Waves and Space

Investigations of aliasing effects in digital waveform sampling will show the existence of a pseudo-alias domain lying to the left of a "Nyquist line" in a plane defining the boundary between two domains of sampling. To the right of the line lies the classic alias domain. We discuss a problem with some band-limited signals below the Nyquist limit, when displayed output can also show a false modulation envelope whenever the sample rate and the signal frequency are related by ratios of mutually prime integers. An improved definition of the Nyquist frequency is proposed.

 wavenotes.pdf

 privacy.pdf

Any presumption that relativistic effects apply only to high velocity situations is contradicted by reviewing situations where velocities near zero affect everything around us. Effects of the Lorentz factor time dilation on observer time with small ? are shown to have implications important to classical physics motions of objects, thermal vibrations, heat, entropy, and the Heisenberg Uncertainty Principle.

 timenotes.pdf

 privacy.pdf

"We examine many of the requirements and factors for an IMAGINED expedition in a large spacecraft to one of the nearest candidates for an earthlike planet orbiting a nearby star. The imagined back story is that approximately in the year 2057, one hundred years after the Sputnic launch, astrophysicists using a high technology space telescope have located a 20 km diameter asteroid that is due to crash into the earth 15 years hence. Noting a 20 km diameter asteroid having eight times the mass of the 10 km dinosaur killing asteroid 65 million years ago would cause the end of civilization, it has suddenly become time for humans to put aside their petty wars and religious differences and face up to how to build a huge spacecraft capable of moving a fragment of the earth's life forms to a new planet."

 travelnotes.pdf

 privacy.pdf