ADSL on its last legs in South Africa

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  By   Daniel Puchert Partially state-owned telecommunications company Telkom announced in its financial results for the year ending 31 March 2025 that its ADSL subscribers had more than halved to under 30,000. According to the company’s operational data, ADSL lines decreased from 64,959 in March 2024 to 29,770. This 54.2% decline highlights that the legacy broadband technology is slowly approaching the end of the road. Telkom’s ADSL business peaked at the end of March 2016 with 1.01 million subscribers — two years after fibre upstart Vumatel  broke ground in Parkhurst . What followed was a sharp decline in Telkom ADSL subscribers. Customers connected to its copper networks decreased by more than 500,000 over the next four years. This was partly driven by Telkom itself, which began actively switching off its copper network in some neighbourhoods. If it did not have fibre in the area, it would offer a “fixed line lookalike” wireless service that ran over its cellular ...

Mars is leaking water into space during dust storms and warmer seasons

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Water is leaking from Mars' atmosphere through changing seasons and swirling Martian storms, scientists found in two new studies. 

There is water on Mars, but it seems to only exist either in ice caps at the planet's poles or as gas in the planet's thin atmosphere. Water has been escaping the planet for billions of years, since Mars lost its magnetic field (and subsequently much of its air and water), and two new studies show how water moves through and leaves the planet's atmosphere. 

The two new studies, led by Anna Fedorova, a researcher at the Space Research Institute of the Russian Academy of Sciences and Jean-Yves Chaufray, a scientist at the Laboratoire Atmospheres Observations Spatiales in France, use data from the European Space Agency's (ESA) ExoMars orbiter, which began its main science mission in 2018, and ESA's Mars Express orbiter, which  to show that the escape rate of mars' water is determined by changing weather and climate on Mars and the planet's distance from the sun. 

"The atmosphere is the link between surface and space, and so has much to tell us about how Mars has lost its water," Fedorova said in an ESA statement

Related: Mars may be wetter than we thought (but still not that habitable) 

Researchers are exploring how Mars' water escapes out into space. (Image credit: ESA)

In these studies, the teams used data from ExoMars' SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument, which observed Mars' atmosphere. 

"We studied the water vapor in the atmosphere from the ground up to [62 miles] 100 kilometers in altitude, a region that had yet to be explored, over eight Martian years," Fedorova said. (One year on Mars is about two Earth year.)

The researchers found that when the planet is farthest from the sun, at about 250 million miles (400 million km) away, water vapor in Mars' atmosphere really only exists less than 37 miles (60 km) from the planet's surface. However, when the planet is closest to the sun, at about 207 million miles (333 million kilometers), water can be found as far out as 56 miles (90 km) above the surface. 

When Mars and the sun are farther apart, the cold makes the water vapor at a certain altitude in Mars' atmosphere freeze out, but as the planet gets closer and warmer, that water can circulate farther. Because water vapor can travel out farther in Mars' atmosphere during warmer seasons, those are also the times when the planet loses more water. 

"The upper atmosphere becomes moistened and saturated with water, explaining why water escape rates speed up during this season — water is carried higher, aiding its escape to space," Fedorova added. 

But it's not just seasons that dictate how much of Mars' water leaks out into space; dust storms also play an important role, the researchers found in these studies. In poring over eight years of data, the scientists found that in the years that Mars experienced global dust storms, water traveled higher in the planet's atmosphere. In these years, the researchers found water vapor over 50 miles (80 km) from the planet's surface. 

The scientists found that every billion years, Mars loses the equivalent of "a global [six feet] two-meter-deep layer of water," according to the statement. 

"This confirms that dust storms, which are known to warm and disrupt Mars' atmosphere, also deliver water to high altitudes," Fedorova said. "Thanks to Mars Express' continuous monitoring, we were able to analyze the last two global dust storms, in 2007 and 2018, and compare what we found to storm-free years to identify how the storms affected water escape from Mars."

Still, this work does not fully explain the amount of water that Mars has lost over the past 4 billion years, according to the statement. "A significant amount must have once existed on the planet to explain the water-created features we see," Chaufray said. "As it hasn't all been lost to space, our results suggest that either this water has moved underground, or that water escape rates were far higher in the past."

These two studies were published Dec. 11, 2020, in the Journal of Geophysical Research: Planets and Jan. 1 in the journal Icarus

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

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