India’s ambitious new solar mission, Aditya-L1, is set to transform our knowledge about solar phenomena, and especially about Coronal Mass Ejections (CMEs). The mission is planned for launch in 2026. Its overarching mission is to track activity on the sun and learn how that activity impacts both space and Earth. Given this historical context, the importance of Aditya-L1 is hard to overstate.
Thanks to the Carrington Event of 1859, the most powerful solar storm on record, we know about solar storms. This cosmic storm wreaked havoc on earth, even taking down telegraph lines around the globe. It was a stunning reminder of the power of solar phenomena to disrupt our technological infrastructure. Aditya-L1 hopes to do the same by improving our predictions and responses to these chaotic, dangerous realities of space weather.
In November 2015, Aditya-L1 recorded one of the largest CMEs, which disrupted air traffic control in Sweden and other parts of Europe, reflecting the immediate dangers posed by solar activity. In addition to disrupting air travel, CMEs may impact critical Earth infrastructure, including power grids and satellite operations.
CMEs can be very massive, sometimes up to 270 million tonnes. At these stars’ origins, temperatures can reach over 1.8 million degrees Celsius! In terms of energy, a CME can release as much as 2.2 million megatons of TNT. For reference, the asteroid thought to have killed all the dinosaurs had a mass of 100 million megatons. Statistics like these show you just how powerful these solar phenomena are, and how much they can disrupt.
Historically, CMEs have caused significant outages. In 1989, a CME knocked out part of Quebec’s power grid, leaving six million people without electricity for nine hours. One year later, another major CME hit the Earth in February 2022. It also resulted in the loss of 38 commercial satellites and illustrated how exposed our modern technology is to solar activity.
Aditya-L1 will use state-of-the-art instruments to closely observe these phenomena. One of its main components is the Visible Emission Line Coronagraph (Velc). It is a testbed for the most efficient means of monitoring and decoding data from coronal mass ejections (CMEs). This device functions as a manmade surrogate Moon. It does this by blocking the Sun’s bright surface, allowing for ongoing study of its faint outer corona.
“Aditya-L1’s coronagraph is the exact size that lets it nearly mimic the Moon, fully covering the Sun’s photosphere and allowing it an uninterrupted view of almost all of the corona 24 hours a day, 365 days a year, even during eclipses and occultations,” – Prof Ramesh of the Indian Institute of Astrophysics (IIA).
Observing CMEs is one of Aditya-L1’s most important science goals. Understanding these solar eruptions will help scientists devise countermeasures to protect satellites in near space and improve knowledge about near-Earth environments.
“The learnings from this will help us work out the countermeasures to be adopted to protect satellites in near space,” – Prof Ramesh added.
During quiet or low-activity phases, the Sun produces two to three CMEs each day, according to Prof Ramesh. This alarming rate underscores the need for vigilant monitoring and research of solar energy.
While CMEs can produce stunning natural displays such as auroras, evidence that charged particles from the Sun are interacting with Earth, these phenomena pose substantial risks to modern technology.
“But they can also make all the electronics on a satellite malfunction, knock down power grids and affect weather and communication satellites,” – Prof Ramesh emphasized.
With solar activity cycles on the rise, it is more important than ever to recognize these events. Aditya-L1’s wide range of observations will set new standards for measuring future solar events in periods of high activity. This could allow scientists to more effectively prepare for impacts.