Very few do. But there is one group, the A Train

https://en.wikipedia.org/wiki/A-train_(satellite_constellation)

Set of sun synchronous satellites from various countries that arrive together to combine their instruments.

What you are most likely seeing is a mixture of the human habit of seeing patterns in random noise and the affect of unconsciously looking more for satellites when you notice one, plus seeing them in good viewing conditions makes seeing them more likely.

Worth noting you really only see them close to dawn and dusk as there still has to be sunlight up above to reflect off them.

How long will it take to get the same amount of energy back to Earth from 1 tonne of solar arrays as it costs to get that 1 tonne to the relevant orbit?

If the answer is a year, then yes. If its 20 years then unlikely.

Energy cost will be your hard floor, if it takes too long to get the energy back then you are wasting your time. Above that comes the economics, how much can you get from consumers for 1 tonne on orbit vs the cost of getting it there. This is a bit more flexible as you can work on the non fuel costs.

Space does offer advantages, you can almost always be at 90^(0) to the Sun and you can have less atmosphere to get through. Its also almost always very sunny. It has disadvantages like the current insane cost to orbit and the difficulties getting energy once you move beyond the tropics and into more oblique angles.

The current answer is a very loud no with current technology. The point where no becomes yes is one of engineering and economics and an open question if you consider current costs to orbit easy to cut.

>arth is spinning and the mass wants to move to the outer edge of the spin, which is the equator, which is why the earth bulges a little there. For the same reason, the water would want to move to the equator.

https://www.reddit.com/r/space/comments/1219zfb/comment/jdlf63q/?utm_source=reddit&utm_medium=web2x&context=3

oceans flow east to west
https://en.wikipedia.org/wiki/Ocean_current#/media/File:Corrientes-oceanicas.png
On Earth this flow is interrupted by continents that form the great ocean gyres. There would be a flow induced by thermohaline pressure differences, that is in the poles water would cool and freeze out making it cold and salty, this would pull currents into the deep that would imitate the Great Conveyer
https://en.wikipedia.org/wiki/Thermohaline_circulation
But without the land masses messing it up.

The planet would also be circled by belts of winds, closer to the abstract 3 cell circulation models.

https://en.wikipedia.org/wiki/Atmospheric_circulation#/media/File:Earth_Global_Circulation_-_en.svg

These would affects surface current directions and thermohaline by evaporating some places and making water salty and raining other places and making its salt concentration drop.

So sort of how they work today without continents.

BUT the great huge steaming elephant in the room would be lack of CO2 sequestration from rock weathering. Spin up an Earth with a few exta kilometers of water to make it Water World and you wuold get huge build ups of CO2 over millions of years.

But here we go from a model running for a month to a model running for a couple of million years.

>On a smooth dry sphere it would flow toward the equator.

For a start there is no water on a dry sphere. Then there would be a slight centrifugal tug pulling water more towards the equator but Coriolis would be the dominant force.

paywalled. What does the article say, I have not heard anything from the mainstream space journalists about this up till now.

>The US rocket program was Kickstarted by kidnapped nazi scientists.

The US rocket program was kick started by Robbert Goodard, Goddard's widow successfully sued for patent infringement. Not something the thieves at the CCP will ever admit too.

>The fascists were more imaginative than your so called democracy

This another lie. The west focussed on code breaking, radar and proximity fuses, weapons that had a massive impact on the war, the Nazis focussed on things like huge liquid powered rockets that had no impact.

The Chinese liquid fuelled rocket program was started on "stolen" Nazi technology. Being a very backward country they had to have it gifted to them from the Soviets.

>The first of the Dongfeng missiles, the DF-1 (SS-2, initially codenamed '1059', while the 'DF-1' designation was initially assigned to the project which later became DF-3[1]), was a licensed copy of the Soviet R-2 (SS-2 Sibling) short-range ballistic missile (SRBM),[2] based on the German V-2 rocket. The DF-1 had a single RD-101 rocket engine, and used alcohol for fuel with liquid oxygen (LOX) as an oxidizer. The missile had maximum range of 550 km and a 500 kg payload. Limited numbers of DF-1 were produced in the 1960s, and have since been retired.[1]

https://en.wikipedia.org/wiki/Dongfeng_(missile)#Dongfeng_1_.28SS-2.29

So China started with stolen German technology that was stolen from the US in the beginning.

> the communists even sent the first satellite and man into space. You overrate democracy and migration too much.

Soviet Union does not exist any more. Seems a fate that has happened to almost all Communist countries. Just a couple left going.

>If it weren’t for Musk & Bezos

SpaceX was built on NASA contracts like the original resupply missions, they won that contract before Falcon 9 had made its first flight. Its as odd as saying if it was not for Boeing and Lockheed Martin the airforce would not be able to fly.

https://en.wikipedia.org/wiki/Commercial_Resupply_Services

Had SpaceX not been in the crew program that would have gone to Sierra Nevadas Dream Chaser and Boeings Starliner (the later having now built a system to fly NASA contracted astronauts. ).

>I’m just disappointed that we can’t all work together for a shared future

Id say stealing technology to use for weapons of mass destruction is kind of an acceptable reason to block people from technology access.

>I have no idea what your point is.

Then your opinions can be dismissed.

The Bootes Void there may be places where you will find the least affect of gravity.

https://en.wikipedia.org/wiki/Bo%C3%B6tes_Void

The space between superclusters of galaxies will be places where there is not enough gravitational attraction from an entire supercluster to hold objects to its gravity, though you may find entire galaxies in these kind of spaces.

But in theory there is nowhere with no gravity.

>That’s disappointing, though. It limits the abilities of countries to develop their own space industries

So basically you are braying like a donkey about nothing. Every developer of advanced technologies has laws on re-export.

>prohibits international collaboration.

China steal technology relentlessly. They stole US technology to use on their nuclear ICBMs. This is why there is such rules to try to limit their thieving. (The Wolf Amendment)

I understand that to people like you, every piece of intellectual property in the world belongs to the CCP. The UAE entered into a legal agreement it understood to buy components for its missions. It is not being "unfairly restricted". Now your greed is driving you be angry that you cannot get your hands on those components to steal the IP from.

They can buy the components China already stole from others. :)

Have a nice day.

>My guess

Why should we pay attention to your guesses? Are you an expert on UAE space projects?

>I think a lot of countries are getting tired of being subject long arm jurisdiction of the US. UAE can't even develop its own space program without approval of the US.

They built a rover using ITAR parts because they are the cheapest and the most widely bought. They have been launched towards the Moon on a SpaceX flight using a Japanese lander.

https://www.nasaspaceflight.com/2022/12/hakuto-r-m1/

You appear high on opinion and low on information.

If you buy components from a country you are subject to their export controls. Its hardly rocket science.

Its behind a paywall. The Emerates lunar lander was launched a few months ago by SpaceX, so its hard to evaluate, but this may be a new mission that is still in early planning to use components from the current mission.

This screams cutting back on quality control to me. Same issue in three systems means your QA is not focussing resource onto making sure that system is not going to break again. Given Soyuz and Progress have 50 years of flights with relatively few incidents (Soyuz 56 years, Progress 44 years) they are pretty robust so likely could absorb some drop in production standards and quality assurance. But it seems they have cut the bone so fine they are producing the same fault and their teams are not testing enough for it.

The budget for that is now probably floating somewhere in the Black Sea with Rogozins name on it.

The fleet should be grounded for a serious investigation, but there is no way that is going to happen politically.

So pandemic lockdown reduced crime.

There are two scientific theory that get cited when "almost the same Earth" comes up.

1. Is the multiworld hypothesis where every quantum event splits into two different worlds so you have alternative realities where everything that could happen has happened.

2. The other is that in an infinite Universe there is enough variety for almost the exact Earth to have evolved the exact same except for some tiny variation. Every possible variation exists somewhere out in infinity.

Not quite what some mean by parallel Universes.

Its a science fiction trope. It has no physics to back it up. There is an idea of a "Multiverse" based on weird version of Braine theory. But in each of those the laws of physics are so wildly different to our every day that they have no space or time or so on. It has no meaning for us, and I am suspicious this theory has no actual science to support it.

Its swirling around an IFLScience style drain.

It really is past its best.

Jet engines mix the incoming air in a flow that feeds into the burning and compression for thrust. This loses efficiency quickly as you go past Mach2. Rockets use a combustion chamber that is sealed off and has a steady and controlled inflow of oxidiser that is mixed in an injector plate.

They are two very different processes. The additional weight to have different engines means you do not gain in terms of mass.

Super complex systems that can burn both ways are on drawing boards. And have been on drawing boards for 70s years.

Curvature. We cannot see any in the observations we have and that places a lower bound on the size of a closed Universe, we would be able to detect curvature if it were smaller.

If the Universe is infinitely big then the point it came from was infinite.

Current the best evidence is that the Universe is (edited at least) 160 times bigger than the observable Universe. But there is no reason to suggest it is not infinite.

You buy the shares, you get a cut of the steady flow of revenue. To maintain the productive capacity the share price retains value and gives returns, so you have an asset you can monetise for its underlying value by selling or maintain a revenue stream from it.

This is how most companies operate. A few like Apple have insane returns, but they have an insane share price. Most of the investor value is locked into share price.

Balloons you are used to tend to be over pressured so burst when a small tear happens (pin prick). Balloons designed to operate at altitudes like that are at an equal pressure with the air around them, so bullets pass through, making small holes that slowly replace the helium with air thus making them heavy and slowly falling.

The missile warhead generates a big pressure and heat wave that disrupts the balloon tearing it apart. Officially they were worried about damage on the ground, in reality they wanted it to land in water and at a spot they could get to quickly so they could recover it.

>s balloons would be reflecting solar IR

Solar IR is a small part of the downwelling solar spectrum.

https://cdn.shopify.com/s/files/1/0823/0287/files/atmospheric-absorption_848x452.png?v=1670339790

And the near infrared is heavily absorbed and emitted by CO2 and H20 so in those wavelengths that would be the ambient IR. The whole sky will look like it is those wavelengths.

You would also have to account for the upwelling radiation (very very very roughly shown here in Khiel and Trenberth 97 https://chriscolose.wordpress.com/2008/12/10/an-update-to-kiehl-and-trenberth-1997/ )

These wavelengths have always been a huge problem for IR.

Operating in these wavelengths is "the endorsement of the air force you think it is!"

>1 out of 2 hit rate for half million dollar seeking missiles versus a balloon

A heat seeking missile hitting an object that would be only a few degrees above ambient air temperatures.

>What a joke

Who is laughing. The worlds second largest military and the US defined pacing threat thought their balloons were near undetectable and untouchable. Here the US pilots are taking pictures of these balloons from above.

https://www.thedrive.com/the-war-zone/our-best-look-yet-at-the-chinese-spy-balloons-massive-payload

The US then had to look at and bring down some random sky trash just to be sure there were not other spy assets using the flight profile of abandoned balloons. It looked silly but again they showed capabilities that surprised some pretty seasoned observers.

The incident will be forgotten in a few weeks. China's "super secret" years long spying on various countries by balloons that were unreachable has now been retired.

http://www.hisutton.com/Chinese-Navy-High-Altitude-Spy-Balloons.html