Sunday, October 13, 2013

Not Too Long Ago

When a person starts an article with "not too long ago" it is a good idea to check to see who is saying this. Paleontologists study fossils and life forms that existed 3 billion years ago up to approximately 200,000 years ago. Thus, to a paleontologist, "not too long ago" might mean 200,000 years ago. Archeologists, on the other hand, typically study the life, culture, and tools of human societies with an emphasis upon the emergence of humans 200,000 years ago up to the time when written languages developed around 6000 years ago. So, "not too long ago" to an archeologist will refer to more recent events than the events to which a paleontologist might refer. But when an astronomer says "not too long ago," as in a recent article in Science News, their time scale is very different again. Astronomers deal with events which happened 13.8 billion years ago right up until our present time. Thus, "not too long ago" in the mindset of an astronomer can mean something like 350 million years ago. Also, because of the large distances which light must travel before an astronomer can detect stellar events, they must be content with seeing events which happened many years before they witness them. If a star is 5,000 light years away from our sun, the light reaching us now and the events unfolding before our eyes started 5,000 years ago. It is like peering back in time.

The recent Science News article speaks of the work of scientists who are closely studying a galaxy referred to as SPGC 6240, "which sits 350 million light-years from Earth in the southern constellation Hydrus."1 This galaxy "recently" collided with another galaxy sending out intergalactic shock waves through the universe, causing a complete rearrangement of the structures of both galaxies, and birthing many new stars. Astronomers watch such events with the collective fascination and horror of pedestrians observing a car accident. The havoc caused in each galaxy allows astronomers to "see" the immense energies generated and the resulting gravitational entanglements of stars and solar systems. But, "recently", and "not too long ago" in this case refer to events that happened more than 350 million years in the past. That was a time when there was primitive life on earth but before God had created humans! Galaxies and points of light were slamming into each other while God looked on with joy and expectancy of the things yet to come.


1 https://www.sciencenews.org/article/galaxy%E2%80%99s-petal-structures-came-collision

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