The Shiny Mountains of Venus

The astronomer Victor A. Firsoff in his book, The Solar Planets (1977), wrote:

“I once described Earth and Venus as ‘non-identical twins.’ It used to be thought that their differences were more apparent than real. But in the words of Sherlock Holmes, ‘Eliminate the impossible and what is left, however improbable, is the truth.’ And it would be hard to find a more improbable planet than Venus.”

Strange Venus

David Grinspoon writes in, Venus Revealed, (1997):

“One of the most puzzling [patterns] was this: the highest mountains of Venus are all surprisingly shiny. At altitudes above about thirteen thousand feet, the reflectivity jumps up and the ground abruptly gets very bright. Surface roughness cannot explain this, so something in, or on, the ground at these high elevations is different, making it highly reflective.”

Grinspoon puts forward the idea that some chemical reaction takes place at the lower temperature found at high elevations, 820 degrees F, to form a radar reflective mineral – fool’s gold. But this requires the unlikely situation that all peaks on Venus have the same chemistry.

A more recent report from the BBC News Online science editor addresses the issue again and comes down on the side of the rocks being coated by condensing lead vapor.

Venus has ‘heavy metal mountains’

By Dr David Whitehouse, 25 November 2003

The highlands of Venus are covered by a heavy metal “frost”, say planetary scientists from Washington University

Because it is hot enough to melt lead at the surface, metals vaporise and condense at cooler, higher elevations. This may explain why radar observations made by orbiting spacecraft show that the highlands are highly reflective. Detailed calculations, to be published in the journal Icarus, suggest that lead and bismuth are to blame for giving Venus its bright, metallic skin.

Bright hills

Frequently seen as a brilliant point of light in the evening or morning sky, Venus has been identified with beauty by many cultures. But the truth is somewhat different. Although it is about the same size as the Earth, its closer proximity to the Sun means that it is a very different planet. Its thick atmosphere – composed chiefly of carbon dioxide – gives it an intense greenhouse effect, whereby trapped solar radiation heats the surface of the planet to an average temperature of 467 Celsius. Also, its pressure is 90 times greater than that at the Earth’s surface.

Comment:
I cannot let this glib reference to the supposed Venusian ‘greenhouse effect’ pass without comment. The very high surface temperature of Venus of 750°K or 900°F is usually explained by the ‘greenhouse effect’ of a thick atmosphere of carbon dioxide, or even the ‘runaway greenhouse effect,’ first suggested by Fred Hoyle in 1955 and worked out in detail in the late 1960s by Ingersoll and Pollack of Caltech. Such explanations assume that both Venus and Earth have had largely parallel development (so-called twins) and that therefore something went seriously wrong with the atmospheric evolution on Venus. However, there is not a shred of evidence for the ‘twin planets’ theory.

As for the greenhouse effect, it is a desperate model clutched at by theorists who have no alternative ideas. Yet the astronomer Firsoff noted: “Earth’s seas are not boiling hot, despite the total greenhouse effect of water and average sunlight stronger than at the ground level of Venus. Nor is it at all clear how such a condition could have become established.”

Venus receives 1.9 times more solar radiation than Earth but its clouds reflect about 80% of that sunlight, so that Venus actually absorbs less solar energy than the Earth. Solar radiation measured at the surface is 10-20W/m2 (compare this with 340W/m2 at the Earth’s surface in the tropics). Even with the maximum greenhouse effect, the effective surface temperature of Venus should be low enough to freeze water. What is being asked of the ‘runaway greenhouse effect’ is equivalent to expecting a well-insulated oven to reach a temperature sufficient to melt lead by having only the pilot light switched on!

The humorous but sadly apt inversion, ‘I’ll see it when I believe it,’ seems to apply to the interpretation of results relayed to Earth from all four Pioneer lander probes as their radiometers began to give anomalous results as they descended through the atmosphere.

“Taken at face value, the anomalies suggest that parts of the atmosphere are transmitting about twice the energy upwards that is available from solar radiation at the same level.”
[Pioneer Venus, NASA Report SP-461, p. 127].

Despite the obvious interpretation that the laws of thermodynamics are not being violated and that, put simply, Venus is intrinsically damned hot and still cooling, the investigators are able to blandly state in the same paragraph:

“In spite of these difficulties in interpreting some of the observations, the greenhouse effect, coupled with global dynamics, is now well established as the basic explanation of the high surface temperature.”

This is merely consensus ignorance, not science.

The BBC report continues:

The only way to glimpse what lies beneath its opaque clouds is by radar, and several missions have carried our radar surveys from orbit, principally the Magellan probe which operated from 1990 to 1994.
Magellan’s images astounded astronomers who were able to see the surface of Venus in detail for the first time. They showed the planet was covered in volcanic features, such as vast lava plains, fields of small lava domes, and large shield volcanoes. But the images were puzzling as well. It appeared that parts of the highlands were abnormally bright, reflecting radar beams much better than lower elevations. Several explanations were put forward ranging from the presence of a loose soil to a coating of metal – specifically, tellurium.

Lined with lead

The theory suggests at Venus’s hot lower layers any metal would be vaporised and exist as a metallic mist. Only at higher elevations, where it is a little cooler, would that metal condense to form a thin, highly reflective layer on the ground. Using detailed chemical calculations involving 660 metal compounds, Laura Schaefer and Bruce Fegley, of the Washington University in St Louis, conclude that tellurium is not responsible, but that common lead probably is. The researchers estimate that the timescale for the coating of the Venusian highlands by metallic frost is somewhere between a few thousand and a few million years, demonstrating that it is an active process. They point out that at the highest elevations on Venus there is evidence that the metallic frost is absent – possible evidence of weathering, they say. If it were possible to examine these lead deposits, from a Venus lander craft, the respective abundances of certain atom types, or isotopes, could give astronomers an estimate for the age of Venus.


Venus lightning

In March, 1997 I wrote in response to Grinspoon’s colorful suggestion that the radar bright highlands of Venus are coated with ‘fool’s gold’:

“A much simpler answer is that diffuse electric discharge, known on Earth as ‘St. Elmo’s fire,’ occurs preferentially at the higher altitudes of the mountains on Venus. In that thick atmosphere it forms a highly conductive dense plasma, which is a superb reflector of radar signals.”

“The density of the atmosphere at the surface of Venus is about 1/10 that of water. St. Elmo’s fire is a highly ionised state involving actual discharge. Put the two together and you have dense plasma – which conducts like a metal and therefore reflects radar like a metal surface. The thickness of such a plasma would have no more effect on radar reflectivity than the thickness of a metal sheet would. Since the plasma would coat the surface rocks (whatever their composition), the radar return would be an enhanced version of that being received from nearby, uncoated, electromagnetically dissipative rocks, and would be greater than that returned from fool’s gold. I consider my hypothesis is simpler than one relying on chemical or physical changes in rocks of unknown composition.”

St. Elmo’s fire should be prevalent at the highest elevations, so the lack of radar reflectivity there would be due to the lower plasma density. As the plasma density falls it becomes more transparent to the radar signal and tends to refract, rather than reflect it. One way to test this might be to use radar equipment at lower frequencies.

Of course, my proposal begs the question of the origin of electric discharge activity in the atmosphere of Venus.

“The most striking [the pun seems unintended] observations made by the Galileo spacecraft during its flyby of Venus was evidence of lightning. [R. L. Guyer: ‘Galileo flyby of Venus’, Science 253 (1991), p. 1463]. The surprise is curious. Earlier reports of lightning were discounted, it seems, because they did not fit the pattern of earthly lightning. The Venera spacecraft found ‘continuous lightning activity from 32km down to about 2km altitude, with discharges as frequent as an amazing 25 per second.’ [NASA News 79-12 (19.4.79), p. 1]. The highest recorded rate on Earth is 1.4/sec during a severe blizzard. The Pioneer lander recorded 1000 radio impulses. Thirty-two minutes after landing, Venera 11 detected a very loud (82 decibel) noise which was believed to be thunder. Garry Hunt suggested at the time that: ‘… the Venusians may well be glowing from the nearly continuous discharges of those frequent lightning strokes.’ A ‘mysterious glow’ was detected coming from the surface at a height of 16km by 2 Pioneer probes as they descended on the night hemisphere. The glow increased on descent and may have been caused by the St. Elmo’s fire and/or chemical reactions in the atmosphere, close to the surface.

Lightning is poorly understood. The mechanism of charging of storm clouds remains a mystery. Because lightning is conventionally associated with violent vertical cloud movement on Earth, it was a surprise when investigators found strong evidence of lightning in the quiescent atmosphere of Venus. ‘On Venus the clouds tend to resemble fogbanks,…. You don’t see much lightning in fog.’ [R. A. Kerr: ‘Lightning found on Venus at last?’, Science 253 (1991), p. 1492].

A planet’s magnetosphere is the region in space surrounding the planet where its magnetic field dominates. Under the influence of the solar wind it is compressed on the sunward side of the planet and stretches away behind the planet like a comet’s tail. The early Mariner spacecraft provided a surprise when they found an extensive ‘cometary’ magnetotail stretching behind Venus along the Sun-Venus line. It is longer than that found for any other planet. The ‘scale length’ of the tail is about 700, compared to Earth’s less than 300. [The scale length is the tail length divided by the size of the planet’s magnetosphere. In the case of Earth, the tail wake stretches for 3000 Earth radii (RE) and the magnetosphere varies between 10 and 15 RE]. Later, it was discovered that the tail of Venus survived to the Earth’s orbit, where it was described as being composed of ‘stringy things.’ Those ‘stringy things’ are diagnostic of Birkeland currents flowing between Venus and the Earth.

The magnetic flux of the solar wind appears to interact directly with the ionosphere of Venus. This was not anticipated either, and is unlike all other planets in the solar family. Spikes in the Pioneer Venus orbiter magnetometer readings were interpreted as twisted magnetic field lines wrapped around each other like ropes. Alternatively, the magnetic field spikes may be induced in the ionosphere by electric current flows in the solar wind. Once again, the twisted magnetic ropes herald field-aligned Birkeland currents flowing between the Sun and Venus.

Another major surprise is the presence of an ionosphere on the night side of Venus. Ionospheres are thought to be formed by dissociation of atoms in the upper atmosphere by the action of solar ultraviolet (UV) radiation. It was thought that the extended Venusian night would be long enough for recombination to take place and for the ionosphere there to disappear.

Any cosmic body which is charged relative to the surrounding plasma has a plasma sheath or magnetosphere. It is a region in which electric current flows and energy is released. The sheath is generally invisible unless the current is strong enough to generate light, such as on the Sun, in auroras, and in the coma and tails of comets.

Venus, with its cometary tail, is evidently still discharging strongly today after a recent cometary past noted globally by ancient witnesses. Venus was described variously as a ‘hairy star’ or ‘bearded star’ and a stupendous prodigy in the sky. Today, Venus’ comet tail operates in the dark discharge mode and is invisible. It can only be detected by magnetometers and charged particle detectors.

More evidence for the electrical nature of Venus comes from the Dutch astronomer Houtgast. He found there is a marked reduction in the solar corpuscular radiation reaching the Earth whenever Venus is interposed between it and the Sun at or near an inferior conjunction. He estimated that the effect could be accounted for on the assumption that Venus has a magnetic field about five times stronger than the Earth’s [Houtgast: Sky and Telescope 15:8 (1955), p. 419.]. Since Venus has no measurable magnetic field, it is better explained as an electrical shielding effect.

The principal difficulty in understanding the origin of lightning is due to the assumption that the Earth and Venus are closed electrical systems with no input from the solar plasma environment via the magnetosphere. The Venusian ionosphere is directly coupled to the solar wind. Intense airglow emission in long wavelength UV was observed to occupy a large volume of the ionosphere on both the day and night sides of the planet. The intensity seems to be linked to solar activity. I would therefore expect lightning activity on Venus to be generated, not from cloud motions, but from electrical input originating in the Sun.

If charged particles are scarce in the lower atmosphere (and there are no counterparts to earthly clouds on Venus), fewer but more equally energetic lightning discharges would be expected than on Earth. There is evidence that this is so; the rate detected by the Galileo spacecraft as it swung around Venus would require 2,000 years for a strike to occur in a given square kilometre. On Earth, 7 strikes would be expected each year in a square kilometre. Six out of nine events detected by the Galileo spacecraft were strongly clustered in frequency spectrum and power, a situation not found on Earth. If the extremely rapid lightning detected by the Venera spacecraft is verified, there may be two modes of discharge on Venus: firstly, a continuous glow of St. Elmo’s fire at high points on the surface with rapid, low energy lightning, and secondly, high energy superbolts which fire from the upper atmosphere – as detected by the Galileo spacecraft.

The comet-like tail of Venus would suggest that the planet has not yet achieved electrical equilibrium after a recent cometary history. That being so, lightning of considerable violence and/or frequency would be expected on Venus. It would also fit the observation that the solar wind is tightly coupled to the planet. The magnetic flux ‘ropes’ of the solar wind, entwined about the planet, are indicative of electric currents flowing from the solar wind directly into the planet’s ionosphere. This is most simply explained by a high potential difference between the planet and its surroundings.

Another manifestation of electrical effects in the ionosphere of Venus is the well-known ‘Ashen light’ which is often seen as a faint illumination of the dark part of the crescent disk. Firsoff wrote, “There can be no doubt that the true origin of the Ashen Light is electric. It is a night-sky glow, similar to that in our own sky but estimated to be 50-80 times stronger. It has a line emission spectrum sufficiently strong to be photographed….”

The associated puzzle as to why Venus maintains a nightside ionosphere, given that night on Venus lasts about 58 Earth days, may now be answered. It is known that the nightside atmosphere is bombarded by fast electrons and that there is an unexplained large, fast drift of plasma (up to 10km/sec or 23,000mph) from day to night hemispheres.

The comet-like magnetosphere, strong electrical interactions with the solar wind and intense lightning, ionospheric and atmospheric activity suggest that Venus has not yet achieved electrical equilibrium with its environment in the solar plasma.

The odd composition of the Venusian atmosphere may also be due to the high levels of heat and electrical activity at the planet’s surface. Venus may once have had an atmosphere more like that of the Earth, with a preponderance of nitrogen and oxygen and water vapor. It was shown many years ago by the French scientist, Louis Kervran, that nitrogen in the presence of a hot iron surface becomes ‘activated’ and may be subsequently resonantly transmuted to carbon monoxide. Carbon monoxide and water vapor in the presence of heat will form carbon dioxide and hydrogen as in a well-known industrial process. The hydrogen combines with available oxygen to form more water vapor, until the oxygen is consumed. Thereafter the hydrogen tends to escape to space leaving behind a heavy carbon dioxide atmosphere. It is significant therefore that the water vapor content of the Venusian atmosphere was found by several Venera landers to mysteriously decrease near the surface of the planet. It can only mean that water is being absorbed or destroyed at the surface. What is more, the rate of disappearance could not be sustained for more than a “geological instant,” Nitrogen remains the only significant constituent of the Venusian atmosphere, following carbon dioxide.

The present cometary Venusian magnetosphere lends strength to the identification of Venus as a comet by early man. If, in years to come, we can measure a steady decline in the temperature of Venus, or a steep sub-surface temperature gradient, or changes in its electrical interaction with the solar wind, then Venus may finally be recognised as the youngest planet in the Solar System and only a distant relative of the Earth.

Wal Thornhill

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