Buzz
STEVE (Strong Thermal Emission Velocity Enhancement) can be spotted across the Milky Way, as seen at Childs Lake in Manitoba, Canada. Image courtesy of NASA Goddard Space Flight Center/Flickr.When it comes to naming celestial phenomena, astronomers often opt for futuristic and whimsical names like magnetar, Thorne-Zytkow object, black dwarf, or hypernova. But on occasion, they surprise us by naming a phenomenon something as simple as STEVE.
Despite its unassuming name, STEVE is no less spectacular and a true spectacle to witness.
STEVE, which stands for Strong Thermal Emission Velocity Enhancement, is a phenomenon visible to the naked eye here on Earth. It is an optical spectacle, much like the aurora, but distinct in that it forms a thin, arching lavender light. Unlike the aurora, this unique display always aligns along an east-west axis and is observed at latitudes far closer to the equator than the usual northern or southern lights.
This purple light formation has been spotted and recorded by aurora enthusiasts for centuries. In fact, it was named 'Steve' by a Facebook group of Canadian aurora photographers who repeatedly observed the phenomenon in southern Canada, long before the European Space Agency confirmed it as a separate event in 2016. Interestingly, the name 'Steve' was also borrowed from the animated film 'Over the Hedge,' where it refers to a newly discovered hedge by a group of forest animals.
How Does STEVE Differ from the Aurora?
STEVE is distinct from the aurora in several observable ways. While both are visible from Earth, their appearances differ in position in the sky and how they manifest. Unlike the shimmering green, white, and red curtains of the aurora, STEVE tends to appear as a solitary purple band, often appearing in a horizontal form, resembling a picket fence.
The scientific differences between STEVE and the aurora are also quite significant. The aurora has long been understood as the result of solar radiation particles interacting with the nitrogen and oxygen in Earth's atmosphere, particularly near the poles where the magnetic field is weakest. STEVE, however, remains a mystery in its exact scientific origins, setting it apart even further from the aurora.
The aurora is a stunning spectacle, yet it serves as a reminder that without Earth's magnetic field, our atmosphere would be rapidly stripped away by the scorching solar plasma moving at incredible speeds. Interestingly, the colors of the lights visible at the poles can provide valuable insights for scientists, revealing much about the chemical composition and dynamics occurring in our atmosphere.
What Triggers STEVE?
STEVE serves as a similar reminder, but its hue and position in the sky indicate that its glow isn't caused by the interaction of electrons and protons from solar radiation with our atmosphere. Instead, STEVE is the result of hot, ionized gas released, often from intense solar storms.
While scientists are still puzzled about why STEVE appears at lower latitudes than the aurora, they have found that this hot ionized gas pushes through Earth's atmosphere, traveling at a remarkable speed of about 13,300 miles per hour (21,400 kilometers per hour). The high velocity and friction generate heat, causing the surrounding gases to light up until the stream of solar gas fades away.
Thanks to social media, advanced camera technology, and the efforts of dedicated citizen scientists, we now have knowledge of STEVE. What we learn about it in the future is in the hands of researchers and scientists.
In keeping with its casual name, "Steve," NASA decided to maintain the original title by turning it into its official acronym, STEVE, which stands for Strong Thermal Emission Velocity Enhancement.
