Our Lives in Perspective

I've always been interested in popular science, but especially in cosmology because it really put everyday things into perspective.  And so lucky for me, one of my co-workers also has the same interest and forwards me interesting articles and videos when he sees them (and I do the same for him).

Today, he sent me to the Astronomy Picture of the Day webpage with this detailed and really interesting note.  I thought it was so interesting and well-written, I decided to share:

This link is to an Astronomy Picture of the Day webpage whose primary attraction is a video that attempts to show what it would be like to travel across the known visible physical universe (as of the scientific knowledge available around 2009).


This video is a bit misleading, though, because it treats the "universe" as a static sphere that has remained unchanged for 13.7 billion years. One has to realize that, in fact, when one views the light from an astronomical object 5 billion of light years away, that means that one is seeing how that object appeared 5 billion years ago. That object does not appear today as it did 5 billion years ago, and is not in the same "place" it was 5 billion years ago, and even the space it was in 5 billion years ago has changed (by expanding, as science currently theorizes.) So, enjoy the video, but understand that, as complicated as it portrays the physical universe, the strictly scientific picture is even more complex and even beyond our ability to accurately portray, since we aren't able to know what's going on NOW anyplace far from Earth. By "far", I mean anyplace from which it takes light a considerable amount of time to reach us (because it's only through light (electromagnetic waves such as visible light, microwaves, X-rays, radio waves, etc.) that we know what we do about astronomical objects.


The other link (in the descriptive text of the webpage itself) is to the "Powers of Ten video" that was made in the 1970's, I think, and that is also worth a look (it only goes out to 100,000,000 light years, but also travels down to the sub-atomic region to simulate a visit to a proton in a man's DNA.)


As you are aware, currently, the known PHYSICALLY VISIBLE universe comprises only about 4% of everything scientists now think was created at the beginning of our physical universe. In other words, everything we think of as being "real" (rocks, trees, water, molecules, atoms, stars, galaxies, electricity, visible light, radio waves, X-rays, etc.) makes up only 4% of everything scientists now think came into physical being at the beginning of the universe (commonly-though-inaccurately called the Big Bang). The other 96% is (currently) two types of "stuff" [Dark Matter (25%) and Dark Energy (71%)] about which they have almost NO idea as to its nature. Scientists have EVERY right to be HUMBLE and NO right to be PROUD about what they THINK they know AND don't know.


I read recently that in the 1700's, the French Academy of Sciences (probably the most prestigious scientific organization at the time of the "Enlightenment" and the establishment of rationalism as the dominant philosophy in the Western world), declared that meteorites were a humbug - not real, without any basis in fact. These scientists dismissed the poor country folk who testified that they found rocks - sometimes peculiarly warm - on the ground that they had seen fall from the sky as liars or, at best, drunks or deluded persons, because THE SCIENTISTS KNEW (believed!) on the basis of their then-current theories about how the world worked that rocks COULDN'T fall out of the sky onto the Earth!