Podcaster: Richard Drumm
Title: Space Scoop: Secrets of an Alien World
Organization: 365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1247/
Description: Space scoop, news for children.
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
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Transcript:
This is 365 Days of Astronomy. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Today’s story is:
Secrets of an Alien World
On January 14, 2005, the Huygens probe dove through the foggy skies of Titan, Saturn’s largest moon. It became the first and only probe to land on a world so far from Earth, which isn’t surprising considering it took over 7 years to get there!
Titan is one of the most Earth-like places in the Solar System. Like Earth, Titan has an atmosphere, but this atmosphere is much thicker and stretches higher into space than ours.
This foggy atmosphere covers Titan’s surface in a hazy orange blanket, hiding its secrets from our eyes. Huygens’ mission was to reveal these secrets and it did! It provided hundreds of images of Titan’s alien landscape!
Now, it is 11 years since that event, and scientists are still exploring this alien world using Huygens’ information as their eyes. It took 10 seconds from first impact until the probe bounced, slid and wobbled to a complete stop.
Scientists from the European Space Agency have created a computer simulation to show exactly what the landing would have looked like. It’s on YouTube. Just search for “Bouncing on Titan” and you’ll find it.
These few moments after impact have revealed new secrets about Titan’s surface. The way the Huygens probe moved when it landed initially caused scientists to think that there’s a thin layer of ice on the surface. Underneath that, it was thought that the ground is a lot like the wet sand we find on Earth’s beaches!
But the analysis has continued and the interpretation has changed a bit over the years.
The analysis reveals that, on first contact with Titan’s surface, Huygens dug a hole 12 cm deep, before bouncing out onto a flat surface.
The probe, tilted by about 10 degrees in the direction of motion, then slid 30–40 cm across the surface.
It slowed due to friction with the surface and, upon coming to its final resting place, wobbled back and forth five times, with each wobble about half as large as the previous one.
Huygens’ sensors continued to detect small vibrations for another two seconds, until motion subsided nearly 10 seconds after touchdown.
The probe’s touchdown disturbed the moon’s thin surface layer of organic aerosols which formed a small dusty cloud which settled out after 4 seconds.
Had the probe impacted a wet, mud-like substance, its instruments would have recorded a ‘splat’ with no further indication of bouncing or sliding.
The surface must have therefore been soft enough to allow the probe to make a hole, but hard enough to support Huygens rocking back and forth.
The latest analysis of the surface of Titan from the transmitted data suggest to the scientists that it’s a kind of sand that is made of grains of water ice.
The probe landed in one of the dark areas that had been thought from images taken during the parachute descent to be lakes of liquid hydrocarbons.
However, the images acquired after landing showed a flat lakebed covered in that ice grain sand and rounded ice pebbles. The pebbles range from 5cm to 15cm, or 2 to 6 inches in diameter.
It has also been determined that a small hydrocarbon lake was not far from the dry landing site. These oasis-like lakes may be fed by underground aquifers of liquid methane and ethane. Larger permanent lakes exist at Titan’s poles.
It appears that the Huygens probe hit a water ice pebble as it landed and drove it into the sub-surface ices. This had been suggested as early as April of 2005 by scientists from the Open University in Birmingham, England.
The rounded ice pebble shape suggests that there had been a liquid lake there in the past that had acted on the ice and had given the pebbles their shape.
Hey, Here’s A Cool Fact:
Titan is the second largest moon in the Solar System, bigger than our moon and even bigger than the planet Mercury. It’d make a nifty planet but not for the fact that it’s orbiting a planet and not the Sun. Oh well. You can’t win them all.
Thank you for listening to 365 Days of Astronomy!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!