Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: 327 & 328: Suddenly Bright & The Heat is On
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- Dr. Grauer himself discovered 2017 AG5. It was far brighter than any previous asteroid discoveries. This was because it was headed outbound from us and its sunlit side was visible.
- 2016 was the warmest year Earth has seen in living memory. Humans are the cause of 90% of the temperature rise. We must study the climate more, not less.
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.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2017, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.
Transcript:
327 – Suddenly Bright
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 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 it’s 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 it’s 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 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 it’s 571 day orbital path around the Sun.
Fortunately 2017 AG5 is not on a impact trajectory with planet Earth.
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 F above the 1951-1980 average. The Arctic in 2016 was 7.2F higher than it was 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 1981-2010. Natural factors such as volcanos, solar changes, variations in the Earth’s orbit, and El Nino 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 no time to cutback on making measurements of our home planet from space and on the ground.
End of podcast:
365 Days of Astronomy
=====================
The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!