Programs 361-390


361-Nearby Planets

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Published PRX June 1, 2017
Recorded May 26, 2017

There are ten times more cool red stars than there are yellow dwarf stars like our Sun in our stellar neighborhood.  This realization has caused astronomers to search for and find two or three planets circling nearly every dim red star they have studied. About a quarter of these are Earth sized worlds  and have temperatures which would allow life as we know it to flourish.  

In 2018 the NASA Transiting Exoplanet Survey Satellite nicknamed TESS will be launched and begin a two to three year mission to discover small Earth sized planets orbiting bright stars in the solar neighborhood.  TESS will accomplish its research by monitoring the brightness of more than 200,000 stars to detect the regular dips in brightness which occur as a planet passes in front of its star.

It is expected that TESS will be able to discover about 70 Earth sized planets orbiting stars close enough to us so that their masses, sizes, densities, and atmospheric composition can be determined by the James Webb Space Telescope when it is launched, the Hubble Space Telescope, and the new generation of giant ground based telescopes which are currently being constructed. 

Engineering studies indicate that habitable planets in our stellar neighborhood could be visited  by ultra light probes carrying cameras, life chemistry detecting sensors, and communications equipment.  To cut the mission time to 20 years or so these nano probes will be propelled by repeated pulses of energy from Earth bound lasers which upon striking their light sails over time will accelerate them to 20% of the speed of light.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 361 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


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362-Asteroid Day

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Published PRX June 1, 2017
Recorded May 26, 2017

On June 30, 1908 a meteor the size of an office building exploded over Tunguska, Siberia causing an airburst which flattened trees over an area about two and a half times the size of New York City.  Fortunately the area of destruction was in a sparsely populated area and caused no known human casualties.  In 2013 a 66 foot diameter asteroid gave humans another wake up call when it exploded over Chelyabinsk, Russia injuring nearly 1,500 people.   Asteroid Day is held on June 30, the annual anniversary of the Tunguska event.  It got started when in 2014, Dr. Brian May an astrophysicist and guitarist for the rock band QUEEN composed a musical score which Grigorij Richters used in the  production of a film about a fictional asteroid impact and its effect on the human population on our planet.  June 30, Asteroid Day resulted from discussions by a group of astrophysicists and artists who previewed this movie at a STARMUS Science and Arts Festival. 

At the current rate of discovery it will take asteroid hunters about a thousand years to find the million or so Chelyabinsk sized space rocks which could threaten the residents of Earth.  In 2017 Asteroid day events are being held at more than 500 hundred locations in 72 countries world wide. Participants at Asteroid Day events are encouraged to sign the 100X Declaration which seeks to increase the rate of discovery of potentially damaging space rocks.  

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 362 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer

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363-Scoping Planets

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Published PRX June 8, 2017
Recorded June 6, 2017

NASA's Spitzer Space telescope has discovered 7 Earth sized planets orbiting a small red star named TRAPPIST-1. It is in the constellation of Aquarius located and is about 40 light years from Earth. Three of them are in the habitable zone where temperatures could be suitable for life as we know it. In the next few years the NASA Transiting Exoplanet Survey Satellite is likely to discover 70 or so Earth sized planets circling nearby stars.

We suspect that aliens finding oxygen and methane in Earth's atmosphere would have strong evidence of life on our home planet since these molecules would not be present in our atmosphere without continuously being generated by living organisms. Recently, Dr. Dimitri Mawet and a group of researchers at Caltech have published papers in the Astrophysical Journal and the Astronomical Journal which describe how the future 30 meter telescope, when it begins operations in the late 2020's, can be used to measure the abundance of oxygen, methane, and other molecules in the atmospheres of nearby Earth like planets. This is an incredibly difficult task since from our perspective the light from a planet is overwhelmed by the glare from the billion times brighter star which it orbits. Dr. Mawet's group's plan is to use an opaque disk, a baffle, and an optical vortex followed by adaptive optics to eliminate most the light from the planet's star and feed the light which remains into a high resolution spectrograph. This instrument is designed to produce a pattern of present and missing colors which reveals the abundance of oxygen, methane, and other molecules produced by living creatures in a planet's atmosphere.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 363 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


364-Laser Surfing

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Published PRX June 8, 2017
Recorded June 6, 2017

When we find a planet which appears to have the chemical signs of living organisms in its atmosphere, the desire to take a close up look at it will be hard to contain. 

In a Scientific American article, Lee Billings describes Yuri Milner's 100 million dollar project "Breakthrough Starshot" which has been created to leap frog our current rocket technology's extremely long travel times to nearby planets.  The plan is to put ultra light space probes on paths which will enable them to collect data as they streak by nearby potentially habitable planets.   Our current iPhone technology is being used to envision a tiny robotic space probe which features cameras, life detecting sensors, maneuvering rockets, computers, and communications gear and yet has a mass of about that of a dime.    Photons from 100 gigawatt pulses from a ground based laser array are then envisioned to reflect off the tiny spacecrafts solar sail where they transfer momentum to the space craft accelerating it to 20% of the speed of light.  Numbers of these tiny robotic investigators could be launched together into Earth orbit and perhaps one a day could be sent towards a nearby star accelerated by laser pulses each of which contains the energy required to send a space shuttle into orbit.   In a few decades closeup views and data from nearby worlds would begin streaming back towards the residents of our planet. The cost of investigating our planetary life hosting neighbors is likely to be less than what the US is planning to spend to upgrade its nuclear weapons.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 364 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


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365-Tabby's Star

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Published PRX June 15, 2017
Recorded June 14, 2017

The mystery of Tabby's star began to unfold when in 2015 Dr. Tabetha S. Boyajian [boy-AA-jee-uhn] of Louisiana State University and her team published a paper describing the irregular dips in the light output of what otherwise would seem to be a garden variety star over the period 2009 to 2013.  Subsequently a list of proposed explanations include swarms of comets, large asteroids, a debris disk, and even a massive alien megastructure.

In what appears to be the best scientific explanation of the strange behavior of Tabby's star, Dr. Brian Metzger of Columbia University and his team propose that the dips in brightness of Tabby's star are the result of its having swallowed one or several of its planets in the recent past. Their calculations published in the Monthly Notices of the Royal Astronomical Society suggest that this cannibalism occurred between 10 and 10,000 years ago depending on the mass of the devoured objects. In their model the gravitational energy released as an object or objects spiral into the outer layers of Tabby's star caused it to brighten while we were not looking and what we are seeing is it now returning to normal with perhaps dips also caused by debris passing across our line of sight. The authors are going to monitor any further activity by Tabby's star to see what else there is to learn.

All is not lost for those with the alien megastructure point of view since this idea cannot be completely ruled out by the data.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 365 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


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366-3 Explorers

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Published PRX June 15, 2017
Recorded June 14, 2017

Recently, my Grandsons, Dane and Hank joined our asteroid hunting team at the Catalina Sky Survey 60 inch telescope on Mt. Lemmon. 

The most interesting of our discoveries, 2017 KJ32 is only 16 feet in diameter, orbits the Sun once every 315 days, and can come closer to us than the communications satellites. 4 days and 16 hours before Dane, Hank, and I spotted it, 2017 KJ32 passed about 41,000 miles from the surface of Earth traveling at a relatively slow speed for an Earth approaching asteroid  of 1.6 mi/sec.  By the time 2017 KJ32 came into one of our images it was already 768,000 miles from Earth and was traveling away from us at 1.5 miles per second.  A few weeks later it was too faint to be detected by our most powerful telescopes.

It is interesting to speculate that given 2017 KJ32's speed and orbit that perhaps it is a piece of our Moon which was blasted loose when a larger asteroid or comet impacted the lunar surface.  Humans have found more than 240 meteorites on the Earth's surface whose chemical composition suggests that they came from our Moon.  These moon rocks were launched from the Moon's surface by an impacting object and traveled around the Sun for a while before being captured by the Earth's gravity.  When such an object enters the Earth's atmosphere, it explodes, and sometimes rains a few pieces onto the ground for us to find as lunar meteorites. 

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 366 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer



367-Future Impactor

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Published PRX June 22, 2017
Recorded June 16, 2017

My Catalina Sky Survey teammate Carson Fuls discovered a 33 foot diameter asteroid which has about a 1.1% chance of impacting the Earth on 569 encounters with our planet between 2045 and 2116. Its name is 2017 LD. It is on the list of the most likely objects to strike the Earth in the next hundred years as reported on NASA's Sentry Earth Impact Monitoring table. Even so, given our current data, there is a 98.9% chance that 2017 LD will not enter our atmosphere on any of its close approaches to Earth in the next 100 years.

Carson spotted 2017 LD 3 days and 6 hours before it made a recent close approach to planet Earth when it was a bit over a million miles from him and was coming towards us at about 3 mi/sec. Unfortunately, Carson's small space rock was bright enough for asteroid hunters to track for only 25 days out of its 601 day long path around the Sun. This lack of additional tracking data gives us a considerable uncertainty in knowing exactly where it will be in the future.

There are likely to be tens of millions of asteroids of 2017 LD's size. One its diameter enters the Earth's atmosphere every 10 years or so, explodes at about 3 times higher than airliners fly, and in some cases rains pieces onto the ground for us to discover. Carson's early discovery means that if 2017 LD had been an impactor, humans would have had time to prepare for the spectacular light show that an object its size produces.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 367 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


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368-Asteroid Alert


To be Published PRX June 22, 2017
Recorded June 14, 2017

When Asteroid hunters discover a new object it is given a score ranging from 0 which means it is likely to be a distant main belt asteroid up to 100 which means that it is likely to come near to us.  Each newly discovered asteroid which receives a score of 65 or greater is posted on the Minor Planet Center's Near Earth Object Confirmation Page so that telescopes around the world can track it to estimate it's size as well as to refine our knowledge of it's orbit around the Sun.

NASA feeds data on each new discovery into it's Scout software system.  Scout is designed to identify those objects which are most likely to make a close approach to Earth in the very near future. It's alert allows astronomers to access the new object's risk of impact as well as to study it before it fades into the distance.    Fortunately, asteroid hunters have not found any dangerous impacting asteroids, however, Scout's rapid alert has enabled astronomers to measure the size, chemical composition, and rate of rotation for a number of close approaching asteroids.  These data are extremely important to plan an effective response should an object be found to be on a collision course with planet Earth.  For the vast majority of Earth approaching objects that asteroid hunters discover, additional observations make it less and less likely that an object will impact or even make a very close to approach to our home planet.  Those few space rocks which have a tiny remote chance of coming very near to us are passed into NASA Sentry system which makes and keeps astronomers aware of nearby objects so that we do not lose track of them.

For Travelers in the Night this is Dr. Al Grauer.
Go to travelersinthenight.org program 368 for more information.
© 2017 A. D. Grauer and ℗ 2017 A. D. Grauer


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