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Fall SAVY 2013, Week 6 – Astronomy (5th/6th grade)

Posted by on Monday, November 4, 2013 in SAVY blog.

Ah, the bittersweet end of SAVY. It never feels like enough time…

This week we thought BIG and talked of galaxies, the Universe, and life out there! We utilized one of the big tools a scientist has: ESTIMATION. Especially for astronomers, we have to estimate a LOT because the Universe is so huge and we just can’t look at all of it.

The first part of our BIG thoughts was a discussion of galaxies. We looked at the Hubble Ultra Deep Field (image, Wikipedia, STSci Press Release). Ask your student about how the HUDF relates to a dime!! We estimated the number of galaxies in the image by counting a little section and then multiplying by how many sections there were. We also looked at the newer version, the Hubble Extreme Deep Field (image, Wikipedia) – it adds data from infrared light to get more galaxies. One can also look at the HUDF in closer detail using the HUDF SkyWalker site.
In the end, we found that there are about 10,000 galaxies in the HUDF!!

From the HUDF image, we looked at the different kinds of galaxies out there (spiral, elliptical, irregular) and the Hubble Tuning Fork classification scheme (image from the Sloan Digital Sky Survey (SDSS)). Check out the data and activities you can find linked from that Tuning Fork website!

One can’t talk about galaxies without talking about how they can crash together and merge into a larger galaxy. Many astronomers work on computer simulations of this kind of event because we see EVIDENCE of such merging happening. There is an excellent YouTube video entitled “Galaxy Collisions: Simulations vs. Observations” that shows a computer simulation and how that simulation can show some of the interacting galaxies we see from the Hubble Space Telescope (that video plus a further playlist from me is here). This kind of “simulations vs. observations” technique is by far the most commonly used thing in astronomy because astronomers can only use computers as our laboratories – everything in the Universe happens so slowly (on human timescales) and so far away…
A way for YOUR student (or yourself?) to try crashing galaxies together is by using the GalCrash website. This was developed by some astronomers who do computer simulations for the general public through part of a grant from the National Science Foundation. Play with it and see if you can get any crashed galaxies to look like the images from Hubble!

After that we had to talk about some of the HUGE numbers in astronomy AND estimate the number of stars in the (observable) Universe. First we found out about the Names of Large Numbers then we worked on our calculations.

Once we figured out there are about 50 SEXTILLION stars in the Universe, we had to talk about life in the Universe for a little while. We used the Drake Equation to facilitate our discussion (EXCELLENT Wikipedia article, interactive BBC infographic, simplistic calculator). By the way, the Wikipedia article is top notch. One thing you have to know about the Drake Equation. I can’t say it any better than Andy Kaiser in an article: “The Drake Equation is indeed important. But realize what it‚Äôs intended to do. It‚Äôs not meant to predict or prove anything. It‚Äôs not supposed to impart hidden knowledge. It was designed to help discuss the possibility of life on other worlds, and to better define our lives in this incredible planet, galaxy and universe.”
This equation is a discussion starter and I hope it generates some discussion in your home.

FINALLY, our personal star party on the Vanderbilt campus will be held on SATURDAY, November 9 starting at 7:00 p.m., ending between 9:00 and 10:00 p.m. I know that it is after our sessions are done but we discovered many conflicts on Nov. 2.
Here is the URL for the Facebook event! Be part of it if you want weather information!

I hope to see everyone again and it was great being your teacher!
Have a great rest of the year!
– Dr. G (Erika Grundstrom)