Geologist research asteroids and moondust to decode the historical past of the photo voltaic system
WEST LAFAYETTE, Ind. — Michelle Thompson is a geologist. However whereas “geo” means earth, she research issues which are decidedly unearthly, or at the least extraterrestrial: the moon and asteroids.
“I examine area weathering: how area environments have an effect on tiny mineral particles on planetary surfaces,” stated Thompson, an assistant professor within the Division of Earth, Atmospheric, and Planetary Sciences at Purdue College’s Faculty of Science. “We will study a lot from these minuscule samples; we are able to study in regards to the evolution of planets and moons — together with our personal. Extra broadly, we examine these tiny samples and might extrapolate the historical past of the photo voltaic system.”
As people gear up to return to the moon, scientists are keenly conscious that the final human to go away a bootprint on the lunar floor departed 50 years in the past, when Apollo 17 started its journey dwelling on December 14, 1972.
The astronauts on the floor throughout that journey, Purdue alumnus Eugene Cernan and Harrison “Jack” Schmitt, collected moon rocks and mud that scientists, together with Thompson, are simply now starting to investigate via the Apollo Subsequent Technology Pattern Evaluation Program.
“It is superb, it is surreal, to be standing in a lab at Purdue analyzing moondust collected by one other Purdue alum — the final particular person to stroll on the moon,” Thompson stated.
The analysis is feasible solely as a result of a lot of the greater than 840 kilos of moon rocks and mud has been saved sacrosanct for practically half a century. Now scientists imagine they’ve even higher instruments which are extra delicate, permitting them to comprehensively examine the samples and reply questions that have been unattainable to discover 50 years in the past.
Thompson is an knowledgeable in the way in which rocks work together with and alter as a result of their publicity to the vacuum of area — a phenomenon known as area weathering. Analyzing the chemistry of moon rocks and moondust can inform her in regards to the setting, evolution and historical past of the moon.
A lunar core pattern, a small column of moondust extracted from the lunar floor by Cernan and Schmitt, the primary and solely geologist ever to stroll on the moon, offers Thompson and her lab these insights. It comes from part of the moon that will have skilled an avalanche, offering even deeper perception into the distribution of minerals and the chemistry of the moon and the processes that form its floor. Thompson is hoping that her analysis group will be capable of perceive what the moon’s floor was like earlier than and after the avalanche, gaining larger information of how its soil, or regolith, has developed over time.
“When these samples have been collected, when males walked on the moon, I hadn’t even been born,” Thompson stated. “This pattern has been on Earth longer than I’ve. It has been sitting in storage, saved pristine, ready for scientists to investigate it because it was returned. Scientists now have instruments and applied sciences that the unique technology of astronauts might solely dream of. So now it is our flip to comply with of their footsteps and examine the moon rocks they introduced again.”
Future moon missions — together with Artemis — will convey again new samples, and new strategies will proceed to make clear the moon for geologists like Thompson.
Time capsules from area
It’s counterintuitive, however among the best methods to review how Earth shaped is by taking a look at rocks that come from nearly wherever else.
“Asteroids are home windows into the very early photo voltaic system; they’re relics,” Thompson stated. “They’re time machines that present us what the constructing blocks have been for the early photo voltaic system, what the constructing blocks have been for all times on Earth. Learning these asteroids offers us the recipe for the early photo voltaic system and what early natural molecules could have seeded life on Earth.”
Tens of millions of meteorites and hundreds of asteroids, together with the Lafayette meteorite, a rocky physique found at Purdue that’s really a broken-off piece of Mars, have hit Earth. Nevertheless, finding out these, whereas fascinating, cannot reply the identical questions as asteroids from area can.
Even a brief interplay with Earth’s ambiance, biosphere and minerals contaminates meteorites and asteroids and makes them tougher to review. To get pristine materials and decide the historical past of those area rocks, and the photo voltaic system’s historical past, scientists must intercept rocks — asteroids — in area. Scientists can examine the asteroid and decide the place it shaped within the photo voltaic system, what different our bodies it may need come into contact with (or come from), and what its evolution could have been like.
In her lab proper now, Thompson has tiny fragments of one of many first asteroids ever sampled in area and ferried to terrestrial laboratories: the asteroid Ryugu, sampled by the Japanese spacecraft Hayabusa2 throughout the first mission to function rovers on an asteroid. The Japan Aerospace Exploration Company launched the mission in 2014. The spacecraft reached Ryugu in 2018 and deployed its rovers. In 2019 it fired what was primarily an anti-tank missile on the floor of the asteroid to gather subsurface samples. These samples landed on Earth in 2020 and have been made obtainable to NASA scientists, together with Thompson. Learning asteroids, and evaluating and contrasting them with the floor of the moon, offers scientists a greater understanding of the origins and variety of our bodies within the photo voltaic system.
Subsequent 12 months, the journey will get even greater. Thompson is a part of the “tiger group” — an elite squad of consultants — in meteorite research for NASA’s mission OSIRIS-REx to the asteroid Bennu. NASA deployed a tiger group to convey the Apollo 13 crew dwelling. OSIRIS-REx (or the Origins, Spectral Interpretation, Useful resource Identification, Safety-Regolith Explorer) will convey rock samples, not beleaguered astronauts, to Earth. The samples will land in Utah after which be flown to safe clear labs in Texas. Thompson might be among the many first people — and the primary lady — to review the items of Bennu. She and the 4 different members of the tiger group can have 72 hours to review the asteroid pattern and put together a preliminary report for NASA.
OSIRIS-REx used two completely different strategies to gather samples from the asteroid. A form of robotic vacuum sucked in loads of the fabric from the floor — probably excess of 60 grams, which was the minimal the scientists hoped for.
The second methodology concerned gently and passively accumulating samples on the floor.
“When the spacecraft touched the floor of the asteroid, it landed on these small round pads, quite a bit like Velcro, which trapped materials proper on the floor of the asteroid,” stated Thompson. “We name them contact pads. The little motes of mud, the mud particles, are caught within the Velcro. We’re finding out these tiny mud particles. All of the stuff I am concerned about is floor processes, what’s occurring to the very prime materials.”
Author/Media contact: Brittany Steff, [email protected]
sources: Michelle Thompson