Monday, 25 September 2017

Goodbye #Cassini mission, bats and heavy lifting, and #SotM Michele Dougherty with @smrolfe

A summary of the Radio Verulam West Herts Drivetime Science Feature broadcast 25/09/2017 5:30-6:00 pm BST

Goodbye Cassini

Michele Dougherty remembers the launch: "I thought, it's going to be exciting. I gave the impression I knew what I was doing but I didn't. When it finally happened [launched] and you're standing there and you're watching this thing go up, the ground shakes and you're standing there, thinking, I hope it's going to be OK, I hope it's going to be - and your heart is in your mouth. It really is."

What do we know now (only a small portion!)?
The rings: the Voyager probes did a fly-by of Saturn in 1980 and 1981, returning pictures that suggested there were around 10,000 rings, Cassini has returned data suggesting there are actually millions, with complex structures such as clumps, holes and gaps.

The rings are probably younger than previously expected - during the final orbits of the Cassini craft it passed between the rings and the upper atmosphere of Saturn and was able to take measurements of the rings to resolve this. If the rings are less massive than previously thought this means that they are younger, perhaps as young as 100 million years, and that means we are seeing Saturn at a special time, the rings as we know them weren't always like this, or may not have existed at all for large periods of the history of the Solar System.

Saturn and its rings

Cassini discovered 7 of Saturn's 62 known moons (Polydeuces, Pallene, Methone, Daphnis, Anthe, Aegaeon, S/2009 S 1)

Titan: The only moon with a substantial atmosphere. Discovered the first known 'rain' outside of the Earth - radar observations a few weeks apart showed methane showers had soaked the surface, but then evaporated. The Huygens lander took images showing networks of streams and rivers, leading into lakes and seas of liquid methane.

News in short: Bats collide with windows
Because bats did not evolve with smooth surfaces such as glass windows, their echo location doesn't work, they
don't receive the reflected signal and this can cause them to think it is a gap and fly into it. Imagine shining a
torch on to a mirror - you would only see the reflection if you are directly in front of it or very close to it.

News in short: Wearable sensors to help save your back
Pressure-sensing insoles were designed by scientists at the University of Quebec to monitor how participants distributed their weight when they lifted heavy items. This was combined with a hat-mounted accelerometer to track how they moved. An algorithm was able judge participant's posture correctly 95 % of the time and hence whether they were lifting correctly or incorrectly.

Sources: New Scientist magazine, 16th Sept 2017;

Scientist of the Month
Michele Dougherty

Michele Dougherty

Michele worked on the Cassini mission, as well as the Ulysses and Galileo missions.
Discovered the atmosphere around Enceledus!
For more on Michele's career please see:

Night Sky this month

Just passed through Autumn Equinox (22nd Sept), so nights are getting longer.

Orionids Meteor Shower, 21-22nd Oct, "The shower runs annually from October 2 to November 7. It peaks this year on the night of October 21 and the morning of October 22. The crescent moon will set early in the evening leaving dark skies for what should be a good show. Best viewing will be from a dark location after midnight." Approximately 20 meteors per hour at the peak, as a result of material left behind by Halley's comet.

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