On Second Thought, Polaris Really Does Seem 434 Light Years Away 75
sciencehabit writes with this excerpt from Science Magazine "Last November, astronomer David Turner made headlines by claiming that one of the sky's best known objects—the North Star, Polaris—was actually 111 light-years closer than thought. If true, the finding might have forced researchers to rethink how they calculate distances in the cosmos as well as what they know about some aspects of stellar physics. But a new study argues that distance measurements of the familiar star made some 2 decades ago by the European Space Agency's venerable Hipparcos satellite are still spot on."
Strange methods (Score:4, Interesting)
Reading up, it turnes out the whole argumentation is exactly the other way round than I would hav eexpected.
You can meassure the distance of stars in multiple ways, most depend on assumptions that can be pretty hard to get right. There is ONE way, though, to accurately determine the distance:
By simple geometry. If you observe the star 6 months apart, you get a trianble with a base of 2AU, which is enough accurately triangulate the distance of stars up to a some 100 ly away.
This was exactly the method used 2 decade ago.
Not this new guy used a very indirect way (measuring the brightness we see the star, guessing its real brightness by looking at spectra and then deciding how far away it must have been), gets a 30% different number and claims his, indirect and error-laden, way is yielding the more correct of the results.
Tard.