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It would be strange if no sign of biological life was found given the fact that there are so many planets

Prof. Omri Vandel from the Rakach Institute of Physics at the Hebrew University explains in an interview with El Hidan, following the winning of Michel Mayor and Didier Coloz, discoverers of the first planet outside the solar system, by the Nobel Prize in Physics, and explains the differences between the Doppler method and the eclipse method.

Prof. Michel Mayor. Source: Wolf Prize Committee.
Prof. Michel Mayor. Source: Wolf Prize Committee.

The exoplanet and astrobiology communities continue to be abuzz after the announcement that Michel Mayor and Didier Koloz of the University of Geneva Observatory won the Nobel Prize for the discovery of the first exoplanet. Pegasi 51 B.

In a conversation with the Hidan site, Prof. Omri Vandel from the Hebrew University says that the importance of the discovery is that it is a planet that orbited a normal star, similar to the Sun and not a red dwarf for example (although among the 4,000 or more planets that have been confirmed so far, many orbit red dwarfs. ).

The innovation - the observation method

Their innovation was in the observation method. The discovered planet was relatively large - half the size of Jupiter, which makes it less interesting in terms of potential for life and even less interesting because it is relatively close to its sun and therefore the temperature on its surface is very high, but nevertheless it was the first planet discovered.

Pegasi 51 b was discovered using the Doppler method in which the force the planet exerts on its sun causes the sun to move in a small circular motion which can be measured because the planet causes its sun to move closer and further away from us in the circular motion. A relatively small effect because the speed of that sun is on the order of tens of meters per second. Before Mayur, it was not possible to measure such small changes. Mayur and Kilo, with the device they built made the method sensitive enough so that they were able to measure these changes. The principle is quite simple and was also known before, but to reach the necessary sensitivity you really needed a special device.

The second method, the eclipse method, used in the Kepler space telescope is the eclipse method. photograph the star, and measure the slight change in the intensity of its light every time the planet passes between us and its sun.

Each method has its advantages and disadvantages. Using the Doppler method, planets can be discovered in any sun cave, and not only those among them that are located so that the planet passes in our line of sight between us and the star. The condition is that the asteroid is large enough, massive and close to its sun that the movement of that planet is fast enough to be able to measure the Doppler effect.

Later, the devices were refined and today they are 10 times more sensitive, so today it is possible to measure even planets with smaller masses and even down to the mass of the Earth. With this method hundreds of planets were discovered and with the eclipse method thousands of planets were discovered mainly in the Kepler project.

life in the universe Illustration: shutterstock
life in the universe Illustration: shutterstock

The Doppler method requires more observations because the change in wavelength needs to be detected by spectroscopy and this can be done in a separate observation of one star over a period of time. With the eclipse method, many more stars can be observed at once, so even if only in one case out of a hundred their orbits are positioned to allow for an eclipse, but since Kepler observed 150 stars at the same time, so even a percent or two of them can lead to many discoveries, and indeed a telescope Kepler discovered 4,000 planets. It is estimated that the new Tess space telescope will succeed in discovering several thousand more. The Tess telescope was launched a year ago, in 2018, and it is smaller than the Kepler telescope, but unlike Kepler, which looked at a very small part of the sky, the Tess telescope scans the entire sky and is only able to discover planets around brighter stars - more similar to our sun. The Kepler telescope was able to discover the planets of even more distant or fainter stars - of the red dwarf type.

As mentioned - the advantage of the Doppler method that was used to discover the first planets is that it is possible to discover in any solar system the solar system does not have to be oriented so that an eclipse occurs. Its disadvantage, at least in the first years - it was possible to discover only massive planets that cause fast enough oscillations to their sun and that are also close enough. The closer and more massive the planet is, the greater the force it exerts. These stars were called hot Jupiters, i.e. stars with the mass of Jupiter, which orbit their suns at very small distances, even smaller than the orbit of a hot star around the sun, and therefore the temperature on their surface is high.


Since the first planets were of the hot Jupiter type, there has been some debate as to whether the prevalence of this type of planet is a real phenomenon or whether it was a bias caused by our instruments. At first we had no information about stars similar in size to Earth and far enough from their sun to not be hot, this was made possible mainly by the Kepler telescope. The eclipse method, which was used by Kepler and the European beam telescope that was launched in 2006 and contributed to the discovery of dozens of planets, he also used the eclipse method.

How did the discovery affect the science of astrobiology?

:"The study of planets outside the solar system is the heart of the science of astrobiology today. There are two branches of the science of astrobiology: astrobiology of our solar system, and the search for biology in other solar systems."

In our solar system, the search has pretty much been exhausted. There are a few niches, such as the moon Europa that orbits Jupiter, where they hope to find life under the ice, but by and large, they have pretty much exhausted the research in our solar system with very modest results, especially on Mars, they found liquid water and some organic molecules of unknown origin. But there are ten billion solar systems for the Milky Way alone.

In connection with this, it is important to note the discovery from a month ago, of water in the atmosphere of the planet K2-18b. Although it orbits a red dwarf and the chances of life on a planet orbiting it are small compared to planets orbiting suns like our Sun.

However, it would be quite strange if no biological life was found on any planet, there are so many solar systems and many of them are supposed to have similar conditions to Earth, and life could develop so it is important to discover as many solar systems as possible.

In conclusion, Prof. Wendel says: "It is not a coincidence that they received the Nobel Prize just now. Although they discovered the planet back in 1995, the importance matured only in recent years after the Kepler project."

More of the topic in Hayadan:

24 תגובות

  1. A. Ben Ner
    Your proof is lacking.

    You wrote that the universe is infinite. This is an assumption (reasonable to me) and not necessarily true.

    Let's assume the universe is infinite. You ignore the time dimension. Let's assume that life survives on a planet for 5 billion years, and the distance between planets where there is life is 10 billion light years. So - in a given place there is life at most on only one planet.

    The fact that something cannot be tested does not mean anything about its correctness. There are many such cases in mathematics (Koltz hypothesis for a sample)

  2. For anyone who underestimates the importance of the discovery,
    First of all, many developments and inventions that improved mankind's life came from discoveries that even their discoverers did not believe were useful, and believed that they existed only for the purpose of pure scientific knowledge. Therefore, it is impossible to know what the science and technology that will develop from these discoveries will yield.
    Second, it is important for human beings to understand the essence of their existence, because if we know our essence, we can better understand the direction in which we need to walk. A big step in understanding this is whether we are alone in the universe and then special, or one of many and then common.
    In addition, although the number of planets is only one parameter in the equation for the existence of extraterrestrial life, this is of great importance, because if there were not many planets, then the other parameters would not be important, because the chances then were zero. Now that we know that this parameter is positive, we can continue to investigate the other parameters.
    Regarding contact with other cultures, first of all you have to find them right? So this generation will find them and the next generation will try to find ways to communicate with them... I believe that we do not fully understand the universe: the two big theories, quantum and relativity do not sit with each other, our theories say that 95 percent of the universe is matter and dark energy that we have no idea what they are , the quanta imply a connection between consciousness and matter, and neuroscientists today say that there is no consciousness in the brain... So maybe there is still a way to communicate with other cultures, we'll leave it to future generations.

  3. From the previous proof that says: "There are stars and / or planets outside the earth that have life in them",
    It follows that: "The number of stars and planets outside the earth that have life in them is.... infinite"(!)
    There are also an infinite number of planets and/or stars outside the universe that have life in them.

  4. It can be proven logically (!) that there is life in the universe outside the universe.
    1]. The universe is infinite, the super geometry is flat, and all the components of matter and energy are uniformly distributed in the universe as far as cosmological standards are concerned.
    2]. from 1]. It follows that the number of stars and the number of planets in the universe is infinite.
    3]. From 2 it follows that the sentence that claims: "There is no life on any planet in the universe except the Earth" is necessarily not true because it is not possible to test all the stars and all the planets.
    4]. If the sentence: "There is no life on any planet in the universe except the Earth" is not true, then the opposite logical sentence that says: "There are stars and/or planets in the universe that have life" is true (!) M.S.L.

  5. They are already here!!!! certainly!!!! Read a bit about ce-5 and after you do it then you will understand

  6. Of course there is a national day.
    – Drake equations
    - The illusion that there is something special about us has been proven wrong over and over again. Yes, Ashkenazim are special, Jews are special, whites are special, humans are 99 percent different from monkeys, mammals, and the same goes for life on Earth.
    – The argument that science is wrong compared to other mechanisms like God, magic, fate and spaghetti monsters has been proven wrong time and time again.

    So where are they all?
    So the range of possibilities is like this -
    - They can't get here
    - They don't want to come here (I don't really blame them)
    - They are already here, but the government/NASA don't want you to know about it, and managed to keep this secret 50 among at least a few hundred people? Sounds a bit problematic. Also Okum's razor...sounds improbable.
    - They are here but we can't see them...because they want to hide, or because they have all sorts of preconceptions about the future of humanity, once again Okum's razor - this is a bit too complicated an explanation, so it's probably not true..

    I'm betting on a combination of they can't / and don't want to.
    The universe is so teeming with life that we are not interesting enough to anyone to spend a few hundred years in the spaceship.
    Despite everything we think about ourselves.
    And there is also the issue of the time and space scales that life forms
    others/ civilizations exist in them,
    Short 42

  7. Not strange at all... apart from the Drake equation, you have to take into account:
    The very long period until the development of complex life... on Earth it took 4 billion years... before that there was only simple unicellular life...
    Catastrophes that lead to the extinction of life such as an asteroid collision ... in cycles every few tens of millions of years

  8. The chance that we are alone in the universe is almost non-existent. The chance that we will know if it is or not is even smaller. I will give you an example for distances:
    Pluto took 10 years to reach. The distance to Pluto is 4 light hours. Now it is clear why we will never know

  9. Is there life outside the earth? This is a question that intrigued me as a child. Kind of like the Harry Potter books that intrigue children. Stimulates imagination without grasping reality. This sci-fi has created classics in the big-budget entertainment industry.
    Today, an ordinary person has no basis to think about life outside of God. Firstly because to this day not a single case of such a way of life has been officially documented and proven, secondly what can be expected in the event that there is such a way of life? Should we initiate a meeting? For what? If intelligence, culture and the possibility to cooperate in large numbers is developed in this life form, and this culture wants to take advantage of us, then it has a good chance to succeed, if it does not want to take advantage of us, then our political and economic interest will make us take advantage of this life form. Scientists will tell superiors about research possibilities, finding a solution to incurable diseases, the possibility of settling other planets. If the tycoons are convinced, they will recruit politicians who will approve space programs funded by countries and corporations that will send research missions to these stars. They will try to explain in the campaigns how important space exploration is to humanity and how small steps of the researchers are advancing humanity in giant strides. You know what, maybe it will actually happen. Even long voyages of the explorers hundreds of years ago looked like this and were daring campaigns. It's just that all of history is like an alternating theater performance with changing characters but the same roles. There are those who will receive a reward for discovery, there are those who will enjoy power and honor, there are those who will count money following success, and there are those who will pay the price. Everyone else buys popcorn and stays to watch the show from the sidelines. We need to insist on the importance of preserving the existing on earth, the climate, the resources, nature. Because most of us will continue to live here to raise future generations.

  10. You have driven the Darwinists to the depths of your soul, that it is strange to you if this proves to be an empty claim...

  11. Suddenly I had an epiphany. All attempts to find life in the universe thousands of light years away.
    stems from the need to prove that life was created cosmically by a rare combination of atoms. and not by something divine. From the point of view of the scientists, this would be the winning proof that there is no God. But even that is doubtful, because we don't know God's plans. Maybe he created more universes!?

  12. Unnecessary studies. Pointless waste of money. It is better that they invest money and efforts in purposeful goals. As long as they don't know how to prevent runny nose, what do I care if they discover in a huge expense that there is a possibility of an unknown life form thousands of light years away. Meanwhile here people are dying of hunger and epidemics because they are unable to raise appropriate research budgets.

  13. Every time you write life, you have to specify and say "life as we know it here, on Earth". That is, carbon-based with the addition of hydrogen and possibly oxygen, in an aqueous solvent environment in a permanent liquid state, with a stable and well-distributed energy source, without lethal ionizing radiation, and without a history of nuclear war.

  14. "Even if there is. How will they discover life at a distance of hundreds or thousands of light years."
    It is more correct that it will not be applicable. They won't be able to communicate and certainly won't arrive. The time that the light passes will take a generation or more. For more than a billion years that the world has existed, there were probably planets and creatures that evolved on them, but that does not mean that they live at the same time as today.
    In my opinion, the information that there is (maybe) life somewhere in the universe does not promote humanity at all.

  15. Why should we look for life elsewhere?
    First of all, all Western governments will tell the truth, the aliens have been here since ancient times and have visited us for thousands of years and even now why not reveal to them and recognize the truth. Extraterrestrials are more advanced than us
    They were, they are the God of sorts defined as a supreme power and the time has come to tell humanity that this is the way things are and to start recognizing a different and advanced world

  16. Obviously.
    Only bigots and believers in God can think that man is something special.
    There is nothing special about man or life. Given suitable conditions and enough time, life will be created.
    Claiming that we are special is like claiming that the sun revolves around the earth.

  17. Don't laugh, our existence on Earth is a miracle, so on other stars? The probability is not possible.
    What is here is enough.

  18. How exactly will they discover life?
    even if there is. How will they discover life hundreds or thousands of light years away.

  19. "It would be strange if they didn't find a sign of biological life given the fact that there are so many planets" - a baseless claim. The number of planets is one parameter in a formula in which very little is known about other parameters.

    As long as we don't know how rare the sequence of events that led to life on Earth, or how rare the conditions that allow life of any kind to form, the number of planets doesn't mean much. If, for example, the creation of life is only probable at a rate of 10^100 - the fact that there are 10^22 planets does not really help...

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