Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 327 & 328: Suddenly Bright & The Heat is On
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s two stories:
- An example that a relatively large space rock can approach the Earth suddenly started with what appeared as a bright star moving across the images that I had just obtained with the Catalina Sky Survey’s 60 inch telescope on Mt. Lemmon, Arizona. It was about 100 times brighter than most of Earth approaching objects asteroid hunters discover. Over the next 64 hours it was tracked by 45 different observatories around the globe. This previously unknown space rock, now named 2017 AG5, is approximately 370 feet in diameter and can come closer than the Moon’s distance to us.
- The National Oceanic and Atmospheric Administration has published an extensive data based review, analysis, and summary of the Earth’s Climate. 2016 was hotter than 2015 which was hotter than 2014. 2016 is the warmest year the Earth has been in the more than 180 years of record keeping. Overall in 2016 the whole Earth was 1.8 F above the 1951-1980 average. The Arctic in 2016 was 7.2F higher than it was the pre-industrial age.
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:
Ep. 327: Suddenly Bright
Music An example that a relatively large space rock can approach the Earth suddenly, started with what appeared as a bright star moving across the images that I had just obtained with the Catalina Sky Survey’s 60-inch telescope on Mount Lemmon, Arizona. It was about 100 times brighter than most of the Earth-approaching objects asteroid hunters discover. Over the next 64 hours, it was tracked by 45 different observatories around the globe.
This previously unknown space rock, now named 2017 AG5, is approximately 370 feet in diameter and can come closer than the Moon’s distance to us. All asteroids are half-illuminated with the lighted side towards the Sun. 2017 AG5 was able to sneak up on the Earth from the direction of the Sun with its illuminated side pointing mostly away from us.
This geometry caused it to brighten more than 250 times in 9 days as it crossed the Earth’s orbit and started pointing its illuminated side towards us. When I spotted it, 6 days after it was closest to planet Earth, it was already moving away from us. On most of its trips around the Sun, it does not come anywhere near the Earth and is invisible to us.
During the next 136 years, it will make 19 close approaches to Earth, 5 to Mars and 1 to our Moon. When it makes a close approach to Earth, it is visible to our current telescopes for about 60 days out of its 571-day orbital path around the Sun. Fortunately, 2017 AG5 is not on an impact trajectory with planet Earth.
Ep. 328: The Heat is On
. The National Oceanic and Atmospheric Administration has published an extensive data-based review, analysis and summary of the Earth’s climate.
2016 was hotter than 2015, which was hotter than 2014. 2016 is the warmest year the Earth has been in the more than 180 years of record-keeping. Overall in 2016, the whole Earth was 1.8 degrees Fahrenheit above the 1951 to 1980 average.
The Arctic in 2016 was 7.2 degrees Fahrenheit higher than it was in the pre-industrial age. The average extent of Arctic sea ice in 2016 has shrunk by 400,000 square miles while the Antarctic sea ice in 2016 has been reduced by 970,000 square miles compared to the respective averages for the years 1981 to 2010. Natural factors such as volcanoes, solar changes, variations in the Earth’s orbit and El Niño accounted for about 10% of the 2016 warming.
The rest, 90%, were due to human activity, particularly the release of carbon dioxide into the atmosphere. The future is much harder to predict than it is to make physical measurements of past and present temperatures. The Earth’s climate is chaotic in the sense that small changes in temperature can initiate events which produce large changes in the environment. This is no time to cut back on making measurements of our home planet from space and on the ground.
For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org program 328 for more information.
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365 Days of Astronomy
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