Earth and Moon view from MESSENGER

From the Earth, we can see seven planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune. They look fabulous when observed through telescopes like phases of Mercury and Venus, ice capped Mars, mighty Jupiter with its four satellites, beautiful Saturn with its magnificent rings, blue worlds of Uranus and Neptune. Now you may ask the question how our Earth looks from the distance space? Is anybody has seen the Earth from the remote space? Yes, there is one, who looked at the Earth from the remote space. It is MESSENGER a satellite on mission to study the Mercury. Above image taken by the satellite on 6 May 2010. In the lower left portion of this image the Earth can be seen, as well as the much smaller Moon to Earth's right. MESSENGER took this image from 183 million kilometers. To provide context for this distance, the average separation between Earth and the Sun is about 150 million kilometers.

This image was acquired as part of MESSENGER's campaign to search for Vulcanoids, small rocky objects that have been hypothesized to exist in orbits between Sun and Mercury. The MESSENGER spacecraft is in unique position to look for smaller and fainter Vulcanoids than has ever before been possible. Vulcunoids are named after the hypothetical planet Vulcan which was proposed to exists between Mercury and Sun by the 19th century astronomers to attempt explanation in peculiarities of Mercury's orbit. No such planet was ever found.

MESSENGER is a unique mission of NASA to study the Mercury planet after Marinar-10. It was launched on 3 August 2004 from Cape Canaveral, Florida. The name comes from 'MErcury Surface, Space Environment, GEochemistry and Ranging' highlighting the project broad range of scientific goals and it is perfect to study Roman mythological messenger of the gods.

AMOL KATE

:image credits to NASA/John Hopkins Applied Physics Laboratory/Carnegie Institute of Washington

Solar Tsunami

Last year solar astronomers observed quietest Sun in almost a century. In 2008, there were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days, some observers suggested that the solar cycle had hit bottom in 2008. Sunspot counts for 2009 were almost same as previous year 260 spotless days (71%). Many astronomers said that our sun is now passing through the deepest solar minimum. But, a few days ago suddenly the Sun emitted a massive belch in to space, astronomers christen it Solar Tsunami.

On August 1st at 8:55 Universal Time, orbiting satellites witnessed a sizable flare erupting from the large sunspot region designated 1092. The strength of this outburst was pegged at C3, modest as flare go, but it still triggered an impressive coronal mass ejection, or CME, that shot out from the solar disk at more than 1000 km per second. The CME hit Earth's magnetic field on August 3rd at 1740 Universal Time. The impact sparked a G-2 class geomagnetic storm that lasted nearly 12 hours--time enough for auroras to spread all the way from Europe to North America.

CMEs are the result of strong solar activity or solar storms. It is a large cloud of charged particles that are ejected from the Sun over the course of several hours and carry up to ten billion tons of plasma. They expand away from the Sun at speed as high as a thousand kilometres in second. A CME can make the 150 million kilometres journey to Earth in just two to four days. This CME will have noticeable consequences beyond producing an aurora. Stronger solar storms could cause adverse impacts to space based satellites, space station and technological infrastructure on Earth.

The Sun goes through a regular activity cycle about 11 years long. The last solar maximum occurred in 2001 and its recent extreme solar minimum was particularly weak and long lasting. Experts don't expect solar activity to peak until mid-2013, but these kinds of eruptions are one of the first sign that after oversleeping for more than a year, our star is finally stirring from hibernation and heading toward anther solar maximum expected in the 2013 time frame.

AMOL KATE

Astronomy for Everyone

I am writing this from the Science Express. Science express is a state of the art exhibition train which was started in the year 2007 as a joint venture of Govt. of India and Govt. of Germany. After having the phenomenal response from the people of India this train run now for at least six months. During the journey of science express I visited many cities and places in India and met more than 5 million people and I got opportunity to communicate astronomy to those people. OK! I forgot to tell you my job on science express is to communicate science to the people. Apart from the exhibition on the train, during second and third phase of science express in the year 2009 we started visiting school and institutes for astronomical program and with that we started our fantastic journey of spreading astronomy among people of various community.

The year 2009 was so significant to make people aware of astronomy because, 2009 was designated as International Year of Astronomy. Exactly 400 years ago from 2009, the Universe changed or, at least, our perception of it did, thanks to Galileo Galilei's scrutiny of the night sky with a telescope. Within a couple of years, his observation of the Moon, phases of Venus and satellites of Jupiter shattered the old Ptolemic model of our Solar System. To the church's dismay, Earth assumed its rightful place as one of several planets orbiting the Sun. Marking Galileo's anniversary, the International Year of Astronomy seeks to remind us of the humbling nature of gazing at the heavens.

So what is astronomy? What does it mean to people in developing regions like India? Well, firstly it must be acknowledge that astronomy belongs to us all. Virtually every culture in the world had already established a relationship with the stars, moon and sun hundreds if not thousands of years ago. In fact, for as long as human beings have walked on the Earth we have looked up at the night sky and wondered about the objects we saw. In India, people have used the stars for centuries, be it for navigation, agriculture, or even story telling. Today, Astronomy as a field of study has developed into something that attempts to answer some of the biggest question imaginable. It is a field that challenges the limits of human understanding and yet never ceases to expand on it. Astronomy, as I have seen on the faces of children, is also a spark that triggers the curiosity and wonder.

During the journey in science express I experienced that in many part of country scientific knowledge amongst the public is not very strong. In many cases traditional knowledge or superstitions dominate, leading to many misconceptions. In this case astronomy can play a key role in addressing this often sensitive relationship between traditional and scientific knowledge systems. Astronomy is often a very interesting topic of conversation and an easy way to start a gradual process of introducing a person to modern understanding of the Universe. By bringing to the public the things we know about the Universe and more importantly, how we know them ( technologies employed, scientific method, etc ), we can spread knowledge of science and technology.

I stress, that the conversation must go both the ways, and an acknowledgement of indigenous knowledge is important and essential in building the relationship and pride of a people. Indigenous astronomical knowledge in India, such as how farmer use constellation and position of sun for harvesting, or mathematical calculation of planets, moon, and sun in Panchang.

In India, many state board education syllabuses either astronomy subject is not included or omitted from from it, therefore understanding of this subject in the school student is very less, so we designed our programs according to need of students.

Our astronomy programs included planetarium show and lectures during day time and during day time & during night time we conduct telescopic observation sessions. I still do this activity on train. Till today more than 45000 students have already participated in this activity. This program is not restricted to the students, we also took this program to the central jails, army camps and many villages. Our aims are as below.

1. Enhance the interest of astronomy among school children.

2. Enhance the practical knowledge of astronomy in university students.

3. Increase the awareness and knowledge of astronomy amongst the people.

Having said this, one may still ask the question "Why are you doing this? Do you really believe that looking at the stars can make a difference to a person living a hard life in India?"

My response is simple. I believe that it, because I've experienced it!

I worked with some of the poorest schools and communities in India I've seen the wonder on a child's face when they look through a telescope for the first time. I've watched youth change their career plans after a long conversation about the Universe - and I've seen the naughty ones stop their games and listen. I've seen the smiles on wrinkled faces as they grasp the mechanism of eclipses for the first time after long lives of fear and misconception.

I've seen people smile peacefully when presented with a view of the earth from space - an earth with no boarders, no nationalities, no wars or anger - simply a little blue planet, a part of the Universe - with life, life that belongs to the Earth as much as the Earth belongs to it! Astronomy is a powerful tool. It is some thing that can alter one's perception of the Universe. It can make one realize how fragile our lives are!Above all, astronomy is a subject that makes one think. It broadens the minds and allows us to appreciate different perspectives - to appreciate the diversity of people and of life - and it is certainly something that is to be celebrated by everyone.

AMOL KATE

Annular Experience

I had been to the Dhanushkodi on 15 January 2010 for observing annular solar eclipse. Dhanushkodi is small village of fishermen nearly 17 kilometer away from Rameshwaram in Tanil Nadu. Dhanushkodi was only place in India, which lies in the central line of eclipse where the Moon passed directly in front the Sun, leaving a ring of fire hanging in the afternoon sky for 10 minutes and 11 seconds. It was an awesome experience seeing such eclipse. Last annular eclipse was seen from Srinagar, Siliguri and Agartala on 23 November 1965 and will not be seen again from India until 2019.

An eclipse of the Sun is caused when the Moon comes in between the Earth and the Sun so that the shadow of the Moon sweeps across the surface of the Earth. This shadow consist of two parts, the umbra or total shadow, a cone in which no direct sunlight penetrates and the penumbra, or half shadow, which is reached by the light from some parts of the Sun's luminous disk. To an observer within the penumbra; the Sun's disk will appear to be partially covered.
From the above, it will be understood that a solar eclipse can occur only at new moon when the Moon is conjuction with the Sun. Had the plane of the Moon,s orbit around the Earth coincided with ecliptic ( that is the plane of the Earth's orbit around the Sun ), an eclipse of the Sun would have taken place at every new moon's orbit is inclined by about five degrees to the ecliptic and it is only at those times when the Moon happens to be at or near one of the Moon and the Earth are nearly in the same line and a solar eclipse can occur at other times the shadow of the Moon just disappears into space.

The kind of eclipse that will result, total or anular, is governed by the fact that orbit of the Moon around the Earth is not perfectly circular but is elliptical, with the result that the Moon is sometimes nearer to the Earth than at other times. When the Moon in is orbit is nearest to the Earth, this phenomenon is known as perigee, and when it is farthest from the Earth, it is known as apogee. The distance of the Moon from earth at perigee is 3,63,300 km and at apogee is 4,05,500 km. As the distance from the Earth to the Moon varies, so does the apparent size of the Moon in our skies. When it is closest, it appears larger in the sky than the Sun and can completely obscure the solar disk, but when it is at its farthest point, it smallest is not enough to cover the disk of the Sun.

In an annular solar eclipse the umbra of shadow cannot reach the EArth, instead a third type of shadow is born; the antumbral, or negative shadow. An annular solar eclipse is visible where the antumbral sweeps across the Earth's surface; this is known as the path of annularity. From within this region, the Moon's dark is centered on the Sun but unable to obscured all its light, leaving a brilliant ring of fire, or "annulus" of light, around the edge of the Moon in the sky. Unfortunately, the Sun's chromosphere and corona, which are visible during a total solar eclipse, are lost in the glare of of an annular eclipse and as such no scientific investigational work, as is carried out during a total solar eclipse is possible during an annular eclipse. But, of course this type of eclipse has its own beauty. I missed first contact of moon and sun, but observed annular phase and able to take some photographs.

There are so many misconceptions about solar eclipse, that we should not eat anything, should not stay outside during eclipse and not to see eclipse. Many people think it is bad omen. But I tell you one thing that solar eclipse is not visible from most planets in the solar system. We are so lucky in that case because nature already has made special arrangement for us, so that we could enjoy this shadow play. It is so happens that disk of the Sun is 400 times larger than that of the Moon and that coincidently the distance of the Sun from the Earth is about 400 times the distance of the Moon from the Earth, so that Sun and Moon have nearly equal angulur diameter of 0.5 degree. Thus, our Moon is just the right size to cover the bright disk of the Sun and cause a solar eclipse.

First, I thought that may be I was the only person from my group who was observing his first annular solar eclipse but, then I came to know that every one from my group were seeing the annular eclipse for first time. That's why we distributed chocolates among us to celebrate our first annular eclipse.

Why Pluto is not planet?

The recent declassification of Pluto from being a planet had made a lot of news. Many people ask me about Pluto ' Why astronomers discard Pluto from planet status?' Actually there was no specific definition for planet before this.

For thousands of years people have observed bright objects in the sky that moved in certain paths against the background of fixed stars, but very little was known about them. In fact the name "planet" given to these, comes from the Greek word for "wanderer". The five planets Mercury, Venus, Mars, Jupiter & Saturn could be seen with naked eye from the Earth & were known since antiquity. On the other hand, Uranus, Neptune & Pluto are objects discovered comparatively recently & were also classified as planets. But, today, hosts of newly discovered large objects in the outer regions of our solar system present a challenge to our definition of a "planet".

Making use of the currently available scientific information the International Astronomical Union (IAU), on August 24, 2006, agreed that a "planet" is defined as a celestial body that

1. is in orbit around the Sun.

2. has sufficient mass for its self gravity to overcome rigid body force so that it maintains a hydrostatic equilibrium (leading to nearly round shape). and

3. has cleared the neighbourhood around its orbit (meaning that there are no other bodies of comparable size other than its own satellites or those otherwise under its own gravitational influence.)

Pluto failed the third condition because it shares its orbital neighbourhood with Kuiper Belt objects such as the Plutinos. Moreover, Pluto & its satellite Charon have their center of gravity lying outside the Pluto. Hence it is not qualified to be a planet. But astronomers classified Pluto as "Dwarf Planet". A non satellite body fulfilling only the first two of criteria is classified as a "Dwarf Planet". Other two members of the dwarf planet category are Ceres & Eris.

Now the solar system consists of eight "planets". Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus & Neptune orbiting in that order of their distances around our star the Sun.

Some astronomers have their strong opinion for Pluto as a planet. I don't know whatever happened with Pluto is right or wrong. But, now at least we can classified Solar System objects with more scientific manner which necessary to understand our planetary system.

AK

Naked Eye Astronomy

One evening back at the end of 1996, my father came to home from work and said to me and my little sister "Let's go outside, I have something to show you." He took me and my sister to one small hill near to our home. From there he pointed towards the west horizon in the sky "That's it! Can you see that? It is a comet!" "A comet!" I had no idea what was comet? But that was my first look at the sky and from then I started looking upward.

I always wondered about the sky. I looked up at the huge number of stars and tried to find a constellation but get lost when I tried to connect the dots. I was eager to know about stars. Then once I found article in newspaper on current month sky with map, from that map I almost identified all major constellations of that month. Then by sky maps and star finder charts I have practiced naked eye astronomy for seven years.

Without any optical aid at all, you can observe a wide range of phenomenon in the sky. You can see the large dark areas on the Moon that are now known as to have resulted from large object crashing into it almost 4 billion years ago. So, easy are they to make out that they have given rise to legends about there being a man, or a hare in the Moon.

You can follow the nightly wondering of five of the planets, and from one place on the Earth or another you can spot the 88 constellations - the traditional star patterns. You can watch certain stars - the variables - alter in brightness over the course of days, week or months. You can see star clusters like the Pleiades in Taurus and gas clouds like Great Nebula in Orion. If the night is quit dark, the vast expanse of our own galaxy, the Milky Way, will be visible winding across the sky.

There are also artificial satellite to be seen, and showers of any meteors, If you go far enough north or south, can enjoy the fabulous fireworks display of the northern and southern lights.

When you start sky watching for the first time, it is best not to rush outdoors to begin learning the constellations as they are plotted on the star finder chart.

For beginner, the sky is a great spur of imagination. On your first night out, try connecting stars to make your own patterns and figures. Let your mind roam. It should be fun and you are unlikely to forget the position of the star in your personal constellations. By doing this, you will start sky watching in an entertaining and memorable way. And you will find the sky is really amazing with your eyes.

Amol Kate

Hello friends

Hello friends,
This is Amol Kate. I am amature astronomer. Currently working as a Science Communicator in the Vikram A. Sarabhai Community Science Center, Ahmedabad. Astronomy is not only my passion but also it is oxygen for me. So, I decide to open my desk in this web world to get connected with other astronomers and amatures from worldwide. Apart from this I want to share my thoughts and you can also share your thoughts with me on this subject. So, my friends you all are invited to my blogspot.
Friendly,
Amol Kate