Ch. Flemming / Lindau Nobel Laureate MeetingBrian Schmidt believes that dark matter could be measured in a laboratory. Dark energy, however, is more complicated.Ch. Flemming / Lindau Nobel Laureate Meeting
from Lindau*
Since 1951, the small tourist town of Lindau on Lake Constance in southern Germany has been the venue for an annual one-week meeting that brings together Nobel Prize laureates and young scientists at the beginning of their careers. In 2012, the 62nd meeting was held from July 1 to July 6. It was attended by 27 Nobel Prize winners who have been awarded the prize for their scientific endeavors. Of these, most were physicists. The event was also attended by 592 students from 69 countries, including Brazil. The objective of the meeting is to promote the exchange of experiences between renowned and successful researchers and new generations of researchers who are beginning their research careers.
This year, a reporter from Pesquisa FAPESP attended the meeting for three days. The event was organized by the Council for the Lindau Nobel Laureate Meeting and by the Foundation Lindau Nobel Prizewinners Meeting, with the support of academic entities from all over the world. Two of the interviews and conversations were highlighted for Pesquisa Fapesp.
The first interview was held with American-Australian astrophysicist Brian P. Schmidt, from the Australian National University. Last year’s Nobel Prize in Physics was awarded to Brian P. Schmidt, Saul Perlmutter, from the University of California, and Adam G. Riess, from Johns Hopkins University and the Space Telescope Science Institute. The trio of researchers observed distant supernova stars and showed that the Universe is expanding very fast. During his lecture in Lindau, the 45-year old Schmidt talked about the difficulties that physicists face to understand the components of the Universe. The so-called Baryonic Matter, the known atoms and molecules, accounts for 4% of the Cosmos. The mysterious dark matter accounts for 23% and the even more mysterious dark energy – that might be the force responsible for the acceleration of the Universe’s expansion – accounts for 73%. In this interview, the astrophysicist comments on the current possibilities of proving the existence of these two elements of the Universe.
The second interview was with Mexico’s Mario Molina, winner of the 1995 Nobel Prize in Chemistry, together with Paul Crutzen and Sherwood Rowland. The three researchers began their work in the 1970s, when they conducted research on chlorofluorocarbons (CFC). They found that these compounds, used for decades in cooling systems but banned nowadays, destroyed the atmosphere’s ozone layer. This layer protects the Earth from the harmful effects of the Sun’s ultraviolet rays. The 69-year old Molina, currently a professor at the University of California in San Diego, talks about the risks of climate changes.
* Journalist Marcos Pivetta travelled to Lindau at the invitation of the German Academic Exchange Service (Daad).
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Searching for 96% of the Universe
Dark energy and dark matter together account for 96% of the Universe, according to the Standard Model of cosmology. What could be done to unravel these two mysterious components of the Universe, given that very little is known about them?
The first thing that we must do is to continue testing the theory. We are conducting more and better tests and so far the theory seems to be working. If we continue testing the theory, it might even be refuted eventually. But it would be very interesting to prove the existence of dark matter in a laboratory experiment. If we discover what this dark matter particle is and measure how much of this matter exists, we will then have a working project. I really think this is possible. There is a good possibility that this will happen next year or perhaps 10 years from now. We don’t know.
What about the dark energy?
Dark energy is a problem of a much more fundamental nature. We will never be able to measure it in a laboratory. Dark energy is not a detectable particle. We have to think very thoroughly about why it exists and why there is such a huge amount of this energy in the Universe. We don’t have a theoretical basis to explain dark energy. We only know that it exists because of gravity. In other words, we need a fundamental theoretical insight. There is a fundamental problem between what quantum field theory states and how gravity functions in the Universe. Something is disconnected. The way I see it, we need to understand this issue. If we unravel this, then perhaps we’ll be able to discover how gravity and the quantum field theory work together or at least we’ll be able to understand why quantum field theory is giving us the wrong answer. This is the gist of the issue, in my opinion.
How can the existence of dark matter be proven in a laboratory?
There are three ways to prove this. We could create dark matter in the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN). In this case, we wouldn’t actually detect the matter; we’d sort of observe the dark matter leaving the detector and we’d realize that something was missing. Another way would be to directly detect dark matter. We would chill a box of some material as close as possible to absolute zero and we’d bury it about three kilometers below the ground, where nothing could reach it. Particles and dark matter go to the Earth, so perhaps something might hit it. If this were to happen, the box will emit a pin [a sound]. This pin is a photon [a sound particle, which is a type of vibrating energy] that goes through the detector. Some scientists did this for three years. So far, nothing has been detected. But these experiments will continue, they will expand and maybe they will detect dark matter. There is also a third way to prove the existence of dark matter. We believe that dark matter might interact with itself and generate gamma rays or something similar that could be detected by astrophysicists. There is some gamma ray emission in the middle of our galaxy that we don´t understand. This might be related to dark matter, or might not. We don’t have any information on this yet.
Is there any way to prove the existence of dark energy in the Universe?
I don’t see any easy way of detecting dark energy. We have already improved our observations of the Universe by a factor of 10. There is no indication that Einstein’s vision of the Universe is wrong, nor is there any indication that he was wrong [Einstein hypothesized that there might be an opposing force to gravity that would make the Universe expand, but later he rejected this hypothesis, which has nowadays been rehabilitated by more recent evidence]. But this doesn’t mean that he was not wrong. Measurements will improve even more going forward, again by a factor of 10. When this happens, we will be able to do better.
So we might have relevant news on dark matter before we have any news on dark energy?
That’s what I believe.
This question is not related to astrophysics. Why did you decide to become a wine grower in Australia?
I have a vineyard, which I planted in 2000, and a winery, called Maipenrai, in the district of Canberra. I produce approximately 3 thousand bottles of Pinot Noir a year. I sell the wine in Australia. I produce wine – which has nothing to do with astrophysics – to prevent astrophysics from taking control of my life. I don’t like to refer to my wine growing endeavor as a hobby, because I pay taxes to make wine. I spend a lot of time and money. Believe me. Wine growing is much more than a hobby. It’s a therapy. Having a vineyard is very gratifying. My family and I do all the work at the winery.
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Ch. Flemming / Lindau Nobel Laureate MeetingMario Molina says that the causes of the problem are not entirely known, but that there is enough information about it to take actionCh. Flemming / Lindau Nobel Laureate Meeting
The risk of climate change
After his lecture on the risks of climate change, physicist Ivar Giaever, 1973 Physics Nobel Prize laureate, gave a presentation in which he denied that human activities have any relation to this process. What is your opinion about your colleague’s presentation?
Unfortunately, he was awarded the Nobel Prize for his work in a field of physics that has nothing to do with climate change [the prize was awarded for Giaver’s work on tunneling in solids.] As he showed in his lecture, he knows nothing about climate change. It’s unfortunate that he made huge mistakes. I would have liked to have had the chance to sit down and talk to him, to make him see that learning about a new field of science takes more than logging onto the internet, getting a few numbers in a couple of minutes and giving a lecture. It is necessary to make an inventory of all scientific literature, which he certainly didn’t do. It was embarrassing to witness a Nobel Prize laureate in such a ridiculous position. The situation illustrates a problem with Nobel Prize laureates. Everybody asks our opinions about everything – religion, politics, etc. It has to be made very clear that sometimes we speak as people and not as Nobel Prize laureates. Mr. Giaever – in relation to climate change – is far from the field of physics he works in. The issue of climate change has been firmly established in scientific literature.
Is the influence of human beings strongly evident in your opinion?
This issue resembles a game of roulette. According to the IPCC’s latest report, there is a 90% probability that climate change will occur. It is quite obvious that it is already happening. There is a great probability that human activities are the origin of these changes. It is difficult to predict what will happen 10 or 20 years from now. There are many elements, such as clouds, whose role is unknown to us. The situation might even be worse than we think it is. Hence the importance of the risk concept. It is very likely that it will be very costly if we fail to do anything. It’s not only the economic issue – there’s also the social issue. We will be totally irresponsible in relation to future generations if we fail to take action. Their lives will be much more difficult. Climate science is complex. We are not 100% sure about the changes, but we have enough information to take action. We have to convey the message that there is a real risk. We have to tell stories so that lay people understand the situation, without any fantasies or exaggerations. This is analogous to the doctor telling you that you have a tumor. It might be malignant or not. But you will be tested for cancer, even if statistically the related risk is 20%. We’re not sure about the changes, but there is a real risk. And we only have one planet.
What do you think of the proposals, such as the one proposed by your colleague Paul Crutzen, of injecting compounds into the atmosphere to cool it?
I think it’s perfectly valid for the scientific community to have a Plan B, that seeks to learn more about the system. There is no harm done if you just study the issue. The injection of sulfur, as proposed by Crutzen, already happens naturally when volcanoes erupt. In the case of a volcano, it takes one week for the effects of the emission to disappear. Perhaps we could inject sulfur continuously and, if this measure doesn’t work, things would go back to the previous situation in one or two years. But this is a risky option. It is much wiser to reduce carbon emissions.
Were you also disappointed by the results of the Rio+20 Global Summit?
Unfortunately, I was unable to attend, but I sent a video. The general consensus is that no commitment was made. I hope that this reflects a temporary situation. It was a sign that society needs to do more. Some issues, such as the global economic crisis, seem to interfere with the discussion of environmental preservation and sustainable development. I hope the economic crisis is coming to an end. The idea of maintaining the economy and not maintaining the environment and vice-versa is not acceptable. The cost will be much higher if we fail to maintain the environment. But there are groups with powerful interests regarding this issue. The losers will make the loudest noise. There is also political pressure. The United States is still a huge barrier. The Republican Party questions the science of global warming and science in general. This is something so irrational that I think it is a temporary situation – there’s no way it can go on for much longer.
Is it possible that a consensus will be reached soon?
I think we’ll be able to reach a consensus, but not in the current context. We’ll have to wait for a few years. The United States’ internal policy is an obstacle. The U.S. Congress is unwilling to ratify an international agreement. The United States is a strong economy. Nowadays, China emits more greenhouse gases, but on a cumulative basis, the Americans are the greatest emitters. The Americans have to be party to an international agreement. California is doing something about this, and so is Europe. Brazil has interesting guidelines on biofuels. As I mentioned in my talk, it’s very clear that extreme events have already started happening and are likely to intensify. When society realizes that climate changes are already affecting us now, that this is not only a problem for our grandchildren, then there will be a lot more motivation. I hope this situation changes when the global economy improves.
