Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 221E & 222E: Tiny Visitor & Salty and Cold
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s two stroy:
- Asteroids are part of our environment. An SUV sized space rock has spent eons traveling through the silent vacuum of space. In the past 50 years, without humans being aware of its existence, it has made 29 close approaches to planet Earth and 11 visits to the vicinity our sister planet Venus. In the relatively near future asteroid hunters will be able to find more space rocks like this one before they impact Earth and thus be able to issue a warning for a space rock which is about to explode over a populated area.
- 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?
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:
221E – Tiny Visitor
An SUV sized space rock has spent eons traveling through the silent vacuum of space. In the past 50 years, without humans being aware of its existence, it has made 29 close approaches to planet Earth and 11 visits to the vicinity our sister planet Venus. In 2016 as it approached the Earth from the direction of the Sun this small asteroid got about 100 times brighter in 8 hours. Twenty three hours before my Catalina Sky Survey teammate Carson Fuls discovered this small space rock, it was about 3 times the Earth’s circumference from us. After Carson discovered it streaking through the night sky at 5.7 miles per second, this tiny asteroid was observed by telescopes in Arizona, France, New Mexico, and Pennsylvania and given the name 2016 DB.
There are likely to be more than 100 million asteroids the size of Carson’s discovery which make close approaches to us. One the size of 2016 DB enters the Earth’s atmosphere every 3 or 4 years, explodes 24 miles above our planet’s surface, and releases the energy of a small nuclear weapon. Currently the infrasound detectors designed to listen for nuclear explosions are able to detect and locate the point of impact of small space rocks. So far we have been able to detect only two of these impactors before they entered the Earth’s atmosphere. In the relatively near future asteroid hunters will be able to find more of them before impact and thus be able to issue a warning for a space rock which is about to explode over a populated area.
222E – Salty and 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.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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