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Determination of the Hubble constant
1Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101.
Summary
Astronomers can now measure extragalactic distances with unprecedented accuracy. New techniques and the Hubble Space Telescope have reduced uncertainties to +/-10%, overcoming historical challenges in cosmology.
Area of Science:
- Cosmology and extragalactic astronomy.
- Astronomical distance measurement techniques.
Background:
- Accurate extragalactic distance determination has been a persistent challenge in astronomy since the 1920s.
- Historical uncertainties in measuring the Hubble constant (H(0)) were as large as a factor of two.
Purpose of the Study:
- To summarize recent advancements in extragalactic distance measurement.
- To highlight the improved precision and agreement achieved in determining cosmic distances.
Main Methods:
- Development and application of new astronomical detectors and distance measurement techniques.
- Utilizing advanced instrumentation, including the Hubble Space Telescope.
- Comparing relative distances to galaxies on a case-by-case basis.
Main Results:
- Achieved precision in extragalactic distance measurements at the +/-5-20% level.
- Established quantitative agreement between different distance measurement methods.
- Reduced the statistical uncertainty in Hubble constant (H(0)) measurements to a few percent.
Conclusions:
- The historical factor-of-two uncertainty in H(0) has been overcome.
- Current total uncertainty in H(0) is approaching +/-10%, marking a significant breakthrough.
- Improved accuracy in extragalactic distances is revolutionizing cosmological studies.