Category Archives: Sun

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! ;)

Radiation and Astronauts

from National Geographic - Biggest solar flare in 4 years

So the Sun flares and bubbles and boils – we’ll learn lots more about that later in the semester.  But when the Sun is doing its thing, what is happening to the astronauts?  And how can humans survive a trip to Mars?

A Facebook friend who works at Goddard Space Flight Center shared a photo and a post by a friend of hers who works with astronauts.  The source of the information in the post is actually from an article on NASA’s homepage and you can find it here.

On that page you’ll find graphs and links and a great description of why it’s actually kind of nice for astronauts to be in the “Solar Maximum” :)  How cool is that!  There are other links on that page to the “Phantom Torso” they study and you can find more for yourself.  In class, we’ll talk about some of the issues of human spaceflight during the last few days of class.

Reflecting, while I am an astrophysicist, I don’t want to be an astronaut right now (and actually never really have)…  Kinda odd many might assume…  But the thing is, I really REALLY want to go see stars and how they work and what weirdo ones look like up close!  But I can’t do that yet – we don’t have the technology :(  Until we do, I’ll keep my feet on the ground and watch the awesome data that comes back to us :)