The growth of black holes in the Galaxy Zoo

The growth of the black holes happens over a large fraction of the age of the age of the universe (z = 1 - 3; from when the universe is 2 billion years old to 6 billion years old). Black holes grow through accretion (gathering stars, dust and other material from around them) and by merging with one other to become the supermassive black holes we observe today. Their mass today is millions to billions of solar masses. Our own supermassive black hole at the centre of the Milky Way has about 4 million solar masses. Most galactic black holes are dormant. However, the ones that are accreting and growing in the process are very luminous objects,  and can be, in principle, observed and understood. They are also very powerful, e.g., the matter funnelled towards the black hole creates enough energy to stop a star from motion.

Why do we care about observing the growth of black holes? Understanding how black holes grow, and how they interact with their host galaxies is an important piece of the puzzle of the evolution of the universe. Meg Urry and her collaborators (including one of her former postdocs Kevin Schawinski, who is now a professor at ETH-Zurich) studied the dependence of black hole growth on the host galaxy morphology.  Kevin S. and Chris Lintott co-founded the Galaxy Zoo, where the public can classify different images of galaxies.  For  example, they separated active galaxies, which are galaxies that each hold a growing supermassive black hole that produces lots of non-stellar light, by morphology. They found that black holes grow differently in elliptical galaxies than in spiral galaxies. It seems that most high mass black holes grow in spiral galaxies and low mass black holes in elliptical galaxies. In elliptical galaxies there may be more mergers, and so this may show that mergers are more important in the growth of low mass black holes than high mass black holes. The Galaxy Zoo facilitated this science. This catalogue is built by volunteers who work on classifying galaxies because they are just too many images for scientists to do all this work. Also, when many people are involved the errors average out and are smaller than when one over-worked postdoc does everything.

http://www.lsw.uni-heidelberg.de/users/mcamenzi/images/Universe_Box.gif

How does the universe evolve from a really hot uniform soup to the complicated structure we have today?

The first light

The oldest light we can see is the light from the Cosmic Microwave Background (z ~ 1100; the universe was about 380, 000 years old), which is the thermal radiation assumed to be left over from the Big Bang. We have instruments both on Earth and in space that are powerful enough to detect fluctuations in the temperature of this light, which are very small - of the order of 1 part per million. These tiny thermal fluctuations are believed to trace slight density fluctuations. The CMB radiation is the first light that can be seen. The universe was not transparent before this time and so we cannot see light that came from an earlier time.

The story of the first black holes

Over time, the amplitude of density fluctuations is amplified by gravity. So, the slightly over-dense regions from the early universe became denser and denser.  Eventually, the dark matter in these regions collapses under its own weight into dark matter halos. These halos then attract H and He gas, which form the first stars (z ~ 15; the universe was 200-300 million years old). The first stars are believed to be different from those we see today in that they are heavy (believed to be over 100 times bigger than our Sun) and almost entirely lack heavy elements. This is all inferred from simulations. The stars eventually collapse to black holes of about 100 solar mass, which grow. These early black holes are much lighter than the supermassive black holes we see today.

I've been referring to z a lot. So, what is z , i.e, the Redshift? 

Most of our instruments detect light, and hence are only sensitive to visible matter. Cosmologists quantify the age of an object through its redshift called z. When light travels from a distant object to us its frequency lowers (lower energy per photon) and its wavelength increases moving towards the red end of the spectrum of visible light and beyond as the light frequency continues to decrease. Today is defined as redshift z = 0. The universe is measured by Planck and other satellites to be about 13.8 billion years old.

Note: This post was inspired by Meg Urry's science talk from April.  I was waiting for ETH to post a video of it so that I can link to it and also clarify some of my own misunderstandings. But there is no video that I can find. The talk and the science she does is very interesting. Of course, I forgot a lot of the things she said by now and got distracted by numerous other things since then. But I thought that the topic was interesting enough to finish the post.

The value of a child's time

A page from "Your Fantastic Elastic Brain" by Deak & Ackerley

Whether we like to admit it or not, the time of a child is most often assigned negative value. 

So, why is a child's time valuable?  A child is both an investment in our future and a way of giving back some of love and care that we received growing up.  When they learn something, they often do it at a deeper level than we do. This is because the neuroplasticity of the brain, which describes our ability to retain new information and use it to shape our brain, goes down with age. So, what we teach our children now, should have more impact on their development than a lot of what they will learn latter as adults.

1. Re-learn to put children first. The family (parents, grandparents, uncles, aunts) is where each child used to receive unconditional love, and it's unclear that there is a substitute for having a loving family.

Note: The love given is not related to the number of pictures or likes to the pictures posted on facebook or to the number of toys given. However, there is some correlation to the time we spend with our children, grandchildren, nephews and nieces.

2. Remember what we received. We should not forget that we have all (or at least most of us) received a lot love and attention to get us where we are today. Raising a child involves giving some of that love and attention back.  If we chose not to raise any children (adopted or our own), we leave a void that is hard to fill. Somehow women seem to feel that void more than men especially in their 30s. 

3. Children learn from many people. Yes, teachers play a very important role, but they often interact with 20+ children a day, and cannot afford to shower too much attention on any one child. So, it's also important to learn from grandparents and extended family from time to time, and even family friends.  Friends are too often replaced by colleagues, who do not have children of their own and are distant and too busy. 

4. Sharing and loving comes with soul growth, and so it's very good for us, too and not just for the people we love. Yes, parenting is hard, but it involves a lot of sharing of what we know and who we are and makes us feel fulfilled (and overwhelmed at times).

5. What should children learn in School?  Schools are not there to keep children out of our way so that parents can work, but to teach them new and exciting things. They should also be flexible and allow a small amount of absences outside vacations as long as they come with some additional learning. When I hear that the purpose of the first year and a half of primary school is mostly discipline with a little practice on reading and writing, I am not too excited. I think the primary focus should be on the new things learned, and, yes, reading and writing are important, but it's perhaps equally important to learn how to think, and how to have fun, and to encourage the building of dreams and aspirations.

6. Improve the local educational system. Schools need teachers who can make learning fun, but are also paid well, and their profession has to be coveted, respected and valued. As the birth rate decreases and the standards of living go up around the world, fewer people will want to leave their families to move to the US or to Europe, and no matter how hard we try to stop progress in countries other than ours, it is bound to happen everywhere due to the flow of information. So, we can no longer afford to have a crappy educational systems - even in poor areas. Some of those children will excel if properly educated and supported. This is a good article in the NY times about a successful approach to improving the chances of college graduation for first generation college students. 

7. We should never take a 'them' vs. 'us' approach. Improving the educational system should not be viewed as taking resources away from 'us' and from 'our children' and giving these resources away to 'them' - these obscure classes of people whom we do not care about. Changes done right lead to long term improvements in the economy. Once the economy grows, everyone gains - the rich and the poor (although former class always gains more than the latter). 

8. Education always starts at home. As a parent/grandparent/etc, it is crucial to love each child, value its time, and if at all possible make sure the school they go to does the same. 

9. Better school, more diversity. If our school systems improve, more people with diverse backgrounds should pass through, and this invariably will include women, black people, etc.

10. Educating women. Just telling women to join the science may help in a few cases, but will not solve the paucity problem. Women educate the next generation together with the men, but we will always do more from the birth to the pregnancy to the breastfeeding and so educating women should be a priority in all countries if we want an educated next generation. 

11. Replace people with robots. We won't need to educate them then.
I don't think robots or enslaving other planets are an alternative path to better education. At least, not yet.  To reach any planets that could be habitable we would need to travel close to the speed of light, and that is well out of reach of modern technology. Furthermore, space travel is expensive.

12. Bad neighbourhoods - bad schools? The segregation should stop. Having some good schools that all the children can attend is crucial.  Even as we automate more and more things, we still need the existent population to be educated and to have emotional availability so that we can be safe and happy.  I believe in the selection and encouragement of talent. Every city area should have at least one good school where talented children can learn things vs. learn to do/sell drugs and being bullied for being talented, and where any child who is talented enough can go. 

13.  Parenting is one of the hardest jobs in the world. We should respect all non-abusive parents and try not to judge because there are many approaches that work and many forms of love. 

Disclaimer:  In retrospective most of what I say here may seem obvious. If my statements sound like platitudes, it may be because they are, but I still felt the need to write them down. Also, keep in mind that my writing stems from my own experience, which is not very broad. I have lived in several countries, but only among people who valued education whether they actually had it themselves or not. I only have on child so far and one nephew I spend significant time with.  I try to do the best I can. I do not aim to be the ideal role model for any person or even the ideal parent. 

Easter vacation in Romania

Ciupi the second and the two ducklings

With Ciupi the 2nd

The ducklings

For two weeks the children had their own pet lamb and two ducklings to follow them around. The ducklings were about one month old and thus big enough to not be in imminent danger from the cats. By the end of the vacation, Edward had the courage to carry one of the ducks across the garden. He felt very strong and smart every time he did it. He would thus come and remind me in the evening that we had to put the ducklings to bed. Ciupi the 2nd was just as friendly as Ciupi the 1st, which is the lamb I had when I was in highschool. We only wished we could have stayed longer.

Easter treats

With Buni Luci's chickens

Investigating baby spiders

Before we left Zurich to go on vacation, we received a package with some Easter candy and treats from Edward's grandparents and two chocolate-Easter chickens from the next door neighbour who regularly gives the children treats.

There was no time to dye or paint Easter eggs this year. When my mom and I were not driving, there was a lot of paperwork to do and people to see. However, the day we arrived in Timisoara Buni Luci (our next door neighbour) gave the children Easter bunnies and chocolate eggs. She also brought us boiled, red-dyed eggs from her chickens, and really good cakes and fresh radishes the garden, which we took back with us. We even planted a very tiny raddish outside our house in Switzerland. It must have gotten pulled out by mistake, but now it's grown quite big. The rest we ate. Mari (a very good family friend) sent us sarmale and cakes and eggs from Clopodia. Tanti Lenuta made fresh orange juice and placinta, and my brother, Mihai cooked wild boar for us. It's the first time he cooked when I was there. I guess it's better to start later than never. My cousin, Delia, also came to see us and brought us really good chocolate and T-shirts for the children, and hair-pins for me. It is always great to see her, and everyone else, of course.

The stone quarry
We visited a stone quarry! It was very exciting! The children climbed

Climbing on gravel

on various piles of gravel and splashed in the water at the bottom of the quarry. The water was much warmer than the Mures river, which flows nearby. We were told the water in the quarry was clean since it is removed every work-day. It was a little muddy. However, I think the probability of it being contaminated by radioactive elements like Uranium is fairly small, and we did not drink it anyway. The volcanic rocks, which broke easily to Edward's delight, were a little tough on our feet. There was also complicated metal machinery for extracting the stones from the mountain, and some fancy bulldozers & other things to investigate.

The run-away boat
Mihai saved a run-away boat that had been taken by the current. It was quite dramatic. The children were crying when they were watching Mihai swim after the boat because they were worried he would not make it back. It was spring and the river was carrying all sorts of trees and trash. 

Pheasants & chicks & little dogs, and wild piglets
We saw pheasants flying by the road and lots of baby chicks in all the farms we visited. One of the
children also had a tiny dog whose name was Haiduc. He had his own little house built for him with the name written on it.

With Grandma on a swing

One farmer showed us two wild piglets they had. They were raising them together with their domestic piglets. They looked stripy, but otherwise similar to the other piglets. The wild pigs can be quite a problem for crops. So, people hunt them and when left behind after the mother is killed, the piglets die if they are not adopted by people. While it is cruel to hunt wild boars when we as people have so much more than animals, it must have been how pigs were domesticated in the first place.

We saw many more birds, pheasants, deer, wolves and wild boars in Romania, Hungary and the rest of Eastern Europe than in Western Europe. This was very evident as we were driving through.  Of course, all agriculture is moving towards monocultures. But some diversity should be encouraged and supported. Otherwise, most wild life will be gone. There should be more parks and forests, and fewer zoos where wild animals are always so unhappy.

Edward's dream 

On Thursday (May 1st) Edward woke up telling me a story. He said he dreamed that all the houses were falling down, but he was not scared because all the people were dead. So, the houses were not needed any more. Instead of people there were dinosaurs and cars and tractors. The machines could all function on their own. However, the crops would run away from the tractors. Then the tractors could not harvest them. Apparently this was very funny. Even the potatoes would run away, which was good because it allowed the plants to live longer. I am not sure what the dinosaurs in Edward's dream ate, but, evidently, this was not a bad dream for him because he likes tractors, cars and dinosaurs. I guess he does not think the world needs anything else.

Dreams, spells and the Kangaru

Lugoj: with Tanti Mia and Costel

Both Edward and David have very vivid imaginations. They each own a "kangaru" in their dreams - which is a flying machine that can do any number of things. It contains a big bed where they both can sleep until late in the morning and pans for cooking pancakes, and lots of candy. And whenever there is something that they are not allowed/cannot have, they will fly with their kangaru and take it. They also pretend to be wizards and compose spells. We read a book about the Buchstabenhexe and were hooked on spells since (no Harry Potter or Wizard of Oz yet).

Since I am mentioning dreams, I should say that we went to Lugoj for a few hours and saw Tanti Mia and Nenea Costel.  They are still just as kind, charismatic and funny as they have always been (I heard how beautiful I am; I am more beautiful than the last time they saw me, and somehow I am going to become even more beautiful in the future) and it's always amazing to see them. Lugoj is still the perfect place on Earth for me and it's present in most of my dreams - although, I admit it is unlikely it will ever be important for my children.

First fine while driving in Europe
I received a fine for not having my lights on in Hungary. It was noon, and the sun was shinning brightly. I was driving slowly on a country road, when two policemen stopped me and fined me in Hungarian. They took almost an hour to write my name on a sheet of paper and then on their computer. It was clearly not because of any safety concerns - they just need money. I suppose the roads in Hungary are good enough and they are building more. So, some of my 30 Euro fine hopefully went to a good cause. However, it was annoying that Mihai had to go back to Hungary to pay it. Since it was in Hungarian, banks outside Hungary did not know what to do with it. Also, Switzerland is outside the EU.

Changing tires

Mihai and the children replaced the front tires of the car. They had fun doing it!

Changing Tires

Note: This post is both overdue and overcrowded with too many things, but it's the best I can do for now.  I am not aiming to include everything - just some fraction of what I remember. I apologize for what I forgot to mention or described too little or too much.

Days to laugh and days to cry

I never used to cry. I never used to get sick. When other people told me they cried or were sick I tried to be compassionate, but I thought of them as inferior. This was ten years ago. There are times I still catch myself thinking that way when I see weaknesses in myself and in others.

 

  One of my best friends from graduate school said she cried almost every day in our first year of graduate school and still often enough afterwards.  I thought it was ridiculous to cry for no "good" reason. The reasons that I considered worth crying for were (1) the death of someone in the family and (2) a serious illness or accident. This is how I was raised. I did not see either my grandmother or my mother crying unless something really awful had happened. Even then, they were always strong and always seemed to have everything under control. It did not make sense that someone who was in her early twenties, smart, beautiful, healthy, living in a city in the mountains full of gorges and waterfalls, and attending one of the best schools in the world would spend her evenings crying. My friend continued to be successful. She received her PhD a number of years ago, has a well-paid job in industry, and is happily married. She said that she chose to work in industry because academia made her unhappy. The office space in the various basements was depressing, and the cold, very competitive, and the sometimes unfair atmosphere was unnecessarily unpleasant. 

I stayed on. As a theorist I do not work in basements, and I do not feel my colleagues are too competitive, but I recently started to cry. Crying still makes me feel weak, useless and inferior. I am also sick fairly often with minor headaches and colds. Nothing really unpleasant, but I no longer feel a tower of strength. I have no good reasons for crying. Zurich is beautiful, and my family loves me. So, why did I cry today? Well...in the beginning of April I started a project with a professor I know well who is really brilliant. As agreed, I drafted a paper over the Easter vacation based on a calculation he did after joint discussion, and then I sent it to him. It's only been 2-3 weeks, but somehow the lack of communication makes me cry. I thought that we established we'd try to finish this project before he went on vacation at the end of May. A week ago he said he'll answer that day, but that day passed and so did 7 others. OK, maybe he thinks what I wrote is total crap and not worth answering to or he just does not have time. Given his one dimensional intellectual brilliancy, I am inclined to believe a combination of the two.  Yes, I know I am behaving like a teenager, and that research takes time, and patience and politically correct behaviour. I am likely upset about nothing. Things accumulate before vacation for many people, but I have several projects with this person which he finally told me will never be finished, and I did not want another one added to that list. I thought this project was short and relatively simple, and that we'd be able to finish it, but now I don't know. Of course,  I have so many other projects to work on. Yet I waste the time that I should be spending doing the many things I need to finish feeling unhappy. At times like this I so want to quit and leave and go do something else, somewhere else. Anything. Anywhere. Not because of this one particular project, but it is just one more thing that makes me feel that I am not fit to continue. 

Will I quit today? Not today or any time in the immediate future. Academia provides flexible jobs to relatively smart people. It's hard to be at the top of a pyramid and it's hard to stay there. However, I now conclude that one does not have to have a "good" reason to either laugh or cry. Whatever the profession, there will be some days when it's easy to laugh and some days when it is easy to cry, and it's ok to do both. Oh...and one does not have to have a profession to either laugh or cry. Such abilities come with being human and being alive. 

Will I quit in the next two or three years?  I am not sure yet. I see so many people who are more talented than I am who quit. Since there is no room for them, it often feels like it would be unfair if there was room for me. I am not sure that staying in academia is the "right" choice for me, but, then, is there a right choice? How is that defined?  I will not be too sad if I had to quit in a few years. As long as I am alive I'll find things to do and try to do them well (from time to time; nobody gets everything right all the time, right?). In the meantime, I will deal with the many immediate problems: moving to another apartment, paperwork, make an effort to finish some of the many existent projects, etc.

Plan: Today I'll go home to my family and I'll be cheerful. I should start working out. It might solve all my problems. Also, I'll practice being less angry with myself and with other people.

Update: I understand that working out & running would have a positive impact on my life, but I am still too undisciplined to do either on a regular basis. I am still not sure that crying for no "good" reason is good, but it's good to be able to feel emotions. To be happy, to be sad from time to time. After all, laughing and crying should make humans feel better. The latter does give headaches when prolonged, but headaches prove that one has a head with a brain with neurons and connections between them, which at times is important to be reminded of.