Interview with Johannes Geiss Fellow Marco Velli

Marco Velli is the Johannes Geiss Fellow 2022 and Professor of Space Physics at the Earth, Planetary and Space Sciences Department, University of California, Los Angeles, USA. A student of the University of Pisa and Scuola Normale Superiore, he has spent research periods at the University of St. Andrews, Scotland, the Observatoire de Paris, France, Università della Calabria, Italy, and the Smithsonian CfA, Cambridge, MA, as well as the Jet Propulsion Laboratory, California Institute of Technology, where he remains a Senior Scientist. In the following paragraphs he answers a few questions – asked by Christian Malacaria, ISSI Post Doc – about his scientific work. Christian Malacaria is an X-ray astronomer with expertise in observations and data analysis of compact objects. He is a member of several X-ray missions such as Fermi/GBM, NICER and IXPE.

Christian Malacaria: What is the main advantage of being a Johannes Geiss Fellow at the International Space Science Institute?

Marco Velli: As a UCLA professor, I have several different official tasks and duties in addition to research, such as administrative, managerial and teaching. All these are an essential part of each scientist’s work but can become so cumbersome that eventually one is left with less and less time for the creative research process, or even just for enjoying in depth scientific discussions with colleagues and friends. The Johannes Geiss Fellowship (JGF) provides time away from the day-to-day hassle, allowing one to rediscover and enjoy pure research.

Being a JGF at ISSI offers numerous advantages, creating a highly favorable research environment. ISSI is a tranquil yet stimulating place, frequently visited by exceptionally interesting guests and featuring a vibrant atmosphere. Here, diverse scientists, both young and senior, from various backgrounds continuously come and go, providing opportunities for diverse brainstorming, which fosters innovative research projects. The peaceful environment and minimal mundane duties of ISSI allow me to feel comfortable and remain focused, free from distractions. Furthermore, ISSI provides a convenient apartment within a short walk of the institute, unlike my usual residence in Los Angeles, where I endure a one-hour traffic jam to get anywhere. In essence, as a JGF, the hassles of everyday life have been removed, making life at ISSI significantly easier. Moreover, at ISSI, I have been able to join several science teams and workshops, and even participate in meetings without being a formal team member. This opportunity is not available anywhere else in the world of space physics. Although my six-month Fellowship is coming to an end soon, I would reapply for the JGF experience right now. This experience has rekindled my enthusiasm for research, in ways that are impossible to replicate elsewhere.

Christian Malacaria, ISSI Post Doc, and Marco Velli, Johannes Geiss Fellow 2022

Christian Malacaria: What are the most important open questions in Heliophysics and how are they going to be addressed?

Marco Velli: One of the most significant and fundamental problem is the existence of the heliosphere itself, closely linked with other essential questions such as: why does the Sun have a functioning dynamo and magnetic field? How is the solar corona heated and the solar wind generated? How are solar flares and coronal mass ejections triggered and solar energetic particles accelerated? Unfortunately, even with years of research, we still lack a comprehensive model that effectively addresses these questions.

The main obstacles to answering these questions can be divided into two categories: the first is related to observations, the second to time-scales: to start from the second point, our knowledge of the basic mechanisms behind the solar dynamo is limited by the Solar cycle periodicity: we must base our statistics onthe 11-year (22-year full) cycle, and though we have some observational proxies dating back centuries, routine mesaurements of the solar magnetic field from Earth is limited to  about 10 cycles, while direct measurements of the solar wind and of the x-ray corona date to the space age (< 5 cycles), with the highest resolution measurements from SDO being only about a decade old.

In addition, understanding the dynamo requires precise measurements of the magnetic fields and photospheric flows all the way to the solar poles, while we are limited from the ecliptic plane to measurements around 60 degrees. Such observations would be key in understanding the solar magnetic field, and indeed the ongoing joint ESA-NASA mission Solar Orbiter will move out of the ecliptic plane within the next few years hopefully providing major new discoveries over the coming decade. Complementary to that, NASA’s Parker Solar Probe is probing the solar corona directly and will be moving to a perihelion inside 10 solar radii from center within the next two years. The direct measurement of the solar wind and its magnetic field in this acceleration region by PSP is already revolutionizing our understanding of the solar corona and promises, in conjunction with Orbiter, a complete paradigm change within the decade.

A predictive theory based on solid observations of the solar dynamo, solar coronal heating and solar wind acceleration is fundamental to understand the dynamics of magnetized plasmas well beyond Solar or Stellar physics, from the interstellar medium to galactic halos, pulsar wind nebulae and black hole magnetospheres, active galactic nuclei and the hot intra-cluster medium. Solar flares and coronal mass ejections are at the lower end of energetic bursty phenomena associated with magnetized plasmas throughout the universe that are associated with the generation and acceleration of cosmic rays and the X-ray and gamma-ray universe more generally.

To progress in our understanding of the Heliosphere, key future missions should include a global constellation of observatories comprehensive of in ecliptic and out of ecliptic (polar) observations, allowing for a 3D reconstruction of the Heliosphere in its complexity and variability. Such a mission is of fundamental interest also in the context of space weather and of providing the plasma context and advance warning for future human exploration of the solar system.


Christian Malacaria: Given the importance of the social melting pot promoted by ISSI, what do you think is the role of science (and scientists) in society?

Marco Velli: Science is experiencing an unprecedented pace of breakthroughs across multiple domains, and the approach to scientific research is also undergoing a significant transformation. Large collaborative teams are replacing the traditional romanticized notion of the lone scientist working at their table. However, the amount of time devoted to science and critical thinking has not improved, and science classes in schools remain limited. This is concerning, as it may lead to generations of scientists with exceptional technical skills, but a limited understanding of the big picture.

The problem of “compartmentalized knowledge” can hinder scientific progress and our understanding of physics in several ways, including the limitations of our science, or the boundaries of our understanding. To prevent this, we need to apply scientific thought and critical reasoning to different environments, including everyday life. This would enable us to greatly expand the way science is practiced, and foster a more continuous form of education as opposed to the current discrete model.

Science no longer requires all-knowing gurus, as it did in the past. As science evolves, the role of “universalists” is fading, and team-based work is becoming the key to achieving groundbreaking goals. Each scientist is now part of a larger chain, and their responsibility is not solely to the advancement of science but also to a necessary knowledge of the limitations of the results and methodologies. This becomes even more paramount with the emergence of machine learning and artificial intelligence methodologies where understanding how a certain result has been obtained can become as difficult as the original question probed.

This also affects human interactions, where we must work together towards a common objective and contribute actively with critical thinking, rather than passively expecting higher organizations to take care of collective challenges. As scientists, we have a responsibility to help standardize this behavior and incorporate it as an ethical requirement. Given the privilege we hold as highly educated people, it is our duty to lead by example and promote a culture of collaborative work and continuous learning.

The Johannes Geiss Fellowship (JGF) is established to attract to ISSI – for limited duration visits – international scientists of stature, who can make demonstrable contributions to the ISSI mission and increase ISSI’s stature by their presence and by doing so will honor Johannes Geiss for his founding of ISSI and his contributions to ISSI, and for his many contributions to a broad range of space science disciplines.