A NASA satellite has discovered unexpected X- and C-shaped structures in Earth’s ionosphere. This layer of electrified gas in the planet’s atmosphere allows radio signals to travel great distances.
The ionosphere is an electrified region in the Earth’s atmosphere that exists because of radiation from the sun hits the atmosphere. Its density increases during the day because the molecules become electrically charged. That’s because sunlight causes electrons to break off of atoms and molecules, creating plasma that allows radio signals to travel long distances. The density of the ionosphere decreases at night — and that’s where GOLD comes in.
NASA’s Global-scale Observations of the Limb and Disk (GOLD) mission is a geostationary satellite that has been measuring the density and temperature of Earth’s ionosphere since its launch in October 2018. From its geostationary orbit above the Western Hemisphere, GOLD recently studied two dense peaks of particles in the ionosphere, located north and south of the equator. As night falls, low-density bubbles appear in these peaks, which can disrupt radio and GPS signals. But it’s not just the rising and setting of the sun that affects the ionosphere: the atmospheric layer is also susceptible to solar storms and massive volcanic eruptions, after which the peaks can merge into an X shape.
In its new observations, GOLD discovered a number of these familiar X-shapes in the ionosphere, even though there were no solar or volcanic disturbances causing them.
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“Previous reports of mergers only occurred during geomagnetically disturbed conditions,” Fazlul Laskara researcher at the University of Colorado’s Laboratory for Atmospheric and Space Physics (LASP), said in a rack. Laskar is the lead author of a paper published in April in the journal Journal for Geophysical Research: Space Physics in which these unexpected observations were described.
“It is an unexpected phenomenon during geomagnetic calm conditions,” he said.
This suggests that what happens in the lower atmosphere has more influence on the ionosphere than extreme solar or volcanic events.
In addition to the strange Xs, GOLD also saw curved C-shaped bubbles appear in the plasma, surprisingly close together. Scientists think they are shaped and oriented according to the wind direction, but GOLD imaged C-shaped and inverted C-shaped bubbles at distances of about 400 miles (643 kilometers). For wind patterns to change so drastically over such short distances is quite unusual, the researchers said.
“It’s really important to figure out why this is happening,” says LASP researcher Deepak Karanlead author of a separate paper published in November Journal for Geophysical Research: Space Physicsthe statement said. “If there is a vortex or a very strong shear in the plasma, it will completely distort the plasma over that region. Signals will be completely lost in a strong disturbance like this.”
This isn’t the first time NASA has wanted to learn more about the ionosphere. Recently, a project called Atmospheric disturbances around the eclipse path (APEP) investigated how a drop in sunlight and temperature affects Earth’s upper atmosphere. During the October 14 annular solar eclipse in the southwestern United States and again during Total solar eclipse on April 8 over North America, NASA launched three suborbital sounding rockets into the path of the eclipse to measure changes in electric and magnetic fields, density and temperature in the ionosphere. The results of the mission are not yet known.