Show notes
Programs 31-60Travelers in The NightProgramsContents 1 31-A Gentle Breakup Of An Asteroid 2 32-A Peanut Shaped Asteroid with a Moon 3 33-A Busy Month in the Earth's Neighborhood 4 34- Number 5000 5 35-An Asteroid With A Ring 6 36- Earth and Moon as Evening Stars 7 37-Slow Movers At The Edge of Our Solar System 8 38-The Big Ones 9 39-Dash Cams and the Anatomy of An Airburst 10 40-Itokawa A Strange Space Peanut 11 41-Navigating The Night Sky 12 42-Astronauts Reveal Sobering Data On Asteroid Impacts 13 43-First Earth-Size Planet in 'Habitable Zone' 14 44-A Unique Metal World; Asteroid Psyche 15 45-A World Full of Holes 16 46-How Far Is Forever 17 47-Earth Approaching Space Rocks Collected Over 6 Nights 18 48-Large Dangerous Asteroids Still Appear Suddenly Without Warning 19 49-Earth Approaching Wannabees 20 50-Asteroid 2014 JO25: What An Incredible Ride 21 51-Asteroid 2007 VK184 - Eliminated As An Impact Risk to Earth 22 52- Another Large Bright Suddenly Appearing Asteroid 23 53- Where Is Juno 24 54- Tour a Neighbor World 25 55-RADAR Telescopes Pair Up to Image Near-Earth Asteroid 26 56-A Whopper or A Comet 27 57-Hold A Traveler In The Night In Your Hand 28 58-NASA Hunts for A Special Asteroid 29 59-Spotting Travelers In The Night 30 60-A Close Visit With A Message31-A Gentle Breakup Of An AsteroidClick to ListenPublished PRX April 3, 2014Recorded March 21, 2014remixed July 15, 2014Newton formulated that the change in motion for an object depends on the amount of force and the length of time it is applied. For this reason a baseball pitcher tries to have a long pull on the ball before releasing it.Astronomers have a theory, called the Yorp effect, that light from the Sun produces a very tiny torque which increases the rate of spin of an object. The effect is so small that it would take billions of years to be produce a measurable outcome. How can such an idea ever be tested?In September of 2013, the Pan-STARRS group found a strange moving object in the night sky. The plot thickened when the Keck Telescope on Mauna Kea Hawaii found that instead of being a single body it appeared to be three small objects embedded in a cloud of gas and dust several thousands of miles in diameter. The Hubble Space Telescope was used to see what is going on.Hubble found that this object changes significantly over a period of months, that it has 6 tails, and that pieces of it continue to emerge from the center and slowly move away at a walking pace.An asteroid collision is too violent to cause what is seen. The object is too cold for expanding gases to cause it to break up. The best explanation which fits the data is that Sun light has slowly, over billions of years, increased P/2013 P5's rate of spin causing it to gently come apart. Some of the dust and small particles which escape from it will orbit the Sun. When the Earth runs into them we may see them as meteors in our night sky.For Travelers in the Night this is Dr. Al Grauer.Go to travelersinthenight.org for more information.© 2014 A. D. Grauer and ℗ 2014 A. D. GrauerMore Information On The Break Up Of An Asteroid32-A Peanut Shaped Asteroid with a MoonClick to ListenPublished PRX April 3, 2014Recorded March 29, 2014remixed July 15, 2014It appears that Hektor and its moon were created by a collision between two icy asteroids early in the 4.5 billion year history of our solar system when things were more chaotic. They happened to land in a gravitational dip which has allowed them to remain relatively undisturbed for billions of years.The asteroid Hektor orbits the Sun at a point where the gravity of the Sun and Jupiter create a stable point 60 degrees in front of the giant planet. In 1907 Hector was discovered as a moving point of light in the night sky. For the next 99 years its true nature remained unknown. In the past few years the Keck Telescope in Hawaii has discovered that the main body is a 230 mile long peanut shaped object. Most recently Keck was used to discover that Hektor has a 7.5 mile diameter moon which has a dense core surrounded by icy layers. This asteroid moon orbits the peanut shaped Hektor in a stable orbit every 3 hours.Recently, NASA scientists using the Goldstone Radar telescope were taking advantage of a close approach of a potentially hazardous asteroid to obtain radar images. These data show 2006 DP14 is a peanut shaped object about 1300 feet long. It slowly spins with a 6 hour period. Previous data from Goldstone and the Arecibo Observatory in Puerto Rico suggests that more than 10 % of near Earth asteroids larger than 650 feet in diameter have a peanut shape. This knowledge will be important if we find one of these strange objects is on a collision course with our planet.For Travelers in the Night this is Dr. Al Grauer.Go to travelersinthenight.org for more information.© 2014 A. D. Grauer and ℗ 2014 A. D. GrauerMore Information on This Program33-A Busy Month in the Earth's NeighborhoodClick to ListenPublished PRX April 10, 2014Recorded April 10, 2014remixed July 15, 2014For us who look for Earth approaching objects, March of 2014 was a busy month. Six asteroids which pass closer than our Moon were discovered and tracked. The smallest of them is the size of an SUV and the largest would fill an NBA basketball court. Fortunately none of them were on a collision course with Planet Earth.Interest in smaller space rocks has increased since a semitrailer truck sized asteroid entered the Earth's atmosphere over Russia in February of 2013. Most of the nearly 1500 injuries could have been avoided if people in the impact area had been warned to stay away from windows.In January of 2014 a refrigerator sized asteroid was discovered about 20 hours before it exploded over the Atlantic Ocean off the coast of Africa. It is estimated that there are a billion near Earth Asteroids of similar size.It is likely that we have discovered 90% of the approximately one thousand near Earth asteroids whose impact would cause global climate change. There are probably 300,000 smaller Earth approaching asteroids whose impact would devastate thousands of square miles of the Earth's surface. So far we have discovered about 5,000 of them. There are many millions of space rocks which could cause window breaking sonic booms. Happily we have not discovered any of these objects which will impact the Earth any time soon.An Asteroid impact is a natural disaster whose effect we have the ability to minimize . The NASA Near Earth Object Program's goal is provide the early detection essential to mitigate such an event.For Travelers in the Night this is Dr. Al Grauer.Go to travelersinthenight.org for more information.© 2014 A. D. Grauer and ℗ 2014 A. D. GrauerMore On Asteroid Close Approaches to Earth34- Number 5000Click to ListenPublished PRX April 10, 2014Recorded April 10, 2014remixed July 15, 2014The 5000th Earth approaching asteroid discovered by the University of Arizona's NASA funded Catalina Sky Survey was found early in 2014. It is approximately 3 times the size of the one which injured 1491 people in Russia in February of 2013. It was discovered by my teammate Jess Johnson. Happily, its closest approach to Earth is slightly farther than our moon.The other 4999 asteroids discovered since 2003 consist of: 141 that are large enough to cause global climate change, 1892 that are large enough todevastate thousands of square miles of the Earth's Surface, and 2966 that upon entering our atmosphere would createwindow shattering sonic booms.Fortunately none of these objects will impact the Earth anytime soon.Our team operates two telescopes, 24 nights per month in the Catalina Mountains near Tucson, Arizona. This effort has discovered 47% of the near Earth Asteroids known to exist. We are part of the NASA near Earth Object Program who goal is to provide the early warning time which is essential to mitigate the effects of an asteroid impact.Fortunately large asteroids which impact the Earth are extremely rare. Small asteroids are the most numerous and thus mostly likely to present a problem. In the future we hope to have the equipment in place to obtain a heads up if a small asteroid is likely to be an impactor. Then people that are in a potentially effected area will be warned to seek shelter in a manner similar to a tornado warning.For Travelers in the Night this is Dr. Al Grauer.Go to travelersinthenight.org for more information.© 2014 A. D. Grauer and ℗ 2014 A. D. GrauerMore on the 5000th Asteroid35-An Asteroid With A RingClick to ListenPublished PRX April 18, 2014Recorded April 12, 2014remixed July 15, 2014Saturn had a strange appearance in Galileo's telescope. At first he described it as being a composite of three objects. A few years later, better telescopes showed a beautiful ring system surrounding Saturn. For more than 350 years Saturn was the only known planet with rings. Now we are aware that Uranus, Jupiter, and Neptune also have ring systems.Chariklo (“KAReekloe”) is an asteroid which orbits the Sun between Saturn and Uranus every 63 years. It was discovered in 1997 by James Scotti an astronomer with Spacewatch on Kitt Peak in Arizona.Chariklo (“KAReekloe”) is the first asteroid to show a ring system. Perhaps there are others.