Space Coffee #5: A moon's moon, strange stars, end of life and more

Curated space stories from the Internet for your weekend reading pleasure.

🌝 A moon’s moon?!

Of all the moons plotted, the only ones capable of hosting submoons were Callisto (Jupiter), Titan and Iapetus (Saturn), and Earth’s own Moon. [...] The question remains: if these moons are all capable of hosting submoons, then why aren’t they? [...] One theory for this lies with the moon Iapetus, which has a significant ridge along its equator. It’s theorized that a collision with Iapetus produced a submoon, and the debris from the collision was tidally pushed into the moon (causing the ridge), while the submoon itself was tidally pushed outwards.

A Stranger Star

A neutron star is like a huge atomic nucleus held together by gravity rather than the strong nuclear force. But we don’t fully understand how neutrons interact at extreme temperatures and densities. It’s possible that within a neutron star the neutrons break down into a soup of quarks, forming what is known as a quark star. If quark stars exist, then it’s possible that high-energy up and down quarks could collide to create strange quarks. And this is where things could get, well, a bit strange.

🌚 Study Reveals That Mercury Is the Not-So-Shrunken Planet

“It flies in the face of conventional wisdom that a body the size of Mercury, the smallest rocky planet in our solar system, has not cooled and become geologically inactive long ago,” Watters said. “Somehow, Mercury has managed to insulate its interior and slowed the loss of heat that provides the driving force for geologic activity.”

🦠 Timeline for life until the end of the Universe

Our Sun is only halfway through its lifetime and is still growing. In a billion years, it will have increased its brightness by 10%. This will increase the average temperature on Earth high enough to evaporate all the oceans. It will have cascading effects, like decreasing CO2 levels, making photosynthesis impossible. Complex life forms won’t survive at this point. As the Sun continues to grow bigger and brighter, slowly all life on Earth will perish as the average surface temperatures cross a thousand degrees. Earth will become more barren than Mars is now.

💻 Cloud Computing at Astronomical Scales

The kind of speculation that puts megastructures on the table is productive because we are the only example of technological civilization that we have to study. We have to ask ourselves what we might do to cope with problems as they scale up to planetary size and beyond. Solar energy is one thing when considered in terms of small-scale panels on buildings, but Freeman Dyson wanted to know how to exploit not just our allotted sliver of the energy being put out by the Sun but all of it.