Glossary
I’ve gotten some feedback that episodes can be too technical. Unfortunately, that feedback came too late to save you from this week’s episode, which requires me to summarize the electromagnetic spectrum, radio astronomy, a concept called interferometry, and government regulations to talk about the topic that originally started me on this path: radio quiet zones. Please, bear with me! Pardon my mess! It was all very interesting stuff, I couldn’t resist digging into it.
Below the cut are my sources, music credits, a vocab list, a timeline of the astronomers I mention, and the transcript of this episode. I’ve bolded those sources I mention in the podcast, including the podcast that started me on this topic: The Adventure Zone! Please let me know what you think I should research next by messaging me here, tweeting at me at @HDandtheVoid, or asking me to my face if you know me. I’d love it if you would subscribe on iTunes, rate my humble little podcast and maybe review it, and tell friends if you think they’d like to hear it!
(My thoughts on the next episode are SOFIA, which you need to listen to find out what it stands for, or the pilot Chuck Yaeger. The next episode will go up February 26th.)
Glossary
aperture synthesis - the process of collecting electromagnetic radiation from a variety of separate, small telescopes and then combining this data to recreate the image at a higher resolution than would be possible with a single telescope.
frequency - the number of times a wave oscillates up and down per second.
hertz - the number of times an electromagnetic wave cycles per second. One cycle per second is 1 hertz.
interferometry - a group of techniques to extract information from superimposing electromagnetic waves to create interference. In radio astronomy, this is done by using a wide spread of receivers to look at the same distant object, then bringing that data together with a correlator that can create a larger, clearer picture than an individual radio telescope alone could.
radiation - energy that travels and spreads out as it goes.
Script/Transcript
Timeline
Joseph-Louis Lagrange, French (1736-1813)
Armand-Hippolyte-Louis Fizeau, French (1819-1896)
Edward W. Morley, American (1838-1923)
Albert A. Michelson, American (1852-1931)
Sir Martin Ryle, British (1918-1984)
Bernard Yarnton Mills, Australian (1920-2011)
Derek Vonberg, British (1922-2015)
Antony Hewish, British (1924- )
Sources
Electromagnetic spectrum via NASA
Observatories across the EM spectrum via NASA
Fermi satellite via NASA
The Neil Gehrels Swift Observatory via NASA
NuSTAR via Caltech
NuSTAR via NASA
Chandra X-Ray Observatory via Harvard
The Galaxy Evolution Explorer (GALEX) via Caltech
Kepler satellite via NASA
Hubble Space Telescope via NASA
Spitzer satellite via Caltech
Stratospheric Observatory for Infrared Astronomy (SOFIA)
Planck satellite via ESA
Spekt-R Radioastron from Russia
High Energy Stereoscopic System (HESS)
W. M. Keck Observatory on Mauna Kea
South Africa Large Telescope (SALT) in Namibia
The Combined Array for Research in Millimeter-Wave Astronomy (CARMA) via Caltech
CARMA public page (decommissioned)
Very Large Array (VLA) via NRAO
Space radio telescope (1997) via NRAO
Highly Advanced Laboratory for Communications and Astronomy (HALCA) via NASA
A timeline of the history of radio interferometry via University of Groningen (Netherlands)
Interferometers via the LIGO Laboratory
Michelson-Morley Experiment via University of Virginia
Astronomical Interferometry via Magdalena Ridge Observatory
Interferometry via XKCD
How Radio Works via How Stuff Works
Radio Spectrum Allocation via the Federal Communications Commission
Interferometry via the European Space Observatory
National Radio Quiet Zone via National Radio Astronomy Observatory
“minimize possible harmful interference to the National Radio Astronomy Observatory (NRAO) in Green Bank, WV and the radio receiving facilities for the United States Navy in Sugar Grove, WV.”
National Radio Quiet Zone via CNN
“Tucked in the Allegheny Mountains, researchers are listening to exploding galaxies at the edge of the universe – a signal that is so faint, it’s about a billionth of a billionth of a millionth of a watt.”
The Quiet Zone: Where mobile phones are banned via BBC News (May 2015)
Enter The Quiet Zone: Where Cell Service, Wi-Fi Are Banned via NPR (Oct 2013)
Green Bank Observatory in West Virginia, USA
Karen O’Neil: “The types of energies we look at are less than the energy of a single snowflake falling on the Earth.”
Characteristics of radio quiet zones via International Telecommunication Union (Sept 2012)
“transmissions below 15 GHz are restricted within a certain radius around the Arecibo Observatory, located in Puerto Rico. Since no observations are carried out, nor are any expected to be carried out above that frequency in the future, no restrictions are needed on higher frequency transmissions. The reverse is not necessarily true, however. For example, some restrictions may be imposed on transmissions below 30 GHz in the neighbourhood of the large international ALMA observatory even though it is not expected to ever observe below that frequency, due to its susceptibility to interference at these lower frequencies in the signal path.”
“It is important to emphasize that a RQZ does not imply a complete absence of radio transmissions. The existence of, and coexistence with, a range of man-made devices will always be necessary. A RQZ may include options for notification of other users and for negotiation in mitigating interference. On the other hand, a RQZ does not consist entirely of mitigating techniques implemented by the radio astronomy facility; some level of control on externally-generated interference is intrinsic to a RQZ.
A RQZ is therefore a buffer zone that allows for the implementation of mechanisms to protect radio astronomy observations at a facility within the zone from detrimental radio frequency interference, through effective mitigation strategies and regulation of radio frequency transmitters.”
ALMA Observatory website
The Scientific Committee on Frequency Allocations for Radio Astronomy (IUCAF) website
Google Map of worldwide radio quiet zones (Aug 2016)
ITU-R Recommendations of Particular Importance to Radio Astronomy by A. Richard Thompson
“the necessity of maintaining the shielded zone of the Moon as an area of great potential for observations by the radio astronomy service and by passive space research, and consequently of maintaining it as free as possible from transmissions.”
The Adventure Zone: Amnesty setup episode via Maximum Fun
Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity
Filler Music: ‘Junkyard Chandelier’ by Radical Face aka Ben Cooper, who primarily releases music as Radical Face but also has at least three other bands or band names he’s working with/has released music as.
Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught
More Posts from Fillthevoid-with-space and Others
On this date in 1902, Greek archaeologist Valerios Stais sifted through some artifacts from a shipwreck at Antikythera. The wrecked Roman cargo ship was discovered two years earlier, but Stais was the first to notice an intriguing bit of bronze among the treasures. It looked like it might be a gear or wheel. That corroded chunk of metal turned out to be part of the Antikythera Mechanism, an ancient analog astronomical computer.
The Antikythera Mechanism tracked planetary positions, predicted lunar and solar eclipses, and even signaled the next Olympic Games. It was probably also used for mapping and navigation. A dial on the front combines zodiacal and solar calendars, while dials on the back capture celestial cycles. Computer models based on 3-D tomography have revealed more than 30 sophisticated gears, housed in a wooden and bronze case the size of a shoebox.
why is there star
gas cloud get squished (gravitational collapse) then sometimes smaller elements can squish together to make bigger elements (nuclear fusion) and this continues as long as the smolest elements (hydrogen and helium) are in the core
I was away at PodCon this weekend! It was a lovely time. Listening to people for 8 hours a day was exhausting, which I should have expected but I fully did not anticipate. I slept on a friend’s floor and passed out homemade business cards shaped like business bookmarks. It was a fun opportunity to use my typewriter! I reused some old cardstock that an office where I temped was going to throw away and I gave out 35 of 36, which is extremely successful in my book. I have some new podcasts to listen to and one or two that I want to contact about guesting on (I could go OFF about Tycho Brahe on Historical Hotties, if no one has already).
It was interesting trying to network and seeing what’s out there right now. It really is anyone’s game, podcasting. You just need time, motivation, and an idea. I shouldn’t be surprised, it was easy enough for me to do it. The hard part, of course, is getting folks to listen. There were tips I overheard about advertising yourselves and such but it still seems like it just depends on what market you tap into? I don’t know, I think the big thing is content and just persisting. I’ve seen it with podcasts I found that have a season or two and they’re gone. Sometimes it’s because they wrapped up and that’s great! Other times I wish there’d been more.
It was more fun than it was work, though! And it was so small for a con, I was relieved. The only other con I’ve gone to was Emerald City, which was also in the Washington State Convention Center, and that was Too Much. This one was a decent size. I hope it happens again! It was kind of inspiring to realize I’m part of a much, much, much larger movement of people who want to talk and made it happen.
I’m back with the last episode of 2018! A conversation with a friend sparked this idea and I just ran with it while I had the inspiration, so please enjoy an episode on the strange and wonderful scales that astronomers have created to quantify data that is very unusual.
Below the cut are the glossary, transcript, sources, and music credits. Send me any topic suggestions via Tumblr message (you don’t need an account for it!). You can also tweet at me on Twitter at @HDandtheVoid, or you can ask me to my face if you know me. Subscribe on iTunes to get the new episodes of my ideally-monthly-updated podcast (I hope I have more inspiration/time in 2019), and please please please rate and review it. Go ahead and tell friends if you think they’d like to hear it, too!
(My thoughts on the next episode are the Coriolus Force, Stephen Hawking, or famous comets. The next episode will go up in 2019, hopefully in early January!)
Glossary
background risk - the average risk from random impacts of space objects with Earth.
Bortle Scale - an objective scale to measure the clarity and effect of light pollution on a night’s stargazing.
Drake Equation - a way to estimate the number of potential active, communicative civilizations in the Milky Way galaxy based on 1) the average rate of star formation in our galaxy 2) the fraction of those stars that have planets 3) the average number of planets that can potentially support life per star with its own orbiting planets 4) the fraction of planets that could support life which actually develop life at some point 5) the fraction of planets with life that actually go on to develop intelligent life and civilizations 6) the fraction of civilizations that develop a technology that releases detectable signs of their existence into space 7) the length of time it would take those civilizations release detectable signals into space.
Hynek Scale - quantifies encounters with UFOs and aliens.
Kardashev Scale - measures how advanced a civilization’s technology is based on their mastery of resources and exploration into space.
METI - Messaging to ExtraTerrestrial Intelligence
Palermo Technical Impact Hazard Scale - categorizes and prioritizes the potential impact risks of objects in space, such as asteroids.
Rio Scale - quantifies the impact of any public announcement regarding evidence of extraterrestrial intelligence.
San Marino Scale - quantifies the impact of sending transmissions from Earth to extraterrestrial intelligence.
SETI - the Search for ExtraTerrestrial Intelligence.
Torino Scale - communicates the risk associated with a particular asteroid or comet’s potential to impact with Earth to the public.
Script/Transcript
Sources
10 Unusual Scientific Scales via Listverse (Sep 2010)
John Bortle’s article on his magnitude scale via Sky and Telescope, July 2006
“I have created a nine-level scale. It is based on nearly 50 years of observing experience. I hope it will prove both enlightening and useful to observers — though it may stun or even horrify some! Should it come into wide use, it would provide a consistent standard for comparing observations with light pollution.”
Bortle dark sky scale via Big Sky Astronomy Club
Bortle dark sky scale via LSU
Palermo Technical Impact Hazard Scale via NASA
The Palermo Scale is the base-10 logarithm of the relative risk.
PS = log10 R.
The relative risk R is given by R = PI / (fB × DT), where PI is the impact probability of the event in question and DT is the time until the potential event, measured in years.
The annual background impact frequency, fB = 0.03 × E-4/5, is the annual probability of an impact event with energy (E, in megatons of TNT) at least as large as the event in question.
Torino Impact Hazard Scale via NASA
Rio Scale via SETI League
San Marino Scale via SETI League
Rio and San Marino Scale history via Wikipedia
Drake Equation via Wikipedia
Nikolai Kardashev via Wikipedia
"energy consumption at ≈4×1019 erg/sec (4 × 1012 watts)."
New Variation of Kardashev Scale Developed via Edgy Labs (June 2018)
J. Allen Hynek's Scale Of UFO Classification via The Night Sky
Hynek's UFO Classification System via The Center for UFO Studies
Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity
Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught
When I was in Ireland in 2013, I kept seeing signs for ‘quasar.’ I finally learned that it’s the European way of saying laser tag. It has nothing to do with quasars, which are a specific type of a specific type of galaxy. Listen to this week’s (pretty short) podcast on two types of active galaxies: quasars and blazars.
Below the cut, I have the transcript, sources, music credits, and timeline of people I talked about! If you have suggestions for topics I could cover, please send me a Tumblr message or tweet at me on Twitter at @HDandtheVoid, or you can ask me to my face if you know me. Please subscribe on iTunes, rate my podcast and maybe review it, and tell friends if you think they’d like to hear it!
(My thoughts on the next episode are the SOFIA observatory, Chuck Yaeger, or the great Stephen Hawking. The next episode will go up April 2nd.)
Glossary
active galaxy or active galactic nucleus- a galaxy with a small core of emission embedded at the center. This core is typically very variable and very bright compared to the rest of the galaxy. These galaxies emit much more energy than they should; this excess energy is found in the infrared, radio, UV, and X-ray regions of the electromagnetic spectrum.
blazar - a subcategory of active galaxy, it is an extremely bright, distant object, powered by a black hole, which emits massive amounts of energy. It is distinct from a quasar because it is even brighter.
extragalactic objects - objects outside our Milky Way galaxy.
interferometry - a group of techniques to extract information from superimposing electromagnetic waves to create interference. In radio astronomy, this is done by using a wide spread of receivers to look at the same distant object, then bringing that data together with a correlator that can create a larger, clearer picture than an individual radio telescope alone could.
lunar occultations - when stars pass behind the Moon. This is the basis for a method of determining and mapping star positions.
quasar - a subcategory of active galaxy, it is an extremely bright, distant object, powered by a black hole, which emits massive amounts of energy. It is distinct from a blazar because it is less-bright. The name is a contraction of “quasi-stellar radio source” (which is not necessarily true of all quasars—90% are radio-quiet).
torus - a donut shape.
Script/Transcript
Timeline
Walter Baade, German (1893-1960)
Rudolph Minkowski, German-American (1895-1976)
Fritz Zwicky, Swiss (1898-1974)
Gordon Stanley, New Zealander (1921-2001)
John Bolton, English-Australian (1922-1993)
Owen Bruce Slee, Australian (1924-2016)
Allan Rex Sandage, American (1926-2010)
Cyril Hazard, English (1928- )
Maartin Schmidt, Dutch (1929- )
Hong-Yee Chiu, American (1932- )
Stephen Hawking, English (1942 -2018)
Jedidah Isler
Sources
Active Galaxies via NASA (Dec 2016)
Galaxy shapes via Cornell University (April 2000)
Galaxies and Black Holes by David Merritt, published on NED by Caltech and NASA
Cyril Hazard via University of Pittsburgh
The Discovery of Quasars and its Aftermath via Journal of Astronomical History and Heritage (2014)
“Characteristically, Fritz Zwicky (1898–1974; Figure 11) immediately pointed out that ‘All of the five quasi-stellar galaxies described individually by Sandage (1965) evidently belong to the subclass of compact galaxies with pure emission spectra previously discovered and described by the present writer. (Zwicky, 1965: 1293).’ A few years later, Zwicky was less circumspect and wrote: ‘In spite of all these facts being known to him in 1964, Sandage attempted one of the most astounding feats of plagiarism by announcing the existence of a major new component of the Universe: the quasi-stellar galaxies ... Sandage‘s earthshaking discovery consisted in nothing more than renaming compact galaxies, calling them ‘interlopers‘ and quasistellar galaxies, thus playing the interloper himself. (Zwicky and Zwicky, 1971: xix)’”
Lunar occultations via Sky and Telescope
Quasars and Blazars by Matthew Whiting (a chapter in his thesis, What made the quasar blush? Emission mechanisms in optically-red quasars) via the Australia Telescope National Facility (2000)
Jedidah Isler on quasars and blazars via TED Talks (March 2015)
Quasar definition via Space.com (Feb 2018)
Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity
Filler Music: ‘Into The White’ by Pixies off their album Wave of Mutilation.
Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught
This is so sweet! What a nice way to spend a Saturday night.
Make Sure You Observe the Moon on October 20
On Saturday, October 20, NASA will host the ninth annual International Observe the Moon Night. One day each year, everyone on Earth is invited to observe and learn about the Moon together, and to celebrate the cultural and personal connections we all have with our nearest celestial neighbor.
There are a number of ways to celebrate. You can attend an event, host your own, or just look up! Here are 10 of our favorite ways to observe the Moon:
1. Look up
Image credit: NASA’s Scientific Visualization Studio/Ernie Wright
The simplest way to observe the Moon is simply to look up. The Moon is the brightest object in our night sky, the second brightest in our daytime sky and can be seen from all around the world — from the remote and dark Atacama Desert in Chile to the brightly lit streets of Tokyo. On October 20, the near side of the Moon, or the side facing Earth, will be about 80 percent illuminated, rising in the early evening.
See the Moon phase on October 20 or any other day of the year!
2. Peer through a telescope or binoculars
The Moon and Venus are great targets for binoculars. Image Credit: NASA/Bill Dunford
With some magnification help, you will be able to focus in on specific features on the Moon, like the Sea of Tranquility or the bright Copernicus Crater. Download our Moon maps for some guided observing on Saturday.
3. Photograph the Moon
Image credit: NASA/GSFC/ASU
Our Lunar Reconnaissance Orbiter (LRO) has taken more than 20 million images of the Moon, mapping it in stunning detail. You can see featured, captioned images on LRO’s camera website, like the one of Montes Carpatus seen here. And, of course, you can take your own photos from Earth. Check out our tips on photographing the Moon!
4. Take a virtual field trip
Image credit: NASA/JPL-Caltech
Plan a lunar hike with Moontrek. Moontrek is an interactive Moon map made using NASA data from our lunar spacecraft. Fly anywhere you’d like on the Moon, calculate the distance or the elevation of a mountain to plan your lunar hike, or layer attributes of the lunar surface and temperature. If you have a virtual reality headset, you can experience Moontrek in 3D.
5. Touch the topography
Image credit: NASA GSFC/Jacob Richardson
Observe the Moon through touch! If you have access to a 3D printer, you can peruse our library of 3D models and lunar landscapes. This model of the Apollo 11 landing site created by NASA scientist Jacob Richardson, is derived from LRO’s topographic data. Near the center, you can actually feel a tiny dot where astronauts Neil Armstrong and Buzz Aldrin left the Lunar Descent Module.
6. Make Moon art
Image credit: LPI/Andy Shaner
Enjoy artwork of the Moon and create your own! For messy fun, lunar crater paintings demonstrate how the lunar surface changes due to consistent meteorite impacts.
7. Relax on your couch
Image credit: NASA’s Scientific Visualization Studio/Ernie Wright
There are many movies that feature our nearest neighbor, from A Voyage to the Moon by George Melies, to Apollo 13, to the newly released First Man. You can also spend your evening with our lunar playlist on YouTube or this video gallery, learning about the Moon’s role in eclipses, looking at the Moon phases from the far side, and seeing the latest science portrayed in super high resolution. You’ll impress all of your friends with your knowledge of supermoons.
8. Listen to the Moon
Video credit: NASA’s Scientific Visualization Studio/Ernie Wright
Make a playlist of Moon songs. For inspiration, check out this list of lunar tunes. We also recommend LRO’s official music video, The Moon and More, featuring Javier Colon, season 1 winner of NBC’s “The Voice.” Or you can just watch this video featuring “Clair de Lune,” by French composer Claude Debussy, over and over.
9. See the Moon through the eyes of a spacecraft
Image credit: NASA/GSFC/MIT
Visible light is just one tool that we use to explore our universe. Our spacecraft contain many different types of instruments to analyze the Moon’s composition and environment. Review the Moon’s gravity field with data from the GRAIL spacecraft or decipher the maze of this slope map from the laser altimeter onboard LRO. This collection from LRO features images of the Moon’s temperature and topography. You can learn more about our different missions to explore the Moon here.
10. Continue your observations throughout the year
Image credit: NASA’s Scientific Visualization Studio/Ernie Wright
An important part of observing the Moon is to see how it changes over time. International Observe the Moon Night is the perfect time to start a Moon journal. See how the shape of the Moon changes over the course of a month, and keep track of where and what time it rises and sets. Observe the Moon all year long with these tools and techniques!
However you choose to celebrate International Observe the Moon Night, we want to hear about it! Register your participation and share your experiences on social media with #ObserveTheMoon or on our Facebook page. Happy observing!
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
A podcast project to fill the space in my heart and my time that used to be filled with academic research. In 2018, that space gets filled with... MORE SPACE! Cheerfully researched, painstakingly edited, informal as hell, definitely worth everyone's time.
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