September 28, 2012
Transit Of Venus Videos Unveiled At Planetary Science Event
Lee Rannals for redOrbit.com — Your Universe Online
[ Watch the Video: New Transit of Venus 2012 Movie ]
[ Watch the Video: Transit of Venus 2012 From Svalbard and Canberra ]
New movies of the transit of Venus that took place earlier this year clearly show the parallax effect that makes the event so important to scientists.
Astronomers compressed six hours of observations and 5,000 individual images taken by optical and solar telescopes into a 40 second video.
The observations were taken from Svalbard in Norway and Canberra in Australia, which are separated by 7,200 miles.
When images from the two locations are superimposed, scientists were able to see the parallax effect, which first allowed astronomers to measure the distance between the Earth and the Sun.
The parallax effect is when the transit is viewed from widely separated points on the Earth's surface. Venus appears to follow a different path in front of the Sun's disc. Precise observations using this technique during the duration of the transit means that the distance to Venus and to the Sun can be calculated through triangulation.
“During the hours of the transit we were delighted by the slow, delicate, gracious passage of Venus in front of the Sun," Miguel PÃ©rez AyÃºcar, one of the observers on the project, said in a statement. "A perfect black circle, containing a world in it, moving in front of its looming parent star. How thankful we were to witness it. Now with these movies, we can share a sense of that experience.”
Michel Breitfellner, who also worked on the project, said that in the 18th century, people realized that transits of Venus could be used to measure the distance from Earth to the Sun.
"Teams of astronomers were sent all across the world to measure this effect," Breitfellner said in the statement. "The 2012 transit has its own historical importance - it is the first that has occurred when a spacecraft is in orbit at Venus. Science teams are now working to compare observations of the Venus transit from Earth with simultaneous observations from Venus Express.”
Colin Wilson, Operations Scientist for Venus Express, said planetary transits do not only have historical significance, but have acquired a new importance in discovering planets around other stars.
"Because we cannot image exoplanets directly, it is only by studying their transits that we can discover whether they harbor liquid water or other potential ℠biomarker´ molecules like methane or ozone," Wilson said in the statement.
He said the transit of Venus offers scientists a chance to test their understanding of how to interpret transit data.
"This certainly added extra interest as we watched the Venus transit in June - particularly knowing it was our last chance that we´d have to wait until 2117 to see the next one," Wilson said.
The researchers presented their work at the European Planetary Science Congress.