Tomorrow, February 29th, is a “leap day”, so remember to set your clocks back by 24 hours! Fortunately, we don’t really have to do that. Even clocks that keep track of the date as well as the hour pretty much all know when we have a leap year. But do you know WHY we have leap days? Or exactly when? Time is a surprisingly complicated topic, even when you ignore general relativity. Hours, minutes, and seconds are essentially arbitrary units, so we can define them to fit our world however we want. Days and years, on the other hand, are […]
The TED talk at the link below provides more detail than I have provided and a LOT more entertainment (as you would expect from TED Talks): http://www.ted.com/…/allan_adams_what_the_discovery_of_grav…?
For the last week I’ve been very excited about the detection of gravitational waves by LIGO, but haven’t written about it because I wanted to first learn more. Last night I attended the Cosmology SIG meeting (a sub-group of RCA, the Rose City Astronomers). I’ve wanted and planned to attend their meetings for years, but somehow never got around to it. It was very well worth it! There are many interesting aspects to the story of this discovery. Probably the most important view is that this is the dawn of an entirely new age in astronomy. The moment that we […]
You may have heard about the announcement this morning that the LIGO project has finally confirmed the detection of a gravitational wave, a phenomenon predicted by Einstein’s General Relativity theory, but never before actually seen. In fact, this observation is considered to be the last component in verifying the GR theory. More importantly, the fact that we can now detect gravitational waves may begin a whole new era of astronomy because it allows us to “see” things that we never could before. In the case of this first observation, scientists were able to determine (with a very good degree of […]
When we talk about the distance between stars there are 2 very different measures that might apply. The actual distance between any two stars (typically measured in light-years, or astronomical units [the distance between Earth and our Sun] if they are very close) is generally not apparent by simple observation, whether aided by a telescope or not. But we might also be concerned with the angular separation between stars. Frankly, this information is most useful in measuring the quality of various optical elements, including human eyes. Many stars are actually “binary stars” that are relatively close to each other in […]