Chemical Science: Astrochemistry

Showing posts with label Astrochemistry. Show all posts

Wednesday, 4 December 2013

A Particle Accelerator in the Radiation Belts

One of the most intriguing problems of astrophysics is the existence in a variety of environments of anomalously high-energy particles, for example, extragalactic cosmic rays up to 1020 electron volts (eV). Closer to home, the Earth’s Van Allen radiation belts, discovered at the dawn of the space age, contain some electrons and ions with energies of millions of eV. In spite of a wealth of observations and many proposed models, clarifying the various acceleration mechanisms represents a long-standing challenge.

The acceleration of relativistic electrons in the Earth’s radiation belts can be described as a two-step process: first, electrons are accelerated to about a hundred keV by the potential drop due to streams of double layers (here represented as a stairway). Once they have enough energy, they can interact resonantly with whistler waves and be quickly accelerated to MeV energies. In a sense, double-layer streams represent a stairway to whistlers.

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Sunday, 13 January 2013

Largest Known Structure in the Universe

An international team of astronomers, led by academics from the University of Central Lancashire (UCLan), has found the largest known structure in the universe. The large quasar group (LQG) is so large that it would take a vehicle travelling at the speed of light some 4 billion years to cross it. The team publish their results in the journal Monthly Notices of the Royal Astronomical Society. For more details click here.

The coloured background indicates the peaks and troughs in the occurrence of quasars at the distance of the LQG. Darker colours indicate more quasars, lighter colours indicate fewer quasars. The LQG is clearly seen as a long chain of peaks indicated by black circles. (The red crosses mark the positions of quasars in a different and smaller LQG). The horizontal and vertical axes represent right ascension and declination, the celestial equivalent of longitude and latitude. The map covers around 29.4 by 24 degrees on the sky, indicating the huge scale of the newly discovered structure. Credit: R. G. Clowes / UCLan

Credit: Royal Astronomical Society

Thursday, 22 November 2012

What is Astrochemistry?

Astrochemistry is the study of the chemical elements found in outer space, generally on larger scales than the Solar System, particularly in molecular gas clouds, and the study of their formation, interaction and destruction. As such, it represents an overlap of the disciplines of astronomy and chemistry. On the Solar System scale, the study of chemical elements is usually called cosmochemistry. For more details about astrochemistry click here.

Photo courtesy of Dr. McCall Research Group 2012

Courtesy: Dr. Guido W. Fuchs

Monday, 20 August 2012

Astrochemistry

Astrochemistry extends chemistry into regimes of exceptionally low density and temperature;

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Do not get over excited over happiness and do not get over depressed over sorrow.

Do not get over bonded with anyone and anybody because it can lead to problems and sorrow.

Never think that my duty is the topmost or lowermost. Every duty is respectful. The responsibility undertaken or given as per the position is the noblest duty.

Elevate yourselves, family, society and nation and never denigrate yourselves, family, society and nation.

We are our own closest relatives and if not properly utilised we will become our closest enemies.

There are possibilities of success and failure in any endeavour. One cannot assure success always.

Death is inevitable for everyone in this world. In any endeavour at the maximum an individual may die.

People may say good and also they may say bad. Approach them with stabilised mind.

Take anything after scientifically, logically and rationally analysing them.

Perform your duty, responsibility and accept the privileges eligible for you.

First change ourselves and then try to change others.

We are all instruments /tools in the hands of the nature for performing the duty. So do not think that I am doing the duty. Think that I am an instrument to do the duty.

Results of action may not be sweet always. Accept what ever may be the result.

Follow the path of great scholars who guided the world. Listen their messages.

Results and rewards will come and go but stick to your duty with devotion, dedication and sincerity.

Subhashitham

उद्यमेनैव सिध्यन्ति कार्याणि न मनोरथै: ।
न हि सुप्तस्य सिंहस्य प्रविशन्ति मुखे मृगा: ॥

अयं निज: परो वेति गणना लघुचेतसाम् ।
उदारचरितानां तु वसुधैव कुटुम्बकम् ॥

न कश्चिदपि जानाति
किं कस्य श्वो भविष्यति ।
अतः श्वः करणीयानि
कुर्यादद्धैव वुद्धिमान् ॥

आचार्यात् पादमादते पादं शिष्यः स्वमेधया ।
पादं सब्रह्मचारिभ्यः पादं कालक्रमेण च ॥

उपकारिषु यः साधुः सधुत्वे तस्य को गुणः ।
अपकारिषु यः साधुः स साधुरिति कीर्तितः ॥

च्छायामन्यस्य कुर्वन्ति तिष्ठन्ति स्वयमातपे ।
फलान्यापि परार्थाय वृक्षाः सत्पुरुषाः इव ॥

जलबिन्दुनिपातेन क्रमशः पूर्यते घटः ।
स हेतुः सर्वविद्यानां धर्मस्य च धनस्य च ॥

अग्निशेषमृणशेषं शत्रुशेषं तथैव च |
पुन: पुन: प्रवर्धेत तस्माच्शेषं न कारयेत् ||

पृथिव्यां त्रीणि रत्नानि जलमन्नं सुभाषितम् |
मूढै: पाषाणखण्डेषु रत्नसंज्ञा प्रदीयते ||

नाभिषेको न संस्कार: सिंहस्य क्रियते मृगैः |
विक्रमार्जितराज्यस्य स्वयमेव मृगेंद्रता ||

स्वभावो नोपदेशेन शक्यते कर्तुमन्यथा ।
सुतप्तमपि पानीयं पुनर्गच्छति शीतताम् ॥

यस्मिन् जीवति जीवन्ति बहवः स तु जीवति ।
काकोपि किं न कुरुते चञ्च्वा स्वोदरपूर्णम् ॥

दनेन तुल्यो विधिरास्ति नान्यो
लोभोच नान्योस्ति रिपुः पृथिव्या ।
विभूषणं शीलसमं च नान्यत्
सन्तोषतुल्यं धनमस्ति नान्यत् ॥

संरोहति अग्निना दग्धं वनं परशुना हतं ।
वाचा दुरुक्तं बीभत्सं न संरोहति वाक् क्षतम् ॥

अहो दुर्जनसंसर्गात् मानहानिः पदे पदे ।
पावको लोहसंगेन मुद्रगरैरभिताद्यते ॥

द्वौ अम्भसि निवेष्टव्यौ गले बद्ध्वा दृढां शिलाम् । धनवन्तम् अदातारम् दरिद्रं च अतपस्विनम् ॥

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