Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 611 & 612: Aurora Mysteries & Day and Night
Organization: Travelers in The Night
Description: Today’s 2 topics:
- Auroral displays contain a continuous pattern of shifting colors and shapes in the night sky following a geomagnetic storm.
- Ongoing research is revealing how changes in very low levels of light at night have positive and negative influences on chronic conditions like mood disorders, obesity, and cardiovascular problems.
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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611: Aurora Mysteries
Auroral displays contain a continuous pattern of shifting colors and shapes in the night sky following a geomagnetic storm. They have been observed and reported on throughout human history. These spectacular light shows are most often seen in far northern and southern regions of our planet. Auroras also make occasional appearances in the midlatitude regions where many of us live in some cases as far south as Key West, Florida and Mexico. Often these extended auroral displays are produced when a particularly energetic stream in the solar wind interacts with Earth’s magnetic field. The solar wind with a median speed of 250 mi/s streams around the Earth’s magnetic field creating a bow shock about 11 miles thick approximately 56,000 miles from the surface of our planet in the direction of the Sun.
On the Earth’s night side a magnetic field tail extends so far that the moon passes through it for 3 days either side of full moon each month. Turbulence in the solar wind as its moves around our magnetic shield causes pockets of energized plasma gas to accumulate over Earth’s night side. Some of these 2000 mile wide blobs of energized gas break free and fall towards Earth creating a beautiful string of 30 mile wide auroral beads which stretch across the sky right before a major auroral display begins. Data from NASA’s 5 Themis (Themm us) satellites analyzed by powerful supercomputers is giving us new insight into how our magnetic shield protects us from the harsh radiation of space and blobs of material ejected from the Sun as well as to how to protect the GPS satellites we have learned to rely upon.
612: Day and Night
Most life on Earth is synchronized to the regular cycles of day and night. The DNA in our cells has multiple clocks which regulate hormone secretion, digestion, sleep and metabolism. Ongoing research is revealing how changes in very low levels of light at night have positive and negative influences on chronic conditions like mood disorders, obesity, and cardiovascular problems. Further the
plants and animals which make human life on Earth possible also need a day/night cycle. Artificial light at night is a two edged sword enabling our everyday activities as well as creating serious safety and economic problems. Fortunately we don’t have to choose between necessary outdoor lighting and the problems it causes. We just need to act smarter. It will even save us money. To protect the night sky we simply need to put artificial light where we need it and not up into the sky where it causes the safety hazard of glare and obliterates an important part of our environment.
Studies have shown that public safety is enhanced not diminished by glare free light that shines where we can use it to move around and not up into the sky where it is wasted. Until about a hundred years ago, the natural night sky was familiar to all humans. Most people could identify a few constellations and had experienced walking by starlight. Now all but a few are denied the privilege of seeing the Milky Way or a meteor streaking across the sky. To gaze into a star filled sky and wonder about other life which may exist in the Universe is worth preserving for future generations. Visit cosmiccampground.org and the International Dark Sky Association at darksky.org
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365 Days of Astronomy
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