'Flaming basketball' meteorite destroys Californian farmer's home.. or not as the case may be!

[Leo S]

I've come across stories like this in the past. They never turn out to be true. Meteorites simply don't do this, but it never seems to stop the media from running with it! I used to think the Telegraph was OK (not that I read papers), but it seems even they do not do basic research anymore.

The following quote is from here:

Quote

A “flaming basketball” meteorite has destroyed a Californian farmer's home.

Dustin Procita was at his residence in Nevada County, about 60 miles north-east of Sacramento, when “a big bang” rang out on Friday.

"I started to smell smoke, and I went on to my porch, and it was completely engulfed in flames," he told NBC affiliate KCRA. Mr Procita said it looked “like a flaming basketball”.

“They said it was a meteor,” he added. “I did not see what it was, but from everybody I talked to – [it] was a flaming ball falling from the sky [that] landed in that general area.”

Mr Procita’s home was quickly engulfed in flames that killed a dog and burned down a travel trailer and a pickup truck.

It took almost three hours for the fire to be contained.

So for those of you wondering why I think this is the case, you only need to look at the map/reports of this event on the IMO fireball database.

Note:

1. the location of the fire "Nevada County, about 60 miles north-east of Sacramento", here.

2. the "blue arrow" which is where the trajectory of the meteoroid has been calculated to be, by collating all the directions submitted by witnesses to the event. With a significant number of reports submitted (117 in total so far), the errors tend to even out, leaving you with what is usually a fairly accurate trajectory.

You can see the obvious mismatch between both.

If you take the trouble to read the comments people have left (I have not in this case, yet), you'll find statements like "it landed nearby" or "it fell just over the hill" from witness separated by 100's of km. Statements like this are common when a big/reasonably bright fireball is observed by many.

If you are confused as to why this happens, it's actually rather simple:

Fireballs can be very bright, and even extremely bright in some cases, with stellar magnitudes that can equal or exceed the brightness of the Sun in the most exceptional cases. While exceptionally bright events are quite rare, smaller fireballs, around the brightness of the Moon (-6 to -12 mag.) are not uncommon, especially at the lower end of the spectrum.

Our atmosphere does not have much depth, and can be thought of as a "thin film" that covers the surface of the planet. Since Earth's surface is curved, meteoroids entering the atmosphere many hundreds of km away will appear to be relatively low down in the sky - "just over the hill" or "just behind those trees".

But because of the brightness, and despite being 100's of km away, a bight meteor or fireball appears to be much closer than is actually is. Apart from a few notable exceptions, most of the time, a bright light suggests that the object emitting the light is close and NOT far. Our brains are wired this way, so when a conflicting situation like the sudden appearance of a bright fireball in the sky occurs, people tend to misinterpret brightness as being close, when that is not the case.

Here are some facts:

Most meteors become visible at altitudes ranging from about 80-150 km above Earths surface. Faster/larger meteoroids become visible higher up than slower/smaller meteoroids. While most disintegrate high up and very quickly, larger/slower meteoroids can get down beyond 50 km altitude, and in extreme cases have been known to remain self-luminous down to high single digit km if memory serves, but in most cases of large fireballs that drop meteorites, they only remain luminous to heights of around 20-30 km above the ground. At these kind of altitudes a bright event can be observed by people from 800+ km away in extreme cases.

It's only below around 50 km that the air starts to become thick enough for sound (sonic booms) to travel to an observer on the ground, and if a large and slow enough meteoroid makes it down this low, it has a chance of being slowed down further, to speeds at which it is no longer self-luminous - around 1 km/s - where it then becomes effectively invisible, slows to free-fall velocity, and falls the remaining few km to the ground, where the air is well below freezing. This last stage of "dark flight" as it's known invariably results in meteorites that are more likely to be very cold to the touch - certainly not warm or hot!

The only way a meteor could cause damage/a fire on the ground, would be if it was extremely large. All hell would break loose, and not just on one property!

So this was just an unrelated fire - there's no doubt.

I just wanted to bring this to the attention of all, since few seem aware of the "meteorite illusion" (my own term) that can occur under these kinds of circumstances. I have experienced this illusion myself on a few occasions as I actively hunt/observe for bright meteors and fireballs. In fact, I observed one a little earlier on tonight (at 21:07 UT), while composing this post - I was not expecting it to be this clear tonight, so I've been nipping out for quick breaks to observe in between typing!