KG3

Ok, I'm relaxed. Sorry. I do really like this particular mission. It looks like they are using the same sample method they used on the first Hayabusa mission. Firing a pellet into the soil and hoping some material gets blasted up into the collection container. It seemed like they got less material with this method than they had hoped for. Did they make any changes to their collection method for Hayabusa 2?

So this right hand rule. If the images and spacecraft around Ryugu are flipped around so that the asteroid appears to be rotating in a prograde direction does that now mean that Ryugu is traveling around the sun in a retrograde direction (along with everything else in the solar system)? I can see how this could be a source of conflict between inter stellar civilizations. "Your world spins in the wrong direction!" "Well, YOUR world is traveling around your sun in the wrong direction!"

According to the Planetary Society article previously posted the right hand rule applies to small bodies. They also say: "The images [of Ryugu] that have been posted so far have had south up; the mission is now disciplining itself to post images with north up."

Ryugu seems like such a human scale object. We actually could build one if we really wanted! Also the Hayabusa2 team says "Ryugu is a retrograde rotator. The images that have been posted so far have had south up; the mission is now disciplining itself to post images with north up. The big funky boulder is at Ryugu's south pole." I wasn't aware of this right hand rule for celestial bodies.

In the Ryugu facts listed in the article it says Ryugu has a mass of around 450 million tons. What would compare to that on earth? Hoover dam, super tanker or something?

Unless you are reading Lewis Carol's Alice's Adventures Wonderland. The Mock Turtle went to school in the sea. His teacher was an old sea turtle named Tortoise "We called him Tortoise because he taught us"

The earth would have to heat up an awful lot to effect the earth's crust. However the melting of large ice sheets can effect the underlying geology just by the redistribution of all that weight. I think if the earth heats up enough to melt the Greenland ice sheet a few extra earthquakes and volcanoes would be the least of our problems! https://en.wikipedia.org/wiki/Post-glacial_rebound#State_of_stress,_intraplate_earthquakes_and_volcanism "One of the possible impacts of global warming-triggered rebound may be more volcanic activity in previously ice-capped areas such as Iceland and Greenland.[26] It may also trigger intraplate earthquakes near the ice margins of Greenland and Antarctica."

Scott Manley did a video on this subject a few years ago. In the description he says "Warning: Big Numbers Ahead" https://www.youtube.com/watch?v=G01NoaTM46o&pbjreload=10

If this bone is from a dolphin and NSEP wanted to get it as clean and bright as these other specimens pictured, would he use some sort of all porpoise cleaner?

Insects use hemolymph instead of blood. They employ an open circulatory system instead of arteries and veins, which means that the hemolymph just kind of sloshes around inside the exoskeleton. The trachea are basically just a bunch of tubes that deliver air into the body of the insect. https://en.wikipedia.org/wiki/Insect "Late Carboniferous and Early Permian insect orders include both extant groups, their stem groups,[27] and a number of Paleozoic groups, now extinct. During this era, some giant dragonfly-like forms reached wingspans of 55 to 70 cm (22 to 28 in), making them far larger than any living insect. This gigantism may have been due to higher atmospheric oxygen levels that allowed increased respiratory efficiency relative to today" If you want to see some amazing adaptations look into aquatic insects. They have come up with some really wild solutions to living in this environment. I could go on and on...

Is it possible for planets in this simulation to capture moons? I'm not sure how the whole moon capture works but I think it has something to do with the orbital speed of the planet being close to the escape velocity of the planet. Also it seems that moons in a retrograde obits are considered to have been captured. Are moons more likely to be captured into a retrograde orbit or do they just stand out more? Great job! Would I have to plot motions and locations for all 800 objects before starting the simulation or have you done that already?

I looked up "ten minute squirrel" on YouTube and didn't find anything that flew other than flying squirrels. In fact there seems to be millions of videos of squirrels on YouTube, it's quite a rabbit hole to go down which is funny because squirrels are rodents and rabbits are lagomorphs. So I abandoned that can of worms before it leapt out the frying pan and into whole nuther kettle of fish. I think what you are telling me is that if the entire wing is very light with most of it's mass at the edges it will have more momentum to turn and more lift. Yes, the flute seems to be even older than the bullroarer. One of the earlier known examples dates back 35,000 years and made out of the wing bone of a vulture. I'm sure combining the two could only improve the aerodynamic properties of the bullroarer! Interesting. What do you call the movements of a bullroarer, does it spin, pitch or roll? An aircraft movements are pitch, yaw and roll. I'm assuming a frisbee and boomerang turn on the yaw axis, a thrown football turns on the roll axis, and a bullroarer turns on the pitch axis? And an untethered bullroar which turns freely as it falls is called a squirrel? As it moves forward is it considered to be gliding? Ok, I think I got this... When the squirrel(?) is at the 10 o'clock(ish) position in it's cycle it's acting as a thin air foil so the center of lift is 1/4 of the way from the leading edge. A fixt wing aircraft needs the center of balance and the center of lift to be the same to remain stable but with the squirrel (really... squirrel?) the 3/4 of the wing behind the center of lift is out of balance and so is going to drop giving the wing momentum to keep turning. After the wing rotates up to and past 12 o'clock the Magnus Effect kicks in and gives it additional lift up to about 3 o'clock. It seems to run so smoothly but if you were to plot the movement of the axis of rotation on a graft would it travel in a straight line or would it dip a bit as the wing traveled through each cycle?

Ok, thanks everyone! Been doin a bit of experimentation. I fished a thick piece of paper out of the recycling and cut a roughly 1"x8 1/2" strip. I drop this from celling height (roughly) 8 feet and it reliably rotates as it falls and travels forward landing about 8 feet forward from plumb! So that's a glide ratio of like 1 to 1 right? Hey, I've made paper airplanes that have flown much worse than that! Is it possible to improve upon this?

You might have seen it in Crocodile Dundee. It's usually associated with aborigines in Australia but it's been around along time. "Anthropologist Michael Boyd, a bullroarer expert, documents a number found in Europe, Asia, the Indian sub-continent, Africa, the Americas, and Australia." It seems to create more lift than it should just through centripetal force.

Is anyone familiar with the bullroarer? https://en.wikipedia.org/wiki/Bullroarer It's an ancient instrument thought to date to about 18,000 bc. "A bullroarer consists of a weighted airfoil (a rectangular thin slat of wood about 15 cm (6 in) to 60 cm (24 in) long and about 1.25 cm (0.5 in) to 5 cm (2 in) wide) attached to a long cord" https://www.youtube.com/watch?annotation_id=annotation_744186113&feature=iv&src_vid=yJN1hDrXtto&v=5PgGDMmBtDg I'm curious about the aerodynamics of this. I know if you simply throw a similar slat of wood like a boomerang (without the cord) it will (sometimes) produce the same roaring sound and travel for a bit parallel to the ground and even sometimes gain a bit of altitude. It spins around the long axis (not the axis perpendicular to it's flight like the boomerang). If you look at the demonstration in the video above you can see that the bullroarer produces some lift. As the bullroarer is swung about it spins twisting up the cord then reverses direction still producing the same sound and lift. Is this somehow related to the Magnus effect? I can't seem to find this described anywhere.

At one point in the Connecticut Yankee tale he tries to introduce the concept of hygiene. He demonstrates by kidnapping the local hermit and washing him with soap and water in front of a bunch of villagers. The hermit dies as a result. Traveling back to a stone age civilization would probably have would have a much more profound effect on the traveler than the civilization.

I think what would be interesting in this scenario is what these stone age people might get (got) right from the perspective of the time traveler. They were probably well adapted to and aware of their environment. People were able to cultivate yeasts, make stuff like cheese thousands of years before the germ theory or discovery of the atom. I'm sure there are things a time traveler would learn from these people. They might only need a few tweaks from what they are already doing to help them out. Also read up on Otzi, the 5000 year old mummy. His gear was quit sophisticated! https://en.wikipedia.org/wiki/Ötzi Also a good read might be A Connecticut Yankee in King Arthur's Court by Mark Twain. It's about an engineer who works for Colt Arms Manufacturing Co. in Hartford Connecticut who goes back in time to King Arthur's time. It's hilarious and a great read... up until the last few pages!

Would it be possible for a rover to use an air compressor to blow dust off the solar panels instead of waiting for a random wind? Would an air compressor work in such a thin atmosphere?

Nitrogen isn't just a diluent gas. It's impossible to make amino acids, proteins and life as we know it without it. I'm interested to know how mar's minerals are different from the earth and how life, plate tectonics and water affect this. Thanks to life here we have free oxygen, carbon in the form of coal, calcium from limestone etc. Are there any useful ores on mars?

Sadly this is true for the poor cephalopod. They live long enough to reach sexual maturity then die soon after reproducing. Some species stick around for a bit to nurture their young but not long enough to put them through college.

Two children are not a statistically relevant sample size for this experiment. She would need to have at least 30 kids before getting any meaningful results.

How is mass measured on the ISS? I mean when they are doing experiments and they need so many grams of this or that. I'm guessing a triple beam balance is useless up there. Maybe experimental stuff is premeasured and packaged on earth before being sent up and then examined after being brought back down?

I've noticed that KSP has both kerballoons and kerbal airships. Why didn't they go with the obvious name Dirigikerbal? Just asking.

Ok, your talking about several billion years worth of the sun's fusion taking place in minutes... cool! It would be interesting to view this from the night side of the moon (viewing it from the night side of the earth might be complicated by the earth's atmosphere and oceans on the daylight side wanting to leave the planet in a hurry). As this tsunami of photons travelled past the moon you would probably be broiled by light reflected by light reflecting off everything else in the solar system. Most of this material is concentrated within a disc surrounding the sun. Asteroids and planets would appear to brighten many times than the (normal) sun. Zodiacal light is sunlight reflected off of dust orbiting the sun and is visible as a faint glow at certain times of the year would become deadly bright as well. https://en.wikipedia.org/wiki/Zodiacal_light Ok here is an XKCD what if that talks about what would happen if everyone on the earth pointed a lazar pointer at the moon. At the end of the article he takes it to ridiculous extreme and vaporizes the surface of the moon. https://what-if.xkcd.com/13/

I think you might also briefly see jets at the polls of the stars as they collapse. https://en.wikipedia.org/wiki/Astrophysical_jet