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From time to time I take a peek at the Europa Clipper’s clean room webcam. Usually not too much action takes place, usually it’s just some guys in hazmat suits moving around.
One thing that got me wondering is
what makes human built probes move through space? It takes years for one of them to reach its destination. Keeping an engine burning for years requires literary tons of fuel. Is a probe moving mostly by inertia (because it is easy to defeat the gravity force of the sun)?
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Basic Newtonian mechanics: a body in motion at a constant velocity will remain in motion in a straight line unless acted upon by an outside force.
And since "space" is mostly a pretty hard vacuum, there is no friction to slow it down (like there is with a car or a ball on Earth, both of which are slows slightly by air friction and much more by friction with the surface they are rolling on). So the only effect is gravity, which is pretty trivial at that distance because of the low mass and relatively high velocity of the probe. The further away from the high mass bodies like the sun and planets the probe gets, the less effect gravity has on it, and the more constant the velocity.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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Now, to leave our planet, it costs some energy. About 400-800 MWh?
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There are ways around some of that: the Space Elevator[^] can use the mass of goods coming down to lift people and material up for free once built. The problem is the immense cost of the initial build, and the materials you would need to build it probably still don't exist (and it would be a massive target for terrorists as well).
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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I'm speaking from current reallity and not what can be done in theory. I mean the range 400-800 MWh has been used for real missions like Mars 3, Vikings, etc. 
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So moving through space is almost free. The only remaining problem is time. If we think in terms of human space travel that means huge amounts of food and water supplies.
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Once you are up to speed, yes. It's getting there that is so expensive - particularly if you need to take enough food, water, and more importantly air for a long journey. All that weighs a lot, so you need massive amounts of energy to get that up to speed as well.
This is why you have replicators on Star Trek: the ships can't carry enough for 5 year missions. Look at nuclear submarines for a comparison: 140 crew, 7000Kg of food, just for 90 days. I'd image that the Enterprise also uses the replicators to "recycle" waste and "used air" as well.
Think about the LDSS Nauvoo from The Expanse: multi generation journey time, so it grows it's own food to recycle the waste and the air. No way could it carry enough food and air for that long a journey! (And it still managed to miss Eros.)
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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You could recycle. They are already recycling water on ISS. You could do that with everything else eventually. However that kind of defeats the purpose of life IMO: it puts you closer to an artificially grown piece of meat or a patient on life support in IR and further away from an earth dweller created by God to enjoy fresh air, water and food each day
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Calin Negru wrote: God created sun
Big assumption, there ... I'd avoid religion here - it could easily devolve into trolling and a ban from the site.
Quote: enjoying every day’s fresh air, water and food.
Says a man who doesn't live in a city ... 
Try the air in London - every time I pass through it (about an hour in total) every time I blow my nose for a week after it comes out full of black muck.
London water also tastes foul, and the food is hardly fresh in most cases - imported from the rst of the world to the large part.
And London isn't anywhere near the dirtiest, smelliest, don't-drink-the-water-ist city I've ever been in.
Recycling water takes energy; food takes time and serious amounts of space; air takes yet more energy. And that power has to be taken with you as well as you'll be far from the sun for a very long time. Even at teh speed of light, it would take 4 years to reach the nearest star - and our technology is vary far from getting near that speed!
I'd still go though.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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OriginalGriff wrote: Try the air in London - every time I pass through it (about an hour in total) every time I blow my nose for a week after it comes out full of black muck.
Aren't you old enough to remember the London smog in the days when houses were heated by coal burning?
I never saw it myself; as a kid I visited London on summer vacations only. Smog was a winter phenomenon. Sometimes, we read newspaper reports about smog so dense that traffic had to stop: The driver couldn't see the car in front of them. Compared to that, London has air as fresh as the countryside. I have visited London in winter time after coal burning was banned, and never thought of the air as any worse than in other metropolitan areas.
It all depends on your expectations, of course. Lately, I have mentioned the books of Bill Bryson a couple of times, "A walk in the wood" is as funny as the others. When reading it first time, I stalled: They are carrying a filter kit, to filter the creek water before drinking it. What's that? This is out in nature, with natural drinking water. Filtering it?? Here in Norway, I would never ever think of filtering creek water. I expect it to be pure and clean and healthy. Maybe Appalachian water is - after all, it is drinkable after a simple filtering - compared to the water in other parts of the U.S. Reminds me of Tom Lehrer: Pollution (YouTube) [^] (Also note that the Lerher song is 60+ years old  )
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>God created sun
I’m not hell bent over it, it’s a figure of speech.
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Couldn't any reference to godly creation, salvation, blessing or whatever be excused / written off as "a figure of speech"?
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The Old Testament for example is a blend of historically confirmed ( or plausible) testimonies on the one hand and testimonies about supernatural on the other. As far as the later is concerned I think that at least some things shouldn’t be taken literally ( the Creation for example).
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> imported food
The food for people living in space is different than anything we have on earth because of how it’s packed and produced. In space the visual appeal of food is gone. The only way to tell it’s food is the label on the package
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That is why most science fiction movies have the passengers in a state of "suspended animation" so they use as little food, water, and oxygen as possible.
"They have a consciousness, they have a life, they have a soul! Damn you! Let the rabbits wear glasses! Save our brothers! Can I get an amen?"
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Or they invent a (totally hypothetical at the moment) faster-that-light drive.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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You need a better title for the subject.
For a moment, I thought about all those who claim to have been abducted by aliens and poked about with anal probes aboard alien spaceships, 
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foo-foo dust. Powers the universe. 
>64
Some days the dragon wins. Suck it up.
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For those looking for an alternative to the standard Winforms numeric UpDown Control, I made a Custom Flat-style Numeric UpDown Control that functions largely the same but does not have those pesky tiny buttons.
The real reason for developing this however was that in some of our (complicated) forms in .NET 6 the standard numeric UpDown Control behaved very badly when changing the font size of the form and sometimes completely disappeared 
It can be downloaded here: GitHub - A Custom Numeric UpDown Control[^]
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An article or tip is probably a better place to put this?
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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Exactly! but it still needs some work I think, so when it's finished (and I have some time left) it will become a tip 
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What I would want in a NumericUpDown is the ability to set a factor for the up and down buttons rather than adding/subtracting a value, multiply/divide by the factor.
So, for instance, I can set it to double/halve the value.
On the other hand, I have only one place I want that, so it's not a high priority for me.
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With this custom control you could do just that.
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Should not be too difficult to implement, just clone the GitHub repo and add a new property named Factor, if it has a value use it in the AddValue() method 
modified 17-Jan-23 12:12pm.
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A factor? Or maybe increment/decrement the digit on which the cursor is?
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