How many stars in observable universe
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Estimating the Number of Stars in the Observable Universe
Introduction to Star Count Estimation
The observable universe is vast, and estimating the number of stars within it is a complex task that has intrigued astronomers for centuries. Various methods and observations have been employed to arrive at an approximate count, leveraging advancements in technology and our understanding of cosmic structures.
Photometry-Based Estimations
One of the recent methods to estimate the total number of stars in the universe is based on photometry. This approach utilizes the energy conservation law and measurements of extragalactic background light levels. By assuming that every radiated photon remains within the universe, the total number of stars has been estimated to be around 6×10²². This method provides a comprehensive estimate by considering the universe as an integrating cavity without losses.
Observational Data and Galactic Surveys
Observational data from various galactic surveys also contribute to our understanding of the star count. For instance, the Optical Gravitational Lensing Experiment (OGLE) has cataloged nearly 66,000 Mira-type variable stars in the Milky Way alone. Such detailed surveys help in understanding the distribution and types of stars within our galaxy, which can be extrapolated to other galaxies.
Average Star Count per Galaxy
Studies suggest that the observable universe contains about 100 billion galaxies, with each galaxy averaging around 100 billion stars . This estimation aligns with the photometry-based approach and provides a consistent framework for understanding the vast number of stars.
Conclusion
Combining various methods and observational data, the estimated number of stars in the observable universe is approximately 6×10²². This figure underscores the immense scale of the cosmos and the continuous efforts of astronomers to refine our understanding of the universe's structure and content.
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