On Tuesday (2009/03/03) at about 9:15 PM Orange County, California was hit with a mysterious "Sonic Boom." see here
Apparently Orange County wasn't alone: see here and here
Seismic grids tracked one of the waves (which moved too slowly to be an earthquake but at the correct speed to be a sonic wave). see here
Although military "stealth" aircraft sometimes make unpublicized flights, they tend to avoid populated areas when they do this; so this is improbable - especially in rapid succession in unrelated places. See here for what the Air Force has to say about it. And see here for information on sonic booms.
There was evidence of a meteor with one of those. see here
We have a known asteroid (2009 DD45) in the neighborhood. see here (Click on image for its source and context.)
Space debris tends to break up into pieces. see here and here
Meteor impacts make a sonic wave just like a sonic boom (for the same reasons) except they can be quite a bit bigger (they can level trees etc.). see here
So: I think we may have taken a few hits from some "small" fragments of that asteroid that just passed. These fragments might have broken loose or had their orbital patterns slightly modified during previous brushes with earth.
Last year I did a study of prehistoric fragmented cometary impacts (where earth missed the main load but got beaten pretty seriously by the attendant debris). Here's my web page on this.
Update 2009/03/14: In addition to these three hits: (California 2009/03/03 9:15 pm); (California 2009/03/04 9:15 am); and (New York 2009/03/07 12:24 am); it appears there may also have been at least five other hits preceding this asteroid's pass (2009/03/02): (in Texas, Massachusetts, Hawaii, Kentucky and Italy). For information on the Texas fireball (2009/02/15 11 am), See here, here, here, and here; for information on its recovered fragments, see here, here, here, here, here, and here; for the Nantucket, Massachusetts hit (2009/02/20 4:30 am), see here; for the Hawaiian Islands hit (2009/02/09 9:05 pm), see here; and finally, see here, and here for hits in Kentucky and Italy.
We may not be finished taking the hits from this asteroid's debris.
Update 2009/03/16: Another Bolide was seen on 2009/02/10 at about 4:30 pm in B.C. Canada.
See here for details. Next, see here for another "mysterious boom" experienced in Idaho on 2009/03/03.
Also, for more on the Kentucky and Italy (both 2009/02/13) strikes, see here.
A friend just emailed me that Orange County had another window shaking experience (2009/03/16 at 3:30 pm). He also sent me the following quote from the Orange County Register regarding the 2009/03/03 event:
"This morning Kate Hutton (of Caltech) reviewed seismograms from the event last night in Orange County, Dollar said in an email. These data are consistent with a sonic event coming onshore near Dana Point and traveling northward inland.
"The energy travelled across our seismic sensor network at the velocity of a compressional wave in air rather than the velocity of a similar wave through the ground, which is much faster. There was no S phase." See here for the Register article.
Update 2009/03/18: More mysterious booms: New York (2009/03/06 7:55 pm) see here, and here. Tennessee (probably about 11:00 pm 2009/02/19) see here, here, here, and here. For a relatively tiny meteorite in Finland ("over the weekend" preceding the asteroid's pass) see here. For more on the Nantucket, Massachusetts hit: see here. And here is more on the second O.C. event.
According to this source, "A body which created the Texas fireball was about five to 10 yards across, and the earth gets hit by a body like this every couple of months to half a year." The question is whether or not the present level of activity is too high to be reasonably accounted for by a statistical fluctuation. This would depend on how many of the "booms" can be explained without meteors. According to this source, the sonic boom which meteors produce can be heard up to 30 miles away -- and that "somewhere between eight and 10 such objects burn up in the atmosphere every year." Since the O.C., California event was violently shaking windows twenty miles from the source, it is improbable that it was generated by an aircraft. Of those who heard the O.C. boom, those who have also heard a space shuttle (on reentry) passing overhead at about 100,000 feet (also about 20 miles) say the O.C. boom was "nothing like" the shuttle -- which was "just a passing rumble" (see here). If the O.C. boom was caused by an aircraft, it would need to be something much larger or much faster than the shuttle on reentry.
See here for some more discussion on the various possibilities.
I'm guessing that we might expect a few more hits between now and about 2009/03/25, then things should settle back down to normal.
Update 2009/03/19: First, there is evidence (see here) that the Staten Island event was just a firework. Other possible meteor related events include Zimbabwe (2009/03/01 5:00 pm) see here; Sri Lanka (2009/02/27) see here, and possibly Redding, California (2009/02/26 4:00 am) see here, where "something" fell from the sky and hit an automobile. Finally, (2009/03/18) it looks like we have another visiting asteroid see here. It does not appear to be another piece which was recently broken off of the same asteroid. Whether or not it is also "towing shrapnel" remains to be seen.
Update 2009/03/23: Another relatively large piece appears to have struck Georgia (2009/03/20 2:30-3:00 am). It was heard as far away as North Carolina. For reports, see here, here, here, here, here, here, here, and here. Then another piece fell over Tasmania (2009/03/21 1:30 pm) See here, and here. For some reports on asteroid 2009 FH, see here, here, here, and here. And finally, see here for another report on asteroid 2009 DD45.
From the summary below, it's starting to look like there may have been three groups of hits, and that I might have missed an asteroid pass at about the time of the Texas hit.
Update 2009/03/26: Pictured at left is asteroid Ida and its small "moon" Dactyl. This is an example of an asteroid which has gravitationally bound attendant debris. And here is some more specific information on the location of the Georgia strike.
And finally, here, here, here, here, here, here, here, here, here, here, here, here, here, and here, are reports on fragments recovered from asteroid 2008 TC3 which struck northern Sudan last year (2008/10/07). It is thought that it may originally have been a fragment which was broken off of asteroid 1998 KU2 long ago.
Update 2009/03/30: Another large event of some kind was witnessed in Maryland, Virginia and North Carolina (2009/03/29, about 9:45 pm). The two contending theories are that the cause was a reentering rocket stage (see here and here) or a meteor (see here). The event may have been too violent to have been a reentering rocket stage; besides, it looks as if the particular rocket stage under consideration may have reentered elsewhere (see here). For more detail, see: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15. The surprisingly high rate of recent meteor impacts is beginning to draw attention (see here), but doesn't yet seem to be causing much suspicion that there might be some reason connecting the events. If the closing comments of my 2009/03/23 update were on track, we might be seeing another small asteroid passing close to earth in the next few days; but there isn't really enough information here to be confident.
Also, see here for a "UFO sighting" in the London area (2009/03/18, 8:30 pm) which was described very much like a meteor. Next, here, is some better information on the Kentucky hit (2009/02/13 10:00 pm). Here is a bit more information on the Texas and Georgia hits. And finally, see: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16, for more reports on the October 2008 hit in the Sudan.
2009/02/09 9:05 pm Hawaiian Islands
2009/02/10 4:30 pm B.C. Canada
2009/02/13 10:00 pm Kentucky ---- xx:xx xx Italy
2009/02/15 11:xx am Austin, Texas
2009/02/19 11:00 pm Maryville, Tennessee
2009/02/20 4:30 am Nantucket, Massachusetts
2009/02/26 4:00 am Redding, California
2009/02/27 xx:xx xx Sri Lanka
2009/03/01 5:00 pm Zimbabwe
2009/03/02 (Apollo asteroid 2009 DD45's closest approach)
2009/03/03 9:15 pm Orange County, California ---- x:xx xx Idaho
2009/03/04 9:15 am Central Coast California
2009/03/06 7:55 pm Staten Island, New York (firework?)
2009/03/07 12:24 am Westchester, New York
2009/03/13 8:30 pm London, UK (meteor?-like "UFO")
2009/03/16 3:30 pm Orange County, California (again)
2009/03/18 (Apollo asteroid 2009 FH's closest approach)
2009/03/20 3:00 am Georgia, North Carolina
2009/03/21 1:30 pm Tasmania
2009/03/29 9:45 pm Maryland, Virginia, and North Carolina
Update 2010/04/08, 2010/04/14: Another asteroid/fireball conjunction:
Asteroid , Fireball , Fireball, Fireball, Fireball, Fireball.
Update: 2013/02/10:NASA's Astronomy Picture of the Day (APOD) is announcing the very close pass of a large asteroid (larger and closer that the asteroid featured at the top of this page) this coming Friday (2013/02/15). This one looks like it's big enough (50 meters) and close enough (inside the satellite parking orbit) to be "towing" a few potential fireballs. If the theory I'm presenting here is "on track," we ought to be seeing a few of them in the news shortly.
Update: 2013/02/17:There were indeed a few fireballs in the news which were near enough in time to be regarded as being remarkably "coincidental." This news report here mentions hits in Chelyabinsk (Russia), the Bay Area of California, and Cuba. This report here says, "In last 2 days exploding fireballs were reported on all sides of the world – Russia, Kazakhstan, Japan, Australia, Cuba, South Africa, Morocco, Germany, Switzerland, northern Italy, Netherlands, Belgium, UK…" The hit in Russia was sufficiently spectacular to dominate the news coverage. Even though the time of the hit would seem to imply a connection with the asteroid, it's direction of approach was opposite to the direction of the asteroid. This is (quite reasonably) understood to be evidence that there was no connection.
The only possible way a meteor orbiting that asteroid (2012-DA14) could have hit Russia, from the direction this one did, would have been if that chunk took the long way around the earth: Starting with a path almost exactly parallel to the asteroid (having a wide and very slow orbit around it); Earth's gravity might pull it into a hyperbolic orbit; with perigee somewhere in the general area of the Arctic -- where it could hit the atmosphere and "skip" back up; losing enough velocity to become trapped in Earth's gravity well; it could then come back down on an elliptical trajectory; which finally hit Chelyabinsk from the north.
If this was the way it happened, the velocity of the Chelyabinsk hit would have to have been somewhere between low-orbital velocity (about 28,000 km/h or 17,000 mph) and Earth's escape velocity (about 40,000 km/h or 25,000 mph). Meteors which hit directly (no atmospheric skip) will acquire velocities with a minimum of escape velocity as Earth's gravity pulls them in. At present, estimates of this meteor's velocity are varying all over the place (depending on what assumptions were used to produce each number). Examples are as high as 66,000 mph; and as low as 17,000 mph, with most estimates running more like 33,000 mph to 40,000 mph. It will be interesting to see if anyone is able to get some kind of reliable direct measurement of this velocity.
Update: 2013/02/26: The direct measurements have been done and the Chelyabinsk meteor was traveling way too fast to have been orbiting asteroid 2012-DA14; See here for details. That really was just a very remarkable coincidence.
Update: 2013/05/31: "About 16 percent of asteroids that are about 655 feet or larger are binary or triple systems, according to JPL."Although today's asteroid is clearly large enough to hold an entourage, it is probably passing too far away from us for it's attendant debris to cause a significant number of fireballs.
But I've been wrong before: Here's one seen "primarily from Ohio and Indiana, ... but reports also came from West Virginia, Virginia, Pennsylvania, Kentucky and North Carolina" (see also here, here and here); ...