The Elephants Trunk In IC 1396 : Like An Illustration In A Galactic Just So Story, The Elephants Trunk

Ep. 23 Quasars and Blazars - HD and the Void

Hear an overview of two of the major types of active galaxies: quasars and blazars! I discuss the history of the study of quasars as well as where we're going with future studies of these extragalactic objects.

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

The Birth of a New Star. IRAS 14568-6304

via reddit

A Lunar Eclipse Animation

Credit & Copyright: Larry Koehn

The Beauty of Webb Telescope’s Mirrors

The James Webb Space Telescope’s gold-plated, beryllium mirrors are beautiful feats of engineering. From the 18 hexagonal primary mirror segments, to the perfectly circular secondary mirror, and even the slightly trapezoidal tertiary mirror and the intricate fine-steering mirror, each reflector went through a rigorous refinement process before it was ready to mount on the telescope. This flawless formation process was critical for Webb, which will use the mirrors to peer far back in time to capture the light from the first stars and galaxies. 

The James Webb Space Telescope, or Webb, is our upcoming infrared space observatory, which will launch in 2019. It will spy the first luminous objects that formed in the universe and shed light on how galaxies evolve, how stars and planetary systems are born, and how life could form on other planets.  

A polish and shine that would make your car jealous

All of the Webb telescope’s mirrors were polished to accuracies of approximately one millionth of an inch. The beryllium mirrors were polished at room temperature with slight imperfections, so as they change shape ever so slightly while cooling to their operating temperatures in space, they achieve their perfect shape for operations.

The Midas touch

Engineers used a process called vacuum vapor deposition to coat Webb’s mirrors with an ultra-thin layer of gold. Each mirror only required about 3 grams (about 0.11 ounces) of gold. It only took about a golf ball-sized amount of gold to paint the entire main mirror!

Before the deposition process began, engineers had to be absolutely sure the mirror surfaces were free from contaminants. 

The engineers thoroughly wiped down each mirror, then checked it in low light conditions to ensure there was no residue on the surface.

Inside the vacuum deposition chamber, the tiny amount of gold is turned into a vapor and deposited to cover the entire surface of each mirror.

Primary, secondary, and tertiary mirrors, oh my!

Each of Webb’s primary mirror segments is hexagonally shaped. The entire 6.5-meter (21.3-foot) primary mirror is slightly curved (concave), so each approximately 1.3-meter (4.3-foot) piece has a slight curve to it.

Those curves repeat themselves among the segments, so there are only three different shapes — 6 of each type. In the image below, those different shapes are labeled as A, B, and C.

Webb’s perfectly circular secondary mirror captures light from the 18 primary mirror segments and relays those images to the telescope’s tertiary mirror.

The secondary mirror is convex, so the reflective surface bulges toward a light source. It looks much like a curved mirror that you see on the wall near the exit of a parking garage that lets motorists see around a corner.

Webb’s trapezoidal tertiary mirror captures light from the secondary mirror and relays it to the fine-steering mirror and science instruments. The tertiary mirror sits at the center of the telescope’s primary mirror. The tertiary mirror is the only fixed mirror in the system — all of the other mirrors align to it.

All of the mirrors working together will provide Webb with the most advanced infrared vision of any space observatory we’ve ever launched!

Who is the fairest of them all?

The beauty of Webb’s primary mirror was apparent as it rotated past a cleanroom observation window at our Goddard Space Flight Center in Greenbelt, Maryland. If you look closely in the reflection, you will see none other than James Webb Space Telescope senior project scientist and Nobel Laureate John Mather!

Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Ep. 16 Voyager Golden Record - HD and the Void

Full disclosure: this is a kissing story. A kissing story about the ultimate mixtape and alien communication plan, sent out in 1977 and now in interstellar space. Hear about the Voyager Golden Record and the people who put it together as a compila...

The process of making an audio and visual compilation to explain Earth and humanity to an alien species is an incredible undertaking, and Carl Sagan undertook it in 1977. The resulting record from his little team was sent out with the Voyager 1 and 2 probes and is now in interstellar space, but there was also a more personal result of this project. Learn about Sagan and his third wife’s meet-cute and also hear what is actually out there in the stars, conveying the best humanity had to offer in the 70s. 

Below the cut are my sources, music credits, a vocab list, and the transcript of this episode. Vote on 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 in real life. And please subscribe to the podcast on iTunes, rate it and maybe review it, and tell friends if you think they’d like to listen!

(My thoughts on the next episode are space race history, the transit of Venus, Edmond Halley, or Dark Sky Preserves. Next episode will be up on December 4th.)

Glossary

electroencephalography (EEG) - a recording that displays brainwave activity by measuring the electrical impulses of neurons firing in the brain

heliosheath - the outer region of the heliosphere. It is just beyond termination shock, the point where solar wind abruptly slows down and becomes denser and hotter as it presses outward against the approaching wind in interstellar space.

heliosphere - a huge wind sock-shaped bubble that extends beyond Pluto’s orbit and contains our solar system, solar wind, and the entire solar magnetic field.

Transcript

Sources

Drunk History episode transcript

Golden record via NASA

Carl Sagan via Smithsonian Magazine, March 2014

Carl Sagan via Biography.com

Carl Sagan via National Geographic

The Voyager project love story via NASA

Ann Druyen: “We know that EEG patterns register some changes in thought. Would it be possible, I wondered, for a highly advanced technology of several million years from now to actually decipher human thoughts?"

Ann Druyen: "a mental itinerary of the ideas and individuals of history whose memory I hoped to perpetuate."

Ann Druyen: "My feelings as a 27-year-old woman, madly fallen in love, they're on that record. It's forever. It'll be true 100 million years from now. For me, Voyager is a kind of joy so powerful, it robs you of your fear of death."

Arthur C. Clarke: "Please leave me alone; let me go on to the stars."

How 8-track tapes work via 8 Track Heaven

How vinyl records work via The Guardian, June 2010

Golden record via Smithsonian Magazine, April 2012

Golden record via the JPL at NASA

Golden record retrospective by Timothy Ferris via The New Yorker, August 2017

Voyager Golden Record - Greetings In 55 Languages via YouTube

The 116 images NASA wants aliens to see via YouTube

The Voyagers documentary by Penny Lane via Brain Pickings

Ann Druyen: “Carl and I knew we were the beneficiaries of chance, that pure chance could be so kind that we could find one another in the vastness of space and the immensity of time. We knew that every moment should be cherished as the precious and unlikely coincidence that it was.”

Article on Sagan’s divorce from Linda Salzman Sagan via People, December 1980

Article on Sagan’s divorce from Linda Salzman Sagan via The Cornell Daily Sun, March 1981

Voyager record available on Soundcloud via Cosmos Magazine

Golden record now available for purchase via The Atlantic, August 2017

Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity

Filler Music:  ‘Dark Was The Night, Cold Was The Ground’ by Blind Willie Johnson (1897-1945) off the album Dark Was The Night ‘Carl Sagan’ by Loch Lomond off their album Paper The Walls

Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught

When the sun sets on Stonehenge on the shortest day of the year, it’s rays align with several important stones.  Twice a year, the streets of Manhattan also line up with the setting sun, a phenomenon dubbed “Manhattanhenge”. Really, most cities with grid systems will see a similar effect (though it’s most dramatic in cities with tall buildings and a view of the true horizon).  You can use a great tool called The Photographer’s Ephemeris to find out the “henge” dates for your city grid - or even individual streets.

Yesterday, (Friday, January 24th) the sun lined up with New York Avenue, a street in DC that runs diagonally up to the White House. (The orange line indicates alignment with the setting sun).

I went out with our multimedia intern Meg Vogel, and captured some images of the sun setting in line with a rather Stonehenge-y sculpture that sits in the middle of that street.

Here are dates for sunset “henge” events in some cities this year:

Manhattan May 25th, July 17th

Philadelphia April 5th, September 6th

Washington DC March 18th, September 24th

Chicago March 16th, September 26th

Phoenix March 20th, September 22nd

Portland, OR March 18th, September 24th

Is your city/town a grid? When’s your henge?

Happy Labor Day. Today I learned about probably the first strike to happen IN SPACE.

Until I get this show rolling, I’m going to be posting some of the things I’ve collected over the years that might make for interesting things to do podcasts about down the line!

After 15 years, the Mars Opportunity rover's mission has ended

It's time to say goodbye to Opportunity. The Mars rover's team made its last attempt to contact Opportunity on Tuesday night, and it went unanswered. On Wednesday, NASA confirmed that the mission is over.

RIP, little buddy. 

Ep. 28 Tidal Forces - HD and the Void

Tidal forces are not only the cause of ocean tides, but affect how satellites orbit objects in space, and they can even tear some objects apart under their extreme stresses. Learn about types of tides on Earth and in our solar system.

This episode’s been a long time coming because the topic’s come up before. I originally conceived of this podcast as a way for me to learn about space things I’d always taken for granted, and truly, there is nothing closer to home that I’ve just agreed to believe than the statement that the tides are affected by the Moon. What? How? Why? All these questions and some I didn’t even realize I had will be answered in this episode on tidal forces!

Below the cut are my standard 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 maybe now monthly-updated podcast (we’ll see how the weeks unfold), 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 Stephen Hawking and his theories, or famous comets. The next episode will go up in September—ideally, September 10th!)

Glossary

barycenter - the common center of mass between two objects that allows them to orbit.

Roche limit - the distance in which a celestial body will disintegrate because of a second celestial body's tidal forces exceeding the first body's gravitational self-attraction, or the force that’s holding it together. Within the Roche limit, orbiting material disperses and forms rings, like how Saturn’s rings are within the Roche zone; outside the limit, material tends to coalesce.

spaghettification - when extreme tidal forces pull an object apart in space.

tidal force - an apparent force (sometimes also called the differential force) that stretches a body towards another, more gravitationally-strong body’s center of mass. This can cause such diverse phenomena as tides, tidal locking, breaking celestial bodies apart to form ring systems within a Roche limit, and in extreme cases, spaghettification. It arises because the gravitational force exerted on one body by another is not constant across its parts: the nearest side is attracted more strongly than the farthest side.

Types of ocean tides:

diurnal tide - a daily tidal cycle with only one high and low tide each lunar day, and a period of a little over 24 hours.

meteorological tide - a tidal change due to weather patterns. Wind, or unusually high or low barometric pressure causes variations between the actual sea level and its predicted height.

mixed tide - a daily tidal cycle with two high and low tides that differ in their peaks. This difference in height between successive high or low tides is called the diurnal inequality. They have a period of 12 hours and 25 minutes.

neap tide - a type of bi-monthly tidal cycle that occurs when the Sun, Earth, and Moon are positioned at a 90-degree angle, so the tidal forces of the Sun are acting against the tidal forces of the Moon. During a neap tide, the difference between high tide and low tide is the least extreme.

semidiurnal tide - a daily tidal cycle with two nearly equal high tides and low tides every lunar day. They have a period of 12 hours and 25 minutes.

spring tide - a type of bi-monthly tidal cycle that occurs when the Sun, Earth, and Moon line up so that the gravitational forces of Sun and Moon are working together to form a large tidal bulge. During a spring tide, the difference between high tide and low tide is at its maximum.

tidal locking - when long-term interaction between two co-orbiting astronomical bodies causes at least one of the bodies to rotate in such a way that one face of the body is always pointed at the body it’s orbiting. This is also called gravitational locking or captured rotation. An example is that the same side of the Moon always faces the Earth, and its synchronous rotation means that it takes just as long to rotate around its own axis as it does to revolve around the Earth.

Script/Transcript

Sources

Tidal Cycles in Tides Explained via beltoforian.de

“a tide is a distortion in the shape of one body induced by the gravitational pull of another nearby object.”

Meteorological effects on tides via the New Zealand Government website

Tides and Water Levels via the National Oceanic and Atmospheric Administration (NOAA)

Tides by R. Nave, my dude, my guy, my friend and yours, of Georgia State University

The Tidal Force by Neil deGrasse Tyson via Hayden Planetarium (Nov 1995)

“A mild increase in distance between two objects can make a large difference in the strength of the tidal force. For example, if the Moon were just twice its current distance from us, then its tidal force on Earth would decrease by a factor of eight. At its current average distance of 240,000 miles from Earth, the Moon manages to create sizable atmospheric, oceanic, and crustal tides by attracting the part of Earth nearest the Moon more strongly than the part of Earth that is farthest. (The Sun is so far away that in spite of its generally strong gravity, its tidal force on Earth amounts to less than half that of the Moon.) The oceans respond most visibly in being stretched toward the direction of the Moon.” 

“When Earth's rotation slows down until it exactly matches the orbital period of the Moon, then Earth will no longer be rotating within its oceanic tidal bulge and the Earth-Moon system will have achieved a double tidal lock. In what sounds like an undiscovered wrestling hold, double tidal locks are energetically favorable (like a ball coming to rest at the bottom of a hill), and are thus common in the universe.”

Forget “Earth-Like”—We’ll First Find Aliens on Eyeball Planets via Nautilus (Feb 2015)

High Tide on Io! via NASA (Mar 2012)

Tidal forces and spaghettification via NASA handout

Spaghettification via Cosmic Funnies

Single atoms feel tidal force via Physics World (May 2017)

Robbins, Tom. Still Life with Woodpecker. Bantam Books: New York, 1980.

“Being four times larger than the moon, the earth appeared to dominate. Caught in the earth’s gravitational web, the moon moved around the earth and could never get away. Yet, as any half-awake materialist well knows, that which you hold holds you.”

Sobel, Dava. The Planets. Viking: NY, 2005.

Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity

Background Music: ‘Sad Business’ by Patients 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.

Filler Music: ‘It’s Getting Boring by the Sea’ by Blood Red Shoes off their album Box of Secrets

Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught