Weirdest space fact that you know

[starcaptain]

Terminal velocity near the surface on Venus is only 11-12m/s (~40kph, ~25mph).

This is about equivalent to falling 16 meters on Earth (50 ft), which is survivable but very likely to cause injury.

You could probably decrease your speed significantly by something as simple as opening the sides of a jacket, or holding onto a free-flapping tarp.

External temperatures make survivability a problem.

 

Terminal velocity near the surface of Titan is only 9.6m/s (~34kph, ~21mph). This is about the fastest a person can sprint on Earth over level terrain.

This fall is also about equivalent to falling 5 meters on Earth (16 ft), which can be survived without injury relatively easily, even unaided.

A person wearing a wingsuit and flapping their arms would be able to sustain level flight, because the gravity is so low and pressure is so high.

External temperatures are colder than liquid nitrogen, so you'll probably want to bring a jacket or something.

(Hey: being too cold is a lot easier to fix than being too hot.)

Edited November 17, 2020 by starcaptain

[kerbiloid]

Umbrella.

[munlander1]

On 11/17/2020 at 4:33 PM, starcaptain said:

External temperatures are colder than liquid nitrogen

So are we talking like some ultra heavy winter gear and an oxygen supply or would it just be better to go with a space suit?

[cubinator]

2 hours ago, munlander1 said:

So are we talking like some ultra heavy winter gear and an oxygen supply or would it just be better to go with a space suit?

Very well insulated, maybe actively heated winter gear and breathing air. You wouldn't want to expose any skin to the air. It would be like a cross between Antarctic winter gear, a diving suit, and a spacesuit. It's about -183 Celsius.  Coldest recorded on Earth is -89.

Since the pressure is 1.5 atmospheres, there is no need for a pressure suit, the only reason for airtight clothes besides the breathing mask would be to keep the cold air from getting in. 

[munlander1]

30 minutes ago, cubinator said:

the only reason for airtight clothes besides the breathing mask would be to keep the cold air from getting in

Are those temps cold enough to warrant those types of clothes

[sevenperforce]

On 11/17/2020 at 5:33 PM, starcaptain said:

External temperatures make survivability a problem.

So beautifully understated.

Randall Munroe explains what it would be like to fly a plane on Venus:

"But physics calculations give us an idea of what flight there would be like. The upshot is: Your plane would fly pretty well, except it would be on fire the whole time, and then it would stop flying, and then stop being a plane."

And he has similar thoughts to you about Titan:

"Humans on Titan could fly by muscle power. A human in a hang glider could comfortably take off and cruise around powered by oversized swim-flipper boots—or even take off by flapping artificial wings. The power requirements are minimal—it would probably take no more effort than walking."

And let us never forget...

Spoiler

 

[starcaptain]

There's a hypothetical type of stellar body called a Thorne-Zytkow Object (TZO) which is a red giant or supergiant that collided with a neutron star, and thus has a neutron star at its core.

Over time, a TZO is expected to decay into either a lone neutron star of some kind, or a black hole, as the neutron star inside eats the larger star. At the interface between the neutron star and the larger star's core, unusual and difficult-to-describe nuclear processes may occur.

There are about 6 objects known that are candidates to be TZOs.

 

A TZO is similar to but not the same as a Quasi-star; a supermassive star with a black hole at its core.  The immense rate of mass consumption by the black hole on the inside generates radiation and heat sufficient to push back out against the force of gravity and maintain the general appearance of a star, even though it has no nuclear fusion processes going on. Quasi-stars are distinct because of their unusual immense size and brightness: they may outclass the largest known hypergiant stars by a factor of 2 or more.

There are no known candidates of what may be Quasi-stars. It is most likely that they existed in the Earlier universe, as they would exist alongside metal-poor Population-III stars.

[wumpus]

On 11/17/2020 at 5:33 PM, starcaptain said:

Terminal velocity near the surface on Venus is only 11-12m/s (~40kph, ~25mph).

Surface gravity on Uranus and Neptune are .9g and 1.2g respectively.  Even though they are well over 10 times as massive as Earth.

[Kerbart]

Setting up an orbit in a two-burn fashion (raise APO, and then at APO circularize)?

Super-high orbits can be achieved that way using less DV than lower orbits.

[sevenperforce]

45 minutes ago, wumpus said:

Surface gravity on Uranus and Neptune are .9g and 1.2g respectively.  Even though they are well over 10 times as massive as Earth.

So you're telling me I'm **less** attracted to Uranus than I am to all the ones on Earth?

[DeadJohn]

I know how to calculate "arcseconds per pixel" when using a camera and telescope. That's a weird, esoteric fact needed by less than 0.01% of the world's population (deep sky and planetary astrophotographers).

I also know that teachers giggle as much as their students when a planetarium presentation mentions rings on Uranus.

[cubinator]

12 hours ago, DeadJohn said:

I also know that teachers giggle as much as their students when a planetarium presentation mentions rings on Uranus.

The presenter does not.

[adsii1970]

Bologna still tastes like bologna whether you're on the surface, in LEO or HEO. I imagine it would also taste the same in orbit around the Moon...

[wumpus]

On 11/21/2020 at 11:29 AM, adsii1970 said:

Bologna still tastes like bologna whether you're on the surface, in LEO or HEO. I imagine it would also taste the same in orbit around the Moon...

It does?  Hot sauce packets  are in high demand on the ISS because it is one of the few things you can still taste.  I'd be surprised if balogna also was an ISS favorite.

Note that this doesn't seem to be dependent on orbit, more likely how long you've been in zero-g.  But in practice "tastes the same in orbit" isn't true.

[kerbiloid]

Now I know that bologna is also a meal.

As in my understanding "bologna" is a waterproof material for coats, I was trying to understand the joke, why taste the coat on ground and in space, but failed.

[magnemoe]

On 11/19/2020 at 4:55 PM, sevenperforce said:

So beautifully understated.

Randall Munroe explains what it would be like to fly a plane on Venus:

"But physics calculations give us an idea of what flight there would be like. The upshot is: Your plane would fly pretty well, except it would be on fire the whole time, and then it would stop flying, and then stop being a plane."

And he has similar thoughts to you about Titan:

"Humans on Titan could fly by muscle power. A human in a hang glider could comfortably take off and cruise around powered by oversized swim-flipper boots—or even take off by flapping artificial wings. The power requirements are minimal—it would probably take no more effort than walking."

And let us never forget...

Now on an domed crater on the Moon, flying would work well, more fun an pool on the moon would probably let you run on water, being fast light or wearing large boots would help. 
You could also jump out of water like an dolphin if using flippers.

[kerbiloid]

12 minutes ago, magnemoe said:

You could also jump out of water like an dolphin if using flippers.

And covering nearby swimmers with a several meters high tsunami.

[magnemoe]

18 minutes ago, kerbiloid said:

And covering nearby swimmers with a several meters high tsunami.

This is an bonus, any kids know lots of tricks to annoy people trying to adjust to cold water by slowly getting into it. 
However the hat tricks here is to jump onto the edge of the pool lot to bomb then falling down again  

[magnemoe]

On 11/19/2020 at 5:26 PM, starcaptain said:

There's a hypothetical type of stellar body called a Thorne-Zytkow Object (TZO) which is a red giant or supergiant that collided with a neutron star, and thus has a neutron star at its core.

Over time, a TZO is expected to decay into either a lone neutron star of some kind, or a black hole, as the neutron star inside eats the larger star. At the interface between the neutron star and the larger star's core, unusual and difficult-to-describe nuclear processes may occur.

There are about 6 objects known that are candidates to be TZOs.

 

A TZO is similar to but not the same as a Quasi-star; a supermassive star with a black hole at its core.  The immense rate of mass consumption by the black hole on the inside generates radiation and heat sufficient to push back out against the force of gravity and maintain the general appearance of a star, even though it has no nuclear fusion processes going on. Quasi-stars are distinct because of their unusual immense size and brightness: they may outclass the largest known hypergiant stars by a factor of 2 or more.

There are no known candidates of what may be Quasi-stars. It is most likely that they existed in the Earlier universe, as they would exist alongside metal-poor Population-III stars.

Yes that is an weird one, I assume it will turn into an black hole at some point as the total mass should be large enough for this. 

The Quasi-star is TZO^x, one issue if if an massive star could form so close to an black hole, however an very massive star would start become an red giant very fast and might expand out so fast the black hole would not be able to eat the materials, still I don't think this would be stable so long the center of gravity would be at the center of the black hole, so you would have an hypergiant with an black hole inside it rotating very fast around the common center of mass. I guess it would be very energetic compared to quasars or stuff you are very happy can not happen in your galaxy anymore  

[Clamp-o-Tron]

On 11/21/2020 at 8:29 AM, adsii1970 said:

Bologna still tastes like bologna whether you're on the surface, in LEO or HEO. I imagine it would also taste the same in orbit around the Moon...

Canadian bacon (arguably bologna) and applesauce was one of the breakfast options on most Apollo spacecraft but I have no way of knowing whether they ate it in Moon orbit or at all.

 

[cubinator]

1 hour ago, Clamp-o-Tron said:

Canadian bacon (arguably bologna) and applesauce was one of the breakfast options on most Apollo spacecraft but I have no way of knowing whether they ate it in Moon orbit or at all.

It might be in the transcripts.

[starcaptain]

2 hours ago, magnemoe said:

Yes that is an weird one, I assume it will turn into an black hole at some point as the total mass should be large enough for this. 

The Quasi-star is TZO^x, one issue if if an massive star could form so close to an black hole, however an very massive star would start become an red giant very fast and might expand out so fast the black hole would not be able to eat the materials, still I don't think this would be stable so long the center of gravity would be at the center of the black hole, so you would have an hypergiant with an black hole inside it rotating very fast around the common center of mass. I guess it would be very energetic compared to quasars or stuff you are very happy can not happen in your galaxy anymore  

There is such a thing as a black hole that stuffs its gob so fast and generates so much radiation and stuff that it pushes the thing it's eating away. This is called the Eddington limit.

[K^2]

On 11/18/2020 at 7:25 PM, munlander1 said:

Are those temps cold enough to warrant those types of clothes

Oh yeah. A tiny leak in your suit will cause instant frostbite. You want to be extremely well insulated on Titan. In addition, your suit will need to have layers with very different properties. Materials that are suitable for internal layers would freeze and shatter if they are used for external layers, while materials that can still remain flexible on the outside of the suit would turn into putty or liquid on the inside. Which does mean that getting into and out of such a suit is somewhat problematic.

The only place other than Earth where you can go outside briefly without a protective suit and survive is upper atmosphere of Venus, about 60km above surface. Depending on exact elevation, both temperature and pressure are comparable to what you'll find on Earth, either a bit above or a bit bellow comfortable. You will want to hold your breath and take a shower immediately after, because you'll get some sulfuric acid on you, but it's still far better than anywhere else in the Solar System. If you wanted to establish a habitat, you'll just need a thin plastic film between you and the environment to keep you safe. If there's a tear, you'll have time to locate it and fix it with some tape. And if you need to go outside to do repairs, a light hazmat suit with a rebreather and oxygen tank can have you set for hours. The only serious problems are lack of firmament to build on and difficulty in obtaining any resources you can't extract from atmosphere. That still leaves it more hospitable than surface of any body except Earth.

[starcaptain]

A boring but fiesable solution for both is a hardsuit, the kind that have interlinked pressure vessels surrounding the person. However these have major movement limitations.

[Lekhan13]

In the constellation of Cancer there is a diamond planet worth $ 26.9 nonillion.
The earth's day in the future will stretch to 870 hours.
The moon leaves Earth's orbit at a speed of 38 mm per year.
Scientists have found a huge number of planets potentially suitable for the formation of life.

The latter is my favorite space fact because there may be a similar form of life, which also still suggests its loneliness in the universe)