Asteroid Vesta found to have channels that look like water-made gullies

The asteroid belt is no stranger to cosmic collisions. Many of its objects bear scars and craters from countless strikes over billions of years, such as the asteroid named Vesta.

But when NASA’s Dawn spacecraft visited the giant asteroid Vesta, it glimpsed more than pockmarks and gouges — it discovered intriguing channels on the rocky surface.

The deep channels on Vesta looked suspiciously like gullies carved by liquid flows, which seemed rather unlikely on an airless body in the vacuum of space.

These gullies challenged the assumptions of how liquids might appear on such a rugged, atmosphere-free world.

Hidden channels on asteroid Vesta

Vesta’s unusual channels stirred interest in whether there might be hidden pockets of ice below the surface. Researchers wondered how any liquid could last long enough to carve gullies instead of evaporating in an instant from the asteroid’s surface.

This puzzle prompted a team to conduct experiments that mimic the conditions on Vesta, to see what might be at work beneath the asteroid’s crater-pocked exterior.

What made Vesta’s channels?

Asteroids the size of Vesta rank among the largest members of the asteroid belt between Mars and Jupiter.

Although the surface has been pummeled by impacts, scientists suspected that some small, deeply buried ice deposits might exist within Vesta.

A NASA-funded project took a closer look at how meteoroid impacts could unearth these concealed layers and release liquid water.

Many researchers had argued that any water would vanish quickly in space. But new lab findings showed that saline solutions might linger long enough to form the winding channels observed in high-resolution images.

“Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California who explained the significance of these results.

This work provides a clue to how short-lived fluids might appear on worlds once deemed too harsh for liquid water.

Moving into the lab

Shortly after the discovery of channels on Vesta, the research team, led by Michael J. Poston of the Southwest Research Institute in San Antonio, set up a series of simulations to re-create post-impact conditions.

They relied on a specialized facility at NASA’s Jet Propulsion Laboratory called the Dirty Under-vacuum Simulation Testbed for Icy Environments (DUSTIE).

Inside this chamber, they subjected small liquid samples to low-pressure environments that match those on Vesta’s surface.

Under these near-vacuum conditions, pure water froze almost instantly. But briny water, which is rich in sodium chloride, took at least an hour to freeze.

That extra time can explain how curvy gullies might form. The experiments proved that salt plays an important role in keeping water liquid, even under conditions that usually turn plain water to ice right away.

Poston noted that if the channels carved by these brines on Vesta were a few yards deep, the liquid phase would persist even longer.

Their study described how this freezing delay could cause fluid to travel and create gullies before it finally solidified.

Salt’s unexpected impact and hidden ice below

Ice and salt often coexist on other airless bodies in the solar system.

Scientists studying Ceres, another object visited by the Dawn spacecraft, found abundant salt deposits near the surface.

Similar processes might occur on Vesta, with hidden ice deposits that melt upon impact and release salty fluids that are capable of flowing.

Why should we care about asteroid Vesta?

While direct evidence of ice on Vesta is still unconfirmed, researchers continue to analyze crater walls and gullies, looking for hints of exposed water-bearing minerals.

If more ice deposits are detected, it would further support the idea that these asteroid surfaces hide unexpected moisture beneath the dusty exterior.

Many experts highlight how this discovery of Vesta’s channels ties in with other research on planetary bodies beyond Earth.

Salt-rich flows have also been proposed to explain active gullies on Mars, where channels can appear seasonally as temperatures shift.

Although the Red Planet has a thin atmosphere, brine might remain stable for short intervals in ways that resemble the results of the Vesta experiments.

Similar processes have been hypothesized for other airless worlds, fueling further curiosity about how widespread water could be in these unexpected places.

Finding water in the asteroid belt

The Dawn mission provided valuable insight into the composition of Vesta and Ceres, and the history of these objects.

Observations of brine activity on Ceres prompted a rethinking of the asteroid belt’s arid reputation. If subsurface ices can be heated by impacts, short bursts of fluid flows might be more common than once assumed.

The new experiments open a door for further study of how these liquids behave and how long they can remain stable in harsh, vacuum conditions.

Some see these lab results as a foundation for understanding what future spacecraft might find on icy asteroids or even distant moons.

Asteroid Vesta’s channels provide a key example and suggest that if other objects harbor briny fluids, they too might form channels when struck by meteoroids.

Although quickly frozen, the liquid can still carve paths before turning to ice. This finding adds another piece to the puzzle of solar system evolution and the hidden chemistry that shapes so many distant worlds.

The research findings were published in The Planetary Science Journal.

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