Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 637 & 638: Martian Dust & Methane
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s two stroy:
- Astronomers have postulated that the zodiacal light is produced by sunlight reflected by dust shed by comets and asteroids.
- Soon astronomers using the James Webb Space telescope will begin to look at the light from stars and the Earth like planets that orbit them.
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:
637: Martian Dust
After sunset in the spring and before sunrise in the fall, at a natural night sky location like the Cosmic Campground International Dark Sky Sanctuary in New Mexico, you will see a triangle of faint glow of light that extends from its broad base on the horizon to a point almost overhead. This phenomenon is called the zodiacal light or false dawn. Astronomers have postulated that the zodiacal light is produced by sunlight reflected by dust shed by comets and asteroids. Recently a team of astronomers led by Dr. J.L. Jorgensen of the National Space Institute of the Technical University of Denmark published a paper in the Journal of Geophysical Research which offers an alternate explanation.
This team of scientists were mystified by streaks of light in images from the Juno Spacecraft which left Earth in 2011, received a gravitational boost from Earth’s gravity in 2013, and arrived at Jupiter in 2016. Turns out that these phantom streaks of light were submillimeter pieces of Juno’s solar panels which were blasted loose by dust particles traveling at 10,000 mph. The more than 15,000 such events revealed a circular donut of dust extending from Earth’s orbit out to past the planet Mars. Earth sweeps up dust near it and Jupiter removes the dust further out giving the dust cloud a donut shape. Mars is the only object which matches the circular orbit of the dust donut which Juno found. Although this research team suspects that dust storms on the red planet are the source of the interplanetary dust they have no idea as to how the dust grains escape the martian gravity.
638: Methane
Imagine a space alien so far from us that the Earth appears to be a dim tiny point of light mixed in with the much much larger amount of radiation from our Sun. In ET’s technological society, a powerful tool splits the light from the Sun plus Earth into its component colors or wavelengths. After ET removes the light from the Sun it would be left with the pattern of colors which are present and missing from the Earth’s atmosphere. This pattern called a spectrum reveals the atoms and molecules which are present in our atmosphere. Soon astronomers using the James Webb Space telescope will begin to look at the light from stars and the Earth like planets that orbit them. The Earth did not have an oxygen atmosphere for a billion years so Oxygen might not be the key to finding life.
On the other hand there are natural sources of methane on Earth produced in wetlands, the oceans, and termite farts. This observation prompted a group of scientists led by Dr. Nicholas Wogan of the University of Washington to explore the possibility that a combination of methane and carbon dioxide could be produced by volcanoes. Their calculations, recently published in The Planetary Science Journal, indicate that it is very unlikely that volcanoes produce biological quantities of methane and carbon dioxide. Indeed if a volcano does produce methane it would be accompanied by carbon monoxide whose presence would signal a non biological origin. This work may point to a distant planet with living organisms on it. Stay tuned.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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