Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 193E & 194E: Toy Asteroid & Stealthy Asteroids
Organization: Travelers in The Night
Description: Today’s two stroy:
- Imagine an asteroid small enough to fit under a basketball hoop traveling through space, making visits to Earth, our Moon, and Mars. I discovered 2015 WP2!
- The NASA NEOWISE satellite has the ability to spot asteroids by their thermal infrared glow. These data provide an independent method to measure an asteroid’s size.
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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193E: Toy Asteroid
Imagine an asteroid small enough to fit under a basketball hoop traveling through space, making visits to Earth, our Moon, and Mars.
Forty Eight hours before I first observed it, this small space rock, 2015 WP2, was completely invisible to humans and was approaching the Earth from the direction of the Sun at a speed of 7.9 miles/second. Twenty five hours before it appeared on my discovery images this tiny asteroid was at its closest , approximately 140,000 miles from us. At the time of its discovery, 2015 WP2 had made a close approach to our moon and was continuing to move away, about 4 times the Moon’s distance from planet Earth. Forty hours later it was once again to faint for asteroid hunters to detect it.
2015 WP2 will make close approaches to the planet Mars in 2022, 2046, 2067, and 2089. It will come very close to planet Earth and our Moon in 2058. It appears that it will not collide with any large bodies for the foreseeable future.
If 2015 WP2 had been an impactor it was bright enough to be detected 28 hours before it would have collided with planet Earth. It is a tribute to the Catalina Sky Survey’s equipment and computer software that humans can detect a tiny space rock 3/4 of a million miles away.
194E: Stealthy Asteroid
In everyday life you can’t see an infrared glow but you can feel it with your hands when you face them towards a hot object.
In the colors of visible light asteroids shine by reflected sunlight. Dark asteroids are dim in visible light, however, they glow brightly in thermal or heat radiation images.
The NASA NEOWISE satellite has the ability to spot asteroids by their thermal infrared glow. These data provide an independent method to measure an asteroid’s size.
Dr. Carrie Nugent, a NASA NEOWISE scientist points out “NEOWISE tends to find large, dark asteroids. When I say large, I mean asteroids hundreds meters across, or asteroids about the size of Disneyland. And when I say dark, I mean asteroids that reflect less than 10% of the sunlight striking them. Some of these asteroids are as dark as black ink.”
Recently the NEOWISE discovered a family of dark asteroids which were created by one of the last great collisions in the solar system some 700,000 million years ago. This family of stealthy asteroids soar high above the plane of the solar system between Mars and Jupiter. Over the eons these asteroids are subject to a gentle nudging by the planet Saturn causing some of them to be placed on an Earth approaching orbit. We don’t know for sure how many more of these dark stealthy Earth approaching asteroids are out there. Asteroid hunters continue to use NEOWISE’s infrared eyes to look for them so that one does not sneak up on planet Earth.
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