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An enormous Martian cloud returns every spring. Scientists found out why

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A cloud longer than California streaks across Mars‘ ruddy cheek. It looks as though an impressionist painter loaded his palette knife with white and scraped a line across the canvas as far as the oily paint would travel.

This is not what astrophysicist Jorge Hernández Bernal first saw in 2018 when the Mars Express Visual Monitoring Camera(Opens in a new window) — affectionately known by the European Space Agency as the Mars webcam(Opens in a new window) — posted a new picture. To the average eye, it was grainy and inscrutable, with the resolution of a standard computer camera circa 20 years ago. But Bernal, who was studying Martian meteorology at the University of the Basque Country in Spain, immediately recognized the shadow as something else: a mysterious weather phenomenon happening on the Red Planet.

It wasn’t until researchers looked at the cloud with better equipment that Mars revealed the cloud in all its sprawling glory. The team dug deeper into photo archives, and discovered it had frequently been there. It was there through the aughts, and it was even there during NASA‘s Viking 2 mission(Opens in a new window) in the 1970s.

A low-resolution camera on the European Space Agency’s Mars Express probe first captured the enormous cloud in 2018.
Credit: ESA

The secret had been knowing when to look for it.

“There were people thinking ESA was faking it,” Bernal told Mashable. “It was a bit hard because I was really young at the time [of the discovery], and I was on Twitter trying to speak to people.”

Bernal and his team published their observations in 2020, dubbing it the Arsia Mons Elongated Cloud, or AMEC for short. With the cloud spanning 1,100 miles, scientists believe it could be the longest of its kind in the solar system. That work was followed with a second report, recently published(Opens in a new window) in the Journal of Geophysical Research: Planets, revealing just how the volcano makes this extraordinary cloud, alone in an otherwise cloudless southern Mars that time of year.

“There were people thinking ESA was faking it.”

How scientists discovered Mars’ long cloud

For decades, the icy cloud arrived at sunrise on the western slope of Arsia Mons(Opens in a new window), an extinct volcano. The once lava-spewing ancient mountain is about 270 miles wide at the base and soars 11 miles into the sky. It dwarfs Mauna Loa, the largest Earth volcano, which is about half its height.

The curious case of the gigantic cloud is how it escaped notice for so long. But some of the spacecraft around Mars, such as NASA’s Mars Reconnaissance Orbiter, are in orbits synchronized with the sun, meaning their cameras can’t take pictures until the afternoon. By that time, the fleeting cloud, which lasts only about three hours in the morning, is already gone.

The Mars Webcam wasn’t originally meant for science. Its purpose was to provide visual confirmation that ESA’s Beagle 2 lander(Opens in a new window) had separated from the Mars Express spacecraft in 2003. In hindsight, the space agency is glad it decided to turn the basic camera back on(Opens in a new window).

Mars Express spacecraft orbiting Mars
A simple camera not even intended for science on the European Space Agency’s Mars Express spacecraft photographed the enormous cloud.
Credit: ESA

Just as southern Mars experiences spring, the cloud grows and stretches, making a wispy tail like a steam locomotive, over the mountain’s summit. Then, in a matter of hours, the cloud completely fades away in the warm sunlight.

For a young scientist working on his doctorate degree, the natural wonder became a sort of muse. While the realist in him said that recreational space travel is impractical — perhaps even unethical given the world’s climate problems — he couldn’t help but try to draw what the cloud might look like from the ground.

“I keep imagining how it would be for a little civilization to have this huge cloud every year at the same time, like maybe the solstice is something for them like a coat,” he said, smiling. “This is the imagination part.”

Why Mars’ Arsia Mons makes the gigantic cloud

So what makes this strange, stringy cloud?

For starters, it’s not smoke billowing from a volcanic eruption. Scientists have long-known the volcanoes of the Red Planet(Opens in a new window) are dead. Rather, it’s the so-called “orographic effect:” the physics of air rising over a mountain or volcano.

The researchers ran a high-resolution computer simulation of Arsia Mons’ effect on the atmosphere. Strong winds whip at its foot, making gravity waves. Moist air is then temporarily squeezed and driven up the mountainside. Those drafts blow up to 45 mph, forcing the temperature to plunge by more than 54 degrees Fahrenheit. This allows water to condense and freeze at about 28 miles above the volcano’s peak.


“I keep imagining how it would be for a little civilization to have this huge cloud every year at the same time, like maybe the solstice is something for them like a coat.”

Arsia Mons cloud returning year after year
The enormous Arsia Mons cloud returns year after year in Mars’ springtime for about 80 days.
Credit: ESA

For about five to ten percent of the Martian year, the atmosphere is just right(Opens in a new window) to make the cloud, with the dusty sky helping moisture cling to the air. Too early in the year and the air would be too dry, according to the team’s model. Too late in the year and the climate would be too warm for water condensation.

But though the scientists’ simulation was successful in forming the cloud under Arsia Mons’ unique conditions, it could not replicate the cloud’s lengthy tail. Scientists say that’s the biggest question of the moment — a mystery that could be solved with spectrometers, devices on spacecraft that identify the kinds of particles in a substance. A closer study of the cloud’s water ice might give researchers more clues.

“I would like to see this cloud with my eyes, but I know where my place is,” Bernal said. “Sometimes we think of space like a utopia. I am happy looking at it from [Earth, through] my spacecraft.”

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Las Vegas Aces Rookie Kate Martin Suffers Ankle Injury in Game Against Chicago Sky

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Las Vegas Aces rookie Kate Martin had to be helped off the floor and taken to the locker room after suffering an apparent ankle injury in the first quarter of Tuesday night’s game against the Chicago Sky.

Late in the first quarter, Martin was pushing the ball up the court when she appeared to twist her ankle and lost her balance. The rookie was in serious pain, lying on the floor before eventually being helped off. Her entire team came out in support, and although she managed to put some pressure on the leg, she was taken to the locker room for further evaluation.

Martin returned to the team’s bench late in the second quarter but was ruled out for the remainder of the game.

“Kate Martin is awesome. Kate Martin picks up things so quickly, she’s an amazing sponge,” Aces guard Kelsey Plum said of the rookie during the preseason. “I think (coach) Becky (Hammon) nicknamed her Kate ‘Money’ Martin. I think that’s gonna stick. And when I say ‘money,’ it’s not just about scoring and stuff, she’s just in the right place at the right time. She just makes people better. And that’s what Becky values, that’s what our coaching staff values and that’s why she’s gonna be a great asset to our team.”

Las Vegas selected Martin in the second round of the 2024 WNBA Draft. She was coming off the best season of her collegiate career at Iowa, where she averaged 13.1 points, 6.8 rebounds, and 2.3 assists per game during the 2023-24 campaign. Martin’s integration into the Aces organization has been seamless, with her quickly earning the respect and admiration of her teammates and coaches.

The team and fans alike are hoping for a speedy recovery for Martin, whose contributions have been vital to the Aces’ performance this season.

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Asteroid Apophis will visit Earth in 2029, and this European satellite will be along for the ride

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The European Space Agency is fast-tracking a new mission called Ramses, which will fly to near-Earth asteroid 99942 Apophis and join the space rock in 2029 when it comes very close to our planet — closer even than the region where geosynchronous satellites sit.

Ramses is short for Rapid Apophis Mission for Space Safety and, as its name suggests, is the next phase in humanity’s efforts to learn more about near-Earth asteroids (NEOs) and how we might deflect them should one ever be discovered on a collision course with planet Earth.

In order to launch in time to rendezvous with Apophis in February 2029, scientists at the European Space Agency have been given permission to start planning Ramses even before the multinational space agency officially adopts the mission. The sanctioning and appropriation of funding for the Ramses mission will hopefully take place at ESA’s Ministerial Council meeting (involving representatives from each of ESA’s member states) in November of 2025. To arrive at Apophis in February 2029, launch would have to take place in April 2028, the agency says.

This is a big deal because large asteroids don’t come this close to Earth very often. It is thus scientifically precious that, on April 13, 2029, Apophis will pass within 19,794 miles (31,860 kilometers) of Earth. For comparison, geosynchronous orbit is 22,236 miles (35,786 km) above Earth’s surface. Such close fly-bys by asteroids hundreds of meters across (Apophis is about 1,230 feet, or 375 meters, across) only occur on average once every 5,000 to 10,000 years. Miss this one, and we’ve got a long time to wait for the next.

When Apophis was discovered in 2004, it was for a short time the most dangerous asteroid known, being classified as having the potential to impact with Earth possibly in 2029, 2036, or 2068. Should an asteroid of its size strike Earth, it could gouge out a crater several kilometers across and devastate a country with shock waves, flash heating and earth tremors. If it crashed down in the ocean, it could send a towering tsunami to devastate coastlines in multiple countries.

Over time, as our knowledge of Apophis’ orbit became more refined, however, the risk of impact  greatly went down. Radar observations of the asteroid in March of 2021 reduced the uncertainty in Apophis’ orbit from hundreds of kilometers to just a few kilometers, finally removing any lingering worries about an impact — at least for the next 100 years. (Beyond 100 years, asteroid orbits can become too unpredictable to plot with any accuracy, but there’s currently no suggestion that an impact will occur after 100 years.) So, Earth is expected to be perfectly safe in 2029 when Apophis comes through. Still, scientists want to see how Apophis responds by coming so close to Earth and entering our planet’s gravitational field.

“There is still so much we have yet to learn about asteroids but, until now, we have had to travel deep into the solar system to study them and perform experiments ourselves to interact with their surface,” said Patrick Michel, who is the Director of Research at CNRS at Observatoire de la Côte d’Azur in Nice, France, in a statement. “Nature is bringing one to us and conducting the experiment itself. All we need to do is watch as Apophis is stretched and squeezed by strong tidal forces that may trigger landslides and other disturbances and reveal new material from beneath the surface.”

The Goldstone radar’s imagery of asteroid 99942 Apophis as it made its closest approach to Earth, in March 2021. (Image credit: NASA/JPL–Caltech/NSF/AUI/GBO)

By arriving at Apophis before the asteroid’s close encounter with Earth, and sticking with it throughout the flyby and beyond, Ramses will be in prime position to conduct before-and-after surveys to see how Apophis reacts to Earth. By looking for disturbances Earth’s gravitational tidal forces trigger on the asteroid’s surface, Ramses will be able to learn about Apophis’ internal structure, density, porosity and composition, all of which are characteristics that we would need to first understand before considering how best to deflect a similar asteroid were one ever found to be on a collision course with our world.

Besides assisting in protecting Earth, learning about Apophis will give scientists further insights into how similar asteroids formed in the early solar system, and, in the process, how  planets (including Earth) formed out of the same material.

One way we already know Earth will affect Apophis is by changing its orbit. Currently, Apophis is categorized as an Aten-type asteroid, which is what we call the class of near-Earth objects that have a shorter orbit around the sun than Earth does. Apophis currently gets as far as 0.92 astronomical units (137.6 million km, or 85.5 million miles) from the sun. However, our planet will give Apophis a gravitational nudge that will enlarge its orbit to 1.1 astronomical units (164.6 million km, or 102 million miles), such that its orbital period becomes longer than Earth’s.

It will then be classed as an Apollo-type asteroid.

Ramses won’t be alone in tracking Apophis. NASA has repurposed their OSIRIS-REx mission, which returned a sample from another near-Earth asteroid, 101955 Bennu, in 2023. However, the spacecraft, renamed OSIRIS-APEX (Apophis Explorer), won’t arrive at the asteroid until April 23, 2029, ten days after the close encounter with Earth. OSIRIS-APEX will initially perform a flyby of Apophis at a distance of about 2,500 miles (4,000 km) from the object, then return in June that year to settle into orbit around Apophis for an 18-month mission.

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Furthermore, the European Space Agency still plans on launching its Hera spacecraft in October 2024 to follow-up on the DART mission to the double asteroid Didymos and Dimorphos. DART impacted the latter in a test of kinetic impactor capabilities for potentially changing a hazardous asteroid’s orbit around our planet. Hera will survey the binary asteroid system and observe the crater made by DART’s sacrifice to gain a better understanding of Dimorphos’ structure and composition post-impact, so that we can place the results in context.

The more near-Earth asteroids like Dimorphos and Apophis that we study, the greater that context becomes. Perhaps, one day, the understanding that we have gained from these missions will indeed save our planet.

 

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McMaster Astronomy grad student takes a star turn in Killarney Provincial Park

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Astronomy PhD candidate Veronika Dornan served as the astronomer in residence at Killarney Provincial Park. She’ll be back again in October when the nights are longer (and bug free). Dornan has delivered dozens of talks and shows at the W.J. McCallion Planetarium and in the community. (Photos by Veronika Dornan)

Veronika Dornan followed up the April 8 total solar eclipse with another awe-inspiring celestial moment.

This time, the astronomy PhD candidate wasn’t cheering alongside thousands of people at McMaster — she was alone with a telescope in the heart of Killarney Provincial Park just before midnight.

Dornan had the park’s telescope pointed at one of the hundreds of globular star clusters that make up the Milky Way. She was seeing light from thousands of stars that had travelled more than 10,000 years to reach the Earth.

This time there was no cheering: All she could say was a quiet “wow”.

Dornan drove five hours north to spend a week at Killarney Park as the astronomer in residence. part of an outreach program run by the park in collaboration with the Allan I. Carswell Observatory at York University.

Dornan applied because the program combines her two favourite things — astronomy and the great outdoors. While she’s a lifelong camper, hiker and canoeist, it was her first trip to Killarney.

Bruce Waters, who’s taught astronomy to the public since 1981 and co-founded Stars over Killarney, warned Dornan that once she went to the park, she wouldn’t want to go anywhere else.

The park lived up to the hype. Everywhere she looked was like a painting, something “a certain Group of Seven had already thought many times over.”

The dome telescopes at Killarney Provincial Park.

She spent her days hiking the Granite Ridge, Crack and Chikanishing trails and kayaking on George Lake.  At night, she went stargazing with campers — or at least tried to. The weather didn’t cooperate most evenings — instead of looking through the park’s two domed telescopes, Dornan improvised and gave talks in the amphitheatre beneath cloudy skies.

Dornan has delivered dozens of talks over the years in McMaster’s W.J. McCallion Planetarium and out in the community, but “it’s a bit more complicated when you’re talking about the stars while at the same time fighting for your life against swarms of bugs.”

When the campers called it a night and the clouds parted, Dornan spent hours observing the stars. “I seriously messed up my sleep schedule.”

She also gave astrophotography a try during her residency, capturing images of the Ring Nebula and the Great Hercules Cluster.

A star cluster image by Veronika Dornan

“People assume astronomers take their own photos. I needed quite a lot of guidance for how to take the images. It took a while to fiddle with the image properties, but I got my images.”

Dornan’s been invited back for another week-long residency in bug-free October, when longer nights offer more opportunities to explore and photograph the final frontier.

She’s aiming to defend her PhD thesis early next summer, then build a career that continues to combine research and outreach.

“Research leads to new discoveries which gives you exciting things to talk about. And if you’re not connecting with the public then what’s the point of doing research?”

 

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