Random thoughts

In the past I have consistently chosen work over most other things. I also chose to have a family to whom I have always been very close to, and I have always lived in beautiful areas - although I have never chosen a position based on location so far.  I have a reasonable level of tolerance, but I have often felt that most members of my family and I were genetically designed to get along.

 The risk I consistently take is that of doing many things. While most people dislike leaving their comfort zone unnecessarily, I repeatedly ignore my comfort zone and my fears, which are always there. I am, of course, afraid of failing, of being too superficial, of choosing the wrong paths too often, and of doing too many things that will not be worthwhile in the end. I do make an effort to finish most of the things I start even if it sometimes takes me a long time - always way longer than I think it should take. All this is against what I have been taught in school. Society wants us to be in the same box doing the same things all our lives. Change is most often seen as a failure to continue in the same direction. My colleagues who switched to industry after having a PhD (and perhaps one or two postdocs) are seen as people who failed to stay in the wonderful academic system by the people who stayed in the academia. The people who stayed in the academia are probably seen as failures by those who left because most of what we do does not have direct, immediate impact on the world. Most articles we write reach a very small community. More often than not this community is just too small to be worth the one or two or several years of work invested. Also, we are always at work, but make a lot less money.

But is it better to stay in the same field forever even after one's productivity drops or to be open to reinventing oneself and have the courage to change careers? How much does the reinventing process reduce the risk of Alzheimer and other problems later in life? Is it worth it?  Every subfield has its own jargon and its own little world, and I have tried hard to not be stuck in local minima for too long. However, it's hard to leave many little worlds behind - and in time it gets harder and more tiring to start over. How many people can start something entirely new, and finish it at a level that is worth the time and potentially the money invested? Is our society right in forcing people to be in the same box doing the same things all their lives? 

I do not have good answers to every one of these questions because the answers depend on the situations they are applied to.  I have always tried to be optimistic and to believe in the people around me. I think that, in time, the rapid transfer of information will completely reform our educational system, the way we work and the way we think. It is likely that this new system will allow change more readily, and perhaps even be able to simulate potential outcomes and come up with optimum solutions. I hope that we will not have to wait for people born before computers (at 31 I am part of the older generation) to die or retire before our educational system and the work place become more fluid because changes are exciting and I want to see them happen.

Could I work in a field that is not in the academia? I do not want to work in a bank, in programming, industry or consulting. All these jobs seems too hard, too boring, and often too far away from anything that feels real. Physics does model reality after all. However, I often wish I lived on a farm (with some help for the various responsibilities) where my children could learn more from experiencing the life around them vs. mostly from books, and that this farm was located in a warmer place than Zurich or central Pennsylvania. I could be a high-tech farmer who controls his tractors from home. But then I dislike monocultures, using insecticides, and killing animals. So, I do not think I will ever be very productive as a farmer.

Temper tantrums

I remember throwing temper tantrums when I was little. I have learned to control my temper and I expect most children do the same in time.  However, I am surprised by the attitude I see among parents who are told they are not supposed to shorten the tantrum of their child, and that it's good to let them cry, to put themselves to sleep, etc.  I agree that it makes children easier to manage on a short term basis, but as a parent I worry more about long-term consequences than about my short-term well being. My instinct tells me it's wrong to let a child cry or let him be unhappy if I can help it, and I see no reason to ignore this instinct. 

Is it good to ignore an angry child - especially in the first few years before they can communicate well? does it make them feel unwanted? unloved? what if the tantrum happens because they are sick or tired or hungry and cannot communicate that to me? is it not 'my job' as a parent to try figure out what is wrong vs. just ignore my child? 

What do I do then? 

I first try tell or show them something interesting that draws their attention.  Its success depends on how well my imagination/brain functions at the time, and of how willing they are to accept an alternative solution. The latter part depends on the cause of the temper tantrum. Also, I dislike lying - so what I tell my child is usually something that I think is true.

I try to remember there are times when it does not matter who is right or who is wrong. This is often hard to do. For example, it is very annoying if children do not eat when the food ready. However, this may just mean they are not hungry enough now and prefer to eat in an hour from now, which is unpleasant but not the end of the world.

I sometimes compromise, sometimes distract them with things they can do that are useful (most children love to help) or just try prevent tantrums by avoiding things that are known to obviously cause them like a trip to the store. If I was in the store, and Edward wanted a particular object I would get it if I did not have a strong objection against it. If I object, which is more often than not the case, we discuss my objection and I try to persuade him that I am right. Sometimes we end up buying a different object that I think is more useful/fun. It helps to get them involved in the shopping, e.g., the child/children put(s) the fruits and vegetables in the cart.

 Should this happen?  I think it's normal to want things, and to go through a negotiation process to get some of the things we want. I  did not ask my parents for toys at their age because I was more interested in observing live things like chickens or dogs and also because there weren't many toys available in Communist Romania. Here we rent. There are plenty of tempting toys and we don't have pets so far. We are lucky that the stores in Switzerland have repetitive and unimaginative enough merchandise that by now (we've been here for two years) we have had most of the toys they wanted from the grocery store. They only have a few toys that stay the same all year round. So, visiting the store is less complicated now.

From time to time I bribe my son (I am not proud of this, but it sometimes works). e.g., IF you stop crying now you will get a candy. It only works if they do not usually get candy and so I try to do this only rarely.

Once they are older, sending them to their room can work. I have tried this a few times.

I try hard to keep calm and behave as the adult. This is bound to be very hard at times. My mother always tells the Robert be calm joke: A man walks on the street pushing a crying child in a stroller and repeating "Robert be calm. Robert be calm. Robert be calm. Robert be calm". An outraged woman stops and tells him "How can you ask a child so young to be calm? He cannot understand you." The man replies: "Madame, I am Robert".

Needless to say I am not an authority in parenting and never will be. These are just some observations. In general, I try to behave naturally around children and not stress them out or myself too much.

I believe that temper tantrums are related to being stubborn, a bit of a perfectionist, and also that in those moments the child sees only what he wants while everything else disappears. When someone is angry or upset (adult or child) their whole "horizon" collapses to a point of interest or distress and they miss seeing anything else. One cannot easily stop this horizon shrinking. OK, sometimes, it is best to wait for the moment to pass mostly on its own. However, I think it's never good to argue in such moments whether the angry person is an adult or a child or to try to teach them who is the boss lesson. Discussions should be had a little later on when everybody has calmed down.

Testing General Relativity with Clocks in Space

Imagine an experiment with a space-traveling clock. This clock travels in a satellite around Earth and broadcasts light pulses to a receiving station on Earth at very precise intervals of time. The arrival times of the light pulses are registered by a local clock and compared with the emitted times. Both the orbit of the satellite and the light traveling time are affected by the presence of the Earth, which bends space-time slowing down time.  In John Wheeler's words: "matter tells space how to curve, and space tells matter how to move".

As the accuracy, reliability and portability of atomic clocks improves, such clock experiments will constrain general relativity, the mathematical theory that models the effects that matter has on space-time, more stringently. Spacecraft clocks offer us the opportunity to simultaneously probe different effects such as Shapiro delay, frame dragging and higher order relativistic effects all within the same astrophysical system.

In http://arxiv.org/abs/1402.6698, my collaborators and I have solved the forward problem where we determine which relativistic effects reach a magnitude above clock accuracy for a clock carrying satellite that orbits the Earth. The best space-qualified clock to date has been built for the Atomic Ensemble in Space (ACES) experiment - a Caesium fountain clock that is expected to reach frequency inaccuracy of 10-16. The best clocks on Earth have reached accuracies of the order of 10-18. We find that already at precisions of 10-16 several higher order relativistic effects are already relevant (see figure).

You may ask why are relativistic effects important. Firstly, relativistic effects are important for their own sake. General relativity is a beautiful theory. Few things can be more exciting than measuring the slow down of time, and understanding that our feet are slightly younger than our head by what is now a measurable amount. However, general relativity is not a complete theory of everything because it breaks down at small scales, and does not allow for a natural unification with quantum mechanics. We dream to unify relativity with quantum mechanics, and also to explain all observations including the nature of dark energy and dark matter. Observations of this dark sector, which is believed to comprise more than 95% of the universe, provide a sign of new physics that remains tantalizingly out of reach. No violations of general relativity have been observed to date.

Secondly, from a more practical perspective, atomic clocks can provide accurate space-craft tracking. As the clock accuracy and our treatment of the other errors improves, relativistic effects will become the dominant noise source, which has to be understood and modelled. Even though noise modelling is rarely the focus of an experiment, it is most often the dominant part of data analysis.

Our code is freely available as a supplement to the Physical Review D version of the paper. If you do not have access to PRD or are so excited about this that you want the code right now before the paper appears, you can email Ray (see his email address on the pdf of the paper) or another one of us. Once you install it, it has a user-friendly interface on which you can select orbit parameters, and the relativistic effect you want to compute the magnitude of. There are a number of simplifications that were made, which in principle could be relaxed, e.g.,  the satellite clock is assumed to communicate tick signals to one clock on Earth with the Earth being transparent to the clock signals. In reality there would be multiple clocks on Earth and the ticks from the space clock would be sent to the clocks on Earth within the field of view of the satellite. Additional terms could be added to the Hamiltonian to see if clocks in space can test your favourite alternative theory of gravity, etc. 

Impressions from ESA's Cosmic Vision meeting

On the 21st January 2014 I attended ESA's comic vision meeting in Paris. It involved listening to presentations of the five mission candidates: ECHO, Macro-Polo, LOFT and STE-QUEST. Out of these only PLATO was selected as the next medium size mission to be launched by ESA in 2022+. STE-QUEST was considered not yet ready from a technological perspective.

Note that, technically, this was a public event - i.e., anyone could attend as long as they registered in advance. However, most of the attendants seemed to be scientists who were somehow connected to the missions.

So, what were each of these new missions about?

 The Exoplanet Characterization Observatory (ECHO):  They propose to place satellite with a  very performant spectrograph in an L-2 orbit, over 1.5 million km away from our planet. The spectrograph separates incoming light into a frequency spectrum that covers visible to infrared wavelengths.  Such a mission could measure the chemical composition of the atmosphere of a wide range of extra-solar planets - from hot Jupiters to SuperEarths. Once the planets are found by TESS or PLATO it is natural to then want to study the composition of their atmosphere. It would be good to a have a mission that can both find the planets and perform an accurate spectrogram vs. one or the other.

PLAnetary Transits and Oscillations of stars (PLATO): This is the winning mission! It's a satellite that will take pictures of the sky from an orbit around the L-2 Lagrange point. It will search for planets with 32 small telescopes & cameras. Each camera covers 1100 square degrees (for comparison the moon is about 0.2 square degrees, the whole sky has about 40, 000 square degrees, and Kepler mission has a field of view of about 100 degrees).  They expect to find transiting planets, i.e., they find dips in the light given by a star when the planet passes in front of the star. They aim to find the planet's mass, radius and age, and also measure oscillations in brightness of the host star.

Large Observatory for X-ray Timing (LOFT) This would have been an X-ray satellite that covers an area over an order of magnitude larger than that of current detectors. It would provide high time resolution X-ray observations of matter in the presence of strong gravity, i.e., investigate the variability of light in X-rays emitted by matter orbiting black holes, neutron stars, active galactic nuclei, etc. Such a mission would severely constrain the range of possible neutron star equations of state. It would also provide measurements for the spin and mass of black holes, and investigate the behaviour of matter close to an event horizon and other aspects of strong gravity. Most of my colleagues favoured this mission.

Marco-Polo: was supposed to return a sample of 1999 JU₃ (a near Earth asteroid) to Earth for analysis. It is believed that asteroids are some of the oldest objects in the solar system, and understanding their composition might help us understand the origin of life. This is a mission that was quite popular, but had a time limit because this particular asteroid can only be reached when it is close enough to Earth. I agree that taking samples of asteroids is something we should be able to do as well as perhaps be able to blow them up if they come to close to Earth and endanger life here.

STE-QUEST: This is a fundamental physics mission that would have originally placed an atomic clock and an atom interferometer in an elliptical orbit around the Earth.   This orbit means that the spacecraft would test general relativity through varying gravitational fields. Due to a limited budget, the mission only kept the atom interferometer and a transponder that would reflect, amplify and re-transmit pulses of light sent by atomic clocks on Earth. However, it was decided the atom interferometer technology was not yet ready to be flown in space. STE-QUEST remains an exciting mission concept that in addition to answering fundamental physics questions provides very good technology tests for instruments that we want to able to put in space as part of other missions. Clocks are used for GPS, space-craft tracking, monitoring changes of the geopotential of the Earth, etc, and the atom interferometers would be the future gravimeters.

Overall impressions: 
This meeting felt like a conference with fewer young people than I am used to from an average US conference (both weddings and funerals feel like conferences to me with sometimes better cookies and no talks.) All presentations went well, and the science presented for each mission was very interesting, which made it difficult to choose. 

However, I am a bit depressed that when we have so much more technology than 15 years ago, the way we present has not changed. I would like to see ESA be at the forefront of outreach. For example, they could be a little more modern by having a short video describing each mission + a toy one could buy to show support for the mission, which can also be used to explain each mission to younger audiences. Instead they sport the same static websites with the occasional broken link. All these presentations of missions should also be recorded and accessible to the public via the internet.

 I cannot get away from the feeling that there is too much bureaucracy everywhere in science (and, of course, not just in science).  The missions drag on for too long. The approved concepts wait until the technology is outdated and the people proposing them are close to retirement. Instead of funding commissions to evaluate, re-evaluate, re...re...re evaluate maybe more science could be funded and more publicity for the existent and future missions could be done.  Of course, some evaluation process has to exist, but we seem to have long lost a sense of balance and forget to correlate the number of evaluations with the progress made. Everyone seems to believe that science should be more open with fewer bureaucratic hurdles. However, the answer to every problem just seems to be more bureaucracy with no direct plans for solving the problem. With better outreach and more of the science and discussions publicly available, perhaps the public will come up with new ideas that solve some of the existent problems of the system.