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The impact of improved measurement technologies (1 Viewer)


New Member
Mar 10, 2013
So there is a dot point asking to assess the impact of improvements in measurement technologies on our understanding
of celestial objects. My understanding is as follows....does anyone have anything to add to criticize??

The ability to more accurately measure radiation from outer space has greatly improved our understanding of the universe. For example:
- Hipparcos satellite - represented an improvement in the measurement of parallax angles of stars. Lead to recalculation of the
age of the universe because it showed that the distances of measured stars were greater than expected. This meant that the universe was older than once thought. (Hipparcos measured distances of 100000 closest stars using trig parallax, whereas earth-bound measurements are limited to the nearest 700 or so stars due to atmospheric "seeing".)
- GAIA satellite - superseded Hipparcos, will measure the distances of the closest 1billion celestial objects, due to mirrors with less aberrations
- Hubble space telescope - collected higher resolution and sensitivity visual images of outer space than what what was possible on Earth. Also provided us with near UV and near IR images that weren't possible on earth. Also helped us narrow down the age of the universe to about 13bn years by observing Cepheid variables. (From this, the Hubble constant was more accurately measured.)
(Ground-based telescopes are limited in their resolution, due to the phenomenon of "seeing.")

X-rays and microwaves have been recorded from outer space. Examples of technologies:
- COBE satellite - measured microwave background radiation from outer space, which provided evidence for the Big bang theory
- Chandra X-ray observatory satellite - collected X-rays which helped to detect pulsars and black holes; also showed that most main sequence stars release x-rays; detected x-rays from supernovas, which aided our understanding of stellar evolution
These wavelengths are absorbed by the atmosphere,so satellite technology is necessary
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