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The Solar Cycle XRay

Researchers have solved one of the biggest mysteries behind sunspot cycles

Waxing and waning of sunspots is a part of the natural cycle of Sun. However, astronauts do not yet understand this phenomenon fully. Now, new research has brought the conclusion that particular “terminator” events are responsible for ending the sunspot cycles which means that they can be predicted in a better way. Predicting sunspot cycles would mean that advanced warning of the various types of solar storms that could change infrastructure and electronics on Earth. The study has been published in the Solar Physics and Scientific Reports

These findings are based on 140 years of solar observations. They include recordings of coronal bright points which occur during relatively calm periods on the Sun. Researchers say that movement and final disappearance of these points mark a terminator event. Scott McIntosh, an astrophysicist from National Center for Atmospheric Research, US said that this evidence was hidden in the observations for more than a century however we were not aware of what we were finding. Combination of such a wide scale of observations gives new insights to how the interior of the Sun drives solar cycle. 

A sunspot cycle lasts nearly 11 years. After a solar minimum, sunspots slowly increase in number, forming at a latitude of 35 degrees in both hemispheres before reaching the equator and then dying. This takes nearly a decade to complete, with the midpoint being called the solar maximum when the sunspot activity is highest. Recent solar maximum was in April 2014.

The coronal bright points also travel towards the equator from higher latitudes. They overlap with sunspots at some points and scientists think them to be the markers for toroidal magnetic field movement. These wrap around the Sun also moving towards equator. When magnetic fields rise to Sun’s surface, scientists propose that sunspots emerge for joining the coronal bright points. Plasma is built as the spots move and is released when one wave of toroidal magnetic field hits the another in the opposite direction on the equator. 

This release is often quite dramatic. Research tells that solar tsunami of plasma is unleashed, which travels further away from the equator at 300 metres per second. This again meets another toroidal magnetic field in the opposite direction, leading to the formation of sunspots and the cycle continues. 

Although this is a hypothesis presently with the accumulated data and educated guesswork and scientists will be testing their models when the current solar cycle ends and start again the next year. This research shows that observations and multiple data streams can unlock the discoveries which would be more difficult otherwise. Bob Leamon from University of Maryland says that the terminators were identified by observing different types of solar activity, magnetic fields, spectral irradiance, radio flux along with bright points. This shows that along with spacecrafts, we need to use all the data available to understand how things work. 

Journal Reference: Scientific Reports

nasa earth terminator

Unique photo taken from space shows the separation of day and night on Earth

A magnificent image of Earth taken from the International Space Station (ISS) gives the glimpse of a daily event which is otherwise ignored by us and not paid much attention to.

NASA astronaut, Christina H. Koch posted a photo on Twitter which shows how it appears from the ISS when one part of our planet is in darkness while bright daylight shines on the other half. This is actually a very rare observation for ISS as it does not normally orbit over the line which shows the transition and differentiation between day and night. It is also known as the terminator zone.

Koch wrote in the accompanying post that the ISS orbit aligns over the day-night shadow line of the Earth, only few times in a year. Otherwise, the Space Station is always in the sunlight zone and it never passes to the zone of Earth’s shadow from the Sun. She also added that the Earth is always in a dawn or dusk mode and is a great time to observe it. The photo was not processed in any way before posting.

Koch was highly enchanted by the event however the reply to the post from former astronaut, Mike Fossum showed that not all astronauts preferred this view of Earth. He commented that this was his least favourite view of the planet as it was not fully clear, being distorted by low light angles. He preferred the clearer days, nights for capturing images of Earth.

Christina Koch will be spending almost a year in space which makes her the American astronaut to have the second longest spaceflight. She will be staying in space with fellow astronauts Nick Hague and Alexey Ovchinin for 328 days, just a few days short of the record of 340 days set by astronaut Scot Kelly. She will be returning back to our home planet in February 2020.

Koch who is a former National Oceanic and Atmospheric Administration employee paid her tributes to the organisation which is studying the effects of greenhouse gases, recovery of ozone in the stratosphere of the Earth. Before being an astronaut, she was an employee at the Baseline Observatory of GMD in Alaska and also as a station chief in the American Samoa Observatory.

“From here,” Koch said of her perch in orbit, “we have an amazing view of our home planet, Earth. Looking outside the window of the ISS is a humbling and inspiring experience. It really brings into focus how important it is that we treasure this planet that we have.”

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