Tag Archives: Physics

The Celestial View From A Relativistic Starship: Part 4

This series of posts is about what the sky would look like to an observer travelling at close to the speed of light. In Part 1, I described the effects of light aberration on the apparent position of the stars; in Part 2, I introduced the effects of Doppler shift on the frequency of the … Continue reading The Celestial View From A Relativistic Starship: Part 4

The Celestial View From A Relativistic Starship: Part 3

This is the third of a series of posts about what the sky would look like for the passengers aboard an interstellar spacecraft moving at a significant fraction of the speed of light, like the Bussard interstellar ramjet above. In the first post, I wrote about light aberration, which will cause the apparent direction of … Continue reading The Celestial View From A Relativistic Starship: Part 3

Stephen R. Wilk: How The Ray Gun Got Its Zap

I sometimes think that we should spend at least a little time explaining everyday manifestations of physics to undergraduates, so that they can talk about phenomena that appear in everyday lives. How The Ray Gun Got Its Zap (2013), is subtitled Odd Excursions Into Optics, which (combined with the manifesto above) pretty much covers what … Continue reading Stephen R. Wilk: How The Ray Gun Got Its Zap

The Celestial View From A Relativistic Starship: Part 2

In my previous post, I described the visual appearance of the starry sky for an observer moving at a substantial fraction of the speed of light—for instance, aboard a working Bussard interstellar ramjet, like the one pictured above. I’ll recap the terminology I established in that post, which comes from Special Relativity. We call the … Continue reading The Celestial View From A Relativistic Starship: Part 2

The Celestial View From A Relativistic Starship: Part 1

This is another one of those topics (like Coriolis effect and human vacuum exposure) that many science fiction writers seem to know enough about to include it in their stories, but not quite enough to get right. So in this post (and an estimated three subsequent posts) I’m going to write about what the starry … Continue reading The Celestial View From A Relativistic Starship: Part 1

Coriolis Effect In A Rotating Space Habitat (Supplement)

I’ve received a few enquiries in response to my post “Coriolis Effect In A Rotating Space Habitat”, concerning something I didn’t address at the time—what happens to the trajectory of objects moving parallel to the axis of rotation. (Though I did mention this topic in passing in my post about the Coriolis effect in general.) … Continue reading Coriolis Effect In A Rotating Space Habitat (Supplement)

Radiation Fog

Radiation fog sounds like something that might occur during a nuclear winter, but it’s not that kind of radiation. The radiation here is heat radiation—infrared wavelengths radiated by the ground during the night, particularly when the skies are clear. Usually, the air temperature gets lower as you get higher—a rising packet of air expands and … Continue reading Radiation Fog

Greg Egan: Dichronauts

Geometry might well kill them in the end, but only a rigorous understanding of its principles could make their situation intelligible, let alone survivable. That quote comes from Part 4 of this novel, but it encapsulates what’s intriguing and (at least potentially) frustrating about the story—it’s about spacetime geometry. I’ve written about Greg Egan before, … Continue reading Greg Egan: Dichronauts

Coriolis Effect In A Rotating Space Habitat

In a previous post describing the Coriolis effect, I mentioned its relevance to space travel—if a rotating habitat is being used to generate simulated gravity, Coriolis deflection can interfere with the performance of simple tasks and, at the extreme, generate motion sickness. As an example of the sort of effect you could expect to encounter, … Continue reading Coriolis Effect In A Rotating Space Habitat