HN user

djkorchi

34 karma
Posts0
Comments11
View on HN
No posts found.

No, because it would create a contradiction. If a "perfect, endless repeat of pi" were eventually found (say, starting at the nth digit), then you can construct a rational number (a fraction with an integer numerator and denominator) that precisely matches it. However, pi is provably irrational, meaning no such pair of integers exists. That produces a contradiction, so the initial assumption that a "perfect, endless repeat of pi" exists cannot be true.

Is there actually a balance needed between pressure and collapse? Radiation pressure presumably doesn’t do anything to the constituent dm particles. Similarly, wouldn’t the particles in the star be on various elliptical trajectories and not collapse?

The precession of mercury has a few contributions. The largest is the tug of planets (500 arc seconds/century), the next largest is from general relativity (50 arc seconds /century). There are other, smaller contributions stemming from the sun being oblate. Knowledge about the anomaly in the precession was partly what motivated Einstein, and was one of the early predictions of the theory.

Geosynchronous orbit is at 37,000km (well above ISS which iirc is at 400km), so by most definitions that is in space. Often that threshold is put as low as ~100km, when the atmosphere becomes too thin to support winged flight.

The parent post said that only observations at dusk and dawn are affected. I'm pointing out that, even at astronomical midnight, large fractions of the sky aren't in earth's shadow. For other wavelengths the shadow is irrelevant, since satellites contaminate data even without the sun's direct illumination.

The idea of assembling large space telescopes is very exciting, although there are obviously many engineering challenges to solve. What that doesn't yet address is large, ground based radio telescopes. Consider the square kilometer array, which will have one million square meters of observing surface. How many launches would it take to get something comparable into orbit? Oddly, the bandwidth requirements (about one terabyte/second) for the SKA might be the hardest thing to meet in space.