posted on Mar, 20 2013 @ 09:32 PM
The American Meteor Society
has just published a statistical analysis of fireball events reported to the society
since 2005 which can be found here: HTML format
With all the talk about fireballs on ATS (and other forums) about an apparent "increase in the frequency of fireballs" recently, this analysis could
not have come soon enough.
Here are a few paragraphs from the report:
As the graph below illustrates, the number of reports filed with the AMS has been increasing over the last few years. The level of traffic on the
site, the popularity of the site and improvements to the software are all contributing to more reports being filed. More people are able to find the
site and more easily complete the report application. These factors contribute to an increase in witness reports being filed with the AMS.
Circumstances effecting the number of reports and events collected by the AMS
There are circumstances affecting the data collected by the AMS that should be understood to prevent misinterpretation regarding the change of
Things to note:
1) From January 2005 through December 2010 the AMS fireball reports system was based on the same data collection form and process created by Bob
Lunsford in 2005.
2) In December 2010 the AMS fireball reporting system was upgraded to a database google maps system developed by Mike Hankey and Associates.
3) The new software made it much easier for witnesses to file reports and resulted in more witnesses successfully reporting events.
4) Internet traffic on the AMS site has increased since 2005. In current years, more people are connected with mobile devices, laptops and computers
than ever before. This leads to more people reporting fireballs.
5) At least one huge event with over 100+ reports in 2009 was space trash, and there was at least 1 space trash event for 2012. The graph of 100+
events has not been adjusted to account for space trash.
6) A percentage of reports received are cloud contrails, planes, sun dogs or phenomenon other than fireball meteors. These reports are deleted when
detected and generally tend to be events reported by only one witness.
7) In November 2012, the AMS fireball reporting software was upgraded again and this upgrade resulted in an immediate increase of reports received. It
is believed that improvements to the user interface lessened the amount of form abandonment and other training issues that may have kept witnesses
from successfully logging events on the previous version.
The AMS fireball reporting tool, while a useful service to the public and scientific community, is not a controlled scientific environment that
one can use to reach conclusions about the frequency of fireballs. The AMS in no way suggests that the frequency of fireballs has increased or is
increasing. This is not to say that fireball and bolide rates are not increasing, they may in fact be increasing, we simply cannot prove this with the
AMS reports alone. We can only conclude from the data collected that more users are submitting fireball reports. It is understood that the rates of
fireballs will increase and decrease year to year, but in order to answer the question “Have the rates of fireballs been increasing lately?” a
more comprehensive study is needed.
Analysis of DOD & DOE Bolide Data
As documented in, The Flux of small near-Earth objects colliding with Earth (Letters to Nature–vol420, 2002), the United States Department of
Defense and Department of Energy operate space-based systems that are capable of detecting bolide events across the entire globe. From the period of
February 1994 to September 2002 bolide data from this system was analyzed, and based on that analysis these conclusions were made:
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 kton of energy. Every ten years, an object of energy,50 kton strikes Earth.
Letters to Nature–The Flux of small near-Earth objects colliding with Earth, P. Brown, R.E. Spalding, D.O. ReVelle, E. Tagllaferri & S.P. Worden
NATURE | VOL 420 | 21 NOVEMBER 2002
Re-executing this 2002 study using the DOD bolide reports from 2003-2012 would provide definitive insight into the recent perceived increase in
fireball rates. Another benefit resulting from this study would be the development of a worldwide large-bolide frequency table covering a 20-year time
period. It appears the DOD agrees more study of fireballs is needed and they have recently stated they will re-enable the sharing of bolide data with
the public, as reported by Leonard David at space.com on February 26th, 2013.
On March 14th NASA announced the release of a Fireball and Bolide website where the analyzed results of the DOD data will be published. The AMS hopes
NASA will give attention to the most significant bolide events that were recorded over the USA and reported to the AMS over the last five years. The
release of bolide data relating to these events will help the AMS calibrate the reporting of our system so that future analysis will be more accurate.
We will also be able to use this data to better understand past events and reach more meaningful conclusions about the size, locations and origins of
these asteroids and meteoroids that have already struck Earth.
Since 2005, the AMS fireball report system has logged over 17,000 reports, identified more than 8,000 unique fireball events and been successfully
used for different purposes by the scientific community and various government agencies including NASA, the Coast Guard, and the Air Force. Several
meteorite recoveries have occurred in part due to the data collected by the AMS and the AMS fireball reports have assisted meteor and meteorite
research at NASA Ames and other NASA offices. The re-entry of satellites and space debris has been confirmed by AMS reports. The Coast Guard has also
used the AMS reports to vet calls about crashed airplanes off the coast of Florida (which later turn out to be fireball meteors). The AMS continues to
improve the systems that collect and analyze the fireball report data. We have developed trajectory analysis programs that automatically determine the
flight path of fireball meteors (within a margin of error) and we are in the process of creating orbital analysis programs for the improvement of
meteorite recovery and meteor research. The AMS fireball log is the most comprehensive set of public data regarding bolide and fireball events that
have taken place over the United States since 2005.
While the AMS fireball log has many uses and benefits, based on the AMS reports alone it is not possible to make conclusions about an increase or
decrease in fireball/bolide events from year to year. However, the data shows that reports submitted to the society have been increasing and a
significant increase in large events was specifically noticed in 2012. This warrants further study.
I know it will disappoint some members on here who touted the increase in reports of fireballs as supporting evidence for an increase in the frequency
of fireballs, but as some of us have been saying all along, an increase in the number of reports collected by the AMS does not necessarily mean that
actual fireball rates are increasing, although as pointed out by the analysis, that might
be the case.
edit on 20-3-2013 by
FireballStorm because: ran out of room
edit on 20-3-2013 by FireballStorm because: formatting
edit on 20-3-2013 by
FireballStorm because: edit to add HTML link