A well-worn road to go is that of a ringworld. A hollow structure, more like a car tyre, as big as necessary. For a large enough radius, the spindle is invisible (not so the opposite section of the ring, which would reflect daylight).

You will need scrith - a material possessing the impossible tensile strength required to keep the ring stable and prevent it from exploding outward. Since the "weight" is generated through rotation, the spokes need to withstand, literally, the weight of ten times the surface of a planet.

The origin of the material is, if memory serves, left unspecified in Larry Niven's Ringworld series, but a handwavium process is described in some detail in Timothy Zahn's Spinneret - not too different from Van Vogt's ten-point steel.

You'll want at least twenty-kilometer mountains on the "walls" of the ring, to keep the atmosphere in (gravity will "fall off" more slowly on the Ring).

For the day, you need a ring 1.8255 million kilometers in radius, rotating once per day. This yields a surface "gravity" of Earth normal. The ring will have a surface of 11.47 million square kilometers per each kilometer in width; since the Earth has a surface of 510 M, and you want 5100 M, your ring needs to be 5100/11.47 = at least 445 km wide. Each 44.5 km of extra width add another Earth's worth of surface (note that inhabitable surface on Earth is 40% of that, because of oceans).

The ring will have a terrifying amount of momentum and will keep its orientation in space. You want it to be edge-wise to the Sun. For a G0 star like the Sun, at a distance of 1UA, its angular size is about 0.5 degrees, and a 445 km wide ribbon has an angular width of 0.007 degrees; there is no risk of an "eclipse", with the shadowed edge intercepting all the light of the illuminated edge.

If the ring has an angle, it will have seasons not unlike Earth, but at twice the speed (it will have a "year" of six months).

In the extreme case its axis of rotation lies in the same plane as the orbit (sort of like Uranus), it will have two "winters" each year, when the ring receives the light edge-wise: so, very little light, very little heat, and most of them intercepted by the sunward side wall (six months later, by the other). The light arrives at an angle of about 1.825:149, so in 445 km it will dip about 5 kilometers; that is to say, only the top five kilometers of the spaceward sidewall will get sunlight. Atmospheric diffraction should be more than enough to allow at least scotopic sight 24h/24 (in my own country there's a town, Viganella, in that situation due to having high mountains on all sides).

Climate variety: you can play with height and air currents. You can also play with the insulation of the ring bottom: the outside face of the ring is potentially exposed to the cold of space (every night), and can be insulated by mirrors during the day. That's a significant source of either warmth (about 1200 W/square meter) or cold (about 315 W/sq m assuming a source at 0 °C).

You can have a sort of tectonic activity - it will be artificial, of course. There's something like that in John Brosnan's Mothership (all land very, very slowly migrates towards the sea, where it gets dissolved. The sea is continuously purified and dredged by hidden automatic machines, and the waste mass ejected near the walls).

A well-worn road to go is that of a ringworld. A hollow structure, more like a car tyre, as big as necessary. For a large enough radius, the spindle is invisible (not so the opposite section of the ring, which would reflect daylight).

You will need scrith - a material possessing the impossible tensile strength required to keep the ring stable and prevent it from exploding outward. Since the "weight" is generated through rotation, the spokes need to withstand, literally, the weight of ten times the surface of a planet.

The origin of the material is, if memory serves, left unspecified in Larry Niven's Ringworld series, but a handwavium process is described in some detail in Timothy Zahn's Spinneret - not too different from Van Vogt's ten-point steel.

You'll want at least twenty-kilometer mountains on the "walls" of the ring, to keep the atmosphere in (gravity will "fall off" more slowly on the Ring).

For the day, you need a ring 1.8255 million kilometers in radius, rotating once per day. This yields a surface "gravity" of Earth normal. The ring will have a surface of 11.47 million square kilometers per each kilometer in width; since the Earth has a surface of 510 M, and you want 5100 M, your ring needs to be 5100/11.47 = at least 445 km wide. Each 44.5 km of extra width add another Earth's worth of surface (note that inhabitable surface on Earth is 40% of that, because of oceans).

The ring will have a terrifying amount of momentum and will keep its orientation in space. You want it to be edge-wise to the Sun. For a G0 star like the Sun, at a distance of 1UA, its angular size is about 0.5 degrees, and a 445 km wide ribbon has an angular width of 0.007 degrees; there is no risk of an "eclipse", with the shadowed edge intercepting all the light of the illuminated edge.

If the ring has an angle, it will have seasons not unlike Earth, but at twice the speed (it will have a "year" of six months).

In the extreme case its axis of rotation lies in the same plane as the orbit (sort of like Uranus), it will have two "winters" each year, when the ring receives the light edge-wise: so, very little light, very little heat, and most of them intercepted by the sunward side wall (six months later, by the other). The light arrives at an angle of about 1.825:149, so in 445 km it will dip about 5 kilometers; that is to say, only the top five kilometers of the spaceward sidewall will get sunlight. Atmospheric diffraction should be more than enough to allow at least scotopic sight 24h/24 (in my own country there's a town, Viganella, in that situation due to having high mountains on all sides).

Climate variety: you can play with height and air currents. You can also play with the insulation of the ring bottom: the outside face of the ring is potentially exposed to the cold of space (every day), and can be insulated by mirrors, or not, during the "night". That's a significant source of either warmth (about 1200 W/square meter) or cold (about 315 W/sq m assuming a source at 0 °C).

You can have a sort of tectonic activity - it will be artificial, of course. There's something like that in John Brosnan's Mothership (all land very, very slowly migrates towards the sea, where it gets dissolved. The sea is continuously purified and dredged by hidden automatic machines, and the waste mass ejected near the walls).

A well-worn road to go is that of a ringworld. A hollow structure, more like a car tyre, as big as necessary. For a large enough radius, the spindle is invisible (not so the opposite section of the ring, which would reflect daylight).

You will need scrith - a material possessing the impossible tensile strength required to keep the ring stable and prevent it from exploding outward. Since the "weight" is generated through rotation, the spokes need to withstand, literally, the weight of ten times the surface of a planet.

The origin of the material is, if memory serves, left unspecified in Larry Niven's Ringworld series, but a handwavium process is described in some detail in Timothy Zahn's Spinneret - not too different from Van Vogt's ten-point steel.

You'll want at least twenty-kilometer mountains on the "walls" of the ring, to keep the atmosphere in (gravity will "fall off" more slowly on the Ring).

For the day, you need a ring 1.8255 million kilometers in radius, rotating once per day. This yields a surface "gravity" of Earth normal. The ring will have a surface of 11.47 million square kilometers per each kilometer in width; since the Earth has a surface of 510 M, and you want 5100 M, your ring needs to be 5100/11.47 = at least 445 km wide. Each 44.5 km of extra width add another Earth's worth of surface (note that inhabitable surface on Earth is 40% of that, because of oceans).

The ring will have a terrifying amount of momentum and will keep its orientation in space. You want it to be edge-wise to the Sun. For a G0 star like the Sun, at a distance of 1UA, its angular size is about 0.5 degrees, and a 445 km wide ribbon has an angular width of 0.007 degrees; there is no risk of an "eclipse", with the shadowed edge intercepting all the light of the illuminated edge.

If the ring has an angle, it will have seasons not unlike Earth, but at twice the speed (it will have a "year" of six months).

In the extreme case its axis of rotation lies in the same plane as the orbit (sort of like Uranus), it will have two "winters" each year, when the ring receives the light edge-wise: so, very little light, very little heat, and most of them intercepted by the sunward side wall (six months later, by the other). The light arrives at an angle of about 1.825:149, so in 445 km it will dip about 5 kilometers; that is to say, only the top five kilometers of the spaceward sidewall will get sunlight. Atmospheric diffraction should be more than enough to allow at least scotopic sight 24h/24 (in my own country there's a town, Viganella, in that situation due to having high mountains on all sides).

You can have a sort of tectonic activity - it will be artificial, of course. There's something like that in John Brosnan's Mothership (all land very, very slowly migrates towards the sea, where it gets dissolved. The sea is continuously purified and dredged by hidden automatic machines, and the waste mass ejected near the walls).

A well-worn road to go is that of a ringworld. A hollow structure, more like a car tyre, as big as necessary. For a large enough radius, the spindle is invisible (not so the opposite section of the ring, which would reflect daylight).

You will need scrith - a material possessing the impossible tensile strength required to keep the ring stable and prevent it from exploding outward. Since the "weight" is generated through rotation, the spokes need to withstand, literally, the weight of ten times the surface of a planet.

The origin of the material is, if memory serves, left unspecified in Larry Niven's Ringworld series, but a handwavium process is described in some detail in Timothy Zahn's Spinneret - not too different from Van Vogt's ten-point steel.

You'll want at least twenty-kilometer mountains on the "walls" of the ring, to keep the atmosphere in (gravity will "fall off" more slowly on the Ring).

For the day, you need a ring 1.8255 million kilometers in radius, rotating once per day. This yields a surface "gravity" of Earth normal. The ring will have a surface of 11.47 million square kilometers per each kilometer in width; since the Earth has a surface of 510 M, and you want 5100 M, your ring needs to be 5100/11.47 = at least 445 km wide. Each 44.5 km of extra width add another Earth's worth of surface (note that inhabitable surface on Earth is 40% of that, because of oceans).

The ring will have a terrifying amount of momentum and will keep its orientation in space. You want it to be edge-wise to the Sun. For a G0 star like the Sun, at a distance of 1UA, its angular size is about 0.5 degrees, and a 445 km wide ribbon has an angular width of 0.007 degrees; there is no risk of an "eclipse", with the shadowed edge intercepting all the light of the illuminated edge.

If the ring has an angle, it will have seasons not unlike Earth, but at twice the speed (it will have a "year" of six months).

In the extreme case its axis of rotation lies in the same plane as the orbit (sort of like Uranus), it will have two "winters" each year, when the ring receives the light edge-wise: so, very little light, very little heat, and most of them intercepted by the sunward side wall (six months later, by the other). The light arrives at an angle of about 1.825:149, so in 445 km it will dip about 5 kilometers; that is to say, only the top five kilometers of the spaceward sidewall will get sunlight. Atmospheric diffraction should be more than enough to allow at least scotopic sight 24h/24 (in my own country there's a town, Viganella, in that situation due to having high mountains on all sides).

Climate variety: you can play with height and air currents. You can also play with the insulation of the ring bottom: the outside face of the ring is potentially exposed to the cold of space (every night), and can be insulated by mirrors during the day. That's a significant source of either warmth (about 1200 W/square meter) or cold (about 315 W/sq m assuming a source at 0 °C).

You can have a sort of tectonic activity - it will be artificial, of course. There's something like that in John Brosnan's Mothership (all land very, very slowly migrates towards the sea, where it gets dissolved. The sea is continuously purified and dredged by hidden automatic machines, and the waste mass ejected near the walls).