China's planned artificial moon

[khadgar567]

This isn't a game of D&D, things don't just happen because somebody wanted it to. Getting to space is tricky, you cant just strap a cannon to your rocket and have an orbital battle station, and you absolutely cannot turn a mirror into a death laser... ever, under any circumstances, no matter where it is.

I know this is not d&d but its good to be prepared when eventual real world reveal

[Keltest]

I know this is not d&d but its good to be prepared when eventual real world reveal

If China, or anybody else, is sufficiently technologically advanced that they can put a death ray on a satellite without anybody recognizing that's what theyre doing, theres no meaningful preparations we can make anyway.

But that's not actually a thing that can happen, so were fine.

[warmachine]

Those who study science and technology regard James Bond film plots and gadgets as nonsense.

[Lissou]

Thanks, @wumpus, that was really helpful! So if I understand correctly, it will also light up part of California 12 hours later for 8 hours (which may means it's now night over there)?

[Beleriphon]

If Wikipedia is getting American culture wrong then I'm seriously worried...

Yellow journalism is intentionally being unprofessional in your application of the news, usually by what should be a legitimate and ethical source. If the New York times as a policy intentionally sensationalizes facts on the basis that it will sell more papers/clicks that is Yellow Journalism. William Randolf Hearst would be well acquainted with the idea, its also been around for over 150 years and probably fell out of popular use in the mid-50s or 60s when tabloid sized news papers became the standard for such sensational stories, thus the tabloids.

[georgie_leech]

I know this is not d&d but its good to be prepared when eventual real world reveal

What if it turns out your phone is secretly a transformer, sent to infiltrate your life until it eventually turns itself into a ninja star and cuts your head off? You need your fears and preparations to be grounded in reality and what is plausible, otherwise there's no shortage of stuff to be alarmed about. Name anything, and it'll be easy to come up with theory for how it could be some insidious plot to take over the world.

[Razade]

If Wikipedia is getting American culture wrong then I'm seriously worried...

Yeah, this was a thing in like...the early 1900s. Probably shouldn't use Wikipedia to make sweeping claims about current American culture.

[wumpus]

Thanks, @wumpus, that was really helpful! So if I understand correctly, it will also light up part of California 12 hours later for 8 hours (which may means it's now night over there)?

Only if they wanted to focus it. And I still think it can only light up a single city, not a whole state.

[Lord Torath]

So we're saying that this mirror will hit perihelion (closest point of orbit) over China, and then and hit it again over the Eastern US/Atlantic Ocean (China's not opposite the Western US)? Or are we saying it hits Perihelion over China, and Aphelion over the Eastern US? In the second case, it would have to hit aphelion over South America, rather than North America.

Also, how do you get the orbit to precess so it stays the same relative to the sun over the course of the whole year?

[The Glyphstone]

Yeah, this was a thing in like...the early 1900s. Probably shouldn't use Wikipedia to make sweeping claims about Absolutely Anything In Existence

Expanded upon for accuracy?

[halfeye]

So we're saying that this mirror will hit perihelion (closest point of orbit) over China, and then and hit it again over the Eastern US/Atlantic Ocean (China's not opposite the Western US)? Or are we saying it hits Perihelion over China, and Aphelion over the Eastern US? In the second case, it would have to hit aphelion over South America, rather than North America.

Also, how do you get the orbit to precess so it stays the same relative to the sun over the course of the whole year?

No, they are saying apogee over China, perigee over somewhere south, then apogee over the USA, then perigee over somewhere else in the south, then apogee over China again. Always apogee in the night.

Presumably the precession is taken care of by having the duration of the orbit slightly off the exact 12 hours, dunno myself whether it needs to be short or long.

<Edited perihelion to perigee and aphelion to apogee. Thanks DavidSh.>

[DavidSh]

You mean apogee and perigee, or more generally apoapsis and periapsis, not aphelion and perihelion. We're orbiting the earth here, not the sun.

[halfeye]

You mean apogee and perigee, or more generally apoapsis and periapsis, not aphelion and perihelion. We're orbiting the earth here, not the sun.

Yes, I knew "~helion" was wrong, but I couldn't remember what the right thing was.

[Lord Torath]

Presumably the precession is taken care of by having the duration of the orbit slightly off the exact 12 hours, dunno myself whether it needs to be short or long.

Precession is how the orbit itself rotates, and just making the orbit a bit short or a bit long wouldn't work. You'd end up six months later with the perigee occurring over South America and apogee (thanks, DavidSh!) occurring over China, with the orbit still oriented the same way relative to the rest of the galaxy.

[wumpus]

So we're saying that this mirror will hit perihelion (closest point of orbit) over China, and then and hit it again over the Eastern US/Atlantic Ocean (China's not opposite the Western US)? Or are we saying it hits Perihelion over China, and Aphelion over the Eastern US? In the second case, it would have to hit aphelion over South America, rather than North America.

Also, how do you get the orbit to precess so it stays the same relative to the sun over the course of the whole year?

If you are asking about a Molniya orbit, it would have perigee over the southern Atlantic and Indian oceans. The reason it has apogee only in the northern hemisphere is that it has a single orbit that spends most of its time in the Northern Hemisphere and swings around close to the Earth in the Southern Hemisphere. The reason it is over two different places is because the orbit is only 12 hours long (if you went high/fast* enough for a 24 hour orbit you would just go straight to geostationary orbit) and the Earth only rotates half way around each time the satellite orbits.

* The faster you make the satellite go, the higher it orbits and the longer it takes to get around the Earth. LEO (low Earth orbit, where the ISS is) is cheapest place to put satellite (about a 90 minute orbit, but bring fuel to compensate for what little atmosphere is there as it slowly drags you down), Molniya is a bit more expensive, and Geosync/Geostationary is most expensive of all (unless you want to go out to other planets or something).

[khadgar567]

What if it turns out your phone is secretly a transformer, sent to infiltrate your life until it eventually turns itself into a ninja star and cuts your head off? You need your fears and preparations to be grounded in reality and what is plausible, otherwise there's no shortage of stuff to be alarmed about. Name anything, and it'll be easy to come up with theory for how it could be some insidious plot to take over the world.

well the chance my iphone turns in to deception transformer is low enough that if ever happens i will be playing lottery that day since i have more solid chance to win the lottery then apple secretly creating transformers.

[Lord Torath]

Ah. I assumed it would hit perigee over China. I guess if you want maximum time of reflection, though, you'd want the light beaming in while the satellite is moving more slowly (at apogee). And, yeah I was pretty much asking if it was a 12-hour or 24-hour orbit.

[georgie_leech]

well the chance my iphone turns in to deception transformer is low enough that if ever happens i will be playing lottery that day since i have more solid chance to win the lottery then apple secretly creating transformers.

So it turns out that there's roughly the same odds of this satellite being a secret death laser as of your iphone being a transformer with murderous intent.

[Rockphed]

Well, the chance my iphone turns in to deception transformer is low enough that if it ever happens I will be playing lottery that day since I have more solid chance to win the lottery than apple secretly creating transformers.

Probability does not work that way. Your phone turning into a death robot and winning the lottery are independent events.

[Algeh]

Probability does not work that way. Your phone turning into a death robot and winning the lottery are independent events.

I don't know - have there been any rigorous studies that look for a correlation between death-robot-phone owners and lottery winners? It could be that death robots are good at rigging lottery drawings on behalf of their owners, and I'm not sure we've done enough research to be sure that isn't the case.

[Lvl 2 Expert]

They're also different types of odds. Winning the lottery is an event we know has a small chance of happening, iPhones secretly being transformers is a thing that either is or is not the case, we just estimate from everything else we know about the world that it seems unlikely. But ones your iPhone turns out to be a transformer we can say the chance of it being one was 1 all along, we just didn't know it. We could make the same case for the lottery using a deterministic worldview, but the drawing of one winning ticket is in principle a random event, the unveiling of the transphoners is not.