chelyabinsk.

Whether or not it was part of the beta Taurid meteor stream, it is thought to have originated in the space between Mars and Jupiter commonly known as the asteroid belt.  But – nobody saw it coming.  And we do have a Near-Earth Object observation program in place.

Based on its entry direction and speed of 19 kilometres/second, the Chelyabinsk meteor apparently originated in the asteroid belt between Mars and Jupiter. It was probably a fragmented asteroid. The meteorite has veins of black material which had experienced high-pressure shock and were once partly melted, due to a previous collision. The metamorphism in the chondrules in the meteorite samples indicates the rock making up the meteor had a history of collisions and was once several kilometres below the surface of a much larger LL-chondrite asteroid. The Chelyabinsk asteroid probably entered an orbital resonance with Jupiter (a common way for material to be ejected from the asteroid belt) which increased its orbital eccentricity until its perihelion was reduced enough for it to be able to collide with the Earth. – source: Wiki

Here’s an abstract for a paper on this particular subject of meteors and the Taurid stream resonance.

Discovery of a new branch of the Taurid meteoroid stream as a real source of potentially hazardous bodies

1. Spurný, J. Borovi?ka, H. Mucke, J. Svore?

(Submitted on 24 May 2017)

Taurid meteor shower produces prolonged but usually low activity every October and November. In some years, however, the activity is significantly enhanced. Previous studies based on long-term activity statistics concluded that the enhancement is caused by a swarm of meteoroids locked in 7:2 resonance with Jupiter. Here we present precise data on 144 Taurid fireballs observed by new digital cameras of the European Fireball Network in the enhanced activity year 2015. Orbits of 113 fireballs show common characteristics and form together a well-defined orbital structure, which we call new branch. We found that this branch is characterized by longitudes of perihelia lying between 155.9-160o and latitudes of perihelia between 4.2-5.7o. Semimajor axes are between 2.23-2.28 AU and indeed overlap with the 7:2 resonance. Eccentricities are in wide range 0.80-0.90. The orbits form a concentric ring in the inner solar system. The masses of the observed meteoroids were in a wide range from 0.1 g to more than 1000 kg. We found that all meteoroids larger than 300 g were very fragile, while those smaller than 30 g were much more compact. Based on orbital characteristics, we argue that asteroids 2015 TX24 and 2005 UR, both of diameters 200-300 meters, are direct members of the new branch. It is therefore very likely that the new branch contains also numerous still not discovered objects of decameter or even larger size. Since asteroids of sizes of tens to hundreds meters pose a treat to the ground even if they are intrinsically weak, impact hazard increases significantly when the Earth encounters the Taurid new branch every few years. Further studies leading to better description of this real source of potentially hazardous objects, which can be large enough to cause significant regional or even continental damage on the Earth, are therefore extremely important.

Comments:	24 pages, 22 figures, 5 tables. Accepted in Astronomy and Astrophysics
Subjects:	Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference:	A&A 605, A68 (2017)
DOI:	10.1051/0004-6361/201730787
Cite as:	arXiv:1705.08633 [astro-ph.EP]
	(or arXiv:1705.08633v1 [astro-ph.EP] for this version)

 

As it is, the discussions that followed Chelyabinsk included many references to the large meteor impact known as the Tunguska event, which is now thought to have been a large, dense member of the  Taurid meteor stream. Note the two parts of the Taurid stream in the first S&T graphic in the article linked below.

https://www.skyandtelescope.com/astronomy-news/stalking-the-taurid-swarm/

Sky & Telescope (see link) has a good graphic image of the two Taurid swarms, which appear to be a cloud of smaller particles orbiting the Sun between Jupiter and Mercury, and another portion of what appears to be much denser material in opposition to the other stream. And Earth travels through these convocations on a recurring basis. The massive bolide that impacted the Yucatan peninsula and formed the Chixclub crater more than 65 million years ago is now thought to have been part of the Taurid swarm.

Per Sky & Telescope’s article: “Most recently, an observing team led by Pavel Spurný (Czech Academy of Sciences) recorded more than 100 bright fireballs traveling en masse within a particular branch of the TRS, and several near-Earth asteroids have matching orbits.

….this month and next, the core of the TRS will pass closer to Earth than it has since 1975. Although dynamicists aren’t expecting any Tunguska-like encounters, the close passage will offer observers the chance to discover sizable near-Earth asteroids with advance knowledge of where and when to look.” – S&T article.

Space.com’s article offers the possibility that the Beta Taurids contain bigger, far more dangerous chunks than the primary stream, which is awash in smaller bits, comparable to the Perseids (summer) and Geminids (winter), both of which are full of particles that are mostly the size of sand grains.

“A new study, soon to be published in the Monthly Notices of the Royal Astronomical Society of Canada, suggests that the Beta Taurid meteor stream may camouflage dangerous space rocks.” (See above referenced abstract.)

https://www.space.com/beta-taurid-meteor-shower-tunguska-explosion-planetary-defense.html

“May camouflage dangerous space rocks…?” No, really???  I guess we should all be grateful that Jupiter, the King of Planets, had enough pull with Madame Gravity to guide Comet Shoemaker-Levy into its atmosphere. 28 large chunks of cometary material impacted Jupiter’s cloud-capped atmosphere, leaving scars that took weeks to months to be absorbed. Comet Hale-Bopp, with an orbital period now thought to be 4,000+/- years, will be showing up again some day. Oumuamua missed us only because its angle of momentum brought it into our solar system just inside Mercury’s orbit, and its speed was enough below solar delta V to allow it to use the Sun’s gravity field to change directions, at the slow gait of 250,000 MPH.

Oh, yeah – meteor strikes are considered an Act of God and aren’t covered by your Homeowner’s policy, but the fragments are worth good money to meteor hunters.

Hey, maybe we could use this to scare the silly ecohippies and the politicians who worship them and their votes.  Just a thought. ? They all insist (along with their idol AOC) that the Earth is doomed! Doomed, I tell you!

Any questions? Keep an eye on the sky, folks. Pack your stuff. We may be going away with no notice.

Party time!!!

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