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Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Sun Dec 12, 2010 5:30 am
by SsDd
RJN wrote:What I was doing was entering the search term "meteor' and/or "fireball" and then selecting only videos that had been uploaded "This week". This technique still fails to find the video you linked to. So please tell us how you found it!

- RJN

RJN, I almost do the same exact thing when I look for videos. You will observe, however, that along with looking for videos indexed "this week", you will achieve better results if you also ask Youtube to index them by "Upload Date", not "Relevance". Alternatively, I also used a lot of different search terms like "meteorite" "meteor UK" etc.

A late Northern Taurid?

Posted: Sun Dec 12, 2010 7:23 am
by neufer
RJN wrote:
Searching the web with Google, I found several accounts of this fireball were reported to the
Armagh Observatory Fireball report web site here: http://arpc65.arm.ac.uk/cgi-bin/fireballs/browse.pl
http://arpc65.arm.ac.uk/cgi-bin/fireballs/browse.pl wrote:
* Date: 2010-Dec-08
* Time: 17.40pm wed 8/12/10
* Location: Campsie, Londonderry. heading northward along A2 in my car.

* Report: white fireball entering atmosphere, i was driving north and the object appeared in front of me for approx 5 seconds heading vertically down, then split into a fork as it disintigrated. Initially thought it was a firework until i read bbc news meteor report tonight. No noise from object i could hear whilst in the car.
I found this report particularly interesting. The "northward" A2 runs essentially west to east at Campsie so the meteor was probably coming from due east of Campsie (at Lat. 55º N) while heading vertically down. This would most likely make it a late Northern Taurid coming out of the M45/Pleiades's vicinity and crossing the UK almost exactly along the 55th parallel. I believe that this is consistent with the other reports including the drawing of the meteor passing through the Big Dipper.
http://en.wikipedia.org/wiki/Taurids wrote:
<<The Taurids are an annual meteor shower associated with the comet Encke. They are named after their radiant point in the constellation Taurus, where they are seen to come from in the sky. Because of their occurrence in late October and early November, they are also called Halloween fireballs.

Encke and the Taurids are believed to be remnants of a much larger comet, which has disintegrated over the past 20,000 to 30,000 years, breaking into several pieces and releasing material by normal cometary activity or perhaps occasionally by close encounters with the gravitational field of Earth or other planets (Whipple, 1940; Klačka, 1999). In total, this stream of matter is the largest in the inner solar system. Due to the stream's size, the Earth takes several weeks to pass through it, causing an extended period of meteor activity, compared with the much smaller periods of activity in other showers. The Taurids are also made up of weightier material, pebbles instead of dust grains. Typically, Taurids move slowly across the sky at about 17 miles per second (27 kilometers per second).

Due to the gravitational effect of planets, especially Jupiter, the Taurids have spread out over time, allowing separate segments labeled the Northern Taurids and Southern Taurids to become observable. Essentially these are two cross sections of a single, broad, continuous stream in space. The Beta Taurids, encountered by the Earth in June/July and which many astronomers consider the cause of the Tunguska event, are also a cross section of the stream. Beta Taurids approach from the Earth's daytime side; so cannot be observed visually in the way the (night-time) Northern and Southern Taurids of October/November can.

The Taurid stream has a cycle of activity that peaks roughly every 2500 to 3000 years, when its core passes nearer to Earth and produces more intense showers. In fact, because of the separate "branches" (night-time in one part of the year and daytime in another; and Northern/Southern in each case) there are two (possibly overlapping) peaks separated by a few centuries, every 3000 years. Some astronomers note that dates for megalith structures such as Stonehenge are associated with these peaks. The next peak is expected around 3000 AD.

Some consider the Bronze Age breakup of the originally larger comet to be responsible for ancient destruction in the Fertile Crescent, perhaps evidenced by a large meteor crater in Iraq. However the Bronze Age was c. 6000 years ago and the original break up of the parent comet, as mentioned above, occurred long before that. Ancient peoples may have been used to Tunguska Class impacts which occur approximately every 300 years as calculated by Eugene Shoemaker and Krakatoa type eruptions both of which have widespread climatic effects and which would dwarf any climatic effects from the slight increase in upper atmospheric dust caused by bolides due to passing through the tail of Comet Encke.

An impact event was observed by NASA scientist Rob Suggs and astronomer Bill Cooke while testing out a new 10-in telescope and video camera they had assembled to monitor the moon for meteor strikes. After consulting star charts they concluded that the impact body was probably part of the Taurid meteor shower. This may well be the first recording of this type of lunar event which some have claimed to have witnessed in the past. During the week ending November 4, 2005, the large number of fireballs seen all over the world led some to suggest UFO visitations. These fireballs may have been space junk or the Taurids.>>

Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Sun Dec 12, 2010 5:59 pm
by RJN
Shown more discerning methods for searching YouTube for fireball and meteor videos, I just came across this one:
Click to play embedded YouTube video.
Now this video doesn't say where it was taken or even what time, but it appears to me at first glance consistent with the recent UK fireball. If so, perhaps this and the above video were taken sufficiently far apart to determine a 3D path for the meteor that better indicates from whence it came and to where it went. It does seem, though, that decrypting good sky information from the videos would take a some effort.

Also, considering the source of these two videos, perhaps I need to rethink what video sources might be most useful for meteor recovery. This one, for example, appears to be a traffic video. I hadn't thought of that, but perhaps traffic videos might be another useful source for fireball information.

- RJN

Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Sun Dec 12, 2010 8:29 pm
by neufer
RJN wrote:
I just came across this one: http://www.youtube.com/watch?v=db6QFfR16xg

Now this video doesn't say where it was taken or even what time,
but it appears to me at first glance consistent with the recent UK fireball.
On second glance: http://www.bashewa.com/meteor-showers-21-Nov-2009.php
http://www.psychohistorian.org/display_article.php?id=200911220139_20091121-bright-meteor.content wrote: [youtube]http://www.youtube.com/watch?v=VHH8cXM4_n4&NR=1[/youtube]
Late on Saturday night, 2009 November 21, a very bright meteor
was seen flashing across the sky from the northern parts of South Africa.

Tim Cooper, Director of the ASSA Comet & Meteor Section, estimates that the apparent magnitude of the meteorite was –18.

"I think it is highly likely it hit the ground somewhere north of our borders," Tim writes. He notes that the most northerly sighting came from north of Gweru, Zimbabwe. "Reports also from as far west as Rustenburg, and as far east as Ezulwini, Swaziland" were received, he writes.

The size of the meteorite has been estimated as that of a rugby ball.

In an update today (2009 Nov 30), Tim mentions the possibility that the object was a cometary fragment. "What lends credence to this possibility is the short duration (nearly all reports say 3-4 seconds) and the fact that this was claimed to be a very, very energetic event," he writes.

Another update today, from Freddie Roelofse (Senior Petrologist, Council for Geoscience):

"Only one of our seismic network's stations, the one at Musina, picked up something, possibly a sonic boom at ~23h00 local time on 21 November 2009. We are presently still waiting for feedback from the CTBTO regarding the infrasound data, but it appears as if the event may have been recorded at three infrasound stations. As these things go, the data interpretation may take some time to do, but hopefully we'll get to the bottom of this in due course.

"Please also see the attached Google Earth image that I've constructed using details from the eye-witness accounts posted on your website."

Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Mon Dec 13, 2010 5:52 am
by SsDd
Great job neufer. I was wondering why the video looked familiar.

Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Sat Dec 18, 2010 6:59 pm
by alain
?
1. Uk and South africa have nearly same longitude but times are very different
2. If bolids occur at about 100km altitude, how can it be seen from such different latitudes as UK and South Africa ?

Re: Fireball48 Alert: Fireball Over the United Kingdom

Posted: Sat Dec 18, 2010 7:05 pm
by neufer
alain wrote:?
1. Uk and South africa have nearly same longitude but times are very different
2. If bolids occur at about 100km altitude, how can it be seen from such different latitudes as UK and South Africa ?
Other than the possibility that they are both Taurids the two meteors are totally unrelated.