Heliophysics: The Science of the Sun

As society’s dependence on space-based technology increases, it becomes more crucial that we better understand the dynamics and processes that govern the environment around Earth. The Sun accounts for 98% of the mass and a vast majority of the energy in the solar system, so most of the physics of our solar system is driven by the physics of our local star. Although it’s sometimes broadly referred to as “space physics” or “space science”, the discipline that studies the science of the Sun is known as “heliophysics“. This broad term includes everything from the study of the Sun itself to the constantly streaming solar wind to the interaction of the Sun with the Earth and other planets. It also includes the study of the magnetic fields and atmospheres of our planet and others. Heliophysics brings together solar, magnetospheric, ionospheric, and atmospheric physics and overlaps with astrophysics, earth and planetary science, and plasma and nuclear physics.

This image from NASA’s Solar Dynamics Observatory (SDO) shows the atmosphere or corona of the Sun. Taken with the Atmospheric Imaging Assembly (AIA) instrument, the image shows the atmosphere and filaments of the Sun in ultraviolet (UV) light at a wavelength of 19.3 nm. Credit: NASA

It’s easy to forget the size and power of the Sun as we look at in the sky each day from Earth, especially on cloudy days in the heart of winter when the temperature is low and it feels like we may never see the Sun again. We can see the Sun rise and set, but otherwise it seems a static disc of yellow light. The truth though is that the Sun is extremely dynamic, constantly burning and releasing enormous amounts of energy and radiation, both in the form of light and highly energized particles. Some intense solar events, such as solar flares and coronal mass ejections (CMEs) can throw out millions of tons of highly energetic particles that can seriously affect our satellites and other technology. The cumulative effects of solar activity is known as “space weather” and it poses just as big a threat to our modern society as terrestrial weather on Earth. The most common manifestation of space weather is the aurora that occurs near the planet’s poles, commonly referred to as the northern or southern lights. Fortunately these beautiful displays are rather harmless, but there are much more serious effects of space weather. In addition to damaging satellites used for telecommunications, GPS, and national defense, highly energetic particles emitted by the Sun can also cause geomagnetic storms that can overload transformers on the ground and damage the power grid. An April 2013 report from the White House Office of Science and Technology Policy estimated that a single severe space weather event could lead to $1-2 billion in damage to infrastructure, both in space and on the ground.

The aurora (seen here over Iceland) is the most common and well-known effect of space weather. Energetic particles in the near-Earth environment collide with and excite molecules in the atmosphere. As those atmospheric molecules relax, they emit light at distinct colors (wavelengths) depending on the structure and type of molecule. Green aurora like this is extremely common and comes from collisions with oxygen. Credit: APOD

Federal funding for heliophysics research is spread across multiple agencies, including NASA, NSF, NOAA, and the Departments of Energy and Defense. At NASA, heliophysics research is centralized within the Heliophysics Division, part of the Science Mission Directorate, while it is split across two separate directorates (Geosciences and Mathematical & Physics Sciences) at NSF. Unfortunately, although heliophysics research directly impacts all of the other divisions within NASA’s Science Mission Directorate, it receives the lowest level of funding*. Both Earth and planetary science are heavily influenced by the interaction of the planets with the Sun and astrophysicists can use the Sun as a nearby comparator when studying other stars. Space weather also heavily affects other mission directorates, such as Space Technology and Human Exploration and Operations, which can benefit greatly from increased understanding and advanced prediction capabilities that could result from heliophysics research.

So welcome to our new blog, where we aim to educate and advocate regarding the impact and relevance of heliophysics research. Stay tuned for new posts and be sure to share the news and information with your friends, family, colleagues, and most importantly legislators because the Sun really is at the center of it all and affects life as we know it in many ways.

*While the Astrophysics Division appears to receive less than the Heliophysics Division, the James Webb Space Telescope (JWST), which has its own line-item in the budget, is an astrophysics mission and when included more than doubles the NASA funding for astrophysics research.


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