Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. Eps. Eps. 243E & 244E: Earth/Venus Express & Pale Blue Dot

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s two stroy:

  • Carson Fuls discovered 2016 HD3, which will make 53 close approaches to Earth in the next 100 years.
  • Voyager 1 took the famous “Pale blue dot” photo over 25 years ago. New telescopes will enable us to look for pale blue dots around other stars! A spectrum that includes traces of oxygen would be even better, of course

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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243E – Earth/Venus Express

We will probably never know the details of the collision that put my Catalina Sky Survey teammate Carson Fuls’ recent discovery, 2016 HD3, on its current path. What we do know is that Carson’s new space rock is about 25 feet in diameter and in the next 100 years will make 53 close approaches to planet Earth and 12 to our sister planet Venus. In 2016 this small object passed to near both the Earth and our Moon. It’s 322 day orbit around the Sun can someday bring it to about a quarter of the Moon’s distance from where we live.

The fact that Carson was able discover this small asteroid 4 days before it made its closest approach to us means that if it had been an impactor we could have let people know well in advance. Not that 2016 HD3 would have posed much danger since one this size enters the Earth’s atmosphere every 5 years or so producing a light show at an altitude about three times higher than airliners fly. If you are lucky you will witness such an event and perhaps even be able to pick up a small piece of it that is able to reach the ground. Such meteorite contains a record of collisions which it has had going all the way back to the formation of our solar system. Even if you don’t see a meteorite fall, with diligence, you can find one with your eye, a powerful magnet and/or perhaps a metal detector. In some cases your discovery could be worth more than its weight in gold and diamonds. In any case, being able to hold an object from space will make your effort rewarding.

244E – Pale Blue Dot

More than 25 years ago Voyager 1 took a picture of the Earth from beyond Pluto’s orbit. This image shows our home planet to be an isolated tiny pale blue dot floating in the vastness of space.

Dr. Carl Sagan used this photograph in the title of his 1994 book “Pale Blue Dot: A Vision of Human Future in Space”. His description of this image and how it demonstrates our fragile unique place in the cosmos is still valid today.

The next generation of space and ground based telescopes will be able to identify the pale blue dots among the thousands of planets that we have discovered to be orbiting distant stars. These discoveries will inspire humans to discover methods to identify those worlds on which they could live and prosper.

Recently a team of scientists published a paper in the Astrophysical Journal in which they investigated the degree to which the color of a planet can be used to measure its potential as an abode for life. They found that the light reflected by the Earth from the ultraviolet to the near infrared has a unique “U” like shape. Further, there are subtile differences between the light reflected by the Earth and the light reflected by hypothetical uninhabitable bluish planets which are in reality frozen lifeless worlds with thick atmospheres. They could not completely rule out the possibility of uninhabitable blueish imposters. Very large telescopes will be necessary to obtain the spectra which will allow humans to discover worlds which have oxygen rich atmospheres and the other molecules which could only be there as a result of the chemistry of life.

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