Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Tiny Visitor & Fragment
Organization: Travelers in The Night
Link : Travelers in the Night
Description: Today’s 2 topics:
- Space rocks close approaches with Earth
- Left over of asteroid collision.
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:
233 – Tiny Object
An SUV sized space rock has spent eons traveling through the silent vacuum of space. In the past 50 years, without humans being aware of its existence, it has made 29 close approaches to planet Earth and 11 visits to the vicinity our sister planet Venus. In 2016 as it approached the Earth from the direction of the Sun this small asteroid got about 100 times brighter in 8 hours. Twenty three hours before my Catalina Sky Survey teammate Carson Fuls discovered this small space rock, it was about 3 times the Earth’s circumference from us. After Carson discovered it streaking through the night sky at 5.7 miles per second, this tiny asteroid was observed by telescopes in Arizona, France, New Mexico, and Pennsylvania and given the name 2016 DB.
There are likely to be more than 100 million asteroids the size of Carson’s discovery which make close approaches to us. One the size of 2016 DB enters the Earth’s atmosphere every 3 or 4 years, explodes 24 miles above our planet’s surface, and releases the energy of a small nuclear weapon. Currently the infrasound detectors designed to listen for nuclear explosions are able to detect and locate the point of impact of small space rocks. So far we have been able to detect only two of these impactors before they entered the Earth’s atmosphere. In the relatively near future asteroid hunters will be able to find more of them before impact and thus be able to issue a warning for a space rock which is about to explode over a populated area.
235 – Fragment
Millions of years ago two large asteroids collided in the asteroid belt. Pieces were sent flying in all directions. A few of them were put into orbits which rise high above and below the plane of the solar system as they continued to travel around the Sun.
Recently my Catalina Sky Survey teammate Richard Kowalski discovered one such a fragment. He was observing with a 60 inch telescope on Mt. Lemmon in Arizona when a fast unknown moving point of light appeared on a set of his images. Over the next six nights this new object was tracked by telescopes in Arizona and Texas.
Scientists at the Minor Planet Center used these data to determine it’s orbit, estimate it’s size, and give it the name 2016 DP.
Richard’s new Earth approaching asteroid, 2016 DP, is about a quarter of a mile in diameter, orbits the Sun once every 377 days, and can come to about 13 times the Moon’s distance from us. It is categorized as a Potentially Hazardous Asteroid which means that asteroid hunters will need to keep special track of it. In 1943 Richard’s large space rock came much closer to Earth than it did in 2016 when he discovered it. In 2062, 2016 DP, will come much closer to our sister planet Venus than it ever does to Earth.
Fortunately 2016 DP will not strike the Earth anytime soon. It will continue to orbit the Sun in the silent vacuum of space until it has a collision with another asteroid or comet in the far distant future.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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