Monday, 22 July 2013
Monthly Science Feature with Science Correspondent Sam Rolfe
Sam Rolfe our science correspondent was tonights guest on Drivetime tonight, here is what Sam told us about;
The world is being asked to look up on Friday and smile in the direction of the ringed planet, Saturn.
The Cassini probe, in orbit around the gas giant, is going to take a picture of Earth, and the imaging team wants everyone to wave and smile.
Because of the great distance to Saturn, our home will appear as a mere pixel in the final photo.
But Cassini scientist Carolyn Porco says it is a moment to "celebrate life on the Pale Blue Dot".
"Waving time" - the period when the spacecraft's cameras will be operating - starts at 21:27 GMT and ends at 21:42 GMT (22:27-22:42 BST).
These timings include the 80 minutes it will take reflected light from the surface of the Earth to travel the nearly 1.5 billion km (900 million miles) to reach the outer Solar System.
Dr Porco's Ciclops imaging team will be producing a large mosaic of Saturn and its ring system on Friday.
Earth will appear as small speck in the lower-right of the final picture.
It is likely to be several days before the first images are processed and released.
The probe snapped a similar mosaic in 2006. On that occasion, Earth was positioned in the upper-left of the frame.
But Dr Porco says the set-up six years ago was not ideal. For the re-shoot, she plans to use Cassini's highest resolution camera, and the most appropriate filters to capture Earth in natural colour.
More than that, however, she says, people on Earth will know this time they are on camera, and that offers everyone the opportunity to participate.
Dr Porco hopes the picture will be reminiscent of the famous "Pale Blue Dot" image captured by the Voyager-1 probe in 1990.
That was a picture she helped organise with the astronomer and popular science writer Carl Sagan.
He memorably described the Earth as looking like a "mote of dust suspended in a sunbeam", such was its apparent insignificance in the vastness of space.
Inspired in part by the Cassini team's plans, scientists working on the Messenger probe at Mercury will also be picturing Earth on Friday and Saturday.
Messenger will see Earth as it scans the skies for any previously unrecognised objects that might be circling the innermost world.
Timings for these pictures are 11:49, 12:38, and 13:41 (all GMT) on both Friday and Saturday.
Parts of the Earth not illuminated in the Cassini images, including all of Europe, the Middle East and Central Asia, will appear illuminated in the Messenger pictures.
The Perseid meteor shower is perhaps the most beloved meteor shower of the year for the Northern Hemisphere. The shower builds gradually to a peak, often produces 50 to 100 meteors per hour in a dark sky at the peak, and, for us in the Northern Hemisphere, this shower comes when the weather is warm. The Perseids tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn. They radiate from a point in the constellation Perseus the Hero, but, as with all meteor shower radiant points, you don’t need to know Perseus to watch the shower; instead, the meteors appear in all parts of the sky. They are typically fast and bright meteors. They frequently leave persistent trains. Every year, you can look for the Perseids around August 10-13. They combine with the Delta Aquarid shower (above) to produce the year’s most dazzling display of shooting stars. In 2013, the Perseid meteors will streak across the short summer nights – August 10-13 – from late night until dawn, with little to no interference from the waxing crescent moon. Plus the moon will be near the planet Saturn in the evening hours, giving a colorful prelude to late-night Perseid show. Best mornings to look: August 11, 12 and 13.