Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Cold Ocean in Giant Planet’s Satellite
Organization: Travelers in The Night
Link : Travelers in the Night
Description: Today’s 2 topics:
- Europa & Enceladus Ocean
- Enceladus Ocean
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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Transcript:
234 – Salty & Cold
There is increasing evidence that Jupiter’s moon Europa, Saturn’s moon Enceladus, and other bodies in our solar system have oceans of salty liquid water in contact with warm rock layers. We know that on Earth life abounds under these conditions around volcanic vents. Could such biodiversity be happening elsewhere?
Caltech’s Dr. Mike Brown and JPL’s Dr. Kevin Hand have used the giant Keck telescope on the island of Hawaii to obtain evidence that the surface of Europa contains chemicals from it’s subsurface ocean. These findings suggest that energy from Europa’s interior is warming its 60 mile deep ocean to the point that some material is being extruded from cracks and then deposited on it’s surface. These data have led Brown and Hand to hypothesize that the subsurface ocean on Europa contains sodium and potassium chlorides and may be very similar to the oceans here on planet Earth.
The fractured icy terrain on Europa containing sulfur and iron has led planetary scientists to similar analog sites on planet Earth. One of these is Blood Falls on the Taylor glacier in Antarctica where an iron rich spring creates a blood red frozen waterfall at the edge of the ice sheet. The other is Borup Fiord Pass on Ellesmere Island in the Canadian arctic. The sulfur-oxidizing and sulfur-metabolizing bacteria found there produce a bio-signature, which if present on Europa, could be read by an orbiting spacecraft. We need to get with it since climate change could eliminate these Earthly research sites in the next 20 years.
236 – Enceladus’s Ocean
Pound for pound Saturn’s moon Enceladus is the brightest object in our solar system. It is so shiny that it reflects most of the sunlight that strikes it. Since Enceladus absorbs little sunlight it’s surface is 330 degrees below zero Fahrenheit. Below its icy exterior the story is very different.
For almost two hundred years since William Hershel discovered Enceladus, little was known about this point of light orbiting the distant planet Saturn. The situation changed when the NASA Cassini spacecraft began to take pictures as it orbited the ringed planet. Scientists were amazed when Cassini images showed plumes of gas being ejected into space from Enceladus. In the past ten years a number of spacecraft flybys have been used to uncover evidence that it is likely that this icy moon has a layer of liquid water beneath its surface.
We know that on Earth life abounds near volcanic vents on the ocean floor. Could such a situation exist on Enceladus? This is a tough question to answer about an object whose diameter is about the width of the State of Arizona and never gets closer than about 3/4 of a billion miles from us. Recently Dr. Christopher Glein and his team of researchers used Cassini spacecraft observations to find some interesting clues about Enceladus’s oceans. Their data suggests that what is happening on this tiny moon of Saturn is similar to what we find near the low temperature hydrothermal vent field called the lost field in the Atlantic Ocean. What next.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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