New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#26 2016-10-03 01:18:26

karov
Member
From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Moreover on interstellar planemos

Terraformer wrote:

That's a hard one, but I'll give it a shot - a black hole. Nothing else allowed, you have to extract all the mass-energy you need for a supramundane shell from the black hole itself (well, you're allowed the seed equipment...).

Blackholes are PRIME realty.

https://en.wikipedia.org/wiki/Penrose_process  & https://en.wikipedia.org/wiki/Blandford … ek_process

So given only a black hole + only some seed equipment one could mine all the energy / mass needed for construction and running of a form of ultimate habitat.

http://www.orionsarm.com/fm_store/TheKernel.html

Places, I'd suggest inside a star. Only really doable with exotic matter and wormholes.

Star-lifting. Supra-stellar habitats.

Re. red dwarfs, the smallest are expected to last for 10 trillion years. That's very roughly 1000 times as long as the universe has lasted so far. I don't think running out of stars is going to be the biggest worry, unless there's a grey goo scenario that dissembles them all. It's far more likely the universe will die off before that point...

Yes, there are PLENTY of asymptotically optimal, but human life on Earth is not confined to the optimal locations, isn't it?

Offline

#27 2016-10-03 19:32:13

Void
Member
Registered: 2011-12-29
Posts: 3,884

Re: Moreover on interstellar planemos

Karov,

I appreciate your position, and will relent on that.

I am concerned about black holes however.  I don't think both energy and mass can be taken from them.  Possibly either/or, but not both, ?

It seems I have problems grasping the true nature of black holes.

If you drop matter into them, we believe that before it gets sucked in, the matter radiates intense energy due to friction and collisions.
However, I am thinking that since a black hole is supposed to be very cold inside, it is like a fist squeezing the matter, and rejecting it's heat.  So, it stores the mass without the heat?  In what form is the mass?  Particles of some kind?

If a laser beam were shined on a black hole, what would happen?
Light has no mass, but has momentum.  So, with a fantastically giant laser, can you heat up a very cold black hole by adding vibration to the mass within it?  I understand that light supposedly will stay in a black hole due to the curvature that it creates in space-time, but not due directly to gravity I presume.

If black holes are very cold, then they must have rejected vibration upon their formation, and shed it to the explosion which created them.  Of course if there are primordial black holes which comprise much of dark matter, then I don't know how those formed.

I am tempted to think that a laser shined on a black hole might reflect off of it.  Only because black holes being very cold, suggests that they naturally reject vibration.

Hawking Radiation:
https://en.wikipedia.org/wiki/Hawking_radiation

Hawking radiation is black-body radiation that is predicted to be released by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974,[1] and sometimes also after Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy.[2]
Hawking's work followed his visit to Moscow in 1973 where the Soviet scientists Yakov Zeldovich and Alexei Starobinsky showed him that, according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles.[3] Hawking radiation reduces the mass and energy of black holes and is therefore also known as black hole evaporation. Because of this, black holes that do not gain mass through other means are expected to shrink and ultimately vanish. Micro black holes are predicted to be larger net emitters of radiation than larger black holes and should shrink and dissipate faster.
In June 2008, NASA launched the Fermi space telescope, which is searching for the terminal gamma-ray flashes expected from evaporating primordial black holes. In the event that speculative large extra dimension theories are correct, CERN's Large Hadron Collider may be able to create micro black holes and observe their evaporation.[

And then time:
https://en.wikipedia.org/wiki/Black_Hol … Time_Warps

By introducing quantum behavior to curved spacetime, several physicists have suggested that black holes do not possess a true mathematical singularity, but rather a region of chaotic space, in which time does not exist. The behavior of this space and the material which approaches it are not well understood, with a complete marriage of relativity and quantum physics yet to be achieved.

So that's something perhaps.  And time is supposed to slow down near a black hole.

My question on black holes and time, is "If there are primordial black holes, do they reach back in time to the big bang?"

Secondly, "If Hawking Radiation (Of particles) are created at the event horizon of black holes and this results in some evaporation of the interior(?) contents of the black hole, then in the case of primordial black holes, is this a leakage of "Substance" from the beginning of time to our space time?".

Yes, I don't pretend to understand, I am confused, and admit it.  That's OK though, they don't have a unified theory yet, so how likely could it be that I would get this right?

Oh, just one more thing;
So, if virtual particles interacting with black holes creates Hawking Radiation, and the black holes evaporate, then OK, maybe you do get mass and energy, but it is moving particles, and I am not sure you can regulate or speed up the process.  So, if black holes are very cold, then the particles created if they are hot, must be allowed to keep their mass and energy of creation, if a partner virtual particle is pulled into the black hole.  And that process, then destroys a small part of the black hole.  Perhaps a small part of the black hole becomes virtual, and so disappears, as payment?

Last edited by Void (2016-10-03 20:09:50)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

Offline

#28 2016-10-03 20:03:14

Void
Member
Registered: 2011-12-29
Posts: 3,884

Re: Moreover on interstellar planemos

Now, back to the planemos smile

Very, well, if we are to maintain a human type substantially and sufficiently like us, as you require, I therefore would have different plans for the different objects (If I were actually ever in that sphere of space-time).

OK, Terrestrials, (Whatever your definition), could be amusement parks, just to provide a "Natural Fossil Environment" for humans.

Other than that, if the objective is to provide habitat for a human type substantially and sufficiently like us, as you require, then I suggest, nested shells.

The outer mega shell, being substantially at a background vacuum.
Nebula materials could be sucked into it for processing, perhaps by magnetic fields.

The next shells could be bubbles interconnected with sufficient atmosphere, and then finally inside of each of those, spinning machines to provide synthetic gravity.

While the nebula or ordinary space dust and gasses might be collected, planemo's which are not "Terrestrial" in type would be disassembled (Mined), to provide the materials for the nested shells.

Last edited by Void (2016-10-03 20:15:36)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

Offline

#29 2016-10-04 11:32:43

Void
Member
Registered: 2011-12-29
Posts: 3,884

Re: Moreover on interstellar planemos

OK, here is a much better description of black hole processes (In theory), than the spew I put out:
http://www.space.com/34281-do-black-holes-die.html

For one thing I should not prefer to speak of particles, but underlying fields, that makes it make more sense, at least to me.

Last edited by Void (2016-10-04 11:33:50)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

Offline

#30 2021-06-28 08:42:29

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Moreover on interstellar planemos

I'm not a big fan of our current model of the Universe, you have that whole matter anti matter annihilation going on, hidden dimensions, stars that should not be as old as they are, planets and heavy elements showing up sometimes in places where they shoulld not be, the simplest model of inflation requires that the early universe contained what’s called a kind of magic work around dimenison expansion math fix, the physics called the scalar field. This field is like this magic ether fix that permeates all of space and is responsible for causing space to expand faster than the speed of light but it doesnt so don't worry about it, now they are trying to fix it all by way of string theory. I would not be shocked to see some of this stuff revised and fixed as we learn more, for now some areas of Cosmology are based on the real science coming from Fermilab and Cern while other areas are more like scifi fantasy and philosophy.

But because some ideas are before their time and its science this stuff will be falsifiable, examined and proven.


Did We Just Find The Largest Rotating ‘Thing’ In The Universe?
https://www.forbes.com/sites/startswith … -universe/
How this supercomputer will use A.I. to map the universe’s dark energy
https://www.digitaltrends.com/news/desi … rcomputer/

Giant Mega-Comet discovered falling toward the sun. Comet Bernardinelli-Bernstein is estimated to be about 1000 times more massive than a typical comet, making it arguably the largest comet discovered in modern times. It has an extremely elongated orbit, journeying inward from the distant Oort Cloud over millions of years. It is the most distant comet to be discovered on its incoming path.


Giant comet found in outer solar system by Dark Energy Survey
https://www.spacedaily.com/reports/Gian … y_999.html



A giant comet from the outskirts of our Solar System has been discovered in 6 years of data from the Dark Energy Survey. Comet Bernardinelli-Bernstein is estimated to be about 1000 times more massive than a typical comet, making it arguably the largest comet discovered in modern times. It has an extremely elongated orbit, journeying inward from the distant Oort Cloud over millions of years. It is the most distant comet to be discovered on its incoming path, giving us years to watch it evolve as it approaches the Sun, though it's not predicted to become a naked-eye spectacle.

A giant comet has been discovered by two astronomers following a comprehensive search of data from Dark Energy Survey (DES). The comet, which is estimated to be 100-200 kilometers across, or about 10 times the diameter of most comets, is an icy relic flung out of the Solar System by the migrating giant planets in the early history of the Solar System. This comet is quite unlike any other seen before and the huge size estimate is based on how much sunlight it reflects.


Perhaps ‘Stellar Jets’ Come From Protoplanetary Disks, Not Stars Alone
https://www.forbes.com/sites/startswith … ars-alone/

Young Chaotic Star System Reveals Secrets of Planet Formation
https://scitechdaily.com/young-chaotic- … formation/

Last edited by Mars_B4_Moon (2021-06-28 08:52:42)

Offline

#31 2021-06-28 09:28:40

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Moreover on interstellar planemos

The giant comet is an interesting discovery and suggests Oort cloud objects may be larger than previously believed.  It used to be assumed that these bodies would never greatly exceed 10km in diameter.

It may have interesting implications for eventual human colonisation of the Oort cloud.  Take a ball of ice some 40km wide and you will find that the pressure at its centre, from its own gravitational attraction, is 1 bar.  Sink a nuclear reactor or fusion reactor to the centre of a comet >40km in diameter and it will gradually melt from the inside out due to waste heat.  That inner melted region would be a comfortable environment for humans, with plenty of warm liquid water and a pressure range close to Earth sea level.  The centre of a comet may be one of the easiest places to terraform.  Only two catches: (1) You have to bring along your own energy source; (2) It is close to being a zero-g environment.  Bouyant forces will be close to zero, so air filled volumes could be created using polyethylene bubbles.  Dust and rocky materials would accumulate around the core, around which an aquatic ecosystem will form.

Human beings evolved on dry land and we tend to assume that our migration into the solar system and cosmos will involve more of what we already experience.  But the truth is that the most abundant material in the outer solar system is water ice.  Human beings will be drawn to these icy bodies, because they will provide heat sinks for our power sources.  The further human beings venture from the sun, the more aquatic their environments will be.  By the the time human beings get around to colonising the cosmos, small inner rocky planets will be less interesting to us than gas giants with icy moons and the Kuiper belts and Oort clouds of other stars.  This where the water will be.  Assuming that humanity has mastered nuclear fusion at this point, it will no longer be necessary to find places with lots of sunlight.  We will be looking for dark places, with lots of water, carbon and nitrogen.  Places like that newly discovered comet.

Last edited by Calliban (2021-06-28 09:43:27)


Interested in space science, engineering and technology.

Offline

#32 2021-06-28 10:16:08

Void
Member
Registered: 2011-12-29
Posts: 3,884

Re: Moreover on interstellar planemos

Very good elaborations.  40 km, I like having that reference.   
I think you are correct.  It might even be that eventually larger ice bodies will be converted into many ~40 km objects for convenience.

Good enough.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

Offline

#33 2021-06-28 14:47:36

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Moreover on interstellar planemos

The maximum sustainable population of a cometary body will ultimately be set by the rate at which it can lose heat into space.  Eventually, all of the ice in the comet will melt due to waste heat.  At that point, it will be necessary to build a pressure shell around the body to prevent the water from evaporating into space.  If we assume that the maximum practical surface temperature of the water ball is 27°C (300K), we can calculate the rate at which it will lose heat tonspace using the Stefan-Boltzmann equation.

Q = 4pi x r^2 x sigma x T^4

For a radius of 50,000m and temperature of 300K, Q = 14.43E12 watts.

Human beings need between 2000 and 2500 Calories per day, say approximately 10MJ food energy.  Using artificial light to grow food, may require as little as 100MJ/day (using algae) or as much as 1000MJ/day, using a standard mix of vegetables and grain crops.  Lets say about 500MJ/day, if 50% of calories come from algae.  That is a continuous energy use of 5.8kW.  What about other energy needs?  Human energy consumption on Earth is about 4E12 watts, which works out at 500 watts per person.  So all human needs amount to 6.3kW.  Let us round it up to 10kW each to account for other parts of the ecosystem.  How many people could live in the 100km wide comet?

14.43E12 / 10E3 = 1.44billion.

That is enough to constitute a civilisation.  In just one 100km wide ice world.  It would seem to me that the solar system could one day support a lot of people.

Last edited by Calliban (2021-06-28 15:04:13)


Interested in space science, engineering and technology.

Offline

#34 2021-06-28 22:57:28

Void
Member
Registered: 2011-12-29
Posts: 3,884

Re: Moreover on interstellar planemos

If we presume a solar civilization which does not commonly butcher it's children, then your prescription looks interesting. 

As I see it, it will be much easier to move metals and rocky materials outward in the solar system using the solar wind.  This is not unlike cutting trees down and floating them down rivers to places where habitations might be built.

And so we have the four major outer planet's moons, and we have Pluto and Charon, and yet still what is in the outer darkness.

In the early stages I do believe that it will be quite sensible to try to use concentrating mirrors, and fission nuclear for power.  But upon the time where fusion is real, and perhaps things we have not proper notion of, then all the way out.

And perhaps eventually to Proxima Centaury with the similar methods, even without fast travel speeds.

Done.

Last edited by Void (2021-06-28 23:01:02)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

Offline

Board footer

Powered by FluxBB