Fingerprinting the stars, Science

Assignment Help:

Fingerprinting the Stars:

Astronomers use various methods to measure the distances to stars. For determining the distances to nearby stars, the method of  stellar parallax  is used  (see Fig. 9.6). For stars farther away, more sophisticated methods are used. We will not go into their details. The distance to astronomical objects situated very far away is found by measuring  the 'red  shift'  of  their spectral lines. As far away objects, such as galaxies and quasars, move away from us, the lines in their optical spectra are shifted towards the red end. This shift can be measured and their distances calculated by using appropriate formulae. 

Maximum  information about starlight can be derived  from its spectrum. When a lens-sized prism is put over the front (or objective) end of a telescope, each star can beseen as a colourful spectrum. We can place a photographic  film at the focal plane of the lens-sized prism. Then it becomes possible to register the spectrum of  starlight. Ironically,  the astronomer sees the spectra, not as brilliant rainbows, but as black and white patterns shown in Fig. Each star has its own characteristic spectrum-a fingerprint of its individual personality. From its spectrum, we can learn what elementsa star is made up of, what  its temperature is, how bright  it  is, how fast it is moving etc. Stellar Motion Stars are not fixed  in  the heavens. They are moving within  the galaxies. The speed of a star moving toward or away from the Earth is indicated by a shift of  its spectral lines. If a star is approaching  the Earth, its lines shift towards the blue end of  the spectrum. If itis moving away from the Earth, its lines shift towards the red end of the spectrum. Thegreater the star's speed, the more its lines shift. 

You have read that there are many kinds of stars-blue, yellow or red, normal or giant,pulsating or releasing excessive energy. Most stars nlove together in groups. Only one out of four stars may  travel alone. Of  the rest, almost a third are double stars and the rest are groups of many stars. In a double star system, known as a binary, two stars orbit one another.  In a triple system; there are three stars-all  three may move around each other, or two of  them may move around the third. Then there are loose clusters, with a few dozen stars, to the large globular clusters containing hundreds of  thousands of  stars, all moving in many possible ways.  


Related Discussions:- Fingerprinting the stars

Solar family, The Solar Family: Let us now take you on a journey acro...

The Solar Family: Let us now take you on a journey across the universe. We begin from our planet EQrth. It  is our home. The Earth  is active, lush and fertile. It is a place

Heaping water up in a glass, Heaping water up in a glass Place a drinki...

Heaping water up in a glass Place a drinking glass in a shallow pan or on a saucer. Rub the top edge of the glass with a dry cloth. Pour water into the glass unless it is full

Classification of hazardous chemicals, Classification of Hazardous Chemical...

Classification of Hazardous Chemicals : The classification of chemical hazards as recommended by the UN Committee of Experts on the Transport of Dangerous goods has been widely ad

Nitrogen cycle, Nitrogen Cycle: Nitrogen is vital part of many essentia...

Nitrogen Cycle: Nitrogen is vital part of many essential organic  compounds especially nucleic acids and proteins. It also forms a major part (79 per cent) of the atmosphere. I

The ventricular system, The ventricular system While the ventricular syste...

The ventricular system While the ventricular system is naturally not involved in cognitive processing since it consists of cavities filled with cerebrospinal fluid, it is good to

Properties of a beating heart - cardiovascular system, Properties of a Beat...

Properties of a Beating Heart Heart Let us study a few interesting properties of a beating heart which make it such a unique organ. 1. Automaticity 2. Rhythmicity 3. L

Explain presence of foodstuffs - movements of gall bladder, Explain Presenc...

Explain Presence of Foodstuffs - Movements of Gall Bladder Presence of foodstuffs: Fatty foods particularly cream, fatty acids and proteins to a less extent, stimulate the cont

Elements of a gar model of risk assessment, Question 1: (a) Enumerate ...

Question 1: (a) Enumerate the five safety rules that you must observe at all times during boarding (b) Show the six elements of a GAR model of risk assessment. (c) What

What are the impacts of minimally processed foods, Q. What are the impacts ...

Q. What are the impacts of minimally processed foods? Impacts of minimally processed foods are: it maintains freshness and quality; convenient and ready-to-cook form products;

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd