Morle

### Atmosphere composition

~85% CO2, 10% Nitrogen, 1.2% Argon, 2% Water Vapour, 1.2% Oxygen, 0.4% trace gasses

### Is life present?

No

Morle is a terrestrial planet orbiting Penlos. It is the fourth planet of the system, and is a bit smaller than Bullara. Morle is believed to have once been habitable and more Bullara-like, with lakes, seas, a larger atmosphere, magnetosphere, and even a large moon. However, what is left today is a dead rusty wasteland with a thin decaying atmosphere. and two minor, likely captured moons.

## Properties

Morle is a small terrestrial world and the fourth and final terrestrial world of the system. It is divided into a large crust, fairly large mantle, and small core. It is strikingly rust-red due to iron oxide compounds in its soil. It is quite flat, with occasional low-lying darker basaltic plains and also hills and mountain ranges. The planet supports a thin atmosphere of mostly CO2, and the planet's cool core supports a small magnetosphere which slows atmosphere loss slightly. The planet has notable ice caps, of an off-white colour due to dust. These polar caps are composed of water ice, and during the winter also some dry ice.

## Moons

### Phemea

Phemea is a small asteroidal minor moon of Morle. It is the largest of the two, and the innermost. It completes an orbit in only about 12 hours, and is unsurprisingly tidally locked. Within 30-50 millions years, tidal dissipation will cause it to collapse in the Morlean Roche limit and create short-lived rings.

### Del

Del is a small asteroidal minor moon of Morle. It is the smallest of the two, and the outermost. It orbits in about 1.5 days, which is longer than Morle's day of about 1.25 days. This saves it from tidal dissipation, and it is slowly drifting outward to escape Morle's hill sphere in 800 million-1.5 billion years.

## Former Habitability

It is generally accepted that Morle had a period of habitability from around 2.5 billion years ago, up to 1 billion years ago. However, the mechanism which caused the end of this eon is not certain. The leading hypothesis is that Morle was too small to keep a hot enough core to have a large magnetosphere for a long time, thus causing its magnetosphere to dissipate and the inevitable destruction of its atmosphere and surface water. However, another hypothesis says that Morle may have not had a strong magnetosphere at all, and that this stage was intermediate between a more massive atmosphere and the modern thin one. Nonetheless, another branch in hypotheses occurs later. About 800 million years ago, when the atmosphere dissipated, the water went with it too, and the leading theory is that this caused a temporary warming of the planet which allowed atmospheric life to bloom. This is reinforced by the remains of bacterial life close to the poles where it could not have survived on the surface. The only way they could have reached here is by atmospheric convection or by water, which did not exist at the time; the fossil is dated to about 792 million years ago. After this era, life ceased to exist as the atmosphere cooled and thinned, and underground water pockets subsequently froze or evaporated into the atmosphere, as evidenced by high levels of water vapour in the atmosphere as fine mist. However, the other hypothesis says that this quickly dissipated into space, leaving no window for atmospheric life. This hypothesis is usually marked as false due to the overwhelming evidence for hypothesis #1.

Nevertheless, Morle is uninhabitable nowadays, and the only time things breathe freely on it is in science fiction.