So I wanna tell y'all about something very near and dear to my heart.
This is the Psyche asteroid, or, at least an artist's representation - we don't know what it actually looks like yet, but this is a fair enough guess. It's a roughly 200 mile wide asteroid in the asteroid belt, and it's made almost entirely out of metal. Its composition makes it unique; it’s the only large metallic body we know of in the entire solar system.
We think it might be the core of what used to be a planet.
When solar systems form, they start out as disks made of interstellar gas and dust, called protoplanetary disks. Here's a picture of HL Tauri, one of the best images of a protoplanetary disk we have.
That dust globs together into larger and larger pieces, and eventually forms hundreds of "planetesimals", which are rocky bodies about a kilometer across. Planetesimals had very erratic orbits compared to the modern planets - the dust of the protoplanetary disk caused friction and drag, which threw them off course.
They frequently collided with each other, and either broke apart or stuck together and grew even larger. Arrokoth is actually a leftover planetesimal, a time capsule from the early solar system, and we were able to visit it wayyy out in the Kuiper belt with the New Horizons probe!
Once planetesimals get to be about the size of the moon, we call them "protoplanets". Protoplanets were fundamentally different from their planetesimal siblings - we believe they were differentiated. When an object in space gets big enough, a combination of radioactive decay, impacts, and gravitational pressure causes them to heat up and melt. Denser materials like iron and nickel sink towards their centers, while the lighter materials rise to the surface. The differentiation process is why Earth's core is made of iron, while the surface is primarily rock.
While protoplanet orbits were much more stable than those of planetesimals, they still eventually collided with each other until everything settled into the planets we see today (though gas giants had a few extra steps - that's a different post!).
We think the Psyche asteroid was a protoplanet, well on its way to becoming a bona fide planet, when an impact struck it hard enough to strip away its rocky layers, leaving behind the dense, metallic core - like in this illustration.
More and more, we think the properties of a planet's core are fundamental to its long-term evolution. Venus, Earth, and Mars are all roughly the same size and roughly the same distance from the sun, cosmically speaking, yet they're so different! Venus has hell death clouds, Earth is home, and Mars is dry and dead - why?
The Psyche asteroid gives us the unique opportunity to actually observe a planetary core directly - it's much harder to dig to the center of a planet than it is to go to space, so that's exactly what we're going to do!
On Thursday October 12th at 10:16am Eastern, the Psyche spacecraft will launch and begin its journey to the asteroid belt! You can watch at https://www.nasa.gov/nasatv/!
I've been a part of this mission for over four years now, and I can't speak highly enough of the team that made it happen through all of the ups and downs. Good luck out there, buddy. We're all rooting for you :')
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Onew’s new agency is called Griffin Entertainment, a new entertainment agency
Griffin Entertainment is inspired by the guardian animal 'Griffin', which guards jewel despite any adversity. It is expected to be a solid support that protects their artists who shine in their own colours, and help blossom their talents and capabilities.
sns: ig twt
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