The Washington herald., 1922-05-28
CCheHcy
Scientific
Notes
Q2dCon7ncW


HOW METEoRITEs
ARRIVE ON EARTH.
Within the past few weeks IN.
Eastern part OF the United States
has been visited by two meterortss
Of considerable size. while a third
has been seen in Southern Cali
fornia. In all three Instances the
nights Of the meteorites were OBJ
served over an area OF many square
miles and were attended by inten,.
flashes OF light from the meteorit..
luminous rocket-like trails. and
loud detonations and concussions
These attendant phenomena are
All produced by friction with the
earth's atmosphere which meteorites
Z enter with velocities that have been
known TO rum as high as forty-fve
miles per second. This initial We
locity is so rapidly reduced by frie-
ton that most meteorites strike
the service with the ordinary ve-
locity OF falling bodies.
The depths 20 which a sneteorft.
penetrates the earth's surfac. ts
r'rely more than few feet
Peary's huge Cape York ue,eori,.
, the largest known, which weigh,
! thrty-seven and a half tons. was
found only partially covered ana
showed no surface marks that
would indicate Il had struck the
surface with high velocity. The
3 second largest stone known as the
Bacubirito iron. weighing % tons lie.
I where IL fell on the plain near
Bacubirito. Mexico. only slightly
below the level OF the surrounding
held. The Willamette metorite. the
third largest known. which weighs
J hfteen and a half tons and is now
, In the American Museum ~ Natural
History in New York was found
lying In forest IN Oregon only
partially buried.
The temperature Of tunnedista,v
after falling differs greatly in indi-
y1dual cases, some meteorites ha-
Ing too hot TO handle for several
hours while others have been in.
tensely cold or even coated WITH
Ice when found. At the time IL
enters the earth's atmosphere the
mass is invariably intensely cola
for II has been subjected 10 the
temperature OF interplanetary spare
which is not far from the absolute
zero OF 45s degrees Fahrenheit
The heat produced by fric'I~n
with the atmosphere 10 usually SUI
hcient TO cause a fusion or even
Ignition OF the surface materials
and nearly all stony meteorites are
found coated with a thin. black.
glsss-like crust.
The composition OF a neteori'. Is
so characteristic that one can reve-
terrestrial origin OF vice-versa All
meteorites are composed Of igneou>
material. that is. material that has
oeen subjected to intense heat. and
they were found where free oxygen
and water vapor were scarce.
They may all be classed under
one OF the three divisions ~
siderites or iron meteorites. cor1-
posed chiefly ~ an alloy n nickel
iron. aerolites or stony nete0r'ra-1
consisting chiefly % silicstes ~ al
form and structure totally unIft.
any that occur IN the earth
crust and siderolites or stony-l-r-''
meteorites in which a sponge or
net work Of nickeI-Iron alloy -
filled with the stony material
Though there is some uncertain
4 ty as 20 the origin Of rnctao-sc,
stones or meteorites. they proha hlv
/ are the minute fragments ~ the.
: primitive solar nebula that failed
I TO be swept M originally In tNa'
/ formation ~ the larger ner1Ne-SI
/ ~ the system and which hnaIIv|
chsnced To he trapped hv the earth 4
atmosphere-Pv Isabel NJ Lewis. cd
/ L. s. Naval Observatory.