Anthony Zuppero, 
Idaho National Engineering Laboratory by day, by night
208 526 5382          208 525 8682

 The distribution falls too precipitously at Mars and inward.

We ought to see comets inside Mars, unless Mars and/or Earth are herding them, just as we see Jupiter doing to them.

Perhaps the "hole" is a whole formation of herded comets, but we don't see them because they are herded into a place where it is too hot. The hole might be evaporated comets, which look like near earth asteroids.

Perhaps this is the source of the Lou Frank Objects.

We ought to see comets just past Jupiter. At the orbit of Jupiter, the change in brightness of a comet does not change that much between 4 and 6 A.U. But the density changes sharply.

 The inner planets gravity changes the orbits with high cross section, but collide with low cross section. of 4 june 97

Dark, Close, Dry, Many, Deceiving

What would a 3 meter piece of comet from inside the ZWL Hole (comet hole discovered by zuppero, whitman and larson, "zuwila hole?") do and look like if it hit our atmosphere?

Its properties (It Looks Like)

Rich in Hydrogen, Carbon and Oxygen, in that order

The objects in the ZWL Comet Hole (zuppero, whitman, larson), if there are any would be denuded of ice and consist of material very much like the observed dust graines of comet P/Halley.Average atomic abundances of 17 elements in dust grains of P/Halley, normalized to Mg = 100
Element Haley dust +/-
H 2025.00 385.00
C 815.00 165.00
N 42.00 14.00
O 890.00 110.00
Na 10.00 6.00
Mg 100.00
Al 6.80 1.70
Si 185.00 19.00
S 72.00 23.00
K 0.20 0.10
Ca 6.30 1.90
Ti 0.40 0.20
Cr 0.90 0.20
Mn 0.50 0.20
Fe 52.00 9.00
Co 0.30 0.20
Ni 4.10 2.10


Brian Marsedn points out that inside the orbit of Mars, a comet gets too hot to keep its water. Anything that gets into that region for a long time, becomes dry.


Mekler, Prialnik and Podolak point out that the objects have density 0.08 - 0.24 Mg/cu.m, when they have water, and that they are highly porous. Huebner's book, in a secitn written by Hans Rickman and Walter F. Huebner, page 262, says .280 Mg/cu. m, with range from 0.2 to 0.7 Mg/cu. m. mg, when full of water ice. In a secition discussing the nucleus written by H. Uwe Keller discusses density on page 68.
The water ice sublimes on the surface and a very fluffy structure of grains remains. The grains themselves may be of the core - mantle type, whtih tiny cores of silicates, similar to chondritic materials in composition. The retio fo refractory to volatile material seems higher than previously assued. The frefractory material may even dominate ofer the icy component by mass.

The observed fluffiness and low density, even of small grains, supports the idea that the small-scale structure of the nucleus is based on the dust particles and not on the ice. It is not an agglomeration of dirty slowflakes but rather a porous matrix of refractory material, the pores and surfaces fo which are covered with water ice. The dust matrix is so porous that the addition of water ice may even increast eh average specific density.

dark, exceptionally hard to see

H. Uwe Keller outlines evidicenced that the albedo is between 0.02 and 0.04. This is about as dark as the carbon soot on the inside of a chimney.

A 3 meter object with this albedo will be excpetionally difficult to spot. Even just before it hits the non-sensible atmosphere at 600 km, it will be like trying to spot a chunk of black soot the size of a truck at night, 500 miles away.

Low Actual Mass

A 3 meter comet object will have mass of order 3 cubed times a density with values between 80 and 200 kg per cu. meter, or between 2 and 6 tons.

However, if the object is dehydrated and fluffy, its density will be an order of magnitude lower. It could weigh less than a ton.

What Would It Do?

Evaporate Quickly

Atomic or Molecular oxygen moving at 11 km/s (earth escape velocity, the velocity of something with zero V-infinity with respect to Earth), or an atom of comet refractory dust, or a carbon atom in that dust, has (MV2/ 2) / M joules per kilogram, or about 60 Megajoules per kilogram. High explosive, such as Baritor, has about 4.4 Megajoules per kilogram. The comparison shows that the relative energy of earth's atmosphere is an order of magnitude more than that of a layer of high explosive laid directly on the material. As the comet material blows away, the atmosphere itself continuously lays another layer of high explosive on the remaining chunk.

No pressure builds up to slow the thing down at 600 km altitude. the

The one-atom-at-a-time erosion deposits the energy into the comet foof target, unlike the case where it finally gets into the atmosphere and pressure builds up to slow the particles down.

dim, very hot,fast flashes

With many times the energy of high explosive, the flash will be hotter than high explosive, and thus will be in the UV.

 The sky is black to UV, so we won't see most of the flash.

 If it hit the surface of the moon, the flash would be over in the time it takes to hit the moon, under miliseconds.

Act Like It Were Massive

If the object with 2 to 3 hydrogens per carbon atom hits atmospheric oxygen and picks up just one oxygen per hydrogen, then we get a mass of 16 amu, the oxygen, for a cometary input mass of 1, the hydrogen. Each ton of foof looks like an order of magnitude more tons of water.

The carbons also act energetic. They will make CO, but not much CO2. The atoms have too much energy. They will be splitting atmospheric Oxygen. We will get huge quantities of ozone, O3, because of all that atomic oxygen. in the atmosphere. The atmospheric Nitrogens


Yuri Mekler, Dina Prialnik, and Morris Podolak, "Evaporation from a Porous Cometary Nucleus", The Astrophysical Journal, 356: 6y82-686, 19909 June 20

Huebner, Walter F. (Ed.), "Physics and Chemistry of Comets," (Astronomy and Physics Library) Springer-Verlag, New York, 1990, ISBN 3-540-51288-4 and ISBN 0-387-51228-4 Springer-Verlag New York,
from chapter by Eberhard Grun and Elmar K Jessberger on "Dust", page 168

H. Uwe Keller, page 68,of Huebner's book section "2.7.2 Composition and Structure"

as of Sunday 2 pm, 8 june 97