Astronomy Club

Science and Technology Council

Students’ Gymkhana

Indian Institute of Technology, Kanpur

Presents

CYGNUS

The Wall Magazine

2002-2003 II

Club Coordinators	Other Contributors
Amar V. Chandra	Anshuman Sinha
Ashutosh K. Gupta	Vinay Mishra
Jaya Jha	Amitabh Virmani
	Archisman Ghosh
	Saujanya Golwelkar

On the lines of VIBGYOR

Spectral Classes of Stars

Categorizing the stars, all different and huge in number had really been a challenging task for astronomers. In the classification of stars mentioned here, the stars are classified in various categories according to the strength of the Balmer lines of their hydrogen absorption spectra, each class being denoted by an alphabet. The alphabets have been arranged in an order so as to correspond to a sequence of decreasing surface temperatures and hence intrinsic luminosity i.e. energy emitted per unit time.

So various spectral types of stars are: O B A F G K M (R N).

But how to remember this odd sequence of alphabets?? There are many sentences that had been formed for the same. One of the famous ones is: O Baby, a Fine Girl, Kiss Me (Really Now!).

Mythology cannot go unnoticed

Cassiopeia- In Greek Mythology

Cassiopeia was the beautiful wife of Cepheus, king of Ethiopia, and the mother of Andromeda. She is most famous in connection with the myth of her daughter, Andromeda. The queen made the mistake of bragging that she was lovelier than the Nereids and even Juno herself. The goddesses were, needless to say, rather insulted, and went to Neptune, god of the sea, to complain. Neptune promptly sent a sea monster (Cetus) to ravage the coast. The king and queen were ordered to sacrifice their daughter to appease Neptune's wrath, and would have done so had Perseus not arrived to kill the monster in the nick of time. As a reward, the hero was wedded to lovely Andromeda.

By most accounts, Cassiopeia was quite happy with the match. In some versions of the myth, however, the queen objects to the marriage and is turned to stone when Perseus shows her the head of the Gorgon Medusa.

Although Neptune placed her in the heavens, the sea-god saw fit to humiliate her one final time (and for all eternity). He placed her so that she is seated on her throne, with her head pointing towards the North Star Polaris. In this position, she spends half of every night upside-down.

They dared change time!

Gregorian calendar

The calendar we use now days is Gregorian calendar. It was reformed from Julian calendar. It was originally a brainchild of Emperor Julius Caesar who decided to make a new calendar system (Julian calendar). After him his successor Augustus Caesar made some corrections in it. And in 1582, Gregorian calendar comes in existence after changing Julian one a lot. There are several opinions about the dates of corrections. Some documents say even something like this last correction being the result of some conspiracy!

Initially, Julius Caesar ordered to have year of 365 days and leap year in every 4^th year (In 43 B.C.). But due to some misunderstanding it becomes a leap year in every 3^rd year. And It was corrected by Augusts Caesar in 10 B.C. This new calendar was out of phase with tropical year by 1 day in every 131 years. One and half millennium later it was observed that Ester is moving in summer. And calendar is increasingly out of phase with seasons. So, In 1852 Pope Gregory XIII ordered these changes in Julian calendar.

Since 0 A.D. Julian calendar was 12 days ahead from season cycles so 10 days was removed from calendar. Means 5 October 1982 becomes 15 October 1982.
There will be leap year every 4^th year. (As Julian Calendar)
Years dividable by 100 will not be leap but year dividable with 400 will be leap year. (By this they have removed 3 days in every four hundred years from Julian calendar which means 1 day in every 133.33 years)
There is one more rule proposed. As Julian calendar was inaccurate by 1/131 in a year but they corrected it by 3/400 every year, it creates an error of 1 day in every 3300 years. So it was proposed to add 1 day after 4000 years. But it has not yet been implemented. This was not included in the orders of Gregory either.

After all these changes, Julian calendar becomes Gregorian calendar, but it was difficult to ensure that everyone follows these changes. This dispute remained for a long time and it finally settled down in start of twentieth century.

Dates for different countries accepting the reform:

Austria: Different regions accepted it on different dates. At some places 5^th October 1583 was followed by 16^th Oct 1583. At other places 14^th December 1583 was followed by 25^th December 1583.

Bulgaria: 8^th Mar was followed by 1^st Apr 1916.

China: Some authorities say 18^th Dec 1911 was followed by 1^st Jan 1912 while according to others   18^th Dec 1928 was followed by 1^st Jan 1929.

Czechoslovakia: 6^th January was followed by 17^th January in 1584.

Denmark: 18^th February was followed by 1^st Mar in 1700.

France: 9^th Dec was followed by 20^th Dec in 1582.

Germany: Catholic states on various dates in 1583-1585.

Prussia: 22^nd Aug 1610 was followed by 2^nd Sep in 1610.

Great Britain and Dominions (including USA): 2^nd Sep was followed by 14^th Sep in 1752.

Greece: 9^th Mar was followed by 23^rd Mar 1924.

Hungary: 21^st Oct was followed by 1^st Nov in 1587.

Japan: According to some sources 19^th Dec 1872 was followed by 1^st Jan 1873. Others say              18^th Dec 1918 was followed by 1^st Jan 1919.

Latvia: During German occupation in 1915 to 1918

Poland: 4^th Oct was followed by 15^th Oct in 1582.

Portugal: 4^th Oct was followed by 15^th Oct 1582.

Prussia: 22^nd Aug was followed by 2^nd Sept 1610.

Russia: 31^st Jan 1918 was followed by 14^th Feb 1918.

Spain: 4^th Oct was followed by 15^th Oct in 1582.

Transylvania: 14^th Dec was followed by 25^th Dec in 1590.

Turkey: 18^th Dec was followed by 1^st Jan 1927.

Contemporary Subjects

Neutrino Astronomy-Mysteries and Challenges

For last 1000 years astronomers have looked in to all parts of electromagnetic spectrum and they have collected good amount of information about the content, structure and evolution of our universe. Still our knowledge is far from complete. We are learning further about the cosmos beyond the solar system by observing cosmic rays (essentially protons). But these charged particles do not point to their place of origin because of the galactic and extra-galactic magnetic fields affecting their path.

What is needed is a particle, which goes un-deflected by these magnetic fields and doesn't get attenuated by dust or gas on its journey, a "weakly interacting particle". Neutrinos are the best candidate. They are neutral, weakly interacting particles and come to the detector without any disruption, straight from their source. It is doubtless that we will get a wonderful view of the universe in neutrino light. It is possible to see even sun in neutrino light during "night hours".

Neutrinos were made in huge amount as universe cooled after big bang. Stars, supernova etc. are good producer of neutrinos. Flux of neutrinos at earth is largely dominated by neutrino produced in sun. Lots of neutrino observatories around the world are operating to measure this neutrino flux. Note that it is a difficult task because neutrinos are weakly interacting. India is on its way of constructing Indian Neutrino Observatory (INO).

As these observation came up the whole community was surprised to see that flux observed is nearly half of what is predicted from standard stellar physics. This thirty-year mystery persists in the deficit of about a half in the numbers of neutrinos detected compared to expectations, the so-called "Solar Neutrino Problem". All kinds of ideas came up to explain this puzzle and perhaps more then 200 "solutions" are floating in literature. But these observations clearly made astronomers realize that they have not yet understood these particles at a satisfactory level! Unfortunately, still there is no conformity among physicist about the masses and types of neutrino. Search is on and we will see many new surprises in the coming years.

Amazing Facts

Do you know

· That just a pinhead of the Sun's raw material could kill someone up to 160 kilometers away!

· That Saturn has such a low density that it would float if put in water!

· That Jupiter’s magnetic field is so massive that it pours billions of Watts into Earths magnetic field every day!

· That the energy in the sunlight we see today started out in the core of the Sun 30,000 years ago - it spent most of this time passing through the dense atoms that make the sun and just 8 minutes to reach us once it had left the Sun!

· That the star known as LP 327-186, a so-called white dwarf, is smaller than the state of Texas yet so dense that if a cubic inch of it were brought to earth it would weigh more than 1.5 million tons!

Quiz Corner

Find the answers to the following questions and post on iitk.gymkhana. The first person posting all correct answers will get a prize.

1. Name the planets:

a) The planet, which rotates about an axis almost in its plane of orbit, is ___________.

b) The satellites of this planet were first identified after the moon. The planet is

c) The planet whose existence was predicted before it was seen is __________.

d) The planet, which has moons whose names mean, “fear” and “death” is__________

2. Match the objects in the first column with the constellations in the second columns:

a) Brightest star 1. Centaurus

b) Galactic Centre 2. Cancer

c) Nearest spiral galaxy 3. Taurus

d) South Pole star 4. Leo

e) Closest Star 5. Andromeda

f) Beehive 6. Sagittarius

g) Plaides 7. Octans

h) Sun on 15^th Aug 2002 8. Canis Major

3. Given the description of a few astronomical phenomena, identify them:

a) One of the most energetic explosive events in the sky. It occurs at the end of a star's lifetime, when its nuclear fuel is exhausted and it is no longer supported by the release of nuclear energy.

b) Extremely dense star, perhaps the densest form of matter in the universe and fate of all stars whose masses are within a certain range.

c) Radio-waves emitted by a star that has undergone an explosion and is rotating very fast.

d) Dark spots on the surface of the sun, related to magnetic activity.

e) A huge cloud of solar gas ejected from the surface of the sun.

Answers

Answers to the Quiz in Cygnus-Volume I

1. Varuna 2. Total time of precision 3. Sirius 4. Meteor Showers normally happen when some debris from some comet enter the earth’s atmosphere and glow up due to friction there by producing a spectacular shower of light. 5. Angle between the axes of both the motions is about 90 degrees. 6. Some meteors hit the Siberia (Tanguska) jungles. The shape of destruction, which appears (from air) on the field, is in the shape of butterfly. 7. Mrig (Deer) 8. Milky way! 9. Cancer 10. Undefined.

What do the coordinators say

Activity… Activity… Activity… Astronomy Club

Be it the heat of April, or the rains (drought!!) of August, the club is on its way, trying to do as much as possible. And as consequence here are we, as promised, with the second issue of Cygnus- the wall magazine.

The response towards the activities we have organized has been quite satisfactory, but we still hope to see more and more of you getting involved with the club and explore the light from behind the dark sky (that’s what we prefer!).

Suggestions, regarding the activities of the club, always help us know the expectations of Junta and encourage us as well. Please do keep pouring in your suggestions.

Activities done so far

Promises are to be kept!

Celebration of Astronomy Week in April, 2002 with lots of events
Two Observation sessions in April itself.
Two issues of Cygnus.
Assembling of the telescope acquired in the last term during the summer vacation.
Acquiring new mount for the 6” telescope.
Freshers’ Astronomy Quiz on August 15^th, 2002
Telescope Making Workshop on August 16^th, 2002

We believe in doing more than what promised. All we need is an enthusiastic participation from you!

Before We End

Quotes Not to Be Quoted ;-)

"Comets are like cats. They have tails, and they do precisely what they want."

David Levy (Comet discoverer, observer and writer)

At the physics exam: Describe the universe in 200 words and give three examples.
When people run around and around in circles we say they are crazy. When planets do it we say they are orbiting.
Which would be the last planet an astronomer would choose to live?

Answers invited… Chocolate promised!

Joining the Club

It is Simple

Drop a mail to astro@iitk.ac.in.