Horribly nerdy email to my school staff re: Transit of Venus
All,
As you would be aware, the transit of Venus is taking place on Wednesday. Please indulge my nerdiness as I give some information on its background, its significance and our viewing plans for the day.
BACKGROUND
A transit of Venus is when the planet Venus crosses the disc of the Sun. This is when the Earth and Venus are lined up perfectly in relation to the Sun. It is similar in theory to a solar eclipse, but it lasts much longer (6 hours) because Venus is much farther away than our Moon. For this reason too, we can’t notice any change in sunlight intensity, but through our Solarscopes we will clearly see the disc of Venus crossing the Sun.
It is a predictable but rare event. Transits of Venus occur in patterns that repeat every 243 years. They occur in pairs eight years apart (the last one was in 2004), and then longer periods elapse until the next pairing. The next transit of Venus will take place in 2117 - 105 years from now - which makes this a once in a lifetime event for all of us.
SIGNIFICANCE
As Level 3 have discovered, there is a historical link with Captain Cook. Cook’s first voyage was mainly concerned with making observations of the 1769 transit of Venus, which he made in Tahiti. He then opened the sealed orders which directed him to find the ‘great Southern land’.
Observations of the transit of Venus have resulted in great astronomical discoveries. For example, observations in the 18th century lead to estimations of the size of the solar system, by timing the transit from different positions on Earth and comparing the measurements. This year’s transit will be used by astronomers to provide further information when looking for exoplanets, or planets circling stars well beyond our solar system.
As far as the kids (and we) are concerned: the transit is a rare opportunity to appreciate and grasp the reality of our solar system and the way it works. It’s a very rare opportunity to witness an astronomical event during school hours.
VIEWING PLANS
We have two Solarscopes ready for use on Wednesday. These devices gather light from the Sun, which passes through a lens and a long tube. The light is then reflected on a mirror and projected onto a white card inside a dark box. This allows a number of kids to see an enlarged, projected image of the Sun, upon which features such as sunspots and the corona can be seen. When Venus moves across the sun, it will appear as a dark disc. The transit will begin at 8.16am on Wednesday (just as staff briefing begins) and will end around 2pm
Our plan is to set up both Solarscopes and keep them trained on the Sun during the transit. Level 4 kids will be making observations and taking photos of the image.
You are welcome to bring your Grade out to view the transit. If you have any specific time that will suit (working around Jump Rope For Heart activities), please let me know and I will note down your time. We are keen for every child to see the event, so I will send Grade 6 kids to collect you and your Grade.
In the case of partly cloudy weather, we may have to send for you as soon as the Sun comes out. You are most welcome to bring your kids for more viewing throughout the day, as they will notice Venus’ passage across the Sun.
Could you please take the time to remind your kids NEVER to look directly at the Sun; they will be able to see the transit very clearly through the Solarscope.
And if it is rainy/cloudy all day? You can view a live feed of the event via http://sunearthday.nasa.gov/2012/transit/webcast.php . It would be a great idea to have the live feed displayed on your interactive whiteboards.
Thanking you for your indulgence, and hoping for clear skies and a great opportunity for wonderment and awe for our kids on Wednesday.
Damian