Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Eps. 273 & 274: Hunt for Planet 9 & New Horizons Continues
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- The evidence for an unseen planet 9 orbiting our Sun is getting hard to ignore. It could have an elongated orbit with 300-1,000 AU dimensions. Unfortunately it’s likely at its most distant part of the 17,000 year orbit.
- 2014 MU69 is the next target for the New Horizons spacecraft. It’s a small target, though, being only 13-25 miles in diameter. But visiting it and learning about it is a chance for scientists to study pristine 4 billion year old material from the earliest days of the solar system’s formation.
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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:
273-Hunt for Planet 9
Evidence continues to mount that there is an unseen body, Planet 9, orbiting far from our Sun. Ideas of where to look for it are being guided by it’s gravitational influence on objects in the distant region of our solar system called the Kuiper Belt.
Dr. Renu Malhotra of the University of Arizona’s Lunar and Planetary Laboratory and her collaborators have found that a hypothetical Planet 9 would explain the the curious relationship between the orbits of the four longest period Kuiper Belt objects. These researchers calculations suggest that Planet 9 could have a mass more than ten times that of Earth, a 17,000 year orbit, and a path that takes it from several hundred to more than thousand times the Earth’s distance from the Sun. Dr. Malhotra’s work as well as that of Dr. Mike Brown and Dr. Konstantin Batygin of Caltech suggest the places to look are where Planet 9’s orbit takes it furthest from the Sun. Unfortunately, at this position, more than a thousand times the Earth’s distance from the Sun, the scant light it reflects, makes it exceedingly faint in our telescopes.
On a different tack, Dr. Nicolas Cowan of McGill University in Canada and his collaborators point out that at a temperature 30-50 degrees Kelvin Planet 9 is warm compared to the Cosmic Microwave Background radiation from the Big Bang which is only 3 degrees Kelvin. They suggest that Planet 9 should be detectable by the five experiments which are mapping signals from beginning of the Universe. The faint thermal glow from Planet 9, measured in this way, will give us new clues about the inner workings of the giant planets.
274-New Horizons Continues
The NASA New Horizons spacecraft obtained intriguing images and data during it’s trip through the Pluto system which will keep planetary scientists busy for years to come. Now the New Horizons has it’s sights set on an object, a billion miles past Pluto, which is called 2014 MU69. It is too faint for all but the most powerful telescopes which is why the Hubble Space Telescope was systematically used to discover it.
2014 MU69 orbits the Sun every 293 years on a nearly circular path in the ecliptic which seems to have been unperturbed by other objects. Currently the NASA New Horizons Spacecraft is on a trajectory which will come within 1,900 miles of this distant world on December 31, 2018 or 1 January 2019 when both are in the constellation of Sagittarius.
Even though 2014 MU69 is out near Pluto it is very different from the famous dwarf planet. At 13 to 25 miles in diameter it is 50-100 times smaller and 500,000 times less massive than Pluto. It may have an atmosphere and even moons. On the other hand 2014 MU69 is a thousand times more massive than the comet which the Rosetta landed on. This intermediate sized object will give scientists the opportunity to study 4 billion year old material which has been stored in the best deep freeze that exists. What it has to say about the primitive material which formed out solar system will be worth the trip.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
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