The 2017 Nashville Eclipse!

In class yesterday we talked about eclipses and so here’s the post about it!

The totally awesome (and very dedicated) Mr. Eclipse (i.e., The Ultimate Resource for Eclipse Photography) is a favorite of NASA so they use his diagrams on their eclipse website.

The foremost resource for the 2017 eclipse is  The Interactive Google Map they have linked is AMAZING.  The image below is from that map.  The Wikipedia article is pretty good as well.

Path of the 2017 Total Solar Eclipse.  Can't see totality unless within that line.

Path of the 2017 Total Solar Eclipse. Can’t see totality unless within that line.

On the map, you can zoom in and click on a location which will bring up information about time of partial eclipse start/end, totality start/end, duration of totality, and anything else you might need.  The map also has information for areas in the partial eclipse regions.

You should make plans!!

Ooo, you can also see a great map here of total solar eclipses in the US in the next 50 years!!  Make more plans!

For my 2014 class…

If you’re in my 2014 Solar System class, please put a comment here showing that you’ve found my blog and that you’re following it :)  Please include your first name and last name initial.  Note that you MUST be logged in to your own WordPress blog when commenting!

Also make sure you have bookmarked the big class blog aggregator: Astro201 – The Solar System.  From there, you can follow everyone or specific classmates if you like.


The whole asteroid thing!

There have been some pretty amazing things going on with asteroids the past couple of days, namely the passing of Asteroid 2012 DA14 and the Russian Meteor Event.   But they were completely unrelated!  Here is an excellent infographic for you (click to make bigger):

Infographic from The Telegraph (UK)

Infographic from The Telegraph (UK)
– click to make bigger

We weren’t going to be seeing that little 50-foot asteroid coming at us from Sun-ward…  The Sun is the most powerful gravitational slingshot in the Solar System but if we know the trajectories of ALL little rocks in the Solar System, then we could know a bit more.  But it will take a LOT of observing time to see them…  These little ones (like the Russian one) are VERY difficult to see, I just don’t see us catching them all but we can sure try :)  I think we just need a big force field ;)

Here are some of my favorite posts about the Russian event:

Moon Landing Evidence! :)

In class today (Wednesday), I showed some of the lunar landing footage available to we, denizens of the Internet, for FREE!  NASA is a public entity and as such, happily will show us many awesome things and has given us the Apollo Lunar Surface Journal (ALSJ).  Much of the text was written by former astronauts from the missions themselves and many of the best/crowd-favorite clips provide some context.

Whilst meandering the internet last summer looking for great astronaut videos to use in outreach, I came across this great website: Top 10: Videos From the Moon Landings (from How It Works Magazine).  I’d already found some of them in browsing the COPIOUS video clips in the ALSJ but this website really does have some of the very best :)  My favorites almost always involve the Apollo 17 mission it seems (this is a FANTASTIC Wikipedia page – check out the multimedia at the end!!)…  But I suppose that one was the one with the geologist and he seems a bit more jovial than the others sometimes :)

In the end, don’t let anyone tell you we didn’t land on the Moon.  You can find “Bad Astronomer” Dr. Phil Plait’s debunking here along with a page of several links to debunkers (and deniers!).  You can find the Mythbusters episode debunking here (never mind – you have to find that yourself, they keep taking the versions I know down).  You can find an excellent debunking website called here.

Hypatia – Historical Astronomers in Context

<note to students: I went farther than you need to because no one can use Hypatia as their historical figure>

Hypatia – 350?? to 415 C.E. pic source Mathematician, astronomer, philosopher, teacher

Hypatia was the first woman KNOWN to contribute to mathematics and science.  Her father, Theon of Alexandria, was a well-known academic and taught his daughter to follow in his footsteps.  Remarkably, she was the head of the Platonist school of philosophy in Alexandria, Egypt.  She was advisor to rulers and sought out by scholars and those who wanted to learn for she was famed for her oratory skills, her sharp mind, and her virtue.  She worked on astronomical bodies and tools (astrolabes especially), on density, and abstract mathematics of the day.  Her greatest contribution to mathematics turned out not to be an original work but one that described the mathematics of conic sections (ellipses, parabolas, hyperbolas) in a manner more easily understood than the original author.  Unfortunately, she is perhaps most well-known for her manner of death: a mob of Christian fanatics kidnapped her, took her to a church, stripped her of clothing and then of her skin using roofing tiles, then burned her mutilated body.  Many historians say this event was really the end of rigorous scholarship in the once great city of Alexandria.

Other sources of interest about Hypatia:

  • Hypatia biography (from University of St. Andrews)
  • Biographies of Women Mathematicians: Hypatia (from Agnes Scott College)
  • Women in History: Hypatia (Humanist Network News Ezine)

Contemporary person:

Contemporary events:

  • Stained glass starts getting used in Roman churches
  • The Sack of Rome by the Visigoths (410 CE) – basically ended the Western Roman Empire (though the Byzantine (Eastern Roman) Empire lasted another 1000 years).  Generally said to be the end of “classical history” and the start of the “Middle Ages”
  • Hadrian’s Wall (separating “barbarian” Scotland and “civilized” (a.k.a. Romanized) Britain) is overrun for pretty much the final time and allowed to fall into ruin (406 CE)
  • In China – Jin Dynasty
  • In IndiaGupta Empire (“The Golden Age of India”)
  • In Africa – People start settling the area of the Great Zimbabwe (but don’t build stone structures yet)
  • In Mesoamerica – the Maya and Zapotec were the most well-developed cultures but were mostly city-states with Teotihuacan as the most powerful (too early for Aztec)
  • In America – Southwest: Late Basketmaker II Era ; In Midwest/East: Hopewell Culture
  • In South America – most significant cultures are Moche and Nazca (the ones with the lines) (too early for Inca)


I really enjoyed seeing what was going on in the world of Hypatia’s – the things that affected her spheres and what was going on throughout the globe.  Hypatia’s specific world was one where scholarship was valued but it could really be affected by the politics of the era, especially with fanatic Christians.  It seems once Christians of the day got a bit of power or really just stopped being murdered, they adopted some of the same intolerant tactics.  She just happened to be in the wrong city in the wrong time period but she did get to live a scholarly life and be appreciated by MANY in her rather long (for that period) lifetime.  However, she lived when the mighty Roman Empire was finally defeated – what a strange time!  The Western Empire (i.e., not Byzantine) was floundering anyway but that Visigoth sack of Rome was so disheartening to the people of the day.

Elsewhere in the world, I found that what was going on in the Americas particularly interesting – I always have trouble with putting the ancient American civilizations into context.  We hadn’t gotten anywhere near Incans or Aztecs or Iroquois, but the civilizations that were there were mighty themselves.  I always wonder at what we’ve lost over the years from American cultures (from idiotic conquerers), from Mediterranean cultures (from the fires that happened at the Library of Alexandria and from religious zealotry), from just the passage of time…

For my 2013 class…

If you’re in my Solar System class, please put a comment here showing that you’ve found my blog and that you’re following it.  Please include your first name and last name initial – let’s not have last names :)

Also make sure you have bookmarked the big class blog aggregator: Astro201 – The Solar System.  From there, you can follow everyone or specific classmates if you like.


Slime molds are smart?

During class on Wednesday, I promised that I would post this story that I read on slime molds following the interstate system.  By the way, this is related to astronomy because “astrobiology” is part of astronomy :)

Photographic evidence!

Click to go to Gizmodo story

Slime molds on a US map - they start at the capital city and there is food (oats) at major urban centers - look at how they grow!

The scholarly journal article is from the preprint server called arXivAre motorways rational from a slime mold’s point of view?  They study 14 different countries and find that, in general, yes, they are rational :)  The Gizmodo article (“Slime Mold and Highways Take the Exact Same Paths“) is also a great synopsis.

What I find just awesome about this is that it seems the interstate system grows pretty naturally.  This makes sense because usually, big highways are the result of people (or animals) going from one place to another and finding the best route…  Why break new ground?  I’ve always felt that certain roads, especially in Atlanta, GA, are really just paved-over cowpaths… Only cows can meander so much in order to be lazy :)

Astronomically, it IS an early spring!!

So I read this article and I had to share it with you – I think it’s very good :)

Article:  Spring Arrives With Equinox Tuesday, Earliest in Over a Century
by Joe Rao, Skywatching Columnist

As an introduction, here in Nashville, we’ve been experiencing a really mild spring – personally, I’m pretty happy about it because I go observing with the lab students a lot and it’s been so nice to not have to bundle up ;)  Thus we’ve been having an early spring meteorologically.

But let’s think about what the start of spring means ASTRONOMICALLY.  The start of spring is technically the date of the vernal equinox which technically is when the Sun’s position in the sky goes from being in the southern celestial hemisphere to being in the northern celestial hemisphere.  You can see this with Stellarium!!  Plus you can see how the actual location of the equinox in the sky (comparing it to the constellations) changes over time – this is called the precession of the equinoxes and it is why we are entering the Age of Aquarius!

Heliocentric vernal equinox

The vernal equinox location (see arrow) according to the heliocentric perspective.

Geocentric vernal equinox

The location of the vernal equinox according to a geocentric view

Here’s a lovely graph from Wolfram Alpha that shows the date of the vernal (spring) equinox for certain time periods (see axes ;) ):

Date of the vernal equinox VS time - from Wolfram Alpha

Note that we’re bottoming out for our cycle in the left graph (stupid axes if you ask me so it is kinda hard to see).  The short-period cyclic nature on the left shows the “resetting” every leap year and then the big jumps on the right plot show the effect of not having a leap year during century years (i.e., 1800, 1900, 2100, 2200) unless those years are divisible by 400 (i.e., 2000).  To learn more about this (and to see a better graph), go to Wikipedia :)  Dudes, on Wikipedia, I learned about the Iranian calendar which has 8 leap days in every 33 year time period – it’s more accurate :)

Anyway, the aforementioned article is a good article – Dr. G approved! ;)

Awesome Planetary Formation Videos

Computer Model of Planetary Formation

In class on Monday, I showed a whole bunch of videos that show planetary formation – some showed certain parts better than others but they all are pretty awesome.  Just in case anyone wanted to look at them again, here they are:

  • Short, beginning of formation (from gas cloud to disk) from ESA – here
  • By NASA for the James Webb Space Telescope, uses data from computer models – here
  • Narration by Harrison Ford, I like that it has some timescale information in it, part of a larger series – here
  • From “Space with Sam Neill” Episode: “Star Stuff”, I really like how this one is done (I started it at 1:27) – here
  • If you liked the “Formation of the Moon” video from the end of class (it does happen to be one of my favorites despite the speeding up of some events that they did), it is here


Below is an image of the Orion Nebula (we can see it during our observations this semester ;) ) from the Hubble Space Telescope showing some of the protoplanetary disks that have been found in this nebula.  Look!!!  New baby planetary systems! :)

Click to go to the Astronomy Picture of the Day website for this image.

"Proplyds" (protoplanetary disks) in the Orion Nebula

Go outside on March 12 and 13!!

Mercury, Venus, and the Moon aligned. Taken from Paranal Observatory in Chile, March 2008 by Yuri Beletsky.

Right when we come back from Spring Break, we will be able to see a planetary conjunction!  You will be able to see Jupiter and Venus be within three degrees of each other and that’s an especially close separation and will be especially brilliant due to the biology of your eyeball – they will be so close that the “hi-def” part of your eye (the fovea) will be activated.  Here is a NASA article about it: Cold and Spellbinding: An Alignment of Planets in the Sunset Sky

Note that this conjunction is just the kind of thing that early astronomers were trying to predict using the Geocentric (Ptolemaic) model of the Solar System (with all of the epicycles and such).  To be honest, the geocentric model worked pretty well at the beginning, but errors combined over the centuries.  This conjunction is also the kind of thing that astronomers used the Heliocentric model of Copernicus to predict but was just as inaccurate due to Copernicus’ need for perfect circles.  Kepler’s models helped take care of the prediction problems thus the heliocentric model became the accepted model of the Solar System :)

To see how the conjunction works, I’ve put a line on this picture from the NASA/JPL Solar System Simulator.  Note that the line from Earth passes by both Venus and Jupiter :)

Solar System on March 12, 2012

Solar System diagram for March 12, 2012 to illustrate the conjunction of Jupiter and Venus. Note that Venus and Jupiter are along the same line-of-sight from Earth.