Podcaster: Host: Dr. Carrie Nugent ; Guest: Dr. Ramirez
Title: Eternal Sunshine of the Galactic Center
Organization: Spacepod
Link : Twitter @listen2spacepod, www.listentospacepod.com
This podcast has been aired in: http://www.listentospacepod.com/episodes/2016/7/3/episode-52-eternal-sunshine-of-the-galactic-center-with-dr-ramirez
Description: Hear stories about the alien worlds orbiting our Sun, of cold stars, and the future of space exploration. Every week, scientist Dr. Carrie Nugent chats about an amazing part of our universe with an expert guest. Spacepod is the podcast that gives you an inside look into space exploration.
Bio: Host: Dr. Nugent is a scientist studying asteroids.
Guest: Dr. Ramirez is an astronomer at the Infrared Processing and Analysis Center at Caltech.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2015, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org
Transcript:
Nugent: Welcome to Spacepod. I’m Carrie Nugent. I’m a scientist on the NASA NEOWISE Mission studying asteroids. I have a pretty cool job and one of my favorite parts is getting to meet all of the interesting people who spent their days exploring space. Each week I’ll introduce you to one of those smart folks and ask them to tell us about their corner of the cosmos. Today, I’m very delighted to have Dr. Solange Ramirez. Solange is an astronomer at the Infrared Processing and Analysis Center at Caltech.
Welcome to the podcast.
Ramirez: Oh, I’m thrilled to be here.
Nugent:Excellent. So, Solange, she requested an iced mocha which is an excellent choice. It’s really hot outside. How’s your drink?
Ramirez: It’s amazing. I actually love iced mocha. It combines the sweetness and kind of savoury of the coffee. That is what I like about it.
Nugent: Excellent. So, Solange studies the galactic center. What is the galactic center?
Ramirez:The galactic center is an area in the sky that is located at the center of our own galaxy which is the Milky Way. It’s a very interesting place because it is very dense. It has a lot of stars. All this material is bound to the galaxy by the central black hole that lives in the center of the Milky Way.
Nugent:So, there is a giant black hole in the center of the Milky Way? Can you tell us about it?
Ramirez:Yes. In fact most people that are interested on the galactic center do science that is related to the black hole. People at Caltech and UCLA for example studied how the stars orbit this black hole and try to estimate how massive it is. The current estimate is about a few million times the mass of the sun.
Nugent:Wow. This exceptionally large black hole, is it different from the normal black holes most people think of?
Ramirez: Yes because the normal black holes are remnants from a star. Usually their masses are around the mass of the sun which is about one, one solar mass. This one is a few million of that size. So, it is, that is why it’s called a super massive black hole. It is actually believed that these kinds of objects are in the center of many of the galaxies, many of the spiral galaxies that are similar to the Milky Way.
Nugent: That’s really, really cool. Just to back up a second. What is a galaxy?
Ramirez: What we need to think about is gravity. Gravity binds mass together. There are these sets of billions of billions of stars that are bound together by gravity. Started by the central objects that are in the centers of these galaxies. But also by the gravity of everything else that makes a galaxy. There are two different types of galaxies depending of the morphology. There are spiral ones that have those branches that are in many of the pictures that we see. But there are also irregular galaxies that can have many forms. There are elliptical galaxies that are like big elliptical globes. The Milky Way is on the spiral galaxy. The area of the galaxies that I am interested on is really on the center whether it is very, very massive and there is a lot of what is called tidal shear and makes an environment that is very unique for forming new objects, for forming new stars.
Nugent: If we happen to be on a planet towards the galactic center or around of all these stars what would the night sky look like to us?
Ramirez:Probably the night sky will be very bright. Maybe as bright as the day like we have right now.
Nugent:There are so many stars.
Ramirez:Because there are so many stars around that the combined light of all those objects will probably be day time. Even if we are revolving around only one [star], we are getting the light from everything that it is around. This is very, very dense. Because it is so dense, it’s always been believed that stars are very hard to form there because there is a lot of gravity to be competing and then you will not form the initial course for forming new stars. But there are other signatures in the gas like the temperature and the luminosity of the light, what is called the radiation field that basically indicates that there must be new stars forming there. That is how I got interested in this topic and it’s because okay, theoretically you cannot form stars. But what you see is that you’re forming it.
So, how is you actually put those to ideas together?
Nugent: So, are you looking for these new stars with your observations?
Ramirez: Yes. So, I was a few years ago I was involved in a project with the space telescope, the data map in the center of the galaxy. I made a catalogue of about a million sources or stars. From that catalogue we started a study of these objects in particular. We selected hundreds of them to actually take spectra because from the spectra of the stars you can actually determine the temperatures, luminosities, and other parameters that can tell you if they are young or not.
From that 100 we determine that about a third were actually young. We had a press release in 2009 which was a lot of fun to me. The title was baby stars jumped in the galactic center, something like that. It was one of the first detections of these massive stars in that area of the galaxy.
Nugent: That’s so cool. Have there been theories proposed about why you can’t have baby stars now? Does this lead to new discoveries in the theoretical understanding of how this works?
Ramirez: Yes. There is some theoretical… it is kind of funny because we know so much about star formation and we know so little at the same time. There are a lot of parameters and physics that in other part of the galaxy they are not as important as they are in the galactic center. Whenever scientists, at least right now scientists don’t understand something very much they said, “Oh that must be the magnetic field.”
So, there are a few theories that involved magnetic fields as a way of helping the formation of the stars that will eventually form stars that can make this happen. But still it is very unusual medium and it’s very good source of new knowledge.
Nugent: That’s awesome. It sounds like what you’re saying is that there is so much going on there. There’s so many stars and so much gravity that you really have to use every little bit of physics you know of. And in other places you can make a lot of approximations perhaps because it’s not as dense, but here you need to take into account all the forces.
Ramirez: Absolutely. That is exactly what I’m saying. When astronomers study star formation they usually try to do it at a very isolated area so they can actually isolate the physics and say, “Oh, this is how I’m forming the stars,” with very simple models that basically have gravity and nothing else. When you go into these other environments that are more complex, then you need to put other types of physics like magnetic fields and do more work on the tides, for example, and put in everything.
That is difficult. So that is why people usually don’t go in those areas to start. But, on the other hand it is challenging. One of the things that I like about science is that it challenges your mind and what you know about the world and the universe.
Nugent: So, you mentioned including the magnetic force. Is that the only type of force they have to include or do you have to get really exotic stuff like the strong force or the weak force?
Ramirez: They usually don’t go out as far as that.
Nugent: Well, that’s goodIt’s hard to enough with the magnetic force as well. So, let’s say I wanted to see the galactic center with my own eyes; could I just go outside and look at night?
Ramirez: You can go outside and look at night but your eyes will not actually see the galactic center. What you need to think about is in the galaxy the location of the sun is within the plane. Within the plane there is a lot of dust. The dust obscures visual light. So, when you’re looking through the galactic center you’re basically looking through the whole amount of dust from the whole galaxy, and that is a lot.
Nugent: That’s crazy. So, you know, there are so many stars that if you were there you wouldn’t even have a night time like we know it. But you can’t see it because of the dust.
Ramirez: You cannot see it because of all the dust. So, when you go outside in a very dark place and you look at the Milky Way, and you look close to, for example, the constellation of the Scorpio and where the tail of the Scorpio is, you are going to see a blob of nothingness. That is where the galactic center is.
Nugent: Interesting.
Ramirez: In fact, the galactic center itself was observed in the late 1960’s when the technology on infrared started to come up because infrared goes, the infrared light goes through the dust. That is how you see the galactic center.
That is the reason why I have used the Spitzer Space Telescope to study the galactic center because that is an infrared telescope.
Nugent: Thanks again, Dr. Ramirez for being on the show. And now we’ve heard all about the galactic center, we got to hear fun facts about Solange.
She’s going to tell us how she was interested in astronomy.
Ramirez: I grew up in a town in Chile, in South America. This town is called La Serena. This area of Chile has a lot of clear nights. For that reason, that time at least while I was growing up there were three international observatories, astronomical observatories in the area.
When I was in second grade, we went to field trip to one of these. I remember getting into this humongous building with a round shape and getting in to where the telescope is.
This telescope was the four meter Blanco telescope at Cero Tololo.
Nugent:Awesome.
Ramirez:I remember walking in and seeing this amazing telescope, and I thought, I want to play with that. So, that is how I really got interested on it. From Chile to Caltech it has been a long journey for me for going to school in university in Chile and then coming for a PhD here at the United States. And then, staying and having the amazing opportunity to work in an institution like Caltech. I have gone back as an astronomer at the four meter telescope in Tololo and I’m still amazed about what it is and what it can do.
There is a second part of the story. The story is that when I was in second grade I was diagnosed with dyslexia. More or less by the time that I visit this telescope. After this field trip I came back home. I told my Mom that I wanted to be an astronomer that these telescopes were amazing. I remember that it took her a couple of seconds to respond back. She said to me, “If you work hard and you are perseverant, you can do whatever you want.”
Years later when I was about to come for my PhD in the United States, my Mom made a confession to me saying that that was one of the hardest moment as a mother because when I told her that I wanted to be an astronomer she saw a little girl that was struggling at school, that it didn’t know what it was going to happen. But she said that she cannot limit my options. Her answer actually made the whole difference for me. At that time, more or less about that time I was told I was never going to learn a second language and English is my second language.
It’s almost a long journey but science and learning and experience is just amazing.
Nugent: That’s just so powerful. Thank you so much for sharing that.
I hope you enjoyed this week’s episode. Visit us at listentospacepod.com and we’re at @listen2spacepod on Twitter.
The views expressed here do not reflect the views of my employer or the employers of my guests. Thanks for listening.
End of podcast:
365 Days of Astronomy
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