Let there be a night again!

I grew up in small town of Kalyan which is located 40 kilometers from Mumbai. Back in 90's decade it was still away from the glamorous life style of metro city like Mumbai. Most of the settlements were in the form of small houses called chawls and they were far for each other. Very few apartments one could see in this town. The sky of this town was not littered with light. I remembered that we could see most of the constellations even faint ones like Cancer, Cetus and Camelopardalis. I learned to identify most of the constellations from Kalyan's sky.

In late 90's town started growing up. Toward its west we could see the light from Mumbai city glows up entire western horizon. Kalyan's light also started to erase stars and constellations from its sky. We have to travel around 60-70 kilometers away from the city to see good night sky. Nowadays we could hardly see any stars from Kalyan. These days even going 60-70 kilometers from city not work, its quite difficult to see deep sky objects from such distances.

I think most of us have seen sky with stars in our childhood (I am talking about children from 80's and 90's decade). Present day if we go in cities or any town we hardly see any stars in night sky. Nowadays cities and town are flooded with the lights. Most of the population in metro cities have never seen sky with full of stars. Even in small towns sky is not that much promising. Artificial lights have cut out us from the beauty of night sky. 

Growing city lights are erasing stars from their sky, Source:internet

One incidence I remember from one of my sky gazing camp. One of my friend from Mumbai also joined us. She suddenly says, 'hey look at that big illuminated cloud it's looking amazing', I said, It's a center of our milky way'. She was stunned by view. She said she had never seen such wonderful object in sky. Most people from city never see such sites in sky. 

We have heard lot about different kind of pollution like air, water, noise and soil. These kinds of pollution directly affect environment and health of humans. So, that's why we are more concern about these pollution. But, there is one more kind of pollution is growing up and that is light pollution. Excess use of light is called as light pollution. We do not bother about light pollution and there no direct effect light pollution on our heath. So, we humans are lighten up more lights with growing cities. But, it does not mean that it not harmful by any means. We might say we don't need nights. But, nights are important to us. Too, much artificial light can cause sleep disorders which further causes many more diseases. You can find more detail about it on this link http://darksky.org/light-pollution/human-health/

Too much light impacts our night. Night give us sense of time. It also help in propelling our biological clock. Not only us but also many animals biological clock derived by day and night. We have disturbed this by using more and more artificial lights. Migratory birds need good night sky view to travel, but due to light pollution they loose their path and most of time get exhausted in flying and die. 

Now many countries are started glowing during nights. It is very necessary to aware people about importance of night. With increasing population, cities and societies we need light for many purposes but we also should understand how much to use and when to switch it off. In many countries people are started doing this. They aware and educate people to use light sensibly. In India too we need this where cities and towns are growing. 

If we look back in history, we find that night sky has shaped our human civilization than any other thing. Night sky gave us direction for travelling on our globe. Clear night skies told us there is cycle in some events which we can use as calendar. Observing night sky developed understanding of our place in universe. Night sky has inspired our religion, philosophy, art and science. This is the one heritage that all civilization shared. But, because of uncontrolled use of artificial lights our present generation is loosing this. Its time to get aware about using light with responsibly and preserve this heritage. 

Center of our galaxy visible from dark place, source: internet

there are various organisations like Dark Skies Awareness and International Dark Sky are working in this area. You can visit their website to understand more about light pollution.

Blue Marble to Pale Blue Dot: Our Earth From Space

Few days back one of my friend shared with us, a picture of Earth from Saturn. It was very beautiful image taken by the Cassini spacecraft, a tiny star of Earth through the Saturn’s dust rings. This image just made me think about the images taken by satellites and space missions from space.

There is little star behind Saturn's dusty ring, that's Earth!

Every time we look at Earth from space it look very calm and beautiful. Most of time wrapped in clouds, its major area covered by water and rest of its area can be seen with different colors of landscapes. Astronauts call her Blue Marble. They often says, it’s beautiful to see peaceful earth from space. No one can imagine that there are many things happening down there. Turbulent tornadoes, gusting wind, running rivers, stormy rain, sliding lands all seems very quiet from space. Borders are not visible from over there. Even Earth never look religious from space. It just appear as calm Blue Marble.

A Blue Marble, Earth seen by Apollo 17

Earth appear as a marble in the vicinity of Earth’s Space. How she look from the distant space? Our spacecraft studying alien worlds in our solar system has looked time to time towards the planet from where they get signals. It’s very amazing to see our world from there. Here is the image of Earth from moon’s horizon taken during Apollo 8 mission. It was the first earth rise seen by humans from moon. Like moon, she also displays phases from moon.

Earth rise over Moon horizon

Messenger spacecraft studying planet mercury seen our earth on 6 May 2010. From that distance earth and moon can be observe separately. If this pair observe for long time one can see moon revolve around Earth.

Pair of Earth and Moon seen from Mercury by Messenger

This image of Earth in Martian sky taken by Mars rover Curiosity on 31 January 2014. It appear like a star for rover camera and later it zoomed in during image processing. For any observer with normal human eye could see earth and moon separately in Martian sky.

Earth and Moon in Martian sky

We in the vast Universe

It was very old quest for humanity to find out our existence in this infinite universe. Human’s affinity towards this quest shown us the real picture of our planet in this universe. Previously it was thought that our world was built by Supreme Being called god and he place our world in the center of the universe. Because, we humans considered ourselves very special to him. He and only he can see our world. But, then humans started observing and studying universe and celestial bodies’ motion very keenly. It helped us in understanding out our planet’s position in solar system. We found our world is moving around the sun. Then, further observation led us towards the conclusion that our sun is also very ordinary star and located in outer region of galaxy. One of our spacecraft, Voyager 1 after starting its journey towards outside the solar system, it looks back towards earth and capture her image. This image first time shown us reality of our planet. Earth from that distance appeared as mere a tiny speck of dust. It showed us that in this infinite space we all are alone on this tiny dust particle. Only particle in known universe carrying life on it. We humans are not special in this universe but this life carrying dust particle in universe is very special. Now it’s time to value our home planet.

In 1990 Voyager 1 captured Earth, famous astronomer Carl Sagan called it a Pale Blue Dot

All images in this article are from NASA's image gallery

Blue Moon Rising

On 31 March we saw Blue moon. It was a rare that one calendar year saw two months of two full moons which was January and March. Next will be happening in 2037. I tried to take some pics of its rising from Sirohi, Rajasthan. Its a small town located down to the one of the mountain in Aravali range. This small mountain named as Mater Mata (named after a local godess) located to the east of town. So, its very beautifull site to watch celestial objects rising over it. This blue moon I captured some of pictures of rising moon. I am still understanding function of DSLR. I hope you will like it.

 As I said, earlier in my article on this blog Blue moon is not actually blue in color. It appear just as normal moon. The term actually meant to indiacate an extra full moon in a astronomical season or in a month.

Blue Moon and how we see it

On 31 March we are witnessing Blue Moon. You might have encounter with term Blue Moon in news media. In media, news usually appear with Blue color moon picture and says 'this month we are going to see blue moon'. Many people wonders  how moon will be in blue color? it must be a great sight in sky seeing blue color moon. But, Blue moon is nothing to do with color. It is a name of moon which occurs as a extra full moon in a month or in a astronomical season.

Blue moon is not actualy blue in color

In every cultures moon has different names. In India too have different names according to seasons and festivals. In western culture, they also given name to full moon according to seasons. Like, October month moon is called as Hunters Moon because peoples who lives at northern hemisphere start collecting food and meat for coming winter. December moon is called as cold moon and March moon is called as worm moon. These names are not uniformly used in entire western culture. These also change from tribe to tribe or culture to culture. 

Every culture or tribe made their own calender based on sun or moon to maintain their yearly activities. Every season like spring, summer, fall and winter usually see three full moons. These seasons happens due to sun motion in Earth's sky. Sun takes 365.24 days to complete one cycle in Earth's sky which we called a year. (Earth move around the sun in space and from earth we see sun is moving in sky. Its a relative motion we observe.). But, to complete one cycle in sky moon takes 29.5 days. When sun colpletes its one cycle in 365.24 days, by the time moon complets 12.37 cycles. So, each calender year get around 11 extra days from moon cycle. Due to accumulation of these days from lunar cycle we see extra full moon in a season after two or two and half calendar year. This extra full moon is called as Blue moon. Indian calender make adjustment in calendar to stay with seasons by inserting Adhik Maas after two and half year. (Incorporating extra moon cycle vary with different calendars.)

Another way to describe Blue moon is, a second full moon in same calendar month. This calendar year 2018 has two Blue moon month one was January and second is March. This is rare, next calendar year with two Blue moon will be 2037. But, sinlge Blue moon month happenes every two and half year. Next, Blue moon will appear in Octber 2020. 

Astronomical events and news media

When people hear or read about blue moon, they usually think that moon will appear in blue color. Because, the way news media present this event. In age of Information and technology news media has become most unscientific mode of information. Many times not enough research happens aroud topic and to just grab attention of public, news are presented in dramatic way which leads to misconception. News Media also wrongly present other natural or astronomical events like eclipses, appearance of comets or when mars comes near to earth in its orbit. For example, news about eclipse will show less about science behind it and more about effect of eclipse on someones zodiac signs and how it will doom person's fate. This leads people and society towards superstions. I think every time nature gives us opportunity to become more rational and logical, we misuse it and becomes more irrational. News media has played very important role for social awareness time to time. Now, in this time it is very much required a role of scientific and rational media to create scientific attitude in society. 

Why we cant see Stars in day time?

Night sky with full of shining stars is always spectacular site to view from the country side. If moon is not present in the night then the site becomes fascinating. We cant see this view during day time. After sun set also we cant see stars suddenly appear in sky. It takes sometime for coming them out entirely until the sky becomes dark after sunlight totally goes off. Question that why we cant see stars in day time wonders most us. Whats the reason behind it?

Straight answer we get for this is due to sun's strong light we simply cant see them. But, what exactly happens when sun comes in our sky and how it limits us from seeing stars. Our Earth's atmosphere plays key part in this phenomenon. When sun comes in our sky sun's light is scattered by the atmospheric gases and dust particles. Due to this scattering earth's sky illuminates. Due to this illumination day time sky outshine other stars.

Night time sky with full of stars

We have seen that on Full moon night we do not observe much stars due to moon light. Sky near the moon is much brighter than rest of sky so in this area we see very very few stars. Same during dawn and dusk also we can see very few stars. We can understand this phenomenon by recalling our experiences, what happens if we lit small bulb in front of much brighter street lamp? in this case we could hardly see light coming from small bulb. This can be observe during night driving, if a small bike is riding ahead truck we could hardly notice bike in front of trucks brighter light. For our eyes it is difficult to sense small intensity of light in front of big intensity light source. 

Then how much brighter object we can see in our day time sky?

Many times astronomers looks distance space objects like galaxies which having magnitude more than 14. In such conditions astronomers looks for the very dark sky means having magnitude more than this object. As atmosphere scatters light due to dust and gas particle it behave as light or illuminated object. If sky appear more brighter then such faint object will disappear. Object visibility in the sky depend on how much object is bright and how much sky is bright or dark. Sky conditions varies during dawn or dusk, presence of sun  or moon in sky and nowadays light pollution from greater cities affects sky views.

Brightness of celestial objects measures in magnitude. There are two types of magnitudes astronomers use, apparent and absolute. Here we will discuss only about apparent magnitude scale. If we look at the night sky, we can see stars with different brightness. Some stars are much brighter on the other hand some are so faint that we hardly notice them. Astronomers in ancient time made a comparative scale to measure intensities of stars. They took one star for a reference which they denoted as 1 magnitude star and with the caparison to this they measure fainter stars and brighter stars. If star appear 2.5 times fainter then it will be 2 magnitude star. If it is 2.5 x 2.5 times fainter then it will be 3rd magnitude star. so, 3rd magnitude star will be 6.25 fainter than 1 magnitude star. Human eyes could observe 6 magnitude star which is 100 times fainter than 1 magnitude star. same way for brighter object if object is 2.5 brighter than 1 magnitude then it will be 0 magnitude. Brightest star of night sky is Sirius which is having magnitude of -1.45 means it is much brighter than fainter stars visible to human eyes. this measurement scale is very ancient. This method is adapted and developed by various astronomers time to time in historical time course.  If we take full moon it have magnitude of -12 and sun is having magnitude of -29 means it is trillion times brighter than any star.

Venus can be observe in day time if know its exact location in sky

Seeing objects in day time depends on many conditions like brightness of object, sky conditions and position of object from sun. Near sun, sky is much brighter so its very difficult to see anything near it although we know exact position of object. if moon is in big enough in size then its easy to spot it in day time. Venus is the second object which can be observe in day time when you know its exact position. Venus shows magnitude of -4.4 means magnitude of day time sky at that region must be below this magnitude. It also depends on position of object from the sun in sky. Sky at different distance have different brightness. It will be maximum near to the sun and as moving away from sun its brightness decrease. Many astronomers do these activity of finding stars or planet in day time sky. Its interesting and test many skills of astronomers. On various website one can get information about this. Human eyes are very poor in spotting celestial objects in day time. For spotting object you also need fine instrument like telescope and position data too. Try out how many celestial objects you can see in day time.

Note: Images used in this article are taken from various internet sources. for information I have referred astronomy books like The Sky by David Levy and Bad Astronomy by Philip Plait and many other internet sources

Total Lunar Eclipse of 31 January 2018

Hi, everyone this is long time I have written anything on my blog. I have been doing my astronomy activities but did not shared them on this blog. Today i am going to share our some experiences and photographs of total Lunar eclipse of 31st January 2018. The special thing about this lunar eclipse was it was on Blue moon means it was second full moon in the same month. This Lunar eclipse was visible from the all of Asia. From India we could not see the first half of the eclipse. When moon rose in our horizon it was almost began the totality of eclipse.

Many people do not find Lunar eclipse exciting as solar eclipse. There might be many reasons like time duration. Lunar eclipse runs for longer than solar eclipse. Solar eclipse produce far more marvelous views than Lunar eclipse. But, I think lunar eclipse is impressive by its own way. It also produce fantastic views, mine favorite is traveling of Earths shadow over lunar landscape. if we observe it through telescope it definitely make you excited. In total lunar eclipse moon never disappeared like sun does in solar eclipse. In fact moon become red in color when it goes to total phase.

        Moon was in total phase when rose in sky

When earth comes in between sun and moon, suns light do not get cut entirely. But due to to earth's atmosphere which stands almost 60 kilometer high turns some of the sun light towards moon. This redness is different in different eclipses. It also depend on the dust particle activities in atmosphere. If dust particle get more in atmosphere then moon color turns more deep red.

 

Earth's shadow shape can be seen here

                                          Last touch of earth's shadow:The eclipse getting over

We arranged event for observing this lunar eclipse with some government teachers and some community members also came. it was nice to have interaction with them. teachers showed full interest in this event. First time they were looking eclipse through telescope. However, we noticed that some of the community members hesitate to watch lunar eclipse. They might have thought that this can bring bad omen to them. We had discussion with them that there is no such thing like bad omen. But for grown ups its very hard to leave their notions.
Before, this eclipse we went to some schools in rural areas and discuss about eclipse with students over there. Students were more curious to know about such things. In my own experience I believe that young students can help us to work towards such myths rooted in society. They are open towards learning. they asks questions to at least their parents and relatives and make them to watch such events which people thinks bad.
Anyway, such events like eclipse gives us opportunity to go in common people and talks about the scientific thinking and rational against traditional thinking of religions and myths. It also help us to make dialogue on such issues and make people aware against false beliefs.

मेरा दोस्त मिस्टर लिकी

मैं जून माह होशंगाबाद विज्ञान की कार्यशाला में गया था| वहा मैंने हाल्डेन की ‘मेरा दोस्त मिस्टर लिकी’ किताब देखी| एक बार मेरे दोस्त ने इस किताब के बारे में मुझे बताया था की, यह एक अच्छी विज्ञान की किताब है| तो मैंने इसे ख़रीदा| लेकिन पता नहीं था की इसे कब पढ़ पाऊंगा| खैर मैं इस तरह किताबे खरीद कर रख लेता हूँ और जब कभी समय मिले तो उन्हें पढता हूँ| इस किताब को वैसे मैंने जल्द ही हाथ में लिया| यह एक विज्ञान कथा है, पर जैसे मैंने पहली कहानी पढ़ी तो मुझे लगा के मैं विज्ञान कहानी पढ़ रहा हूँ या फिर कोई जादुई कहानी| हां, हाल्डेन की इस किताब में मिस्टर लिकी एक जादूगर है| इतना ही नहीं इसमे उनका एक अब्दुल मक्कार नाम का जिन्न है, साथ में एक नन्हा सा नटखट सा ड्रैगन पोम्पई, ओलिवर नाम का एक ऑक्टोपस जो उनका नौकर है, लियोपोल्ड नाम का बीटल, एक उड़ती कालीन और कई सारे जादुई मित्र| लेकिन हमारे लेखक के मित्र मिस्टर लिकी कोई साधारण जादूगर नहीं है, वे जादू के साथ साथ कई सारी वैज्ञानिक बाते बताते है|

जे. बी. एस. हाल्डेन (J. B. S. Halden) की इस किताब को पढ़ते वक़्त हमेशा ऐसा लगता है की उनमे विज्ञान की जटिल बातों को, उनका अर्थ बिगाड़े बिना, अत्यंत साधारण रूप से कहने की विलक्षण क्षमता थी| बच्चों के लिए विज्ञान साहित्य बहोत कम लिखा गया है, और जो कुछ थोडा सा लिखा गया है, वह कभी कभी बच्चों की समझ के बाहर होता है, या उसे इतना हल्का किया जाता है की बच्चे उसमे विज्ञान देख ही नहीं पाते| हाल्डेन का ऐसा मानना था की एक वैज्ञानिक होने के नाते, यदि हो सके तो, विज्ञान को साधारण व्यक्तियों और बच्चों के लिए आसानी से समझाने योग्य कुछ लिखना चाहिए| उनका यह प्रयास इस किताब में दिखाई देता है| एक छोटीसी जादुई कहनी के साथ उन्होंने विज्ञान की कई रोचक बाते बताई है|

इस किताब में कई सारे पौंधे, कीटों, प्राणी और पंछियों का जिक्र आता है, तब हाल्डेन ने उन जीवों की बारीकियों को इस कदर लिखा है की पढने वाले के मन में जिज्ञासा उत्पन्न होती है| जैसे, लेखक को बाथटब में मिस्टर लिकी के पार्टी का न्योता देने आई सुनहरी मछली कोई साधारण सुनहरी मछली नहीं थी, वह तो न्यूजीलैंड के गर्म पानी के सोते में रहने वाली है, इसलिए वह बाथटब के गर्म पानी को सह लेती है| हाल्डेन अलग अलग जगह के बारे में भी लिखते है| एक बार लेखक मिस्टर लिकी के साथ उड़ती कालीन पर दुनिया की सैर पर निकलता है, जब वे हिंदुस्तान पार कर के दक्षिणी गोलार्ध में पोहचते है तो वह से दिखने वाले आकाश में बारे में भी हाल्डेन ने लिखा है| विज्ञान में अध्ययन करने के बावजूद शायद ही किसी वैज्ञानिक ने बच्चों के लिए ऐसा कुछ लिखा होगा|

हाल्डेन एक प्रतिभावान वैज्ञानिक थे| उन्होंने शरीर विज्ञान, जैव रसायन और आनुवंशिकी के क्षेत्र में महत्वपूर्ण योगदान दिया| वे जनसँख्या आनुवंशिकी के संस्थापकों में से एक थे और विकास का गणितीय सिद्धांत उनका बहुचर्चित योगदान माना जाता है| साथ साथ में हाल्डेन मानवमात्र की भलाई चाहने वाले वैज्ञानिक भी थे| अपने विद्यार्थी जीवन में पहले विश्वयुद्ध में ब्रिटन की ओर से सिपाही के तौर पर लड़ते हुए देखा हुआ तबाही का मंजर और बाद में द्वितीय विश्वयुद्ध के भी साक्षी रहे हाल्डेन ने समाज की भलाई के लिए कम्युनिस्ट पार्टी की सदस्यता ली और समाजवादी विचारधारा के समर्थक बने| लेकिन धीरे धीरे कम्युनिस्ट पार्टी के खोकलेपन की वजह से वह चुपचाप इस विचारधारा से अलग भी हो गए|

बाद में ब्रिटिश और फ़्रांसिसी सरकार के सुएज़ पर किये गए आक्रमण से नाराज हो कर वे भारत चले आये, यहाँ की नागरिकता स्वीकारी और मरने तक उन्होंने भारत में विज्ञान के अनुसंधान तथा विज्ञान शिक्षा में कार्य करते रहे| उन्होंने अपने विद्यार्थियों को वैज्ञानिक मान्यताओं को साधारण जीवन के अनुभवों से जोड़ने की सिख दी, जो उन्होंने अपने जीवन में भी आत्मसात की थी|

हाल्डेन का हिंदुस्तान से लगाव इस किताब में दिखाई देता है|1936 में लिखी गयी इस किताब में ब्रिटिश हिन्दुस्तान की कई सारी बाते हाल्डेन बताते है, चाहे वह हिंदुस्तान की चाय हो या आम| वैसे एक हिन्दुस्तानी जादूगर श्री चन्द्रज्योतिष भी है इस कहानी में| मिस्टर लिकी की बस तीन कहानिया इस किताब में है| बाकि तीन कहानियों में मिस्टर लिकी से मुलाकात नहीं होती| पर ये कहानियाँ भी बहोत खुबसूरत तरीके से लिखी है| इनमे से एक कहानी में बड़े होशियार चूहे है जो लन्दन के बंदरगाह पर तबाही मचाते है| एक कहानी में एक सनकी अमिर व्यक्ति है जो अपने सांप को सोने के दांत लगवाता है| और आखरी कहानी में एक जादुई बटन है| इन कहानियों में भी जादू, परियां, अकलमंद जीव और ढेर सारी विज्ञान की बातें है|

एक और खासियत इस किताब की आपको बताना भूल गया था, वह है क्विन्तिन ब्लेक (Quintin Blake) की चित्रकारी| बालकथा के चित्रकार क्विन्तिन ब्लेक जिन्होंने रोआल्ड डाल (Roald Dahl) के कई सारी किताबों में चित्रकारी की है, उन्होंने इस किताब में भी बहोत सुन्दर चित्र बनाकर हाल्डेन के पात्रों में एक तरह से जान डाल दी है| उनका पोम्पेई ड्रैगन, होशियार चूहे और रोज़ी मगरमच्छ बड़े ही प्यारे बने है| क्विन्तिन का मिस्टर लिकी तो हाल्डेन जैसा ही दिखता है| अगर आप बच्चों के (विज्ञान) साहित्य को पढ़ने की रूचि रखते है तो ‘मेरा दोस्त मिस्टर लिकी’ जरुर पढ़े|

मेरा दोस्त मिस्टर लिकी

मूल लेखक: जे. बी. एस. हाल्डेन

हिंदी अनुवाद: अमिताभ पांडे

प्रकाशक: विज्ञान प्रसार