Wednesday, April 25, 2012

Stellar evolution or lifecycle of stars?

Stellar evolution - or lifecycle?

As the title of this schematic drawing demonstrates astronomers frequently use the expression stellar evolution when actually talking about the lifecycles of stars.

The choice of terminology is a matter of language preferences, convenient usages, the associations a given term raises in our minds. But ultimately choice of words is also related to its exact contents and the accuracy of the expression.

Human evolution?
Human evolution - or lifecycle?

Scientists do not use the word evolution when describing the human life cycle from conception and birth to old age and death. Human evolution is something else altogether tracing the history of life of our species on Earth.

The life of a star from its conception in the Mother Hydrogen Cloud to its final demise as a dwarf, neutron star or black hole does not include evolutionary processes that biologists discuss when studying the history of life forms on Earth.

(Of course, we also need to consider in what context the word evolution is properly used in the study of life.)

IMHO, as a scientific expression evolution of stars is less accurate than lifecycle of stars.

UPDATE 24.6.2012
The following facts may explain the introduction of the evolutionary terminology

Henry Norris Russell (October 25, 1877 – February 18, 1957) was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung–Russell diagram (1910). In 1923, working with Frederick Saunders, he developed Russell–Saunders coupling which is also known as LS coupling

Russell was born in 1877 in Oyster Bay, New York. He studied astronomy at Princeton University, obtaining his B.A. in 1897 and his doctorate in 1899, studying under Charles Augustus Young. From 1903 to 1905, he worked at the Cambridge Observatory with Arthur Robert Hinks as a research assistant of the Carnegie Institution and came under the strong influence of George Darwin.

1 comment:

  1. There is a class of stars that science has not discovered (through no fault of their own). Our science with technology is merely decades old. Instantaneous Hyper Expansion. I am not a scientist, but I know what I saw. Others near us also saw this event.