Recent content by ChrisA

Proximity to mass vs. gravity field. This is an easy experiment. You do not need to go to the center of the Earth. All you need to do is be closer to the center. A deep coal mine could work. And if you want to test this in space, a Lagrange point works. I suggest not bothering to try...

Spinning a point mass works mathematically, but mathematics like that does not model the real universe at scales that approach geometric points. A geometric point is MUCH, much smaller than any subatomic particle, and even the Planck length is huge compared to zero. You have to guess the size...

The best way to explain why you can not go faster than light is to remember that there are FOUR, not three, dimensions. The fourth one is time. All objects move through all four. You sitting at you desk, using the chair as the reference point as not mong in X, Y, Z but you are moving in...

The only good argument for manned spaceflight is the same argument we use to justify "summer vacation". There is no economic justification for flying to Rome and looking at a 2,000-year-old sports stadium or hiking a trail in the mountains. We do those things because we like doing those...

Your argument is what I call "Standing on a sheet of paper" In theory if you are taller you can see further. In fact it it's obviously true. I want to see further so I take a single sheet of paper with me and stand on it. What is wrong with my idea and yours? We call it "hand waving"...

Let's pretend for a minute that 3 is equal to 5. I know 3 is not equal to 5, but let's pretend it is for a minute. If this were true what else might be true? Well literally ANYTHING might happen when you suspend the rules of mathematics, common sense, and logic, ANYTHING can happen. Perhaps...

My opinion is that classical physics is just a shortcut. It is the result of summing trillions of quantum effects. Other examples of this are (1) the illusion of solid surfaces. We all know that a brick wall is a mostly empty space. But at the macro level, it seems solid. Why. It is the...

General relatively is a field theory, It is like Maxwell's equations. Both are field theories. I guess you would argue that a magnetic field can not be curved because there is "nothing" to curve. BTW, you can't say something is wrong without proposing a better idea and showing how it is...

You see a flat disk that is not perpendicular to our line of sight. The disk would appear to have an elliptical or "arched" shape. Then the "disk" is not a solid disk but might have verifying density. The arc is in fact a brighter part of the disk. Also EVERYTHING you can see is OUTSIDE of...

If you are looking to reduce the cost you first have to have a very good cost model that adds up the cost of all the parts you need. Then you look at the most expensive parts and see what can be done. Building with materials found or made on Mars only addresses the cost of the pressure shell...

It is possible for methane/oxygen rockets to be carbon neutral. As of today, they are not. What matters is where you get the methane from. If it is a natural gas then it is a fossil fuel. But Mathane is CH4. It can be made by extracting carbon from atmospheric CO2. Then when it is burned...

You were right to do so. A colony needs a way to support itself economically. Even if we assume the colony has a perfect communist system where each person contributes as they are able and each person is given what they need and no money is needed. Even if idealist communism could work...

I just wrote about the relative magnitude of household cook stove to rocket launches. But why stop there? Why not compare the relative amount of pollution from rocket launches to the pultion caused by biolocial decomposition in landfills. Or from raising cattle. Rockets are very small...

Why compare it to the airline fleet? Why not compare Starship to the emission of kitchen stoves in the city of Dallas TX? I think the larger pollution problem is the stoves in people's homes, by orders of magnitude. Even a small city uses vast amounts of Methane. The fuel is exactly the...

Of those only the last one would require humans in space. No. Please don't tell the humans are better then robots. The are today but that will change in 50 years and if not then in 200. So even if you want to mine an astreroid, no humans are needed in space. All of the above and even the...