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#51 2006-08-28 13:25:57

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Mercury - Is anyone this crazy?

What if you placed a sun shade at the L1 point between the Sun and Mercury, probably slightly further away that that so you can uses a solar sail as the sunshade and use radiation pressure to maintain a constant distance from mercury. In the center of that sunshade, you cut a hole of the prcies diameter so that it presents a yellow disk that when viewed from the surface of Mercury appears the same size as does the Sun from Earth. This solves the problem of Mercury's carying distance from the sun. Normally the Sun would appear to get bigger as Mercury got closer and would appear to get smaller as Mercury drew further away. As seen through the hole in the sunshade, the "Sun" would always appear to be the same size. the Surface of mercury would cool.

In some respects, Mercury's lack of an atmosphere is an advantage. You can spin up the planet by positioning rockets, mass drivers or whatever directly on the surface and pointing the sideways. Fire those rockets long enough and you will increase the rotation rate of Mercury to 24 hours, and then after you do that you can add the atmosphere.

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#52 2006-09-01 07:02:39

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

Re: Terraforming Mercury - Is anyone this crazy?

Sunshade is super!!! Yes, you can puncture it in the center to keep passivelly or with iris constant solar illumination. You can use it as coronograph or artificial constant solar eclipse -- so your sun would be in shape of ring or crescents rather than circle or point , you can puncture the sunshade offcenter and to use it`s rotation for more normal day/night cycles... The sunshade could be not stopper , but difuser and filter of light if it is just a micrometer / nanometer mesh forming Fresnel lense optical and other EM system... In all cases the stability of the structure it is logical and natural to be provided by balance between light and solar wind pressure , gravity and rotation, etc.

BUT, if we have such good optics, why we for gods sake, would need to waste so TREMENDOUS amounts of energy to move and spin planets ( except when we do this to extract energy...) ?????

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#53 2006-09-01 22:44:22

Chaos Master
InActive
Registered: 2006-08-31
Posts: 2

Re: Terraforming Mercury - Is anyone this crazy?

what about slowing Mercurys rotation, so one side always faces the Sun, then place a huge (very huge) solar sail on the outer side, anchor it somehow on the planet's surface (perhaps with carbonite nanotube like materials, like they wonna do it with the space-elevator) and pull the planet with the pressure of light, and solar winds further away from the sun, and after that spin it around to a 24h day.
new position could perhaps be the L4/5 point of Venus (if they'd have separate orbits, near each others, I'd be afraid, that venus would bias mercurys orbit, and throw him into the sun, or out of the solarsystem, or worst into the Earth)

don't know whether this is possible, to drag a planet with solar sails, someone should do the calculations..
but i guess, it would take some time  roll

and maybe the planet should be spinned in backwards direction, to decrease centrifugal force, while getting a 24h day (also don't know, whether that makes such a big difference..)

my two cents..

PS: I'm from germany, so please don't wonder about my english

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#54 2006-09-03 11:37:59

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Mercury - Is anyone this crazy?

I think that since Mercury has a near vacuum as an atmosphere, you can take advantage of this fact to spin it up before you add the atmosphere. If you use just a sun shade to make night and day, you've already eliminated half the available surface for habitation. Of course Mercury is slowly rotating, you what you'd end up with is a planet with seasons, the summer season would alternate between periods of night and day, while the winter season would be all night. If your going to expend the energy to slow down the rotation so it tidally locks, why not use that same rotation system to speed up its roation and produce a 24-hour day/night cycle in the first place. Seems that no matter what you do,your going to have to set up a planetary spin-up system in any case system. I say If your going to change the planets rate of rotation, you might as well increase its rotation rate, since you'll need the same infrastructure in any case to slow it down.

Venus is another problem, it rotates slow but it is not tidally locked with the sun. In one proposal I heard, you place a sun shade inbetween Venus and the Sun and then you place a mirror in polar orbit to reflect the sun's light down to Venus to produce day and night. The only problem with this is the slight detail that the Sun would always be rising and setting in a different location each day. You could probably get the mirror to orbit in a sun synchronius orbit so that it has constant daylight to reflect towards Venus, but Venus would slowly rotate underneath the mirrors orbit. A Venus terraformed in this manner would have a constantly shifting apparent "North" direction. What is at one time the "North Pole" would then become the "Equator" and then the "South Pole" and then the "equator" once again. The same problem exists for Mercury if we don't change its rate of rotation.

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#55 2006-09-04 08:39:55

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

Re: Terraforming Mercury - Is anyone this crazy?

1. Why to spin the planets? This is tremendous waste of energy just to get 24 hours cycle, totally unnecessary thing! We don`t have it even here on Earth. It is much easier to leave Venus and Mercury just as they are now. 4 months diurnal cycle on Venus, 3 months on Mercury, just fine compared with the Earth`s 12 months one within the polar circles...
If this diurnal cycle is not suitable for most of the earth kind of life ( necessary for furnashing the human freindly environment ) -- it is easier just to adapt the life than to spend so much power...

2. The Mercurian vacuum is not an avantage for spinning the planet, cause the imported atmosphere is momentum carrier.

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#56 2006-09-04 14:12:15

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Mercury - Is anyone this crazy?

What if you mount a plasma or fusion rocket on the planet's surface and fire it sideways. Assume each rocket is firmly attached to the crust and the rocket exhaust exceeds the excape velocity of the planet. Now suppose you dotted the planet's surface with 100 billion fusion rockets all pushing on the surface at the same time in the same spin direction. I figure Mercury is just like any other asteroid only bigger. Why is this a problem?

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#57 2006-09-04 20:10:17

atitarev
Member
From: Melbourne, Australia
Registered: 2003-05-16
Posts: 203

Re: Terraforming Mercury - Is anyone this crazy?

1. Why to spin the planets? This is tremendous waste of energy just to get 24 hours cycle, totally unnecessary thing! We don`t have it even here on Earth. It is much easier to leave Venus and Mercury just as they are now. 4 months diurnal cycle on Venus, 3 months on Mercury, just fine compared with the Earth`s 12 months one within the polar circles...
If this diurnal cycle is not suitable for most of the earth kind of life ( necessary for furnashing the human freindly environment ) -- it is easier just to adapt the life than to spend so much power...

2. The Mercurian vacuum is not an avantage for spinning the planet, cause the imported atmosphere is momentum carrier.

Hello, Karov!

Agree with you 100%. We discussed this with you a while ago. I haven't posted for quite some time but I enjoy reading your posts about terraforming.


Anatoli Titarev

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#58 2006-09-06 11:06:40

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

Re: Terraforming Mercury - Is anyone this crazy?

Hi , Atitatrev!!!

It is nice to read you again! Where`ve you get lost for so long?
Do any fresh ideas occured to you meanwhile?

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