[meteorite-list] Rock on the ground or not?

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Sun, 30 Mar 2008 19:25:20 -0600
Message-ID: <056401c892ce$1c591ea0$0a01a8c0_at_bellatrix>

Hi Rob-

It's certainly possible. I've seen three head-on meteors, and recorded a
few dozen on cameras. But I'm an astronomer, and spend a lot of time
looking.

I don't know how accurate the 10-second time estimate was. If accurate,
it's not only too long for most meteors, but also a bit long (but not
impossibly) for an Iridium flare. More to the point, however, is that
Lasse was comparing the event location to surrounding stars. Iridiums
move pretty fast, and a 10-second flare would move significantly. It
sounds like he was enough in tune with the stars to notice something
like that.

Another possibility, depending on the time and sun angle, would be a
reflection from a weather balloon (or its payload). I've seen them do
some pretty odd things, and they appear stationary for a long time.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "Rob Matson" <mojave_meteorites at cox.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, March 30, 2008 7:15 PM
Subject: Re: [meteorite-list] Rock on the ground or not?


Hi Chris and Lasse,

There is another possibility to consider: Lasse may not have seen
a fireball at all. Consider:

1. So-called "point meteors" are very rare; they are rarer still
when the radiant is close to the observer's zenith.

2. The 10-second duration is probably too long for a point meteor
at such high elevation angle. Even at the slowest possible initial
entry velocity (11.2 km/sec), a meteor only 14 degrees from zenith
cannot maintain a velocity above 3 km/sec for that length of time.

I offer an alternate explanation: Lasse may have observed a
glinting satellite, perhaps an Iridium satellite. This is easy
enough to check, knowing the date, time and location of the
observation. On March 28th and 29th there were high elevation
Iridium flares for Sweden in the early evening in the eastern
sky -- in the vicinity of the bowl of the Big Dipper. --Rob
Received on Sun 30 Mar 2008 09:25:20 PM PDT


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