The record of solar and galactic radiations in the ancient lunar regolith and their implications for the early history of the Sun and Moon

1977 ◽  
Vol 285 (1327) ◽  
pp. 587-592 ◽  
Keyword(s):  
Solar Wind ◽  
Solar Flare ◽  
Solar Flares ◽  
Lunar Regolith ◽  
Galactic Cosmic Rays ◽  
Flare Activity ◽  
New Techniques ◽  
The Past ◽  
History Of ◽  
Individual Grains

A variety of techniques are available for studying past variations of solar wind, solar flares, galactic cosmic rays, and micrometeorites. Lumar rock results which average over the recent past ( ~ 10 Ma) indicate no major changes in any of these components. At longer times, recent data suggest secular changes in the 15N/14N ratio in the solar wind, possibly due to enhanced solar flare activity. With the deployment of new techniques, it now appears possible to measure solar wind, solar flare, and micrometeorite records in individual grains removed from different layers of lunar cores. Such grains have been exposed for brief intervals of time (103-104 a) for times extending at least 109 a in the past. Lunar and meteoritic breccias are promising candidates for extending the record back still further, perhaps close to the beginning of the solar system.

Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

scholarly journals The Evolution of Mathematics in Ancient China: From the newly discovered 數 Shu and 算數書 Suan Shu Shu Bamboo Texts to the Nine Chapters on the Art of Mathematics

2020 ◽  
Vol 19 (37) ◽  
pp. 25-78
Author(s):  
Joseph W. Dauben
Keyword(s):  
History Of Mathematics ◽  
Plenary Lecture ◽  
Ancient China ◽  
New Techniques ◽  
Tsinghua University ◽  
Warring States ◽  
The Past ◽  
Peking University ◽  
History Of ◽  
Mathematical Texts

The history of ancient Chinese mathematics and its applications has been greatly stimulated in the past few decades by remarkable archaeological discoveries of texts from the pre-Qin and later periods that make it possible to study in detail mathematical material from the time at which it was written. By examining the recent Warring States, Qin and Han bamboo mathematical texts currently being conserved and studied at Tsinghua University and Peking University in Beijing, the Yuelu Academy in Changsha, and the Hubei Museum in Wuhan, it is possible to shed new light on the history of early mathematical thought and its applications in ancient China. Also discussed here are developments of new techniques and justifications given for the problems that were a significant part of the growing mathematical corpus, and which eventually culminated in the comprehensive Nine Chapters on the Art of Mathematics. What follows is a revised text of an invited plenary lecture given during the 10th National Seminar on the History of Mathematics at UNICAMP in Campinas, SP, Brazil, on March 27, 2013.

scholarly journals Hydrogen molecular ions and the violent birth of the Solar System

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180403 ◽  
Author(s):  
Cecilia Ceccarelli ◽  
Cecile Favre ◽  
Ana López-Sepulcre ◽  
Francesco Fontani
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Past History ◽  
Classical Problem ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Molecular Ions ◽  
Observational Constraints ◽  
The Past ◽  
History Of

Many pieces of evidence indicate that the Solar System youth was marked by violent processes: among others, high fluxes of energetic particles (greater than or equal to 10 MeV) are unambiguously recorded in meteoritic material, where an overabundance of the short-lived 10 Be products is measured. Several hypotheses have been proposed to explain from where these energetic particles originate, but there is no consensus yet, mostly because of the scarcity of complementary observational constraints. In general, the reconstruction of the past history of the Solar System is best obtained by simultaneously considering what we know of it and of similar systems nowadays in formation. However, when it comes to studying the presence of energetic particles in young forming stars, we encounter the classical problem of the impossibility of directly detecting them toward the emitting source (analogously to what happens to galactic cosmic rays). Yet, exploiting the fact that energetic particles, such as cosmic rays, create H 3 + and that an enhanced abundance of H 3 + causes dramatic changes on the overall gas chemical composition, we can indirectly estimate the flux of energetic particles. This contribution provides an overview of the search for solar-like protostars permeated by energetic particles and the discovery of a protocluster, OMC-2 FIR4, where the phenomenon is presently occurring. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Solar flare activity: Evidence for large-scale changes in the past

Icarus ◽  
1977 ◽  
Vol 32 (1) ◽  
pp. 106-126 ◽  
Author(s):  
Herbert A. Zook ◽  
Jack B. Hartung ◽  
Dieter Storzer
Keyword(s):  
Solar Flare ◽  
Large Scale ◽  
Flare Activity ◽  
The Past

scholarly journals Four Subjects in Solar Physics from the Point of View of the Electric Current Approach

2020 ◽  
pp. 33-45
Author(s):  
Syun-Ichi Akasofu
Keyword(s):  
Solar Wind ◽  
Electric Current ◽  
Solar Flares ◽  
Solar Physics ◽  
Current Approach ◽  
Point Of View ◽  
Coronal Temperature ◽  
The Past ◽  
Electromagnetic Processes ◽  
Difficult Subjects

Four major subjects in solar physics, the heating of the corona, the cause of the solar wind, the formation of sunspots and the cause of solar flares, are discussed on the basis of the electric current approach, a sequence of processes consisting of power supply(dynamo), transmission (currents/circuits) and dissipation(high coronal temperature, solar wind, sunspots and solar flares).This is because the four subjects have hardly been considered in terms of the electric current approach in the past, in spite of the fact that these subjects are various manifestations of electromagnetic processes. It is shown that this approach provides a new systematic way of considering each subject; (1) the long-standing issue of the coronal temperature, (2)the long-standing problem on the cause of the solar wind, (3)the presence of single spots(forgotten or dismissed in the past) and its relation to unipolar magnetic regions and (4) the crucial power/energy source and subsequent explosive processes of solar flares. The four subjects are obviously extremely complicated and difficult subjects, but it is hoped that the electric current approach might provide a new insight in considering the four subjects.

Magnetic Reconnection in the Earth's Magnetotail

1985 ◽  
Vol 38 (6) ◽  
pp. 981 ◽  
Author(s):  
Edward W Hones Jr
Keyword(s):  
Solar Wind ◽  
Magnetic Reconnection ◽  
Plasma Sheet ◽  
Solar Flares ◽  
Reasonable Doubt ◽  
Physical Processes ◽  
Geomagnetic Disturbances ◽  
Magnetospheric Substorms ◽  
The Past ◽  
Fundamental Physical

Over the past few years satellite observations of the plasma sheet in the Earth's magnetotail during magnetospheric substorms have established beyond reasonable doubt that magnetic reconnection occurs in the magnetotail and that it plays a central role in the substorm process. The features seen at Earth by which substorms were originally identified (e.g. the auroras and geomagnetic disturbances) are simply superficial manifestations of a more fundamental physical process-the magnetosphere divesting itself of stored energy and plasma that was acquired earlier from the solar wind. It does so by shedding a part of its plasma sheet. This is accomplished by magnetic reconnection near the Earth that severs the plasma sheet, forming a plasmoid that flows out of the tail and that is lost to the solar wind. Recognition of the existence of plasmoids and our developing understanding of them have been important elements in confirming the occurrence of reconnection in the magnetosphere. In an analogous way, the best evidence for the occurrence of reconnection on the Sun has come from observations of closed magnetic configurations (plasmoids) in the solar wind and in the corona. But while magnetic reconnection is certainly the key ingredient in solar flares and substorms, analogies between them should not be carried too far, because there are basic differences in the environments in which they prevail and in the physical procesSes that lead to their occurrence.

scholarly journals New Triggering Mechanism for Red Dwarf Flares

1983 ◽  
Vol 71 ◽  
pp. 609-611
Author(s):  
M.K. Das ◽  
J.N. Tandon
Keyword(s):  
Solar Flares ◽  
Galactic Cosmic Rays ◽  
Flare Activity ◽  
Radio Bursts ◽  
Triggering Mechanism ◽  
X Ray ◽  
Flare Stars ◽  
M Stars ◽  
Radio Band ◽  
Radio Flare

The flare phenomenon associated with dMe stars has received much attention in recent years (Gershberg 1975). Most of the flares have been detected in both optical and radio band (Lovell 1969; Kunkel 197U; Karpen et al, 1977). But as expected (Tandon 1976) only a few display weak soft X-ray emission (Karpen et al, 1977; Haisch and Linsky 1978)- Simultaneous X-ray, optical and radio observations of YZ CMi by Karpen et al (1977) shows no X-ray emission above 3σ level accompanying minor flares. Even coincident X-ray coverage with seven radio bursts shows no enhanced X-ray emission. Recently Haisch et al (1981) detected one well resolved X-ray flare on dM5e flare star Proxima Centauri and one coincident optical and radio flare out of five optical and twelve radio flare events. However, the X-ray flare on Proxima Centauri is not accompanied by any ultraviolet, optical or radio emission. Observations on flare stars show that they are more energetic, 102 - 103 times, than the corresponding solar flares. Considering the flare activity in dwarf M-stars to be similar but more energetic to that of a large solar flare, Tandon (1961) proposed red dwarf flares to be the source of low energy galactic cosmic rays. This hypothesis has been reexplored recently by Lovell (1974).

scholarly journals Initial Test of a Bayesian Approach to Solar Flare Prediction

2005 ◽  
Vol 22 (2) ◽  
pp. 153-156 ◽  
Author(s):  
Michael S. Wheatland
Keyword(s):  
Solar Flare ◽  
Bayesian Approach ◽  
Past History ◽  
Initial Test ◽  
X Ray ◽  
The Past ◽  
Other Information ◽  
History Of ◽  
Large Flare ◽  
Initial Prediction

AbstractA test of a new Bayesian approach to solar flare prediction is presented. The approach uses the past history of flaring together with phenomenological rules of flare statistics to make a prediction for the probability of occurrence of a large flare within an interval of time, or to refine an initial prediction (which may incorporate other information). The test of the method is based on data from the Geostationary Observational Environmental Satellites, and involves whole-Sun prediction of soft X-ray flares for 1976–2003. The results show that the method somewhat over-predicts the probability of all events above a moderate size, but performs well in predicting large events.

Long Duration Solar Flare Events and Cosmic Ray Modulation (1969-1992)

1994 ◽  
Vol 144 ◽  
pp. 499-502
Author(s):  
A. Antalová ◽  
K. Kudela ◽  
D. Venkatesan ◽  
J. Rybák
Keyword(s):  
Solar Cycle ◽  
Solar Flare ◽  
Solar Flares ◽  
Cosmic Ray ◽  
Flare Activity ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Modulation ◽  
Long Duration ◽  
Flare Index ◽  
Galactic Cosmic Ray

AbstractWe present here the results of the correlation analysis between the galactic cosmic ray intensity decrease p (as observed on Calgary neutron monitor station) and the occurence of SXR long-lasting (LDE-type) solar flares, represented by the LDE-type flare index FI. It is shown, that for the solar cycle with the lower monthly values of FI (the 21-st solar cycle) the correlation coefficient is slighter (about 0.4) comparing to the cycles with the higher LDE-type flare activity (about 0.6, in the 20-th and the 22-nd cycles).

International Diffusion of Agrarian Technology

1974 ◽  
Vol 34 (1) ◽  
pp. 51-73 ◽  
Author(s):  
Robert Evenson
Keyword(s):  
Agricultural Change ◽  
New Techniques ◽  
International Diffusion ◽  
Central Focus ◽  
The Past ◽  
History Of ◽  
Development Agencies

Improved techniques of production have been an important part of the history of agricultural change in all modern economies. The search for policies to bring about the rapid introduction of improved techniques of production in traditional or less developed agricultural sectors has been a central focus of development agencies for the past two decades. It has proven to be a very difficult task, however, to develop policies which actually achieve the transfer of new techniques. The record of success in development efforts towards this end in agriculture has been, on the whole, rather poor.

Sign in / Sign up

Export Citation Format

Share Document