Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Lost & New Asteroid
Organization: Travelers in The Night
Link : Travelers in the Night
Description: Today’s 2 topics:
- Our view of Mars has changed over the centuries. There may have been shallow lakes on Mars in the last few tens of millions of years.
- Jess Johnson of the Catalina Sky Survey, while observing on Mount Bigelow, discovered the hazardous NEO 2016 EE156.
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:
239 – Martian Lakes
It is likely that the first humans on Earth were aware of and had names for what we now call the planet Mars. They knew it as a light in the night sky which radically changed in position and brightness relative to the stars. When the telescope was invented observers on Earth saw Mars to be a small world similar to our own. When the first space craft photographed Mars close up it looked like our Moon and not very Earth like. The human view of Mars changed radically again when orbiters started sending back detailed images and robotic probes began to land on the red planet. Turns out that Mars has surface conditions somewhere between the Earth and our Moon. It appears that in the past the red planet was much more Earth like than it is now.
Recently Dr. Alexis Rodriguez of the Planetary Science Institute in Tucson, Arizona and his coauthors have published a paper in which they suggest that shallow lakes could have formed on Mars in the past few tens of millions years in a way similar to what occurs on the Tibetan plateau here on Earth. Dr. Rodriguez plans to followup this paper with an expedition to Tibet to explore land forms which appear very similar to what we observe on Mars. In particular he plans to visit the sediment ridges seen at the edges of Tibetan lakes since they are strikingly similar to what can be seen on high resolution images of the shore lines of ancient Martian lake beds.
The ancient lake sites which Dr. Rodriguez and his colleagues are studying on Mars are places were warm liquid ground water is likely to have been discharged for billions of years. These areas on the red planet have the right temperatures, liquid water, and nutrients to support life as we know it. They may be the best places to look for evidence for life on our neighbor Mars.
240 – Why
Recently my Catalina Sky Survey teammate Jess Johnson answered the question “Why do asteroid hunters go to the telescope?”. Jess was observing with the University of Arizona’s Schmidt telescope on Mt. Bigelow when a fast moving streak of light showed up in a set of his images. Over the next two days Jess’s new object was observed by telescopes in Arizona, New Mexico, England, France, Kansas, and Texas. The Minor Planet Center used these data to give it the name 2016 EE156, calculate its size, and plot it’s orbit around the Sun. Turns out that this object is exactly the type of dangerous asteroid that the United States Congress directed NASA to search for. One the size of 2016 EE156 impacts Earth every 440,000 years or so releasing the energy of 46,000 million tons of TNT producing a crater 8.5 miles in diameter. Such an event is likely to create global climate change on our home planet.
Fortunately, Jess’s object, 2016 EE156 will not strike Earth in the foreseeable future.
We now know about approximately 900 close approaching asteroids like 2016 EE156 and suspect that there are at least 100 more out there for us to find. It is these large ones that continue to motivate my Catalina Sky Survey team members to use our three telescopes 24 nights per month to search for objects that could pose a threat to humanity.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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