Comprehensive coverage

"Technological improvement in the field of spectroscopy made possible the wave of discoveries of planets outside the solar system"

This is what Prof. Michel Maior from the University of Geneva says in an interview with the "Hidan" website, who together with Prof. Didier Cavaloz was a member of the team that discovered Pegasi 51b, the first planet discovered outside the solar system and which orbits a normal sun. The discovery of "hot Jupiters" such as Pegasi 51b has forced astrophysicists to revise their theories concerning the formation of planets

Prof. Michel Mayor met with President Reuven Rivlin. Source: PR photo.
Prof. Michel Mayor met with President Reuven Rivlin. Source: PR photo.

Two huge discoveries in the field of astronomy took place in the nineties of the 20th century. One - the discovery of the fact that the expansion of the universe is accelerating, through the Hubble Space Telescope, and the first discoveries of planets outside the solar system.

This year, two of the discoverers of the first planet orbiting a 'normal' sun in 1995, Pegasi 51b, won the Wolf Prize. Prof' Michel Mayor and Prof. Didier Cavaloz from the University of Geneva in Switzerland. The prize committee's emphasis on the fact that it is a planet orbiting a sun similar to ours (although, as we will see, the planet itself is different from anything in the solar system), stems from the fact that three years earlier, in 1992, Wolszczan and Frail published results A study in the journal Nature, indicating planets orbiting the pulsar B1257+12. A pulsar, a neutron star is a star that has exhausted its hydrogen supply, ended its life and is now burning materials heavier than hydrogen.

The first confirmed discovery of a main-sequence extrasolar planet orbiting the Sun (51 pegasi) was published by Michel Maior and Dieter Klotz in Nature on October 6, 1995. The astronomers were surprised by the discovery of “hot justice", but immediately afterwards they discovered similar planets with great success.

"I was interested in every kind of science when I was a teenager, not only astrophysics, but also geophysics, plants, ornithology, but I especially liked mathematics and physics, so I started studying theoretical physics at the University of Lausanne, and when I finished my master's thesis, I moved to a PhD at the University of Geneva and studied the dynamics of spiral galaxies . It was just the time in the sixties, when we were just beginning to understand the nature of galaxies. Spiral galaxies have two arms but their rotation is uneven. The center rotates faster than the edges. This was supposed to cause them to break up. Prof. Lin En Shun argued that what holds the stars of these galaxies together is not matter but compressed waves. I did my doctoral thesis on this topic, and after I finished I thought it would be interesting to test this theory by measuring the speed of stars close to the sun."

"I wanted to prove the theory that indeed the velocity field around the sun corresponds to the hypothesis. Determining the speed of many stars is a boring job but luckily I met an English astronomer who developed a first of its kind device that does it with more efficient technology. At that moment I moved from theory to instruments and developed together with colleagues from Marseille, the first type of spectrograph in 1977 (CORAVEL). It was an excellent instrument but not enough to search for planets. About twenty years later, we started building a new device with new technologies: optical fibers andCCD, and we increased the accuracy 30 times with a spectrograph called ELODIE. Only then, in 1993, did we reach a level that allows us to discover planets."

"The instrument was so accurate that we immediately began to systematically search for the holiday planets around stars like the Sun. We selected a sample of 142 stars. My students and I, including Didier Cavallo, measured their speeds night after night, trying to find tiny changes in the star's speed caused by a companion object. After a few months we discovered the first planet Pegasi 51b. This was a surprise because it is a gas giant very close to its sun. At that time the theory stated that gas planets should have orbits in which the orbital period takes at least ten years - more or less like Jupiter. We discovered such a planet that took 4.2 days to orbit its sun. Since it was an important discovery, we wanted to check if something affected our measurements, for example magnetic spots on the star. In 1995 we observed the star again - the phenomenon still existed and its characteristics had not changed and despite the risk we decided to publish. It was the first planet outside the solar system.”

A new chapter in astronomy

"The discovery of Pegasi 51b was the first hint that we need new physics to explain the formation of planets. The new explanation given was that they formed at the edge of the solar system, where the star could not evaporate its gas atmosphere and migrated towards the sun. A few months later American scientists discovered another planet, and this started the new industry. To date, over 4,000 planets have been discovered and the number is increasing day by day. Thousands of scientists are engaged in the field and develop new techniques. The ground telescopes have also improved and of course dedicated space missions have been launched to search for planets in other solar systems, the best known of which is Kepler."

Simulation of Pegasi 51b - a gas giant that orbits a star similar to our sun, but very close to it, which gives it and others like it the nickname "hot Jupiter". Source: NASA/JPL-Caltech.
Simulation of Pegasi 51b - a gas giant that orbits a star similar to our sun, but very close to it, which gives it and others like it the nickname "hot Jupiter". source: NASA / JPL-Caltech.

Why would life be like ours, carbon based?

"Already in ancient times there were those who estimated that there should be more worlds in the universe. We were lucky to arrive at a time when technology allowed us to give a real (and positive) answer to the question. Today the big challenge is to look for planets with organic materials and to develop technologies to search for biological markers - spectroscopy that shows that life exists."

"We need to determine what we consider to be life - complex organisms that are able to exchange energy with the environment to protect themselves from the outside and the most important characteristic is that they need to pass the information on how to do this from generation to generation. If there is one creature with both of these traits, it must produce two cells and pass the information on and the next generation will pass the information on. The only way we know to transmit information is the genetic code - a long chain of atoms that encode the details of all the complex mechanics. That's life. Carbon is the only element that can form long chains. There is no equivalent of organic chemistry based on another substance. If you heat the chain above 120 degrees, the chain breaks down and you destroy the information. Below minus twenty the chemistry is so slow that nothing happens. The area where water is in a liquid state is essential for the development of life. This is not an anthropogenic claim, it is a basic law of physics. The transmission of information is limited to this temperature range, so planets with liquid water are being sought. Beyond that, the details are unknown. We have all the ingredients of life everywhere. The size of the planet is also important: if it is too small, the atmosphere will evaporate. If it is too large, the atmosphere will be compressed and global warming will occur. This is what is left for future generations to explore."

The bright future of planetary exploration

"After the discovery of the first planet, we built the ARPS device - the spectrograph connected to a 3.6 meter diameter telescope and copied it to another telescope in Chile - known as Galileo. The Galileo telescope and spectrograph tracked the suspected planet targets in the Kepler space telescope data. My team and I have discovered at least 300 planets using these instruments. Among them are light and rocky planets."

"The development of a huge telescope with a high-resolution spectrograph is required to discover the spectra of stars that the planet passes in front of or behind. The combination of a large telescope and a spectrograph will give us access to the chemical composition of the planets' atmospheres. Great progress is expected in the field of spectral determination of planetary atmospheres. We have also developed a large spectrograph that will connect to the VLT telescope (eight meters in diameter). Even in space there are several active missions dedicated to planets outside the solar system such as TESS - search for planets orbiting bright suns. Later, the European Space Agency will launch the large "Plato" telescope, which will search for planets that pass in front of their suns.

What would be the consequence of discovering life on another planet in the universe?

"It will help to understand the place of humanity and life in the universe, but it is mainly a philosophical question. I don't see a direct implication. The distances are so great that we will not have direct contact with these creatures. This will help give an answer to the question of how life was created, whether it is a normal or special process for the earth. If we discover life on many planets it might help us answer the question. at least partially. I don't believe it will have a bigger impact than revelations about finding hominid remains in Africa and reordering human evolution.

It is hard to ignore the fact that we are in a time that is turning its back on science, and almost all of the Wolf Prize winners said this at their scientific lecture event.

Prof. Mayur: "It is true that there is a strange attitude of the population that on the one hand understands that science brings a great benefit to man and the best example is in the field of health. But there will always be people who criticize science. I cannot ignore the fact that even though there are negative effects of man on the planet such as pollution or climate change, when we say that something needs to be done about it, suddenly some of the population begin to deny the existence of the problem. Climate skeptics.”

"It's very embarrassing. It's strange that you have people working in lots of labs, for many years to understand the complexity of the climate. On the other hand, there are people who throw a comment on Twitter and claim that it is not true. They are wrong but they make a lot of noise. There is an unfair competition between ignorant people in the climate field who attack without knowledge what is done in the best laboratories in the world. It's a strange situation."

More of the topic in Hayadan:
Hell around Pegasi 51
Astronomy has officially become a science of BIG DATA - an interview with the 2017 Du Doud Prize winner, Prof. Shrinivas Kulkarni

2 תגובות

  1. Regarding the last paragraph it is certainly embarrassing that a field of knowledge that has the predictive ability of a dead dog calls itself science. The fact that there are people in white coats and there are people working in university laboratories does not mean that the field of climate knowledge can be called science. It has no controlled experiments, it has no predictive ability, even the lowest explanatory ability. See the great explanation of hurricanes that was up until three years ago on the US government's World Hurricane website. They claimed (and like them all the climate "scientists" in the world) that the energy stored in the warm waters of the ocean fuels the storm and therefore the warmer the water in the ocean, the more hurricanes there are and they are stronger and it is intended that the world is warming and the water with it then we will see more hurricanes and stronger. Then came the last years when the water were warmer and there was a sharp decrease in the number and strength of hurricanes. In the first year they explained that there was a layer of dry air above the surface of the water that isolated the space between the water and the forming storm. The year after that, when their theory was shattered again, they removed the explanation from the website. In my opinion, to this day, the main theory of the formation of hurricanes has disappeared From the website of the Hurricane Research Institute completely. What they lack is a little modesty and an understanding that we still don't have a good orderly theory in the field or we still don't have the computational power to understand so many variables at once. We need to understand the limitations of our knowledge. This reminds me of the joke about 4 Indians Blind people trying to understand what an elephant is...

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.