Tuesday, April 22, 2025

SPACE/COSMOS

Innovative approaches advance search for ice on the moon




University of Hawaii at Manoa

Future cosmic ray radar instrument 

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An artist rendering of what a future cosmic ray radar instrument could look like, attached to a satellite orbiting the Moon. 

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Credit: Christian Miki, Department of Physics, University of Hawai‘i at Mānoa





Scientists and space explorers have been on the hunt to determine where and how much ice is present on the Moon. Water ice would be an important resource at a future lunar base, as it could be used to support humans or be broken down to hydrogen and oxygen, key components of rocket fuel. University of Hawai‘i at Mānoa researchers are using two innovative approaches to advance the search for ice on the Moon.

ShadowCam scouts for surface ice 

Water ice was previously detected in the permanently shaded regions of the Moon’s north and south poles by Shuai Li, assistant researcher at the Hawai‘i Institute of Geophysics and Planetology (HIGP) in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST).  A new study led by Jordan Ando, planetary sciences graduate student in Li’s laboratory, examined images from a specialized camera, the “ShadowCam,” that was on board the Korea Aerospace Research Institute Korea Lunar Pathfinder Orbiter. 

Craters in the Moon’s polar regions receive no direct sunlight, but sunlight that bounces off of one side of a crater can indirectly illuminate another side. The ShadowCam, designed specifically to look only at the dark, permanently shaded areas on the Moon, is extremely sensitive to the indirect light reflected off the lunar surface.

“Ice is generally brighter, that is, reflects more light, than rocks,” said Ando. “We analyzed high-quality images from this sensitive camera to look really closely into these permanently shaded areas and investigate whether water ice in these regions leads to widespread brightening of the surface.”

While the ice in the shaded regions did not significantly brighten the surface, the team’s analysis of the ShadowCam images helps to refine the estimate of the amount of ice that could be on the lunar surface. Li’s previous method suggested that the lunar surface contains between five and 30 percent water ice. The analysis of Shadow Cam images narrows the range—indicating that water ice makes up less than 20 percent of the lunar surface. 

Cosmic rays help search for buried ice

In addition to these investigations of lunar ice at the surface, another group of UH Mānoa researchers with HIGP and Department of Physics and Astronomy recently published a study in Geophysical Research Letters that outlines an innovative approach to detect buried ice deposits at the Moon’s poles.

“With our recent study, we showed that a new technique for detecting buried water ice on the Moon is possible using naturally-occurring cosmic rays,” said Emily S. Costello, study lead author and postdoctoral researcher at HIGP. “These ultra-high-energy cosmic rays strike the lunar surface and penetrate to the layers below. The rays emit radar waves that bounce off buried ice and rock layers, which we can use to infer what’s below the surface.”

The team used an advanced computer simulation that tests how radar waves travel through the lunar soil and how they encode information about possible buried ice layers.

“This method for searching for water ice on the Moon is brand new and really exciting,” said Christian Tai Udovicic, a co-author on the study who presented the findings at the recent Lunar and Planetary Science Conference in Houston, Texas. “Since it relies on high-energy physics that only a few scientists in the world are experts in, even planetary scientists who are studying ways to find lunar water ice are often surprised when they hear about this technique.”

A team of HIGP and Physics Department researchers are working to assemble a radar instrument specifically tuned to listen for these signals on the Moon and hope to test the full system by early 2026. They will look for opportunities to send it to the Moon to hopefully detect large deposits of buried water ice on the Moon for the first time. 

“More and more, Hawai‘i is becoming a hub for space exploration, and specifically the exploration of the Moon,” said Costello. “These projects, led by UH Mānoa scientists, represent up-and-coming opportunities for students and professionals in Hawai‘i to lead and participate in the budding space industry.”   


An artist's depiction of what could be large buried ice deposits below cold, permanently shadowed regions on the Moon. The UH Manoa researchers' technique could reveal the first evidence of thin ice layers at 5-10 m depth. 

Credit

Costello et al. 2025. ​​​​​​​




Permanently shaded regions on the Moon’s north (L) and south (R) poles were investigated for water ice.

Credit

Shuai Li


Astronomers discover a planet that’s rapidly disintegrating, producing a comet-like tail


The small and rocky lava world sheds an amount of material equivalent to the mass of Mount Everest every 30.5 hours.




Massachusetts Institute of Technology

Disintegrating Planet 

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A disintegrating planet orbits a giant star. “The extent of the tail is gargantuan, stretching up to 9 million kilometers long,” says Marc Hon, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research.  

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Credit: Jose-Luis Olivares, MIT




MIT astronomers have discovered a planet some 140 light-years from Earth that is rapidly crumbling to pieces. 

The disintegrating world is about the mass of Mercury, although it circles about 20 times closer to its star than Mercury does to the sun, completing an orbit every 30.5 hours. At such close proximity to its star, the planet is likely covered in magma that is boiling off into space. As the roasting planet whizzes around its star, it is shedding an enormous amount of surface minerals and effectively evaporating away. 

The astronomers spotted the planet using NASA’s Transiting Exoplanet Survey Satellite (TESS), an MIT-led mission that monitors the nearest stars for transits, or periodic dips in starlight that could be signs of orbiting exoplanets. The signal that tipped the astronomers off was a peculiar transit, with a dip that fluctuated in depth every orbit. 

The scientists confirmed that the signal is of a tightly orbiting rocky planet that is trailing a long, comet-like tail of debris. 

“The extent of the tail is  gargantuan, stretching up to 9 million kilometers long, or roughly half of the planet’s entire orbit,” says Marc Hon, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research.  

It appears that the planet is disintegrating at a dramatic rate, shedding an amount of material equivalent to one Mount Everest each time it orbits its star. At this pace, given its small mass, the researchers predict that the planet may completely disintegrate in about 1 million to 2 million years.

“We got lucky with catching it exactly when it’s really going away,” says Avi Shporer, a collaborator on the discovery who is also at the TESS Science Office. “It’s like on its last breath.”

Hon and Shporer, along with their colleagues, will publish their results in the Astrophysical Journal Letters. Their MIT co-authors include Saul Rappaport, Andrew Vanderburg, Jeroen Audenaert, William Fong, Jack Haviland, Katharine Hesse, Daniel Muthukrishna, Glen Petitpas, Ellie Schmelzer, Sara Seager, and George Ricker, along with collaborators from multiple other institutions.

Roasting away

The new planet, which scientists have tagged as BD+05 4868 Ab, was detected almost by happenstance. 

“We weren’t looking for this kind of planet,” Hon says. “We were doing the typical planet vetting, and I happened to spot this signal that appeared very unusual.”

The typical signal of an orbiting exoplanet looks like a brief dip in a light curve, which repeats regularly, indicating that a compact body such as a planet is briefly passing in front of, and temporarily blocking, the light from its host star. 

This typical pattern was unlike what Hon and his colleagues detected from the host star BD+05 4868 A, located in the constellation of Pegasus. Though a transit appeared every 30.5 hours, the brightness took much longer to return to normal, suggesting a long trailing structure still blocking starlight. Even more intriguing, the depth of the dip changed with each orbit, suggesting that whatever was passing in front of the star wasn’t always the same shape or blocking the same amount of light. 

“The shape of the transit is typical of a comet with a long tail,” Hon explains. “Except that it’s unlikely that this tail contains volatile gases and ice as expected from a real comet — these would not survive long at such close proximity to the host star. Mineral grains evaporated from the planetary surface, however, can linger long enough to present such a distinctive tail.” 

Given its proximity to its star, the team estimates that the planet is roasting at around 1,600 degrees Celsius, or close to 3,000 degrees Fahrenheit. As the star roasts the planet, any minerals on its surface are likely boiling away and escaping into space, where they cool into a long and dusty tail. 

The dramatic demise of this planet is a consequence of its low mass, which is between that of Mercury and the moon. More massive terrestrial planets like the Earth have a stronger gravitational pull and therefore can hold onto their atmospheres. For BD+05 4868 Ab, the researchers suspect there is very little gravity to hold the planet together. 

“This is a very tiny object, with very weak gravity, so it easily loses a lot of mass, which then further weakens its gravity, so it loses even more mass,” Shporer explains. “It’s a runaway process, and it’s only getting worse and worse for the planet.”

Mineral trail

Of the nearly 6,000 planets that astronomers have discovered to date, scientists know of only three other disintegrating planets beyond our solar system. Each of these crumbling worlds were spotted over 10 years ago using data from NASA’s Kepler Space Telescope. All three planets were spotted with similar comet-like tails. BD+05 4868 Ab has the longest tail and the deepest transits out of the four known disintegrating planets to date. 

“That implies that its evaporation is the most catastrophic, and it will disappear much faster than the other planets,” Hon explains. 

The planet’s host star is relatively close, and thus brighter than the stars hosting the other three disintegrating planets, making this system ideal for further observations using NASA’s James Webb Space Telescope (JWST), which can help determine the mineral makeup of the dust tail by identifying which colors of infrared light it absorbs.

This summer, Hon and graduate student Nicholas Tusay from Penn State University will lead observations of BD+05 4868 Ab using JWST. “This will be a unique opportunity to directly measure the interior composition of a rocky planet, which may tell us a lot about the diversity and potential habitability of terrestrial planets outside our solar system,” Hon says.

The researchers also will look through TESS data for signs of other disintegrating worlds. 

“Sometimes with the food comes the appetite, and we are now trying to initiate the search for exactly these kinds of objects,” Shporer says. “These are weird objects, and the shape of the signal changes over time, which is something that’s difficult for us to find. But it’s something we’re actively working on.”

This work was supported, in part, by NASA.

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Written by Jennifer Chu, MIT News

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