SkyTour Radio Presents: Mind the Gap: The Rungs of the Cosmological Distance Ladder
Sunday, September 9th 2018
In this episode of SkyTour Radio, we take a look at some recent mysteries in space, including awaiting on Opportunity to respond from Mars and the discovery of a small hole in the crew cabin of one of the docked Soyuz spacecraft that allowed precious air to leak out of the ISS. We also learn about The Cosmological Distance Ladder, so called, as different techniques for each ‘rung’ of the ladder are used to determine distance to planets and asteroids, then nearest stars, then objects in spiral arms of our galaxy, distance to galaxies and then finally distance to clusters of distant galaxies. Join us as we try and put things into “perspective” throughout space and the show.
The Cosmic Distance Ladder
Also known as the extragalactic distance scale is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are “close enough” (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.
The ladder analogy arises because no single technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.
SkyTour Radio explores the Universe in a down to Earth manner explaining the science we know in fun and bite-sized terms. Science is for everyone and people shouldn’t require an advanced degree to understand as long as it is delivered in an easy to follow way. From Black Holes to Extraterrestrial Life, we will explore the Universe like never before. Join us to check out such things as how stars form, how they live and, how our fate is intertwined with theirs. On the extraterrestrial life front, we will be speaking to the UFO and science arena’s top researchers and bring UFOlogy into the 21st century.
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