Transit of Venus on this 6th June will be a unique celestial treat
Demonstrating special protective Solar filter eyewear
Ahmedabad, 30 May 2012
The Transit of Venus this year on 6th June 2012, is going to be among the rarest astronomical phenomena and won’t happen again until the year 2117. Only seven such rare events have occurred since the invention of the telescope in 1608.
“The transit or passage of a planet across the face of the Sun is a relatively rare occurrence. As seen from Earth, only transits of Mercury and Venus are possible. On average, there are 13 transits of Mercury each century. In contrast, transits of Venus occur in pairs with more than a century separating each pair” said Ravi S. Saxena, Additional Chief Secretary, Science & Technology Dept., Govt. of Gujarat, while explaining the phenomenon at Gujarat Science City.
“6th June 2012 is going to be our date for rendezvous with Venus. The next transit would take place only after a long gap of 105.5 years. What is more, this is an historical scientific event that helped measure the distance of earth from the sun, and consequently of all the planets. This transit is special because it is the last time in our lifetimes that we will have an opportunity to collect data for a planet as well characterized as Venus” Mr Ravi Saxena explained.
Scientific Significance: Venus Transit has continued to yield fascinating new information for scientists and the public. “The unique astronomical event has a lot of potential for science education, from elementary to college level. Various educational projects are being initiated that will increase students’ understanding of the solar system and the historical development of scientific knowledge, as well as open up their horizons to today’s scientific frontiers” Mr Saxena added.
Safe viewing Venus Transit
“One can experience the transit of Venus safely, but it is vital that to protect eyes at all times with the proper solar filters. Care must be taken to follow safety procedures for safe viewing of Venus Transit. No matter what recommended technique you may use, do not stare continuously at the Sun. Take breaks and give your eyes a rest!
Do not use sunglasses: they don’t offer your eyes sufficient protection” Informed Dr Narottam Sahoo, Sr. Scientist, Gujarat Science City & Advisor, GUJCOST
In order to popularize the astronomy and this unique celestial event across the state, Gujarat Council on Science & Technology (GUJCOST) has designed and developed a series of activities and outreach materials on Transit of Venus for the students, teachers and the community members. This include a unique activity kit with 25 hands-on activities to be conducted during the transit time, a booklet, and informative film depicting the significance of the transit of Venus with its genesis and safe observation practices have been developed in Gujarati language for the mass awareness and further dissemination. State level training workshops has been organized to train local resource persons to guide the students and common public for safe viewing of Venus Transit. GUJCOST through its Community Science Centers and Science Club networks is coordinating a variety of outreach programmes for Venus Transit.
Gujarat Science City in association with Vigyan Prasar has also prepared an activity kit for a country-wide campaign through thousands of science club as well as common people. About 15,000 activity kits and 1000 modular telescope have been fabricated and distributed across the country through VIPNET Science Clubs and State S&T Councils.
BACKGROUND NOTE : It’s a twice in a lifetime moment!
We all are well acquainted with solar or lunar eclipse. Like solar and lunar eclipses, sometimes, the inner planets come in between our Sun and Earth by the way of their orbiting. This is called as transit of planets. The Transit of Venus is a type of eclipse, where the planet Venus traverses the face of the Sun. Scientists has used measurements of transits to work out astronomical data. In contrast to Sun-Moon eclipses, this Sun-Venus eclipse is barely noticeable, because Venus appears only as a small black dot on the Sun, instead of turning day into night.
Earth’s closest planetary neighbour, which is currently in close and spectacular alignment with Jupiter in the night sky, will make its passage across the Sun’s disc on 6 June and can be expected to make scientific headlines – for astronomers hope studies of the transit will provide them with key data for studying worlds that orbit distant stars.
On 6th June 2012, we will see the planet Venus as it moves across the face of the early morning sun. This astronomical oddity has played a very important role over the last few centuries in giving scientists a way to understand the size of the solar system.
The Earth only crosses the plane of Venus’s orbit twice a year, in June and December, due to the angle between the two planets’ orbits. A transit doesn’t occur every six months because both planets need to be lined up exactly, and Venus’s orbit around the Sun (its year) is shorter than the Earth’s (224.7 days compared to 365.3). Venus transits occur in pairs with an intervening gap of eight years and intervals of 121.5 and 105.5 years between the pairs of transits.
Sometimes only one of the transit pairs can be observed, because Venus appears to be slightly above or under the solar disc on the other pass. This happened in the 14th Century and it will happen in December 3089. Overlooking these exceedingly rare events, Venus transits occur in two pairs every 243 years (121.5 + 8 + 105.5 +8 = 243).
A transit is a great opportunity for the public concurrently to study the sun, which influences life on earth on both a planetary and a personal scale. A dynamic between the sun and earth sustains life here, while our personal lives – which are becoming more technology dependent – are impacted by the sun’s shenanigans.
For over 100 years the main quest of astronomers was to pin down the distance between Earth and Sun (the Astronomical Unit), which would give them a key to the size of the solar system. Careful studies of the transit of Venus become the gold mine they would harvest to reveal this measure. This event will not occur again until 2117.
Nevertheless studies of the planet, and its rare transits, have provided scientists with crucial scientific data and June’s event will be no exception. In particular, astronomers will use it to test techniques they are developing to study the atmospheres of exoplanets – worlds that orbit other suns – and to spot those that possess life-supporting gases such as oxygen and water vapour.
In the past few years, the study of exoplanets has gone through a revolution with the launch of spacecraft such as the US observatory Kepler. Its telescopes spot tiny falls in light emissions of stars that occur when a planet passes in front of it. Just as the transit of Venus causes a slight dimming of the Sun’s light, so an exoplanet reveals its presence when it transits a distant star.
That drop in light provides key data about an exoplanet’s size and orbit. However, scientists want to build orbiting observatories that will study tiny changes in the light of a star as it passes through the atmosphere of an orbiting exoplanet. These changes will allow them to assess the composition of that exoplanet’s atmosphere and make estimates of surface conditions. Does it have a thick crushing atmosphere or does it possess only thin levels of gas and is therefore unlikely to support life? Does it contain oxygen or does it have poisonous gases? And that is where the transit of Venus should provide crucial data for further exploration.
Venus Transit in history
As defined, transit of Venus occurs when the planet and Earth, whose paths round the Sun tilt at slightly different angles, line up exactly where their orbits cross. This occurs only four times every 243 years, in pairs separated by eight years. Only six transits of Venus are known to have been observed (though claims are made for earlier observations by Persian astronomers) with the last, in 2004, watched by millions who used telescopes to project images of the Sun’s disc and the dot of Venus on to cards or electronic monitors. After this year’s, the next will be in 2117 and then 2125.
The first transit of Venus was predicted by Johannes Kepler who calculated one would occur in 1631. However, this was not visible from Europe. The next one occurred on 4 December 1639 when Jeremiah Horrocks became the first person to watch a transit of Venus when he shone an image of the Sun on to a piece of white card and was rewarded, around 3.15pm, with the sight of the black dot of the planet crawling across the solar disc. From his observations, Horrocks used triangulation techniques to make the best estimate then attempted for the size of Venus and the distance of the Earth from the Sun, though in the latter case he was still out by many millions of miles.
The next pair of transits – 1761 and 1769 – got a lot more attention. Expeditions were sent across the globe, including Captain James Cook’s first expedition. He visited Tahiti to observe the transit, from a place that is still known as Point Venus. The aim of these various voyages was to collect as many readings as possible from different parts of the world to calculate the size of the solar system with precision.
The expeditions pushed science and many scientists to the limit, the unluckiest being the French astronomer Guillaume Le Gentil, who set out from Paris in March 1760 but was still at sea on transit day, 6 June 1761. The rolling of his ship prevented him from taking observations. So Le Gentil decided to wait for the next transit in 1769 and built a small observatory in Pondicherry, a French colony in India, where he waited patiently for the next transit on 4 June 1769.
Determining the Astronomical Unit:
Based on the calculations of Nicolas Copernicus and Johannes Kepler, the distances of the known planets from the Sun could be given rather precisely in terms of the distance between Earth and Sun – known as the Astronomical Unit (AU). For example, Mercury was located at 0.39 AU, Venus was 0.72 AU, Mars was at 1.5 AU and Jupitor was at 5.2 AU from the Sun. But no one had an accurate measure of the distance from Earth to the sun in physical units such as kilometers, to the true physical size of the solar system was not very well known.
This event would offer science communicators a great opportunity to popularize astronomy, and address unscientific beliefs and superstitions associated with celestial events. Like earlier events like Total Solar Eclipses of 1995, 1999 and Venus of Transit of 2004, this would be an event in which students, teachers, general public, government and non-government organizations would be involved. We do hope you would be a part of this great celestial event.
So prepare now, and don’t miss out on this extremely special event!
For details:Dr. Narottam Sahoo
Sr. Scientist, Gujarat Science City & Advisor, GUJCOST
Dept of Science & Technology, Govt of Gujarat
Science City Road, Ahmedabad 380060, Gujarat, India
Chief Minister appeals to witness the Transit event
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