The method of measuring interstellar distances found false




Recent measurement of the distance to the star cluster Pleiades, put an end to panic that erupted in astronomical scientific community in spring 1997. Then was questioned the effectiveness of modern methods of determining the distance to the stars, and, accordingly, the integrity and scientific value of giant astronomical databases have been accumulated by mankind.

As explained by Valery Makarov from California Polytechnic Institute, all measurements of distances to distant cosmic objects are produced by calculations using the distances to the nearest to us of star clusters, one of which is the Pleiades.

It goes the same distance to the Pleiades is determined by a rather complicated method by which compares the brightness, mass, and the emission spectra of the stars in the Pleiades, a star similar to them, the distance to which is determined by a simple and precise geometric calculations. According to these calculations, the distance to the Pleiades was estimated at 425 light-years, with an error of 12 light years. However, in 1997, with astronomical satellite Hipparcos, a European Space Agency, received data showing that the distance to the Pleiades is estimated at 385 light years. The satellite measured the distance to the stars using the parallax effect: it measures the change in the angle of sight to the star, while on either side of the Sun. Accuracy of the observations was 1 millionth of a second of arc.

If the resulting estimate of the distance was correct, this would result in the need for careful translation distances to nearly all currently known stars and star clusters. Fortunately, recently released the results of investigation is conducted Syaopey Panem and two of his colleagues from California's Jet Propulsion Laboratory, showed that the fears are unfounded. Scientists have developed another technique for measuring the distances to stars. For nearly ten years, they followed the double star cluster of the Pleiades, using two telescopes connected interferometers, studying the changes in their brightness when moving in an orbit around a common center of mass. These observations allowed us to estimate the mass of the stars, which when substituted into the special equation has given the distance to the stars is about 440 light-years.

Thus, the rumors that the previously applied methods were inadequate, are greatly exaggerated. As for the data Hipparcos, on this account, there are several hypotheses. According to one of them, the equipment installed on the satellite measurements give a clear bias, although it is possible the bug is in the software, interpretive readings satellite.

Battery News, 02.02.2004 9:15
Source: Kompyulenta

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