For Questions That Don't Merit Their Own Thread

[Terwin]

43 minutes ago, ZooNamedGames said:

Do black holes orbit? In that, do they move around a star (if it's small enough), or if larger, do they orbit the center of the galaxy? If so, are there any special properties to orbiting black holes as far as orbital mechanics go? Or are they treated as extremely dense planets as far as they're orbital paths are concerned? I know other objects can orbit a black hole (assuming it's outside of it's Swartzchild Radius), but I was wondering if the inverse is true and black holes orbit as well.

Gravitaionally speaking, Black holes act like any other object of similar mass until you get close enough for wonky things to start happening(event horizon for example)

Technically, the earth and the moon are both orbiting their mutual center of mass, it just happens to be under the surface of the earth.

So yes, Black holes orbit all sorts of things, it is just that they are usually the (much) heavier partner, so they tend not to move as much as their partner does.

 

[ZooNamedGames]

38 minutes ago, Terwin said:

Gravitaionally speaking, Black holes act like any other object of similar mass until you get close enough for wonky things to start happening(event horizon for example)

Technically, the earth and the moon are both orbiting their mutual center of mass, it just happens to be under the surface of the earth.

So yes, Black holes orbit all sorts of things, it is just that they are usually the (much) heavier partner, so they tend not to move as much as their partner does.

 

Awesome. Thanks. Good to know.

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Another question- if you had an object, with offset mass from it's center (let's imagine a bowling ball attached to one end of a long stick) orbiting a body, let's say a star (assuming there's only 1 major gravitational effect and any other gravity well's effects are near nil), is it possible, that with enough time, that the mass of the bowling ball, would be pulled towards the star and end up looking like O (star) o (bowling ball) - (stick)      O       o---             since the higher mass of the bowling ball is pulled more towards the star than the stick? I would also assume in this scenario that there's little angular momentum in the bowling ball/stick.

[Terwin]

40 minutes ago, ZooNamedGames said:

Another question- if you had an object, with offset mass from it's center (let's imagine a bowling ball attached to one end of a long stick) orbiting a body, let's say a star (assuming there's only 1 major gravitational effect and any other gravity well's effects are near nil), is it possible, that with enough time, that the mass of the bowling ball, would be pulled towards the star and end up looking like O (star) o (bowling ball) - (stick)      O       o---             since the higher mass of the bowling ball is pulled more towards the star than the stick? I would also assume in this scenario that there's little angular momentum in the bowling ball/stick.

So long as the rotational period of the bowling-ball/stick is exactly 1 orbit, and there are no other effects that might cause a wiggle, then the system can maintain the stick pointing inwards.

If there are any other effects, then I believe the denser side of the stick/bowling-ball system will eventually become tidally locked with the denser side of the system(ie bowling ball) pointing towards the larger mass.  (this is the case with the earth and the moon, the denser side of the moon always points towards the earth, and the earth is slowing it's rotation and will eventually always be pointing it's denser side towards the moon )

(but if the central mass is large enough that the narrow end of the stick is substantially heavier(such as near a black hole), then that denser-side will be the point of the stick)

 

[ZooNamedGames]

4 minutes ago, Terwin said:

So long as the rotational period of the bowling-ball/stick is exactly 1 orbit, and there are no other effects that might cause a wiggle, then the system can maintain the stick pointing inwards.

If there are any other effects, then I believe the denser side of the stick/bowling-ball system will eventually become tidally locked with the denser side of the system(ie bowling ball) pointing towards the larger mass.  (this is the case with the earth and the moon, the denser side of the moon always points towards the earth, and the earth is slowing it's rotation and will eventually always be pointing it's denser side towards the moon )

(but if the central mass is large enough that the narrow end of the stick is substantially heavier(such as near a black hole), then that denser-side will be the point of the stick)

 

Ok, so to build on this, would it be possible to deploy a satellite into solar orbit, away from other bodies, and have it's tidal pull (let's say the fuel, since it's densest part of the spacecraft and the CoM is offset from the rest) pull the fuel tanks so it's aligned as said above. Would it be possible to get it to properly align without the aid of gyroscopes, reaction wheels, or thrusters?

[SuperFastJellyfish]

Here's a good paper on gravity gradient stabilization to add to Terwin's explanation:

https://www.jhuapl.edu/techdigest/views/pdfs/V03_N5_1964/V3_N5_1964_Fischell.pdf

[Terwin]

6 minutes ago, ZooNamedGames said:

Ok, so to build on this, would it be possible to deploy a satellite into solar orbit, away from other bodies, and have it's tidal pull (let's say the fuel, since it's densest part of the spacecraft and the CoM is offset from the rest) pull the fuel tanks so it's aligned as said above. Would it be possible to get it to properly align without the aid of gyroscopes, reaction wheels, or thrusters?

Eventually?  Yes.  Do you want to wait that long?  I doubt it.

We are talking about forces that make ion drives seem over-powered.

Things like the difference in the amount of gravitational force you feel from the sun while standing on the second story of a house at noon as opposed to the first story of the same house at noon.

It would probably be faster to make the parts of the vessel that should face the sun black and the parts that should not, shiny.

That way the sunlight will bounce off the shiny parts(imparting more force) and be absorbed by the black parts(imparting less force).

Or even better, set up a small solar-sail and have it pull on the part that is supposed to face away from the sun.

[ZooNamedGames]

5 minutes ago, Terwin said:

Eventually?  Yes.  Do you want to wait that long?  I doubt it.

We are talking about forces that make ion drives seem over-powered.

Things like the difference in the amount of gravitational force you feel from the sun while standing on the second story of a house at noon as opposed to the first story of the same house at noon.

It would probably be faster to make the parts of the vessel that should face the sun black and the parts that should not, shiny.

That way the sunlight will bounce off the shiny parts(imparting more force) and be absorbed by the black parts(imparting less force).

Or even better, set up a small solar-sail and have it pull on the part that is supposed to face away from the sun.

Interesting. Ok.

[Rus-Evo]

Quick question.  I believe SpaceX has to fly Block 5 a certain number of times for Nass certification.  Does Falcon Heavy 2 count as 3 of those?

[ZooNamedGames]

7 hours ago, Rus-Evo said:

Quick question.  I believe SpaceX has to fly Block 5 a certain number of times for Nass certification.  Does Falcon Heavy 2 count as 3 of those?

No. In the same way that the Delta IV heavy isn't the same as the Delta IV rockets.

[KG3]

Is there any way to tell the difference between a proton that was created by the big bang billions of years ago and a proton that was created very recently like minutes ago in a particle accelerator?

[Cunjo Carl]

3 hours ago, KG3 said:

Is there any way to tell the difference between a proton that was created by the big bang billions of years ago and a proton that was created very recently like minutes ago in a particle accelerator?

To the best of our knowledge, no. At least not if you hadn't been tracking its specific history since the creation. In the moments after creation they're very easy to distinguish because they come zinging out at near the speed of light, and will subsequently embed themselves into nearby objects (like the detector) in ways that normal Hydrogen very much doesn't. When it's desired, we can also catch the newly made atoms and store them in a bottle, like is done with Anti-Hydrogen. But the internal structure is all just the same as far as I've ever heard.

There are two interesting pieces of information that are stored within nuclei though, the excitation state and the spin. Larger atomic nuclei can have their protons and neutrons fit together in different ways, and when the atom is first made they can be fit together very strangely called an excitation state. As they slowly shift down to their happiest shape, the nucleus will release energy in the form of X-rays or gammas. This can take between picoseconds and centuries to happen. The spin on the other hand is a quantum phenomenon, so every proton in the universe has it and it can be pointing in any number of directions. We mostly use it in ridiculously strong magnetic fields, like in NMR or MRIs.

[Cunjo Carl]

On 4/6/2019 at 11:38 AM, Mad Rocket Scientist said:

https://en.wikipedia.org/wiki/Benford's_law

This is bizarre.

Thanks for pointing this out! Had to stare at that graph for a good minute. I think it's because it's the _value_ that's random in these populations and not the leading numerals. Not only are the values randomly chosen from within their populations, but they're from random and entirely unrelated populations. Because they're from random populations, each value is just as likely to be in the thousands as in the ones. I'm finding it hard to explain my thoughts here, so maybe some pictures? The values being of random orders of magnitude should be scattered randomly on a log plot (like this one, ignore the colored lines)

(Example lin-log plot from dplot.com) Imagine our values being randomly scattered dots settling onto that bottom number line. Notice how much bigger the space appears between 1 and 2 than between 9 and 10!

If this is true, we should be able to squish them back onto a linear plot to get that 30% of values leading with the digit 1. Voila!

(plotted at desmos.com) The values are how likely a number is to start with a given digit.

So we should often be using 10^(A*math.Rand) rather than A*math.Rand. That's big. Thanks for bringing this up!

[ARS]

Is it legal if for some reason, I launched a spaceship without any notice (aka no countries are noticed about the launch, not even my own country, but they knew about it once I'm launched), and managed to escape the atmosphere and succesfully landed on Mars and establish a colony there?

[Nightside]

21 minutes ago, ARS said:

Is it legal if for some reason, I launched a spaceship without any notice (aka no countries are noticed about the launch, not even my own country, but they knew about it once I'm launched), and managed to escape the atmosphere and succesfully landed on Mars and establish a colony there?

Legality will be the least of your worries.

[James Kerman]

21 minutes ago, ARS said:

Is it legal if for some reason, I launched a spaceship without any notice (aka no countries are noticed about the launch, not even my own country, but they knew about it once I'm launched), and managed to escape the atmosphere and succesfully landed on Mars and establish a colony there?

It would be illegal in many ways:
 

Quote

Article VI of the Outer Space Treaty deals with international responsibility, stating that "the activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorisation and continuing supervision by the appropriate State Party to the Treaty" and that States Parties shall bear international responsibility for national space activities whether carried out by governmental or non-governmental entities.
https://en.wikipedia.org/wiki/Outer_Space_Treaty#Responsibility_for_activities_in_space

 

[Gargamel]

22 minutes ago, ARS said:

Is it legal if for some reason, I launched a spaceship without any notice (aka no countries are noticed about the launch, not even my own country, but they knew about it once I'm launched), and managed to escape the atmosphere and succesfully landed on Mars and establish a colony there?

I believe the legality of a private enterprise launching to space ends once you leave the airspace.  If you get clearances to launch through your airspace, then the majority of the hurdles should be beat. 

Have your years here been prepping you for some stealth colonization mission we should be aware of?

1 minute ago, James Kerman said:

It would be illegal in many ways:
 

 

Party Pooper.    

[wumpus]

1 hour ago, Gargamel said:

I believe the legality of a private enterprise launching to space ends once you leave the airspace.  If you get clearances to launch through your airspace, then the majority of the hurdles should be beat. 

Have your years here been prepping you for some stealth colonization mission we should be aware of?

Party Pooper.    

Looks like you have to look into just how exclusive those "state parties" are, and would something like Sealand qualify?  If not, there must be some nation state (Lichtenstein?, Trinidad and/or Tobago?) that would be more than happy to sign off just to be declared a "space faring nation"?

[Lisias]

3 hours ago, James Kerman said:

It would be illegal in many ways:

Only for the citizens under the Outer Space Treaty agreement (green are parties, yellow are signatories, red are non-parties and so, don't follow such rules)

On these countries (red), you don't have to follow such rules if you manage to get the money to try the stunt. But you will probably face some serious international backslash, to the point you would never manage to get out of that country without risking prison (not to mention having your assets seized).

 

3 hours ago, Gargamel said:

I believe the legality of a private enterprise launching to space ends once you leave the airspace.  If you get clearances to launch through your airspace, then the majority of the hurdles should be beat. 

TL;DR: 

No. If you are in one of that green countries, there's no possible way to get into space without talking with the militaries first. They claim jurisdiction on the whole shebang

 

Long answer:

The Airspace is divided as follows:

• UIR : Upper Information Region; also known as UTA - Upper Traffic Area
• FIR : Flight Information Region; also known as LTA -Lower Traffic Area
• CTA : Control Area
• TMA : Terminal Area
• CTR: Control
• ATZ : Aerodrome Traffic Zone

On the FIR there's no traffic control. All you have is FIS (flight information service) and ALRS (alert service). Here https://en.wikipedia.org/wiki/Flight_information_region are the list of the current FIRs.

UIR is airspace claimed under military jurisdiction by the country (obviously, delegated to the civil airspace control as appropriated). I managed to find that on UK it starts are Flight Level 245 (24.500 feet, about 7500 meters) and have no upper limit - some aliens would not agree on that.

This is highly dependent of the country - some use a slightly different layout. https://en.wikipedia.org/wiki/Airspace_class

These regions are separated in two kinds of airspace:

1. Controlled airspace is airspace of defined dimensions within which ATC service is provided to IFR flights and to VFR flights in accordance with the airspace classification.
2. Uncontrolled airspace is airspace in which air traffic control does not exert any executive authority, although it may act in an advisory manner.

https://www.ivao.aero/training/documentation/books/Student_Airspace_structure.pdf

So you only need [civil] clearance to get through the CTA region. This is the serious showstopper. 

 

1 hour ago, wumpus said:

If not, there must be some nation state (Lichtenstein?, Trinidad and/or Tobago?) that would be more than happy to sign off just to be declared a "space faring nation"?

The problem is to achieve an orbit that would not offend any other country's UIR.

 

— — — — POST EDIT — — — — 

Interesting.

KSP's Atmosphere indicator. probably by accident, appears to delimiter the FIR / UIR frontier (at least, under UK rules - 7500 meters).

Edited April 14, 2019 by Lisias
manually merging an asnwer

[kerbiloid]

On 4/6/2019 at 9:38 PM, Mad Rocket Scientist said:

https://en.wikipedia.org/wiki/Benford's_law

This is bizarre

The Benford's law depicts the Nature's laziness and unpatience.
Remember how many times you were starting doing something in alphabetical order, and how many times lost patience before getting to Z 'cuz it was too lazy to go on.

The Nature works same way.
So. everything around us consists of her unfinished projects. Always 1s, a lot of 2s, often 3s, sometimes 4s, rarely 5s, and almost never 9s.

P.S.
These numbers are not distributed uniformly along the whole range.
They are like jumps from zero mark, so they depict the probability that a jump is enough high.
Obviously, it should be some kind of the exponent, though at the first glance looks weird.

16 hours ago, KG3 said:

Is there any way to tell the difference between a proton that was created by the big bang billions of years ago and a proton that was created very recently like minutes ago in a particle accelerator?

Photons are even funnier.

3 hours ago, ARS said:

Is it legal if for some reason, I launched a spaceship without any notice (aka no countries are noticed about the launch, not even my own country, but they knew about it once I'm launched), and managed to escape the atmosphere and succesfully landed on Mars and establish a colony there?

Hardly, because there is not enough liquid water on Mars to drop the tea from the Earth and grow Martian one.

[Dropbear67]

I was looking at a tracking site for satellites and it seems that Arabsat 6A (launched recently by Falcon heavy) is not yet in its geostationary orbit ..

 

 Does anyone have any information on what kind of burns they are doing to circularise at apoapsis? are they doing a number of small burns? When is it expected to actually reach a geostationary position?

[Superfluous J]

On 4/13/2019 at 10:27 PM, Lisias said:

Only for the citizens under the Outer Space Treaty agreement (green are parties, yellow are signatories, red are non-parties and so, don't follow such rules)

On these countries (red), you don't have to follow such rules if you manage to get the money to try the stunt. But you will probably face some serious international backslash, to the point you would never manage to get out of that country without risking prison (not to mention having your assets seized).

Am I the only one who noticed that one of those red countries is none other than WAKANDA!?

Edited April 16, 2019 by 5thHorseman

[Lisias]

On 4/16/2019 at 8:05 PM, 5thHorseman said:

Am I the only one who noticed that one of those red countries is none other than WAKANDA!?

Yeah. Wakanda and Latveria (one of the another red ones) are pushing their own space treaty.

That little country in Asia? Kathmandu. They are trying to sell high their privileged territory, as they are both near the Equator and near the USA's east coast, cutting costs as rockets doesn't need to be trimmed down to pass through the Panama Channel. They will probably succeed, as Elon Mush, Paul Allen and Jeff Bezos had bought all that small and scattered red islands on the far east on the map. Had not Paul Allen been kidnaped by the Xenu (what made some of the islands available again), Kathmandu would already had won the dispute and entered that rogue treaty with a higher hand.

Edited April 18, 2019 by Lisias
tyops! tyops! tyops everywhere!

[kerbiloid]

They are going to visit Attilan, it's normal.

[wumpus]

On 4/13/2019 at 8:55 PM, James Kerman said:

It would be illegal in many ways:

Tech news-web-tabloid "the Register" has a project called LOHAN that involves launching a rocket from a weather balloon (the name implies orbital, but I don't think it is designed to pull that off.  Probably will make it to space).  It has been in FAA/NASA limbo for years.  I don't think they've even considered a Jamaica/offshore launch (unlike most rockets, I doubt a balloon needs a stable launch pad) thanks to the legal ramifications.

https://www.theregister.co.uk/Tag/lohan

[ARS]

What's the single heaviest payload ever brought to orbit? And what's the single heaviest possible payload that we can launch today?