Have you always wanted to be in the same timezone as people in the USA, Spain, Iraq, India, Japan, simultaneously?
Longitudes have been the go-to for checking your timezone for a while. Latitudes lay forgotten as a way to bind geographical and cultural distances by a shared sense of time.
To make sure that this coming together is more than just dictated fiat, we need the sun to be a ring of fire centered at the earth that travels up and down, widening around the equator and shrinking around the poles; the locus of a cross- sections of a hollow ellipsoid:
https://imgur.com/a/PKdCIJp
Vote now, and see the boring yellow disk in the sky replaced by a brilliant wide line across the horizon. Bonus: Outer space friends start calling us the Holy Planet because of the halo.-- haskell, Sep 18 2020 Tokamak https://en.wikipedia.org/wiki/Tokamak"Get your hot doughnuts here ..." [8th of 7, Sep 18 2020] Pictured https://imgur.com/a/PKdCIJp [haskell, Sep 18 2020] Summer holiday every day A_20summer_20holiday_20everydayVaguely relevant to the topic, as per nomal [not_morrison_rm, Sep 21 2020] Seems fair for latitude to get its turn-- hippo, Sep 18 2020 As much as I want to upbun this, I don't.-- tatterdemalion, Sep 18 2020 OK, so as I understand it we replace/reconfigure the sun so that the Earth is surrounded by a torus. So, taking the sun as a starting point, volume is 1.4x10^24km3, current distance is 150x10^6km. So if we make a torus at that distance of the same volume we, run out of stuff. Let's knock a 0 off, so now the torus inner d is 150x10^5km, we can kind of make that work. I'm beginning to see why saturn's rings are so thin now. There is debate over whether a torus is gravitationally stable, well, not much debate, it is, but only in the presence of an overwhelmingly massive central body - see aforementioned ring-planet setup. The gravity would diffuse to the point that the star wouldn't be viable, just as a consequence of the shape/density change.
Then, you want to dynamically reconfigure that situation from that max inner d down to a much smaller one above the two poles. Well, this would end the equatorial regions balmy weather since the poles are now getting the more concentrated sun.
What would be a lot easier is just flipping the Earth 90 degrees and spinning it up again around the new longitudinal axis. How the magnetic poles would react to that I'm not sure, I'm not even sure the current flow in the mantle that generates the magnetic field is in any way linked to the sun's gravity.
But a toroidal star would be a much better suited to the name "Halo" than some tedious alien ringworld rip off.-- bs0u0155, Sep 18 2020 //how you're going to turn the sun into a donut.//
Plunging something as hot as an actual star into hot oil is a recipe for disaster IMHO. Also, getting enough sugar to coat large celestial bodies is notoriously tricky.-- bs0u0155, Sep 18 2020 @bs0u0155
I wish we could rotate the earth 90 degrees myself, but that wouldn't give us true latitudes since they would meet at the new poles. Moreover, it opens up a slippery slope. People would demand rotations every week to match their penpals.
The sliding ring of fire solves this by being godlike and non- negotiable. It's risky even to escape the planet, gotta time it right!-- haskell, Sep 18 2020 // a plausible explanation of how you're going to turn the sun into a donut. //
It can be done with a magnetic field*, but the energy requirement will exceed the output of the star; so you need a second one to power the containment field of the first one.
Any minor systems failure tends to be very loud and expensive.
*Like a Tokamak <link>. Containing plasma with magnetic fields is Baked and WKTE, although not usually on a stellar scale.-- 8th of 7, Sep 18 2020 //It's risky even to escape the planet, gotta time it right!//
Well, you'd have to traverse ~1/2 an AU in a few hours, pretty tricky. But, if you've already disassembled the sun and reconfigured it on a whim, we can assume that sort of feat is trivial.
//not usually on a stellar scale.//
That's a matter of time with the fusion crowd, have you been peeking at the minutes of the post-ITER steering committee?-- bs0u0155, Sep 18 2020 We did write "not usually", rather than "never"
// peeking at the minutes of the post-ITER steering committee? //
Ah, yes, sorry. That doodle in the margin ? The sort-of velociraptor-hippopotamus thing on tank tracks attacking a giant raspberry ? ... that was us. You know how it is, all the coffee and biscuits had long gone, someone was droning on about budget appropriations, it was late and we were bored ...-- 8th of 7, Sep 18 2020 Rather than reconfigure the existing Earth and Sol, wouldn't you rather start with a green-field site in the Oort Cloud? It could be far enough away that the actual sunlight wouldn't be too distracting, and you could power your local halo light by leaching energy from passing comets.-- pertinax, Sep 19 2020 You may want it but you're not going to get it with that latitude.-- AusCan531, Sep 19 2020 On closer consideration, the math behind this is very interesting.
At its current range, your primary can be approximated to a point source, but as that diminishes, the position on the surface of a sphere (equator/pole) becomes progressively more siginifcant - the equator being proportionately closer. That isn't really a big factor until the range is the same order of magnitude as the sphere's radius, though.
Still, to stretch a sphere of fusing plasma into a torus and hold it in form against both its gravity (which will want to pull it back into a sphere) and radiation pressure (which will want to push it apart) is an interesting project. It's never going to be stable. It will have to be forced to stay in the toroidal form.
To maintain fusion, there's a minumum temperature and density to exceed. The lower the density, the higher the temperature needs to be, which shifts the emission spectrum up.
To have a toroidal plasma tube with the same emission spectrum as your star is going to need some quite interesting engineering.-- 8th of 7, Sep 19 2020 Morning or afternoon ?-- 8th of 7, Sep 19 2020 OK, but minimum rental is a week. You'll need a major credit card.-- 8th of 7, Sep 19 2020 Certainly ! But in advance. We only need the credit card to verify you're old enough to legally sign the contract.-- 8th of 7, Sep 19 2020 Nobody is concerned about the fact that there would be no more night-time? (Or a maybe little bit, depending on your location and the precise geometry of the oscillation situation...)-- neutrinos_shadow, Sep 20 2020 Pardon ?
Your species has spent millennia taming fire, inventing lamps and candles, then incandescent bulbs, arc lights, LEDs to banish darkness... then you're offered a permanent fix that [kdf] has so generously offered to fund, and you start whining about "no more night time" ... ?
You're an ungrateful bunch of reprobates. Now, apologize to [kdf]. You have a few minutes before the bailiffs come to sieze all his property and possessions, and cart him away to a debtor's prison.-- 8th of 7, Sep 20 2020 Hmm... //..bailiffs...// sp. Borg drones (or workers; I forget the separation-of-works...) //..sieze...// sp. assimilate //..debtor's prison.// sp. Cube...-- neutrinos_shadow, Sep 20 2020 random, halfbakery