Science Buddies: "Ask an Expert"

So, my project is finding the center of the milky way galaxy through globular clusters using the top three galaxies. I have a few questions, I realize I need google earth and I've used it but how exactly do you find the amount of globular clusters? Perhaps there's something obvious that I'm missing. Also, I have a data table but am struggling with it, I'm not sure it it is correct, my teacher never gave the ok on it. But she also never said there was anything wrong with it, so you see my dilemma. Last question once you have which direction the globular clusters are pointing, how do you apply this to the data table? The completed data table is due December 12th, sorry for all the questions, I am a sophomore but my prior school did not require students do science fair so I'm still getting used to it. Thank you for any help, it's really appreciated.

I see no other experts have respnded in the past few days, so I will attempt to give you some general guidance here.

First, I am not an astrophysicist nor have I ever studied the topic.

Second, you'll need to give us a bit more information here. I understand you are doing your first science fair project. It is important you follow the "scientific method" for these types of projects. See this ScienceBuddies article to help you with that:

https://www.sciencebuddies.org/science- ... thod.shtml

You need to ask question, do some basic research and then create a hypothesis. From your note, I cannot determine your hypothesis, nor the question you are trying to answer.

I am familiar with the use of Google earth to look at things on the earth, but not in the universe, so I cannot help you there.

Also, in order to help you with your question about your data table, we'll need to understand what kind of table it is, and what data are in it.

If you can provide us with some of this basic information, we'll do our best to help.

Am I correct in assuming that you are interested in the Science Buddies project found at

https://www.sciencebuddies.org/science- ... p032.shtml

I will attempt to start answering your questions on that assumption.

You ask "I realize I need google earth and I've used it but how exactly do you find the amount of globular clusters?" You do not use Google Earth to determine the locations of the globular clusters. You find the location, which for this demonstration is taken to be the Constellation in which the globular cluster is seen, from the data in the large table.

Also, you state "I have a data table but am struggling with it, I'm not sure it it is correct..." I think you may reasonably assume that the table provided in the project "materials" section is correct. If you wish to be extremely rigorous you could check a few entries against standard catalogs, most of which are on line.

Finally, you ask "once you have which direction the globular clusters are pointing, how do you apply this to the data table?" I think you have gotten things in reverse. You use the data in the table to determine the locations on the sky (specified by the constellation's coordinates) in which the most globular clusters are found. Perhaps an analogy might clarify the concept here. Suppose you were in a strange city, looking for the airport. Because of buildings and trees, etc, you cannot simply look for the airport buildings in the distance with, say, binoculars. But you could look around and note in which directions you see a lot of airplanes flying around. Clearly, the direction of the airport would end to have many aircraft visible, whereas looking in the opposite direction you would expect to find fewer airplanes visible. If you wished, you could even systematically count the number of aircraft you see in the direction of each compass point (N,NE,E,SE,S,SW,W,NW): a plot of number vs direction should show a systematic increase in the number of airplanes spotted through your binoculars around some compass point -- and that would be a good guess as to the direction of the airport. In the astronomy case the globular clusters orbit (too slowly to see) around the galactic center just like the airplanes tended to fly around the airport.

Once you figure out in what constellations you find the most globular clusters, then you use Google Earth, to find out where those constellations are on the sky, and hence where on the sky the galactic center may be lurking beyond the dust clouds that obscure our direct view of the center (just like foreground stuff blocked our direct view of the airport). If you find Google Earth to be overwhelming, you could just as well use an old-fashioned paper star atlas that shows the brightest stars, constellations, and even some of the more conspicuous globular clusters. Most libraries have these star maps.

Please read over the procedure given in the project guide carefully. It is actually quite clear as to what exactly to do -- almost too clear since it doesn't leave a lot of room for you to figure out things on your own.

So I've done everything and am stumped on the last few directions. Particularly 10-12, if there's anybody who could walk me through these particular steps that would be great. The project is getting close to it's deadline so any help ASAP is greatly appreciated.

Hello Marina7131,

Step 10 asks you to decide whether the three constellations with the most globular clusters are near each other. Are they neighbors, or are they scattered across the sky?

Step 11 asks you to let Google Earth show you its location of the galactic center. Was it close to your guess?

Step 12 suggests that you use other constellations that have fewer globular clusters and decide whether they point to the same location or whether these constellations are a poorer indicator of the galactic center.

If you are still having trouble understanding the method used to find the galactic center or don't understand your result, please reread the Background section of the project description and try a web search for something like "find the galactic center."

Good luck, WW