Why is Cosmology so amazing?

Cosmology is basically the study of the physical origins of the whole Universe, its evolution, future and fate so it basically has to do with some of the amazing big questions that all of us dare to ask but few of us dare to actually try to understand in a serious way.

As a cosmologist in formation, I want to tell you why Cosmology is incredibly amazing and why we should be encouraged to keep seeking answers for those primordial questions that we have when we were kids such as "Where does everything come from?", "What is the Universe?".  In my personal experience, I must say that being a kid who was passionate for physics and space made me very enthusiastic about those questions. When I did my undergraduate education in Astronomy (for five years) those questions became even more interesting and complicated "What is the fate of the Universe if it is expanding?", "Will it expand forever?", "What exactly is the Big Bang?", "What the hell is dark energy?", "What do people even mean by dark matter?", "Does the Universe come from the other side of a black whole that swallowed another Universe?", etc.

Now that I am an astronomer and I have the opportunity to study Cosmology at a first world graduate level, I feel like those questions have become part of my life (not only because I have to do homework assignments, research and exams about them) but because I find them more beautiful and amazing every time I think about them.

To be quite honest, I didn't have a strong background in Cosmology before coming to the Netherlands for my master education, so I pretty much made the decision of studying this specialization for curiosity even though I didn't know nor understand much about it. But today as I write this post, I feel like I have made the right decision because I have always wanted to be part of something great and I think the advances in Cosmology are huge for science and humanity in general. Maybe it is the way to go if I want to accomplish my dream of working with top level scientists around the world in very cool things like understanding what the Universe actually is.

Let me try to quickly convince you about how cool and interesting Cosmology is in the context of our current most accepted model, and why I find a sublime motivation in studying this hard branch of physics and astrophysics. Let's state the basics (with no mathematical or physical details):

The very first step to do Cosmology is trying to understand the first stages or the Universe, so we need to start from the basic and natural question which is "How can we learn about the past of the Universe?". As a very basic and non-precise way to answer this question, we note that because all the astronomical objects we observe are going away from us, we assume that the Universe is expanding, so it must have been smaller in the past; the further we go back in time, the smaller the whole Universe was and at some point in time it must have been infinitely small. That simple view of the evolution of the universe is what we know as Big Bang.

The further we can physically see (with our current technology) in the past is the afterglow of the Big Bang (when the photons were able to decouple from the particles so that they could leave this very dense plasma) that we see as a microwave radiation that we call cosmic microwave background (CMB). This is our most precious relic in cosmology, because it allows us to test our theoretical models of expansion,measure the flatness of the Universe, it sets constraints on our basic assumptions about the first observable emission of photons, etc.

The Cosmic microwave background as mapped by Planck (with corrections and modifications).

After the decoupling of photons and the expansion of the universe started it is obvious that some structure started forming in the form of galaxy clusters and large scale structure that we observe today, but how did that happen?. The accretion was not simply a gravitational pull caused by ordinary atoms in over dense regions, the story starts to become more complicated because we need to introduce a different form of matter responsible for the formation of structure.

Observations from rotational curves of galaxies show that they rotate faster in their outer parts as it was expected, the clustering of galaxies, gravitational lensing and other observational effects made scientists came up with the idea of the existence of some strange type of matter that doesn't interact electromagnetically so you can only trace its existence by its gravitational effects, they didn't know what it was so they called it Dark Matter (things are getting really strange). This form of matter would be the one that would create the gravitational potential wells that would make ordinary matter (matter that emits light) come together and form galaxies.

We don't know what dark matter is, but we think that it must be

 there given its gravitational effects.

Now, our observations show that the Universe expands, but not only that, it expands at an accelerated rate (See a previous post about the accelerated expansion of the Universe: http://bit.ly/2gjdYee) so there had to be an explanation for this to happen. This is when Dark Energy came to the game, but it was not only a small parameter to include in Friedmann equations, it became the dominant component of the Universe, being about 70% of the composition of the Universe (things are getting even worse).

So what is the panorama in Cosmology right now?. Well, in a very simplistic way, we have a theory that says that the Universe started in a "Big Bang", then it continued expanding and dark matter was the responsible for creating the large scale structures we see today, and its expansion has been accelerated for a non-understood dominant component of the Universe that we call Dark Energy. This model is called the Lambda-CDM model.

No matter how beautiful you think this model is, you cannot hide the fact that it has great problems that we need to solve, just to name a few (again with no details) we have:

The flatness problem: The Universe seems to be very flat in our CMB observations but a flat Universe is a very unstable Universe that could not have lasted for so long and it would have had to be extremely flat in a precise way that we don't think should be the reality.

Small variations on the flatness of the Universe in the early Universe would result in very

 different fates for the Universe.

The horizon problem: Some parts of the universe could not have been in casual contact in the past so that they were not able to interact thus becoming homogeneous, but the observed CMB is very homogeneous which suggests that there has to be some mechanism like "Inflation" (a short period of time in which the Universe had an exponential acceleration) to make this problem have a congruent solution.

Dark matter and dark energy: About 95% of our Universe seems to be made of something whose nature we absolutely ignore.

Components of the Universe in the Lambda-CDM model.

The singularity associated with the Big Bang: Although many cosmologists would say that it is not a problem with the Lambda-CDM model because the model doesn't go that far, it is still a huge problem in all of our current theories of the beginning of the expansion.

So the conclusion is, we don't know much about the Universe!, we are really ignorant in this time of history and there are a lot of questions to be solved, but this is not necessarily a bad thing, because it means that there is a lot of work to do and maybe a huge advance could be nearly at hand, also there is more work for us cosmologists and we can try to really solve the questions that we had as kids and that now have become even more wonderful.

Regarding this idea that a huge advance in cosmology could be at hand, I must mention that a few days ago, an interesting paper by Erik Verlinde, a renown theoretical physicist from the Netherlands was published. In his studies, he attempts to show that the behaviour of astronomical objects related to the existence of dark matter and dark energy could be explained with a different approach in which the properties of the vacuum entropy and the entanglement in quantum scales made space time behave the way it does in those large scales, although his theory has still many flaws, this is just a great example of how interesting this topic really is and how diverse the ideas can be postulated to solve the puzzle.

One of the most encouraging things that I have had lately was a talk by a world wide expert in the field who made me love Cosmology even more. It was Mark Trodden from the University of Pennsylvania who gave us a talk about the work that is currently been developed in the context of these great problems in Cosmology, mostly regarding the use of scalar fields that make space time behave the way it does, it was simply amazing the way he showed to us the work of many great scientists all around the world.

A huge top level bunch of scientists are currently doing their best to help humanity understand this universe where we live. This is why I think it is so important to keep myself motivated with Cosmology because although every day I realise that it is really hard and challenging, I also realise that it is incredibly interesting and that the dream that I have always had about being part of something great can be fulfilled in this beautiful field of science. Maybe I won't be able to help at all in the creation of a nice theory, but that doesn't mean I shouldn't try to do it. In fact, I can have a great time understanding a little bit about the origin and fate of our Universe, that can be a beautiful motivation for a lifetime.

To all my cosmology friends, professors, and future scientists, I hope you keep on working on these questions because we are a small community and humanity is counting on us to make the difference and get every time closer to understand our position in the Universe as thinking beings.

The beauty of understanding the Universe.

As many of the ideas, concepts and theories were mentioned without any detail, feel free to contact me for more information.

The Netherlands through the eyes of a latinamerican dreamer

This is basically my third week in the The Netherlands, and I couldn't wait to share my thoughts with some of my readers and close friends, this post is written in English because some of the potential public of this particular entry are mostly English speakers. I will just summarise in a short list the most relevant aspects that I find particularly interesting about the Dutch culture, even though I still have a lot to learn and live here.

Relaxed culture: You would think that the behaviour of the people in a first world country like the Netherlands would be very strict and completely organised, but it turns out to be quite the opposite. People in the Dutch culture have a very relaxed way of doing things and organising their schedules.

People here don't usually put much attention on the way they dress just because they focus on comfort rather than in the looks which is something great in my opinion. Social life is a very important part of their culture and that's why they organise parties and social events all the time, and they have study associations for pretty much every activity, usually these types of organisations involve meetings with beer and food every week. Fridays are usually quite days because party has already started since Thursday, also, Monday life starts later than in the other week days. Even our introduction week (which is intended to show us the dutch way of living) had plenty of activities with parties and beer, although the academic content was always at hand.

The use of marijuana is legal so it is very common to see people getting high in the streets, and most people smoke marijuana with some regularity. It is not seen as a bad thing because the culture here has become very liberal in that sense.

Public transportation: So the first thing I have to mention is obviously: Bikes!!. The cycling roads are so nice that it is just stupid not to own a bike and move around with it, so there are millions of bikes in this place and pretty much every road has a parallel cycling road, also, you can find places to store your bike in most buildings and train stations. In fact, people riding their bikes are the priority so that car drivers will always wait for you to cross the road if you are riding yours.

Bike garage, Enthovenplein building, Den Haag

But, besides the bicycles, the public transportation in the Netherlands is very nice and organised and efficient. The busses and trains are usually on time (at least in this time of the year) and they are very modern and fast, moving at velocities of more than 120 km/h.

There is something quite fascinating at least for me, you actually have the chance of not paying for a ride in the train, because some stations don't have entry or exit gates so you can come in and go out as you please, but the Dutch culture is so advanced in this topic that (for the most part) people always pay for the use of the transportation systems even when they have to do the annoying check in and check out at your final destination. I think that is very fascinating because they are aware that they are using a transportation system that works well and that represents a cost for the government to which they belong. By looking at how civilised they are, one realises that the ones who don't pay for their tickets are the people that don't let a nation advance and sadly our latinamerican culture is full of those people.

The landscape: The landscape is beautiful in any sense, there are canals everywhere and the cities and towns have been build within those water systems so you always see nice boats in the middle of the cities. The European-styled constructions are beautiful and preserve the colonial style with a nice touch of modernity. You see nice windmills all over the place and the beaches that I've visited so far are absolutely stunning.

Leiden University: The University campus is spread all over the city of Leiden and it has become the core of the development and infrastructure of the whole town, the buildings are very modern and the faculties are spread in huge areas where every department has a nice to develop the academic activities.

The physics and astronomy departments are very big and the environment is great for a passionate person like me. The walls have astronomy pictures and there are memorials and quotes from great scientists that have been part of Leiden University at some point in time like Einstein, Lorentz, etc. Even the names of the buildings (Oort, Huygens) remind you of the greatness that this amazing place has witnessed.

The height: Dutch people are extremely tall! They are in average the tallest population in the whole world so it is very hard to get used to being short by them. In my home country I was slightly above the average of height but here I see taller people everywhere.

In Colombia, when I was supposed to meet a secretary for any paperwork or academic procedure I would probably meet an old short lady, but here every time I have to do something like that I find a young secretary who is probably taller than me and who speaks three or more languages.

Sports: So far, I am surprised about the way they play sports here because they are not very obsessed and competitive as I was expecting. In general, they tend to practice sports in a relaxed way with the main goal of being fit and keep a healthy life. As far as I've seen, (at least in the University) the competition in sports does not have the same priority as some other activities and it's not the main goal of the people who subscribe to the sports centrum. I suppose that the ones who practice sports at the professional level must be very disciplined but so far most people I've met are very relaxed.

Speaking about that, it is also surprising that most dutch students are usually very slim and don't really care too much about being full of muscle as in the western culture where we actually hit the gym more often.

One last thing, they say they are not very good anymore at football, I don't understand why they say that given the fact that they always top in the world cup competitions.

Freedom of religion: This is also a very fascinating fact about the Dutch culture, because they have been the pioneering nation getting rid of the religious attachments and giving their people the chance to think for themselves. I am sure this is one of the reasons why this nation is so great, they have moved on from those dark ages when religion was the law and realised that the correct way to grow as a nation was to give huge priorities to education.

I like the fact that I've met a lot of people and most of them share the same views as I do in this topic. Most of my new friends are atheists and agnostics with great academic backgrounds which makes the conversations way more interesting and free of useless fanaticism.

They just don't care: And finally, I must say that one of the most fascinating things about the Ducth culture is that they don't really care about pretty much anything, but what do I mean by that? They don't care about other people's interests, they respect other's point of view even if they don't agree with it, they don't judge others by the way they dress or the make up they use, they don't whisper about someone's tattoos, hair colour or sexual preferences, THEY JUST DON'T CARE which I think is great.

I think that is one of the things we need to learn in latinamerica, because our culture judges too much and cares too much about other's decision, the Dutch culture has grown to a point where they have realised that focusing on those small matters in completely irrelevant and it's just a waste of time to do so.

Accelerated Expansion of the Universe

The 90's were fundamental years for the study of the expansion of the Universe, many great Astronomers and Physicists around the world were working on the explanation of the evolution of the Universe since it has been one of the main questions of humanity since the very first stages of history. But there are many remarks to be made in this topic. First, the discovery of its acceleration is quite recent and it has changed many of the models of Cosmology; measuring light from very faint objects in space is really hard so the experimental evidence of this models was not possible in Einstein's times.

In 1929 Edwin Hubble measured the expansion of the Universe, one of the most important discoveries in the history of Astronomy and Physics because it made us see in more concrete terms what we could mean by the fate of the Universe. This discovery made scientists formulate many theories and models that would give a fair explanation to what was observed.

With the expansion of the Universe as an anchor, theory converged on a standard model of the Universe, which was still in place in 1998, the theory was basically a decelerating model of the Universe given by the gravitational attraction of the massive bodies that would eventually stop the expansion and make the Universe contract.

Einstein himself tried to explain the observed expansion of the Universe implying that there must be something that halts the quick gravitational contraction that one usually expects, he didn't like the idea of an expanding Universe. With the cosmological constant Einstein attempted to balance the gravitational attraction with the negative pressure associated with an energy density inherent to the vacuum. His studies were also backed up by some scientists who made the mathematical formulation of this last theory.

The nobel winners Saul Perlmutter, Adam Riess and Brian Schmidt (2011) were the ones that made the great discovery of the acceleration of this expansion, but how did they do it?

A really smart way to measure distances and red shifts from distant objects is by observing Supernovae, you can take the brightness of a supernova as an indicator of how far away it is. The fainter it is, the further away it is from us, and how red it gets tells you how much the Universe has stretched since the supernova exploded, because while the light is traveling to us, its wavelength stretches by the exact same proportion as the Universe stretches. So, this is a very direct way of plotting how much the Universe has stretched as a function of time. Also, the brightness of supernovae is so big that they can be observed even if they are really far from us, even around distances of 6 billion light years.

But only Type Ia is usefull for this manner because they all have the same brightness when they explode, and it was only in the mid-1980s that this subclass of Supernovae was identified, so we see that this studies could not have been in Einstein's time. The interesting result in these observations is that the most distant supernovae are fainter than everyone expected, and that could only be explained by an accelerating Universe.

In the late 90's, at the time when the discovery of the accelerating Universe was made, the standard model was based on the theory of general relativity, and two assumptions. Assumption one was that the Universe is homogenous and isotropic on large scales, and assumption two that it is composed of normal matter, i.e. matter whose density falls directly in proportion to the volume of space, which it occupies. But the discovery of these nobel winners made us re formulate our understanding of the composition of the Universe and its composition in the early times after the Big Bang.

Apparently we have a Universe that is dominated by some new ingredient, some previously unknown “Dark Energy” that makes the Universe expand faster and faster. Recent estimations say that in the composition of the Universe today is 70% dark energy, 25% is dark matter and only 5%is the baryonic matter that is what we are more concerned about.

The most accepted model suggests that early after the Big Bang, the acceleration of the universe was null, but when matter started diluting by the explasion, dark energy became dominant and expansion started accelerating. Recent observations are focused on faint objects that will give us more information about the rate at which the acceleration is correct and it has become one of the main problems of modern cosmologists because we don't know much about dark energy and it could take our understanding of the Universe to a whole new level.

The meaning of Strength

I was asked about strength the other day, and I replied without any type of considerations or further thoughts, but then I gave the idea some time to see what I could get. Here's what I concluded:

Human beings are quite selfish and that makes life a place where the fight for personal interests destroys complete fairness and reasonableness. You evidence it in every sense of life such as politics, power, friendship, fame, war, success and relationships. So in order to succeed in a world like that, you must "be strong" and learn from the struggle.

But, how do you do that?. I believe that priceless teachings always come to you, you take them or leave them but they always show up!, those lessons are always telling you to be tough and stronger every time you are beaten up, and you do that by taking the risk of quitting your so-called comfort zone. So for me, the meaning of strength has to do with embracing the tough work that is mandatory in taking risks that will probably threat your "easy" or "comfort" zone. Every time you are challenged is the time when you have to take those risks, even better if you try to figure your odds.

I can always reminisce a single phrase that reminds me of the amazing things you can get when you take risks, the coach shouted really loud to the whole team that Jon Stacy "got it done" when he, one of the rookies of the Varsity basketball team literally got it done by taking his own risks and scoring the most important points of the game that gave us the victory.
So, knowing the meaning of strength is an important part of this whole issue we call life because when you know what strength means, at least you know what you are supposed to do and it could guide you in the right direction.

So, whether you are tough of not, search for your own concept of strength because that's the only way to profile yourself into eventually being strong.