The Magnetic Force That Shapes Our Galaxy
Susan Clark is helping to uncover the secrets of the Milky Way's magnetic field, a crucial part of understanding our galaxy. This research is crucial for understanding the magnetic force that shapes our galaxy.
Vast pockets of gas combine to form clouds where new stars are born amid turbulent oscillations of Milky Way. Magnetism, important but frequently disregarded factor in this process is crucial to understanding magnetic force that shapes our galaxy.
Susan Clark (astrophysicist at Stanford Univers) offers great explanation: “There is a great adage that goes, ‘You can measure a man’s stupidity by strength of his magnetic field.’ Stated differently, we tend to attribute problems in astrophysics that we don’t fully understand to the magnetic field. We just exclaim, ‘Ah! The magnetic field,’ while waving our hands.”
Through this lighthearted perspective, Clark emphasizes how magnetism, though sometimes a mystery, plays a significant role in the birth of stars in our galaxy.
Understanding how magnetism shapes our galaxy has been a tough challenge for scientists because measuring the galactic magnetic field is difficult. Since it can’t be detected directly, astronomers look for clues by studying dust that the magnetic field has aligned and the light that passes through this dust.
Although there is still much to learn, new tools and methods are helping us get closer to understanding how magnetism influences the development of stars and galaxies. Susan Clark, who leads the Cosmic Magnetism and Interstellar Physics group at Stanford, is at the forefront of this research. She combines new observational techniques, simulations, and theoretical work to solve the mysteries of galactic magnetism. This year, she received the Sloan Research Fellowship for her outstanding early-career achievements and her potential to make major advances in her field.
Clark explained, “We’re not just trying to guess; we want to understand exactly how the magnetic field affects things.”
Quanta recently interviewed Clark at a conference in Santa Barbara, California, to learn more about her progress in studying the galaxy’s unseen forces. The interview has been condensed and edited for clarity.
Table of Contents
What We Want to Learn About Galaxy’s Magnetic Field
There’s still a lot we don’t know about how magnetic field affects our galaxy. We want to understand its role in shaping gas between stars known as interstellar medium (ISM). Magnetic field seems to be important in how this gas evolves into dense, cold clumps called molecular clouds, which are where stars are born. It also affects how these clouds separate apart to create new stars, though details are still unclear.
We note that the gas in the ISM often displays long, thread-like formations when it aligns with the magnetic field. Our goal is to understand the effects of this alignment on gas moving between phases and how it creates turbulence in the interstellar medium.
Different Phases of Gas in Interstellar Medium
Yes, our galaxy has a variety of gaseous states. It exists in a range of states, from very cold, dense molecular clouds to very hot plasma. Galactic evolution & star formation involve movement of gas between these several phases. We want to understand how gas transforms into stars and how these stars eventually return to ISM, where they contribute to future star formation.
Recent discoveries have shown that as we move to denser regions in ISM, filamentary clouds of molecular gas tend to align perpendicular to local magnetic field. It also means that structure of magnetic field may affect formation and ultimate breakdown of these gas filaments into new stars. Our objective is to piece together the mechanisms by which gas and magnetic field interact to control star formation, as there are still many unsolved questions.
How Do You Map Magnetic Field’s Structure?
Although it is difficult to map unseen magnetic field in galaxies, we can use hints from interstellar medium (ISM). ISM is made up of incredibly tiny, asymmetrical dust particles. When light from a background star travels through this dust, it filters the light because the grains align with local magnetic field. The dust absorbs light polarized parallel to its long axis, so by measuring the polarization of the starlight that reaches us, we can infer the magnetic field’s structure.
These dust grains also release light that is polarized according to the direction of the magnetic field. Through the analysis of this polarized light, the magnetic field can be mapped.
How Are Galaxy’s Magnetic Fields Generated?
Origin of galactic magnetic fields is still a big question. We want to understand how large, organized magnetic fields form. Likely, the movements of gas during galaxy formation amplified and structured the magnetic field. Observations of magnetic fields in other galaxies help us study this.
Do Different Types of Galaxies Have Different Magnetic Fields?
Yes, magnetic field patterns of galaxies differ from one another. Antennae galaxies for instance- are a pair of merging galaxies. Based on dust polarization, we were able to identify a coherent magnetic field pattern in their interaction zone. About these discoveries, there’s still a great deal we don’t know.
Can Studying Galactic Magnetic Field Reveal Its Origin?
We want to find out what created the initial “seed” magnetic field that got amplified during galaxy formation. This seed field might be primordial, originating from the universe’s birth. However, current measurements of magnetic fields in galaxies alone won’t tell us where the seed field came from; they only indicate that such a field existed.
Why Did You Become Interested in Galactic Magnetic Fields?
I enjoy taking on challenging, intriguing topics. In my field, there are situations when we are unsure of even proper question to ask, let alone correct response. We must exercise creativity in utilizing astrophysical data to solve these challenging issues.
Concluion: Magnetic Force That Shapes Our Galaxy
Understanding shape of our galaxy requires understanding of Milky Way’s magnetic field. Susan Clark’s work emphasizes how important magnetism is to star formation. New techniques map magnetic field by analyzing dust alignment and polarized light, notwithstanding difficulty of detecting it.
During star formation, gas in galaxy transitions between several states such as thick clouds and hot plasma. Alignment of molecular clouds with magnetic field is indicative of field’s influence on this process.
Although source of galactic magnetic fields is yet unknown, research on several galaxies can help. Our grasp of how magnetism forms our galaxy is being advanced by Clark’s work.
