65_HS1-834228961_62-HQ-83894_Section_006

Text

This text came with the file. It may have mistakes. When the text and the image disagree, the image is right.

'1 •
·•
•
THE UNIVERSITY OF NEW MEXICO
ALBUQUERQUE
INSTITUTE OF METEORITICS
?Jay 23 , 1950
To:
L·.; . Co].onel Doyle Rees > Commandin~ Officer
17th District , O. 3. I .
From:
Lincoln LaPaz , Dir ector
Institute of 11eteoritics
Subject: Anomalous Luminous Pnenomena ( Seventh Report)
1 .
In the second report of this series , dated 1948 , December 20, the
writer listed ten significant differences bet·,'!een the bri:;}'lt green horizon­
tally-moving firebal ls observed in the interval 1948 , December 5-20 , and
typical meteors .
These differences vJere the following :
( l) The horizontal nature of the paths of nos·t of the December
fir eballs is most unusual .
Genuine met eors are rarely observed to move
in horizontal paths .
(2) Age.in the very lo·w height of the December f ireball discussed
in section 2 above sets it off in sharp contrast from the f.;enuine
meteors for ·which heights of the order of 40 or more miles are nf,:-.·­
mally observed .
(3) The velocity determined for the fir eball of Dece1-::ber 12 is
much less than the velocities det ermined from typical meteors (and
yet is considerably greater than the speeds of the V-2 Rockets or
jet planes or of conventional flares) .
( 4) In the case of meteorites that oenetrate to as low levels
as that determined for the firebal l of D~cember 12, t he observed lu­
minous phenomena are always accompanied by very violent noises .
No
noises whatever have been observe,d in connection with the various
December fireballs so far investigated .
(Note added on 1950 , May 23 :
Possible exceptions to the noiselessness of green f ireballs are ·!;he
incidents of 1949 ~ January 30 , and 1949 , December 4.)
(5) Genu:inem.eteorsaormally show remarkable variations in
br ightness , beginning; as "fine thin hai r lines , which are sca.rcoly
visible to the observer , and then brightening up to flash out near ·
the end of their paths .
In t he case of the December fir eballs most
of the observers have reported t ha-\:; t he green balls appeared almost
instantly at their full brigp.tness .