They have to be basically pointed directly at us to be a threat. The chances of one being in the correct range and be directly lined up with our solar system [I'm pretty sure they would be large enough to encompass most of the inner solar system in a beam] is outlandishly small. A few seconds difference and a beam would miss completely at those distances thanks to how fast everything is moving relative to one another at that scale. The fact that this one hit from the distances it did is mind boggling. I also wonder about how much diffusion of the beam there is over those distances, which if it did, would it increase the chances of getting hit or decrease it? Any astrophysics people who would like to chime in here I would appreciate it!

"Human history"? Do they really have good records going back a couple hundred thousand years?

They're not launching it. It is tagging along. Still neat.

Because of expansion of the universe radiation frequency changes with time/distance from any radiation source. Doppler effect. Add diffusion .

Considering humans (Homo Sapiens Sapiens) evolved between 90,000 and 160,000 years ago, that would, on average, allow for up to 16 possible occurrences. I would still have to stand by my statement. Secondly, a 500 year flood does not simply happen once every 500 years, it is a statistical average, and I have seen records of 3 consecutive 500 year floods within one year. Statistics is, over the long term, useful, but useless to the individual.

I think for non-critical thinkers, human history implies recorded history.

Not any more than it already does. We can't shoot people into space from a canon, the acceleration will kill them. Once you get past that idea, g forces aren't really the issue that needs solving. A rocket launch is about 3g's for the astronauts, something a healthy human (hence the rigorous health screenings) can withstand just fine, and that's pretty much the maximum they'll be subjected to (unless there's a crash).

Being able to launch things quick when needed is hardly unnecessary.

I was simplifying to a euclidean perspective, but yes, you're absolutely right.

You have to create fuel out of it, so you will have to store H2 and O2 at some point. That will take massive tanks if you are going to store for more than a few hours, it'll bleed out of smaller tanks. And it will take a long time and significant infrastructure to create that fuel, you don't have a lot of power generation any solar panels (which apparently you will need vast fields of) will have to be launched from Earth, installed and maintained. Temperatures on the moon reach 250F/120C, so you'll need vast amounts of insulation.

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>It's great that they are reliable, but anything made my people will eventually fail.

Even if there is a failure, it won't be a huge setback for manned missions. SpaceX was back to flying just 3 months after AMOS-6 exploded on the pad.

The technology is the same as that necessary to manipulate space-time, so similar in notion to that used to create wormholes and warp bubbles, though perhaps a less complex application of it.

At present our theoretical understanding implies that this requires either exotic negative energy (which has not been proven to exist), or absolutely insane amounts of energy (think mass of planets level energies). So with our current understanding it's either physically or practically impossible.

However gravity is still probably the least we'll understood of the four fundamental forces, so it may be that future discoveries enable space-time manipulation for more reasonable energy expense. It's unlikely to happen soon, but if it can be done it will be. There is already research being done into reducing the energy demand, and much more into gravity itself.

The one difference in the same sharpness of turn between space and earth is that there's already 1g of acceleration always acting on you towards the earth.

So, say, a rocket liftoff always has 1g more acting on you than the pure acceleration of the rocket would suggest. Acceleration towards the ground would have you feel 1 less.

Any side-to-side will always point slightly towards the ground on earth (the earth's g and the side acceleration forming a triangle), while it would be a pure centrifugal effect in empty space. So technically on earth, you'd experience a slightly higher g force, but not by a full g (same as the hypothenuse of a traingle isn't the simple sum of the sides).

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The amount is simultaneously too low to be taken seriously and too high for how unnecessary it is.

It doesn't sound like they were testing to failure, though, since failure wouldn't be an anomaly in that case.

How exactly would launching from the moon make it easier to launch to Mars? Everything that you put on the moon had already been launched from Earth. And in particular, how would having to land on another planetary body, one not far from Earth with it's own gravity and much faster revolution period, make a trip to Mars faster?

Gemini 8 spun fast enough for the astronauts to experience earth-like gravity. The first, only and totally experimental human-scale artificial gravity experiment.

https://en.wikipedia.org/wiki/Gemini_8

That would require that we understand what gravity is. And we don't yet.

Do you know how long it takes government to build something that goes to the moon with the budget NASA has? We'd be waiting for another 15 years. Quick case study: The Shuttle took a decade and it was only going to LEO and back.

Private space companies are definitely shaking things up, but they aren't the main driving force behind anything related the Moon at this time. They're not even in the ballpark for science only missions. NASA, still has a huge role to play. Unfortunately, that means the monstrosity that is SLS in here to stay for at least another decade - hopefully that can get phased out and the money redistributed accordingly.

Technically they're moving in a straight line through curved space. So they experience no inertial forces because their velocity never changes.

Testing to failure before launch seems reasonable to prevent a disaster with massive amounts of fuel & oxygen !

G-forces in the sense you mean are due to the inertia of mass. It's called G-forces because we use the earths gravity as a yardstick for measurement.

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