Radio observations of comets complement studies at other wavelengths as well as providing certain kinds of unique information Studies of continuum emission may probe the thermal emission of the nucleus and large-size dust particles Spectroscopic observations of gas in the coma allow searches for parent molecular species that have no signatures in the optical spectral range The 18-cm wavelength spectral lines of the OH radical now are relatively easy to detect, and observations of them permit long-term and short-term monitoring of the cometary gaseous output Moreover, with the unique spectral resolution of radio techniques, aspects of the kinematics of the coma may be also studied, such as the gas expansion velocity and the anisotropy of gas production from the nucleus In this review, we present recent results of cometary radio observations, and discuss what may be learned from such studies in the future

https://link.springer.com/content/pdf/10.1007%2F978-94-011-3378-4_7.pdf

The Study of Comets at Radio Wavelengths

After a thorough research on the circumstantial changes and the great evolution of life in the Cambrian period, the author propounds such a hypothesis: During the Late Precambrian, about 500-600Ma, a celestial body impacted the Earth. The high temperature ended the great glaciation, facilitated the communication of biological information. The rapid change of Earth environment enkindled the genesis-control system, and released the HSP-90 variations. After the impact, benefited from the protection of the new ozone layer and the energy supplement of the aerobic respiration, those survived underground life exploded. They generated carapaces and complex metabolism to adjust to the new circumstance of high temperature and high pressure. 
This article uses a large amount of analyses and calculations, and illustrates that this hypothesis fits well with most of the important incidences in astronomic and geologic discoveries.

The Cambrian impact hypothesis

The modern astronomic theory of the Milky Way Galaxy is called the “density wave theory” The theory is used to attempt to explain geological catastrophes and paleontological records Coincidentally, although still disputably, each time the solar system enters into the spiral arms, events happen The Earth is heated up while traversing the spiral arms, and the warmed climate reaches its climax at the end of a traverse Calculations reveal that the spiral arms exert an influence on the Earth and the solar system, which is astronomically slight but biologically considerable Energy transfer occurs at the spiral arms' gravitational field, finally decreasing the Earth's mechanical energy and narrowing the Earth-Sun distance Research on lunar vestiges and craters is under way

Possible causal relationship between geological catastrophes and spiral potential revealed by theoretical mechanics and density wave theory

THERE have been seven Great Ice Age (GIA) events during the Earth's evolutionary history of 4.6 ~a"]. Li Siguang put forward an explanation[21 about the causes of their formation and ref. [3] summarized various theories concerned. A commonly accepted point is that the eventual formation of CIA is due to lesser solar radiation absorbed by the Earth. But no one can explain the fact that no GIA had ever appeared from 2.2 to 1.0 Ga B. P. A new viewpoint is proposed in this note that the interaction between galactic magnetic field and geomagnetic field rather than the lesser solar radtation is the cause of formation of the GIA. 1 The long-term cycles of geomagnetic pole and galactic arms According to the studies on palaeo-geomagnetism[4-61, we know that there is a long-term reversal of geomagnetic pole with a period of about 300 Ma. In ref. [6], the latest 70 Ma was defined as "negative polarity-dominated" stage. But the figure in ref. [6] shows that the positive polarity appeared a little larger than 50 % during that period. So it seems more reliable to call it an "alternate period between positive and negative polarity9'. In fact, positive polarity

A new viewpoint on the causes of formation of the Great Ice Age

The solar corona is a highly ionized plasma which exhibits a complex variety of features on different space and time scales [1],[2]. Such features range from sub-arcsec to solar radius scales and show lifetimes of the order seconds to days, indicating that the coronal plasma is basically non-homogeneous and subject to a set of physical processes, which, on one hand, determine such inhomogeneities and, on the other hand, are affected by them in a mutual feedback scheme. The recent progress in instrumental techniques from ground [3] and space [4], [5], [6] and the availability of multi-wavelength observations have been adding new tiles to this frame, but also rendered more puzzling the theoretical modelling on the different scales.

Probing the Solar Atmosphere Through Radiophysics

Investigations on the correlation of historical, geological data with the spiral structure of Galactic System have been made and it is revealed that there exists a close relation between the galactic arms and various catastrophic changes of the Earth from about 600 million years ago up to present. When the Earth moving with the Sun around the galactic center is located inside galactic arms, events such as the creature mass extinction and the geomagnetic direction inverse are of frequent occurence, on the other location however, as the Earth moves outside galactic arms, it is often a period for giant glacials.It is thought that the effects on the Earth of the relevant celestial bodies (asteroid, comet, interstellar gas and dust etc.) inside or outside the galactic arms are the important causes of the catastrophic events of different kinds on the Earth. Based on this, we further analysed a variety of such events and explained some of their main features such as their period, phase, the way in which they occur and the extent to which they influence the earth conditions. Finally, some characteristics of events of same kind but in different developing stages are also discussed.

Luo Xian-han

Papers

A Discussion on the Relationship between the Galactic Arms and the Earth's Catastrophic Events

Solar eclipse observations of a magnetic loop structure at 2, 3.2, 8.2 and 21 CM

Radio observations of the OH line in Comet Halley

Radio observations of the OH line in Comet Halley

A magnetic loop model for the slowly varying radio source observed during the solar eclipse of 1980 February 16