HD and the Void

Not enough people in the real world listened to my stories about my recent stargazing adventure, so I distilled my process and plans so that the process of selecting a site and using a stargazing app seems more attainable for those who have never thought of stargazing. Short, sweet, and a story-based glimpse into amateur stargazing for fun!

There are over 3,500 comets that we know of, so this is just a brief overview of what comets are, and then a list of some Great Comets and a few well-known comets. I also discuss some of the missions that various organizations and nations (i.e., NASA, the Soviet Union, ESA, Japan) have undertaken to examine comets up close and personal.

I have mentioned black holes in previous episodes, but now feels like the right time to talk about them in their very own episode! I also discuss the new photos of the supermassive black hole in the galaxy Messier 87 and the telescope that was needed to acquire those photos.

There is a branch of study where rocks and space meet (sometimes to explosive effect, when asteroids and meteorites are concerned)... It can be called planetary geology, exogeology, or astrogeology. Listen to hear more about what the life of an astrogeologist entails, from identifying features from a distance to exploring craters. The Shoemakers' contributions to the field are also discussed in-depth to give you a sense of what astrogeology can involve.

The Coriolis force is a force in physics that has profound impact on us here on Earth. Listen to hear how this apparent force has influence over the weather, tides, and even some creatures. I refuse to talk about the formulas surrounding it but I will discuss Rossby numbers, Kelvin waves, Ekman transport, and the Eötvös effect, so get ready for a lot of scientist names!

From Bortle to Torino, from asteroids to aliens, scientists have been working to classify experiences in a useful way. Some of those experiences are very specific, unusual, speculative, or just bizarre. Hear about a selection of scales currently in use that astronomers made to quantify very strange phenomena.

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.

Edmond Halley was heavily involved in the establishment of modern astronomy, whether through his direct observational work or through the support he offered others in his field. Hear a quick overview of the man who's popped up so much throughout the span of this podcast!

It's a history-heavy episode this week! Hear about the transits of Mercury and Venus, and learn what they have in common with the oppositions of planets like Mars, Jupiter, and Saturn—they're like eclipses, but with planets instead of the Moon.

I live in the Northern Hemisphere of Earth, which means I see some constellations and stars that people in the Southern Hemisphere don't see. The opposite is true as well, and it's more interesting for me to talk about the constellations I don't get to see, so please enjoy an episode on the important constellations that appear in the Southern Hemisphere: Crux, the Pointers, and the Magellanic Clouds. Bonus: Aurora Australis!

I have spoken about radio astronomy, so it makes sense to move on to infrared astronomy. The method for gathering infrared data involves telescopes mounted in planes that can fly above Earth's atmosphere, and there is a rich history of airborne astronomy. Two topics in one!

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.

As Black History Month 2018 wraps up, learn about some of the African-American men and women who have contributed to space research and exploration! 7 astronomers and 9 astronauts shine in this episode, which spans from the 1700s to modern-day folks.

Be brave in the face of an extremely technical episode where I tackle radio astronomy! Astronomers collect radio waves to map distant objects. To do their work they need a level of quiet that's hard to find without some help from Radio Frequency Interference security folks and some governmental regulations. That's where Radio Quiet Zones come in...

January 28th was the anniversary of the Challenger space shuttle disaster, and while I do discuss what happened, I talk more about the American space shuttle program and what the repercussions of this disaster were for NASA as an agency. I have clear instructions on how to skip the description of the disaster if you don't want to hear it.

How to astronauts shower? How many astronauts are on the International Space Station right now? How do you pack enough food for them? What kind of comfortable housing options are available when orbiting Earth? What can you pack and not pack? All these questions and more are answered in this episode on long-term astronaut survival in outer space.

Zombie stars were in the news in November but get in the holiday spirit by hearing about them now! Learn about the life cycle of a star, the power of a supernova, and what undeath looks like in a star.

Dark Sky Reserves exist to prevent light pollution in select areas. Learn about the reasons why these reserves are so important, and also hear about the Bortle Scale, which amateur astronomers use to quantify sky conditions when they are out observing deep space.

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 compilation of everything amazing about planet Earth.

I've talked about dark matter, now it's time to talk dark energy. Learn why it exists as a theoretical (and maybe actual) object, how we see its effects manifest in the universe, and what it means for all our theories if it is or is not real.

In preparation for a future interview with someone who knows much more about astroparticle physics and dark matter than I do, tune in this week for a quick-and-dirty breakdown of a theoretical particle that, if it exists, would clarify a couple of strange things about galaxy rotations and mass. That's right, it's all about dark matter!

This is a short one but I do explain concepts you can see and track yourself over the months with very little effort. The shapes of the Moon and how long it takes different planets to orbit the Sun! Time is a human construct! Tidal forces and the best real, true physics word I have come across so far!

The hardest part of determining longitude was figuring out how sailors could find their longitudinal coordinates at sea. There were a lot of methods proposed but adding a ship into the equation makes precision difficult. Learn about the Longitude Act of 1714 and how, even though this podcast loves astronomy, the astronomical method might not always be the best option.

An overview of the little machines that taught us about our solar system, from Sputnik to future missions into deep space.

Double digits for the podcast! To celebrate, I'm talking about something I've mentioned a lot in past episodes; spectroscopy! Hear about the history of this area of astronomical science, how it opened up new understanding about the Sun and stars and nebulae, and what advancements were made during the 19th and 20th centuries thanks to spectroscopy.

There are a several amazing, prophetic, portentous astronomical events you can see with the naked eye, and two are coming up! Hear about auroras, meteor showers, and the total eclipse that will be sweeping the United States in August 2017.

Eight planets in the solar system or nine? I go into depth with nine because I grew up with Pluto. The first five planets are visible to the naked eye but how did we find Uranus, Neptune, and Pluto? What are we doing to still learn about our closest celestial neighbors? Learn what makes each planet in our solar system special.

Learn about four ancient (and contemporary, if you work on a ship) devices that utilize very specific areas of astronomy to help you figure out where you are and what time it is, and also predict where celestial bodies will be on other dates and at other times. I talk about the armillary sphere, the astrolabe, the sextant, and the Antikythera Mechanism.

Second in a two-part series about stars and how we classify them. Beginning with the lifecycle of stars, which is what classifying stars is all about, I then talk about the various ways we've chosen to interpret observational data on stars, from observing the bright sky-dots to evaluating how bright they are by comparing them to each other, and all the new things we can do with CCD imaging. Hear about pre- and post-telescope star catalogs and especially hear about Annie Jump Cannon and how she formed the basis for the star catalog standard we use today.

First in a two-part series about stars and how we classify them. Variables are a very specific kind of star that have a regular variation in brightness, like a heartbeat. They were first categorized and analyzed by Henrietta Swan Leavitt at the turn of the 20th century at Harvard University, along with other women computers at the time. Leavitt noticed variable stars in the Magellanic Clouds and came up with her luminosity law, where the pulse rates of Cepheid variable stars are proportional to their luminosity—the brighter they are, the greater their period is. This law helped estimate interstellar and intergalactic distances. Cepheids and other kinds of variable stars have helped astronomers map out the size of our galaxy, the spaces between celestial objects, and the distance to the outer reaches of our universe.

Henges are only one type of astronomical tracking and observation monument. Other kinds include using big rocks that already exist and then building something close enough to observe its interaction with the Sun; building an observatory or a big pyramid; constructing something that interacts with the sun in a very quiet, private way; or hauling a big heap of strange rocks in the middle of the chalk uplands of England (hello, Stonehenge!). Hear me read a bunch of quotes from archaeoastronomers about what their profession is, too!

Different kinds of telescopes and 19th-century photographic techniques demonstrate far more vividly than mere words can convey that taking photos of space is VERY hard, but the Hubble Space Telescope is doing it well at age 27! This episode talks about how we got to where we are with cosmological photography. And then there’s the James Webb Space Telescope going up in 2018... Bonus supermassive black holes, and yes I mean the Muse song.

Learn about some of the major cosmological models that scientists through the ages have assigned to our universe, even when the known universe was only as big as our solar system. I talk about Claudius Ptolemy, Al-Hasan Ibn al-Haytham, Nicolaus Copernicus, *dreamy sigh* Tycho Brahe, Johannes Kepler, Galileo Galilei, Giordano Bruno, René Descartes, Sir Isaac Newton, Pierre-Simon Laplace, Albert Einstein, Edwin Hubble, and finally the most common cosmological model accepted today (because it wouldn't be current science if everyone agreed on it).

Welcome to the first episode of HD and the Void, space edition! Start at the beginning of the universe with the Big Bang, then zoom to the beginning of records of humanity's astronomical observations with the Mesopotamian star chart MUL.APIN. Bonus fun facts: cosmic microwave background radiation, star catalogs, the constellation Triangulum, different kinds of calendars (solar, lunar, and luni-solar) and how to use constellations or seasons to track them, goat-fish, and retrograde motion.