Phys.org is reporting this week that an international team of astrophysicists and planetary scientists has discovered a possible link between magnetospheric activity and ionospheric turbulence. In their study published in the journal Physical Review Letters, the group used data from two sources to compare magnetospheric activity and ionospheric turbulence occurring at nearly the same time.
As you know, the ionosphere comprises the upper reaches of Earth’s atmosphere—it spans from approximately 48 km to 965 km above sea level, holding ions formed from solar radiation, making it electrically charged. The magnetosphere is an area of space surrounding Earth—it has charged particles that are impacted by Earth’s magnetic field. It exists courtesy of the planet’s internal dynamo, and it extends to approximately 65,000 km from the surface, though the distance varies greatly depending on a variety of factors.
Scientists have long known that turbulence in the ionosphere can cause problems with GPS signals, radio communications and even parts of the internet. Researchers have been looking to understand better why it happens, to figure out a way to predict when it will occur, and how strongly. In this new effort, the research team has taken a step toward solving the latter problems.
The team suspected that activity in the magnetosphere might be responsible for at least some of the turbulence that occurs in the ionosphere. To investigate, they used two sources of observational data: one on activity in the ionosphere (from the Japanese spacecraft Arase) and the other on the magnetosphere (from the ground-based ICEBEAR station in Canada).
By comparing data from both over the period January 2020 to June 2023, they were able to see if activity happening in the magnetosphere was followed soon thereafter by turbulence in the ionosphere and found one such incidence.
Data from Arase showed a burst of activity on May 12, 2021, in the magnetosphere. Seconds later, data from ICEBEAR showed turbulence occurring in the ionosphere. The data also showed the activity for both occurred over roughly the same patch of Earth and that the shape and timing of the signals matched to what the team describes as “a high degree of precision.”
The researchers acknowledge that more work is required before a definitive association can be made between events in the magnetosphere and turbulence in the ionosphere, but they suggest their work is a strong step in proving it to be the case.
Popularmechanics.com has announced this week that a team of scientists announced the detection of dimethyl sulfide (along with a similar detection of dimethyl disulfide) in the atmosphere of an exoplanet called K2-18b. This is actually the second detection of dimethyl sulfide made on this planet, following a tentative detection in 2023. Their announcement was made in a paper published in Astrophysical Journal Letters.
Tons of chemicals are detected in the atmospheres of celestial objects every day. But dimethyl sulfide is different, because on Earth, it’s only produced by living organisms.
“It is a shock to the system,” Nikku Madhusudhan, first author on the paper, told the New York Times. “We spent an enormous amount of time just trying to get rid of the signal.”
It may sound surprising that the scientists were “trying to get rid of the signal,” but that’s exactly how detections like this work. Pretty much all of the exoplanets we’ve ever seen are simply too far away to just look at. Instead, to gather more information about what may lie on their surfaces, scientists observe the chemical makeups of their atmospheres.
This is done by capturing starlight that filters through those gaseous layers as a planet completes a transit in front of its host star. Different wavelengths of that starlight are blocked by different atmospheric chemicals, so by reading which wavelengths get filtered out as they pass through an exoplanets atmosphere, we can tell what that atmosphere is made of.
Astronomers have become very good at making these detections, but it’s still a difficult process. And the first step, every time, is to try to filter out noise—errant spikes in a spectrum that can disguise true detections—and false positives that might be caused by, say, a nearly invisible gas cloud in between us and an exoplanet.
So, when the astronomers spotted dimethyl sulfide in the atmosphere of K2-18b, they did everything to try to rule out the possibility that it was a ‘whoops.’
But even after carefully exhausting all the avenues they could think of over the course of two full observation sessions with JWST (which is rare in astronomy, considering how many teams want time with the coolest telescope we have) they found it impossible to attribute the detection to anything other than atmospheric composition. And if you rule out the impossible, whatever remains—however improbable—must be the truth.
May I end this shortened bulletin with a huge appeal to all you radio communicators who read this bulletin or listen to it, to consider sending me some news of your area? You will have noticed that, for months now, I’ve had virtually nothing to say about the South African Comms scene, or about events, activities or rescues that we have been involved in. Does that really mean nothing happens in South Africa? Please consider sending me as little as a paragraph from your area, and I will incorporate it in the bulletin. Thank you.
And now, bearing in mind which Sunday today is, may I warn you not to join the ranks of those in the statistics, to whom the following epitaph applies: “Death by Chocolate”!
This is Dave Reece ZS1DFR, hastily wiping the chocolate smears off all the keys on his keyboard, and reporting for HAMNET in South Africa.