u/GigalithineButhulne

Fourth excerpt from "Leaky Space Blob: Savior of Two Worlds", a permanent exhibition in the Erid Museum of Xenobiology.

Previous: https://www.reddit.com/r/ProjectHailMary/comments/1tbkbzm/the_erid_museum_of_xenobiology_3_sleep/

THE RULE OF FIVE?

[Larger size replica of the original figurine made of Grace by Rocky.]

[Eridian] evolutionary biologists had long speculated that "pentapedalism" -- having five appendages -- is the optimal outcome of natural evolution for sapient beings. And Grace has a central body with five extensions, seemingly confirming this theory. But is it true?

AMBULATION. Grace's five appendages are actually in three types! That's because [humans] are bilaterally symmetrical, with a distinct "bottom" and "top" end. The two bottom-end appendages are nearly useless for grasping or manipulating. These are the "ambulation" appendages, designed to bear the mass of Grace's body and move them around for longer distances.

GRASPING. Grace has two medial or "grasping" appendages that can also be used to help Grace climb. Only two? You might wonder how Grace manages to do anything with some of the amazing [human] technology they brought with them. With five thin claw-like manipulators on the end of each grasping appendage, Grace has a surprising ability to do intricate work, and they can even use their manipulators to speak.

ROUND-APPENDAGE. Grace's topmost appendage is short and round. That's because it's not an appendage at all. [Inset cross-section of human skull.] The round-appendage contains Grace's brain and unifies their sensory, gas-exchange, and nutrient input systems. And unlike the rest of Grace, below a thin covering, it's actually surrounded by a solid structural crust. So maybe the pentapedalism theory was wrong after all.

[Inset summary of the scientific method, testing theories, etc.]

THE "REAL" GRACE? Grace's round-appendage can be seen as an equivalent of the [Eridian] [thorax]. The rest of Grace's body can be seen as a support system for the round-appendage that contains Grace's personality and thoughts.

TOUCH. [Soft-textured 3D model of human fist.] The [human] celebratory greeting, "fisting the bump". is increasingly popular among young [Eridians]. You can't fist Grace's real bump without a [xenonite] barrier as their flesh will be injured. But you can experience what it might feel like with this model of Grace's fist.

ACTIVITY. When the Hero-Survivors of [Tau Ceti] arrived at [Erid] amazing amazing amazing, we bet many of you tried to see what it would feel like to ambulate on only two appendages? Difficult, right? If you didn't, try it right now. Make sure you have a companion to catch you.

[Inset textured diagram of human inner ear]

This is no problem for Grace! They have a complex system inside their round-appendage that allows them to precisely orient towards a gravity source and adjust their ambulation appendages to remain perfectly balanced.

[Inset: 3d model of lab with Eridian engineers working on robotic devices and the caption: "Engineers applying a [human]-body inspiration for balanced movement in repair machinery."]

Third installment of "Leaky Space Blob: Savior of Two Worlds", a permanent gallery in the Museum of Xenobiology on Erid, next to "Star-Eater: Menace and Opportunity" and "Out of the Medium Rough Texture Circle Planet".

Previous: https://www.reddit.com/r/ProjectHailMary/comments/1ta2sbc/the_erid_museum_of_xenobiology_2_atmosphere/

[29,000 seconds]

[Small sculpture of a crouching human gazing at a sleeping Eridian across a xenonite barrier.]

[Rocky] has to sleep unwatched for [46 years] before Grace turned up at [Tau Ceti]. But did you know that they had to teach Grace about proper sleep-watching surprise surprise surprise?

GRACE WATCHES GRACE SLEEP. The brain in their round-appendage doesn't completely stop functioning during the sleep cycle. A secondary brain-system takes over and continues to monitor Grace's sense-organs for basic disturbance patterns. Just like on [Erid], Grace's species had to evolve to avoid predators when they were vulnerable. They evolved their own internal sleep-watcher!

WHY SLEEP? Just like all animal life on [Erid], animal life on [Earth] evolved some kind of sleep. [Earth] scientists say they don't completely understand how it works, but it appears to have some of the same functions as we know [Eridians] have: repair and renewal. So the experience of sleeping may just be universal!

[29,000 SECONDS] EVERY [24 HOURS]. Grace sleeps frequently, and they sleep a lot. For best health, they must sleep an average of 29,000 on a schedule that matches the rotation of [Earth]. Isn't that a lot? But Grace can choose how long he actually sleeps: excitement, noise, light-noise, as well as "bad sleep-hearings" and other disturbances can keep Grace from getting the correct amount.

SLEEP-HEARING. Grace's brain is continuing to work during his sleep, possibly in a clean-up phrase. But [humans] hear and even light-hear things that their brains accidentally "create" that don't exist. Some of these things are bad sleep-hearings. When Grace experiences this he sometimes wants to talk to [Rocky]. But good sleep-hearings can give new ideas to [humans] and inspire their art and culture.

LIGHT-HEARING: A SLEEP TRIGGER. [Eridian] engineers schedule the light sources in Grace's oxygen habitat so that Grace can have healthy healthy healthy sleep. Grace's species evolved with the light from [Sol] reaching through [Earth]'s thin atmosphere during its [24 hour] rotation. Less light means sleep time! [Rocky] and the engineering team work on developing cues to encourage Grace to sleep properly, because they like to get excited! [Human] cognitive function declines with too little sleep. [Translator's note: relatable, relevant to state when working with this Eridian text.]

TOUCH: [Tactile miniature model of Grace's habitat bed with stylized xenonite human lying on it with soft bedding.]

IMAGINATION. What would YOU do if you could stop yourself from sleeping?

ACTIVITY (TRY AT HOME). If you can, stop all your activity while you're awake for [29,000 seconds]. Do you get any inspiration? Do you feel more relaxed? (Honestly, we think it's not a bad idea in our hectic technological world.]

Another excerpt from the Erid Museum of Xenobiology's permanent exhibition, "Leaky Space Blob: Savior of Two Worlds".

Previous: https://www.reddit.com/r/ProjectHailMary/comments/1t9dhiv/the_erid_museum_of_xenobiology/

COLD, THIN, AND CAUSTIC

[3D model of generic human lungs taken from Earth-thinking machine with regular inflation/deflation]

These look something like a pair of [Eridian] gas bladder organs...but they're something marvelous marvelous marvelous.

LOW PRESSURE IS NOT NO PRESSURE. [Earth] life exists both in the air and under water, just like on [Erid]. But the air pressure is only a small fraction of [Erid] air. To an [Eridian], it might as well be vacuum! But Grace would die in pure vacuum just as quickly as an [Eridian] -- and be immediately crushed if they tried to live at [Erid] air pressure, bad bad bad. However, the pressure in their habitat is enough to keep their body water from boiling at their ambient temperature.

LIFE IN A FROZEN WORLD. Grace's habitat is kept at nearly half the absolute temperature of [Erid]'s surface. Much higher, and the proteins that make up Grace's body will denature quickly. How cold is that? Cold enough that water can retain its solid phase for considerable time! [Earth] even has large areas covered in solid water, and [humans] live in those areas covered by heat-retaining materials. So how do biological processes exist in a being that cold?

LIFE-GIVING AIR THAT BURNS. Grace's natural environment is 78% inert molecular nitrogen and 21% molecular oxygen. That's right, Grace lives in a corrosive and caustic oxygenated environment. [Earth] air-dwelling life has evolved to constantly exchange oxygen and carbon dioxide across the biome. [inset relief diagram of Earth CO2 cycle] Grace's gas bladder organs (above) are designed to exchange environmental oxygen and carbon dioxide in their water-blood. This permits their biological processes to occur despite the thin, cold atmosphere.

STILL BURNING. Does that mean oxygen is harmless to [humans]? No no no! Grace's body has elaborate defenses, because the free oxygen is constantly attacking their biological processes! But biologists at the science hive speculate that that's one reason why [human] life spans are only one-ninth that of [Eridians]. That means that Grace will not be living for very long sad sad sad.

IMAGINATION. [Rocky] went deliberately out into Grace's atmosphere on Grace's ship horror horror horror. Without it, Grace would have died and the mission likely fail. Can you imagine going out into a cold, caustic atmosphere to save a friend? Can you think of other examples from [Erid]'s history where someone endured extreme suffering to save a friend and everything else they loved?

[Vacuum bubble containing a small amount of cold nitrogen gas and a laptop.]

ACTIVITY. [Earth]'s cold, low-pressure atmosphere enabled them to invent the [portable Earth-thinking machines] that have to be kept at [Earth] temperatures to work. [Eridian] engineers have replicated the device, but it still has to be kept cold -- they are working on materials that might be usable for [Erid-thinking machines] that don't require containment.

[Tactile keypad and sonar screen connected to the bubble.]

You can enter a message on this keypad that will go directly into this [portable Earth-thinking machine]. When [Erid] sends a probe or delegation to [Earth], we'll pass your message along*. What do you want to say to our future [human] friends?

*subject to inspection by museum and government officials

My idea for a hypothetical exhibit at a new Museum of Xenobiology on Erid as part of the permanent gallery "Leaky Space Blob: Savior of Two Worlds".

[3D xenonite model of Ryland Grace's head]

LIGHT-HEARING

While Grace has enough hearing to perceive most speech, they do not use it to navigate the world! Instead, Grace has two organs on the surface of the round-appendage [inset relief diagram of human eyes] that allow them to hear light and even heat! Light reflected or emitted from surfaces enter these two small biological camera-like organs and sent to Grace's brain in the dome of their round-appendage. Their brain devotes a huge amount of thinking-power to turning the two lightscapes into a single model of where things are in the world...but only for a certain angle in front of them.

How does Grace know what is behind them or anywhere else? The brains of their species instead builds a complex "thought model" based on what they have light-heard previously. Grace can reason around complex spaces easily and even describe routes and structures from places they haven't fully light-heard. Most of their advanced technology is based around reasoning from limited-angle light-hearing! Isn't that amazing amazing amazing?

IMAGINATION: Grace's species has been hearing planets and stars for their entire existence. They take it for granted! If you could hear the stars, what do you think they would sound like? What are they saying to you?

ACTIVITY: Try to pretend you can't hear the rest of the museum. How do you describe where you will go next?