Is the Earth Young?

A Response to the Vacuum Cleaner Sun Argument

Evidences 5 & 6 regarded the influx of dust onto the earth and moon. Evidence 7 is about dust being sucked up by the sun. Though similar, in that it deals with dust, this one is sufficiently different to earn a response of its own.

7. The sun acts as a giant vacuum cleaner which sweeps up about 100,000 tons of micrometeoriods per day. If the solar system were just 10,000 years old, no micrometeoriods should remain since there is no significant source of replenishment. A large disk shaped cloud of these particles is orbiting the sun. Conclusion: the solar system is less than 10,000 years old.
Paul M. Steidl, The Earth, the Stars, and the Bible (Grand Rapids: Baker Book House, 1979), pp. 60-61.
First, allow me to point out that there are many useful references cited in my article on the earth & moon, Meteorite Dust and the Age of the Earth. Although it does not deal with the sun directly, it does deal with dust in the solar system, so the references are relevant here too.

The sun "vacuums up dust", not so much because of its gravity, but because of something called the Poynting-Robertson effect. This is an interaction between dust grains and direct sunlight. The dust grains are small enough to absorb momentum from the photons that make up sunlight, and have their motion affected thereby. But it is a complex process, that affects grains of different sizes in different ways. Furthermore, dust grains are affected by plasma drag (friction with the solar wind plasma), and by collision with interstellar dust which moves through the solar system with a higher speed than the interplanetary dust. All of these processes must be taken into account before one can understand the reality of dust dynamics in the solar system.

A good example of this appears in Jewitt & Luu, 1997. The result is that particles with radii between about 0.06 and 0.5 microns are actually blown out of the solar system by radiation pressure and never get a chance to fall into the sun. For smaller particles, the time scales for falling into the sun range from about 30,000 years for particles as small as 0.01 micron radius, up to about 300,000 for particles just below the 0.06 micron threshold for radiative ejection. On the larger side, the time scales range from about 1,000,000 years for particles just too big for ejection (just over 0.5 micron radius) to just over 10,000,000 years for the biggest particles considered (1000 micron = 1 millimeter radius). [See figure 3 page 342].

So the first thing to notice is that the time scale Steidl uses is not supported by current research. If he used the Poynting-Robertson effect all by itself, then he was mistaken in overlooking radiation pressure and plasma drag. There will clearly be dust in the solar system on time scales at least 1,000,000 years, which makes this argument of no value for the 10,000 year time scale required by the young-earth creationist.

But it is a short time scale no doubt, for a solar system alleged to be about 4,500,000,000 years old (give or take a few million). And this leads us to Steidl's largest error. He says "there is no significant source of replenishment". Not only is this wrong now, it was well known to be wrong amongst scientists well before the 1979 date on Steidl's book (see for instance Dohanyi, 1972, who also references many earlier papers).

Aside from the obvious source, comets in the inner solar system, the major source of dust in the solar system is collisions between asteroids in the main asteroid belt, as well as those in the Kuiper Belt (See Jewitt & Luu, 1997; Dones, 1997; and many other papers in the same volume of ASP Proceedings).

The result is that dust in the solar system is essentially in dynamic equilibrium - the production and destruction rates are about equal. This is not a problem for a 4,500,000,000 year old solar system. It probably is no big deal for a 10,000 year old solar system either; equilibrium is equilibrium. But the argument that one can use solar system dust to distinguish between the young and old solar system theories is specious.


Dohnanyi, J.S.
"Interplanetary Objects in Review: Statistics of Their Masses and Dynamics"
Icarus 17: 1-48 (1972) [Icarus Invited Review paper, 215 references]

Dones, Luke
"Origin and Evolution of The Kuiper Belt"
A chapter in "From Stardust to Planetesimals"
ASP Conference Series, vol 122, 1997; Pages 347-365

Jewitt, David & Jane Luu
"The Kuiper Belt"
A chapter in "From Stardust to Planetesimals"
ASP Conference Series, vol 122, 1997; Pages 335-344

The Kuiper Belt Homepage
Maintained by David Jewitt, who along with Jane Luu has discovered most of the Kuiper Belt objects.

Summary of the Workshop on Interplanetary Dust Particles
Held at the Lunar & Planetary Institute, May 1993.

Interplanetary Dust Particles A Synopsis by P.H. Benoit

The Heidlberg Dust Group
From the Max Planck Institute - many links to info about interplanetary and interstellar dust.