A May 28, 1997 NASA press release entitled “Polar Spacecraft
Images Support Theory of Interplanetary Snowballs Spraying Earth's
Upper Atmosphere” serves to confirm an observation made more than a
decade ago. The press release reads as follows:
Images from NASA's Polar spacecraft provide new evidence that
Earth's upper atmosphere is being sprayed by a steady stream of
water-bearing objects comparable to small comets.
Using Polar's Visible Imaging System (VIS), a research team led
by Dr. Louis A. Frank of the University of Iowa in Iowa City has
detected objects that streak toward Earth, disintegrate at high altitudes
and deposit large clouds of water vapor in the upper atmosphere.
Frank's research was presented at the spring meeting of the American
Geophysical Union at the Convention Center in Baltimore, MD.
The incoming objects, which Frank estimates to be the size of a
small house, pose no threat to people on Earth, nor to astronauts in
orbit. “They break up and are destroyed at 600 to 15,000 miles above
the Earth,” Frank noted.
The Polar cameras have imaged trails of light in both ultraviolet
and visible wavelengths as the objects disintegrate above the atmosphere.
Using a filter that detects visible light emitted only by fragments
of water molecules, Frank has shown that the objects consist
primarily of water.
”The images show that we have a large population of objects in
the Earth's vicinity that have not been detected before,” said Frank,
who designed the VIS instrument. “We detect these objects at a rate
that suggest Earth is being bombarded by five to 30 small comets per
minute, or thousands per day.” Comets are known to contain frozen
water and are sometimes called “dirty snowballs”.
Frank's new observations are consistent with a controversial
theory he proposed in 1986 to explain the existence of dark spots,
which he termed “atmospheric holes”, in images of the sunlit atmosphere
of the Earth. He first detected these holes while analyzing data
from an ultraviolet imager flown on NASA's Dynamics Explorer 1
spacecraft. He theorized that the holes were caused by the disintegration
of small icy comets in the upper atmosphere. The water vapor
they produce momentarily absorbs the ultraviolet solar radiation scattered
from oxygen atoms in the upper atmosphere, preventing it from
reaching his camera and resulting in a dark spot on the image. These
holes have diameters of 15 to 25 miles.
Images of the comets and the atmospheric holes can be found on
the World Wide Web at the following URL:
http://pao.gsfc.nasa.gov/gsfc/newsroom/flash/flash.htm
What does it all mean? Several things chiefly. First of all, such a rain
of house-sized “snowballs” signifies a young solar system. Billions of
years worth of such “rain” might fill the oceans, but it makes more difficult
speculations about their origin. Whence such an endless supply of
snowballs? This is more spectacular than the Oort cloud, the mythical
and mystical, not to mention undetected, cloud of comets which evolutionary
astronomers believe supplies the solar system with comets over
billions of years.
In late 1995, NASA reported that the Hubble Space Telescope may
have discovered a new class of objects which pass through the solar system.
During a time when Saturn's rings are seen edge-on, Hubble recorded
“several orbiting clumps of icy rubble that could be the remnants
of recently shattered moonlets orbiting near the outer edge of Saturn's
ring system.”
Saturn's rings are seen edge-on from earth every 14.5 years, twice in
a Saturnian year. The Hubble photos were designed to confirm the
presence of two new satellites first detected about six months earlier. Instead,
three new objects were observed. All three objects should have
been seen when the Voyager spacecraft flew by Saturn in 1980 and 1981.
The implication is that they did not exist back then.
The three new objects are in different orbits from the two earlier
(May) objects. They look like elongated arcs, very unlike a satellite.
One possibility is that they are large clouds of debris produced when
small satellites collide with each other or with chunks of “space debris”
such as small comets. Just as a small handful of chalk dust can make a
large dust cloud if tossed in the air, a shattered moonlet would be much
brighter and more visible than when all of its mass is compressed into a
single solid body.
The NASA press release states: “The discovery of objects in this transitional
phase is not totally unexpected … because one scenario for the
origin of Saturn's ring system is that it is made up of countless fragments
from several pulverized moons. This idea is reinforced by the fact the
new objects orbit Saturn near the narrow F ring, which is a dynamic transition
zone between the main rings and the larger satellites. Moonlets in
this region can be easily disrupted by Saturn's tidal pull if they are fractured
by an impact, forming a cloud of debris. Eventually such a cloud
would spread around the moon's orbit to form a new ring.
”The dynamics of this 'bumper car' zone are also evident in Hubble's
observations of the satellite Prometheus. Although a third object seen in
the May images was first suspected to be another new satellite because its
location did not match the predicted position for any of the known satellites
charted by Voyager, it now appears that this body is in fact
Prometheus, which has slipped in its orbit by 20 degrees from the predicted
position. Nicholson suggests that this may be a consequence of a
”collision” of Prometheus with the F ring, which is believed to have occurred
in early 1993. The moon may have passed close enough to one of
the denser, lumpy regions of the F ring to have its orbit changed.”
As with the water-rich ice-comets above, the question of age arises. It
is clear that Saturn's rings cannot be billions of years old. The question
is, how can they be sustained for billions of years around Saturn and not
also around other planets? Furthermore, whence such an abundant supply
of moonlets and comets? And is there a relationship between the “dirty
snowballs” falling to earth near the poles and the “exploding” features
which appear about Saturn's rings?