Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. Eps 175 & 176: Ganymede’s Layers & Deep Listen
Organization: Travelers in The Night
Description: Today’s 2 topics:
- Ganymede has an iron-rich core which creates a magnetic field
- Breakthrough Prize Foundation SETI projects.
Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona. This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.
He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.
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175E: Ganymede’s Layers
You can spot Ganymede orbiting the planet Jupiter with any backyard telescope. It is the largest of the four bright moons of Jupiter discovered by Galileo Galilei in 1610. In your telescope Ganymede will be the third farthest moon from Jupiter. This tiny point of light is really a small world composed of ice, water, and rock.
Ganymede has an iron-rich core which creates a magnetic field. This magnetic field causes Ganymede to have a northern and southern aurora similar to the northern and southern lights on Earth. Astronomers have used the Hubble Space Telescope to track these two aurorae’s motion on this distant world. These data enabled them to map the salt water ocean beneath Ganymede’s icy surface. What they found is an ocean 10 times deeper than exists on our own planet.
Recently a NASA funded a research project headed by Dr. Steve Vance at the Jet Propulsion Laboratory in Pasadena, California. He used computer models to calculate how water and ice become organized under the very high pressures in Ganymede’s ocean. This work indicates that below the icy surface there is likely to be a water ocean sandwiched between perhaps three layers of ice covering this moon’s rocky crust. This layered structure allows for the contact of salty water and warm rock layers. Could living things be using the water, nutrients, and energy source found in such a situation on Ganymede? We find rich colonies of organisms near volcanic vents on Earth’s ocean floor. Could something similar be happening on Ganymede?
176E: Deep Listen
There is a mind blowing potential for life in the Universe. Humanity’s ignorance of any life forms beyond Earth has prompted the Breakthrough Prize Foundation at the Royal Society in London to create a program to award 100 million dollars in grants to fund projects to search for signals from intelligent life.
A third of these grant funds will purchase twenty percent of the time on the football sized Green Bank Radio Telescope located in West Virginia as well as on the venerable Parkes Radio Dish in Australia. These two giant radio telescopes will be employed as a part of the most extensive search for intelligent life in the Universe ever attempted.
One third of the Breakthrough Prize Funds will go to giving these giant radio ears extremely new sensitive receivers and processing capability. This will enable them to sort through the radio signals that pass through the Earth’s atmosphere in channels which are not drowned out by the cosmic microwave background radiation. To cover the possibility that advanced civilizations no longer use radio waves for communication purposes the equipment is being designed to be sensitive to detect normal air-traffic control radar should it be emanating from planets orbiting a thousand of the nearest stars.
Identifying an intelligent whisper on one of the billions radio, optical, and infrared channels which could come from billions of locations in the sky is a formidable task. Humans may or may not have the patience for the length of time which could be necessary to find the this tiny needle in the cosmic haystack.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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