Happy Thought for 5 July 2024

Have a Happy Thought:

 We live in an incredible time – a time in which humans are sending robots to literal other worlds, and bringing back pieces of those worlds to study, back here on Earth.

 This has happened twice now in short succession! Just last week, a Chinese-led mission returned samples of the “far side” of the moon back to Earth. This was the Chang-e 6 mission. A couple of things of note about this mission: 

1. The mission name, Chang'e (嫦娥), is an ancient Chinese goddess or mythological figure, who lives in/on the moon with her pet rabbit, which can easily be seen from Earth, in the light and shadows formed by the highlands and craters visible from Earth.

Image: the moon as seen through a telescope. Vaughan Turner, supplied.

2. While there is no Dark Side of the Moon, there is a Far Side of the Moon: The same ‘face’ of the moon always faces the Earth, so different parts of the moon are lit by the sun as the moon orbits the Earth, and the Earth-moon system orbit the sun.
3. Not only is this the first time any bits of the far side of the moon have come back to Earth, China remains the only country to have even landed anything on the far side of the moon!  
4. While the near side of the moon has lots of dark areas, once called mares (oceans) but we know now they are ancient lava flows, leading to the shapes we often see, the far side has a lot more craters and few to none of those mares. No, we don’t know why this is. Yes, we’re hoping that the Chang’e missions can help solve some of the mysteries here!

Global map of the near and far sides of the Moon, from NASA’s Clementine spacecraft. Image credit: NASA.

 

 The second recent sample-return mission was finally completed earlier this year, when a NASA-led mission returned samples of the asteroid Bennu. This asteroid probably used to be a part of the asteroid belt between Mars and Jupiter, but over time this half-kilometre-wide chunk of rock has drifted closer to Earth, and passes pretty close to us every 6 years.

 This mission was named the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer, or OSIRIS-REx for short. It launched from Earth in 2016, collected samples from the asteroid in 2020, and then swung back by Earth to drop off its payload in October 2023. (The spacecraft is now on its way to another asteroid to keep exploring).

 Between October 2023 and January 2024, engineers and researchers at NASA had to clear one final hurdle though… or actually two final hurdles: there were 35 fasteners holding the sample container closed, and two of these just would. not. budge! They eventually had to develop some extra tools specifically to remove those final two fasteners, and this finally worked, after several months of trying!

The great thing though is that the goal of the mission was to bring 60g of material back to Earth, and scientists had recovered more than 70g just from the outside casing – before they even got into that actual sample container! 

Bonus samples 😊 In fact, there was so much bonus material, it actually took them even longer to get to those 35 fasteners in the first place.

And just last week, the team released images and their initial analysis of these samples… So now you get to see the beauty of highly-magnified grains of an asteroid.

Examples of coarse-grained phyllosilicates in sample OREX-501017-0. Image: https://onlinelibrary.wiley.com/doi/10.1111/maps.14227

 

The really cool thing is that some of these minerals can also be found at the mid-Atlantic ridge here on Earth, meaning there may have been a lot of water in and on the planetoid that Bennu was once a part of.

Examples of magnetite and sulfide in samples OREX-501001-0, OREX-803079-0, and OREX-501002-0. (a) Magnetite framboids. (b) Magnetite spheres with radially projecting needles next to dodecahedral crystals. (c) Dodecahedral magnetite with surface etching. (d) Magnetite plaquettes. (e, f) Pseudohexagonal plates of pyrrhotites. Image: https://onlinelibrary.wiley.com/doi/10.1111/maps.14227

 

And they even glow in UV-light: invite Bennu to your next rave!

Optical and UV fluorescence imaging. (a) Reflected light image showing the texture and brightness variation across an aggregate within sample OREX-501006-0. (b) UV fluorescence microscopy image showing the distribution of carbonates and phosphates (blue fluorescence) and organic nanoglobules (yellow fluorescence). Image: https://onlinelibrary.wiley.com/doi/10.1111/maps.14227

 

 How can you get your hands on a bit of asteroid?

Well, if you’re a scientist you can apply to get a bit of Bennu for your research.

 

Or you can find a meteorite, which has made its own way to Earth. They’re pretty rare here in Aotearoa New Zealand, but considering they’re found in deserts, and even rooftops, you never know what you’ll find once you start looking.